Handloading, consistency and accuracy

[Hobbit]

Just wanted to get thoughts on how handloading techniques contribute to accuracy - specifically the mechanisms and what can be done to improve them. I appreciate there is a lot on the forum on this but wanted to tangibly link it to a bit of thinking/learning/testing I am doing. As before I an relatively new to this and am tring to build up my knowledge.

 

I am testing loads for my TRG22 - in .308 - it is a rifle that has a reasonable reputation for being unfussy. At the moment I am working on the basic assumption that accuracy is driven by 2 main components:

 

1, Load interaction with rifle harmonics - the 'nodes' - largely empirically found by ladder testing for group size (although Spud suggested they could be estimated on Quickload - I have QL but how do you do this?)

2, Overall load consistency as driven by charge, OAL etc consistency and demonstrated by MV consistency

 

Is this correct? Any other major drivers?

 

On point 2 - stand alone consistency (as apposed to fit / interaction with rifle)

 

I am reloading with entry/mid level kit.

Have a lee classic turret press, lee dies and a factory crimp (gentle crimp - including a 45degree rotation and repeat to smooth the impact of quartered petals)

Use lapua brass and lapua rounds (prefer 155gr but have used 167gr Scen) but do not sort brass or bullets nor prep beyond tumbling and full length resize. CCI 200 primers but don't pay much attention here

Loading around 44gr of N140 which gives good accuracy although not completely finished with ladder testing

Use a Lyman Gen6 powder system because I'm lazy - do not dump the measures off by 0.1gr back - but might do in future

 

Yesterday shot about 70 rounds at 300m in practice and measured 3 10-shot strings on a Magnetospeed V3

 

The 3, 10 shot SD's, were 8.4 fps, 12.3fps and 13.4fps, Excel calc gives overall SD of 11.2 fps and av MV of groups within 6 fps although av MV was 2752 fps vs 2791 predicted by quickload

 

Now this is not the type of benchrest performance I often hear quoted a lot but it is:

 

A, a statistically significant (ie 30 round) data set and

B, Compares well with real world independent testing of .308 match ammunition - tested SD's of from what I can pick up in the range 20-40 fps aretypical and Bryan Litz aims for SD's "typically under 10fps" in his top of range, applied ballistics, "weighed charge, top component...." match ammo (I am ignoring the cherry picked anecdotes because they are statistically meaningless)

 

presumably lab scales and a trickler will get the charge more uniform but in the spirit of Bryan Litz's WES analysis - where will I get the biggest 'bang for my buck'? (excuse pun) - I can count grains and weigh every bullet, sort or discard the least uniform 50% of my cases (hell I could get the bullets polished between the thighs of Balinese virgins and have my dies blessed by a Tibetan monk) but what gives the best return in the (very considerable) experience of the forum? Is it custom dies? a more rigid press?, I am assuming Lapua components are pretty much up there in quality - does sorting make a huge difference? How accurate and how effective is charge weighing and what is the best method.

 

Thank you for reading this far ;-)

 

Cheers

 

Hobbit

[MTLEADFARMER]

Your SD looks good but what about ES? Thats what will bite you in the a**. Switching from CCI Benchrest to Federal match primers cut ES/SD in half on my 308 load ES 11fps SD 6fps 20 rounds over chronograph. Annealing helps and keep using the LEE FCD.

[Hobbit]

Thanks - My ES was not so good - for 10 rounds group it varied 26-36fps

 

I have never really thought much about the primers - I got sold 1500 Fiocchi large rifle primers when I was brand new to this that are just sat there - will at least test them but may have top chalk it down to experience and go with the feds if they do not work out.

 

Annealing helps with neck tension?? as well as case life

[Hobbit]

MT leadfarmer

 

you've got me thinking - very interesting article here on primers - http://www.targetshooter.co.uk/?p=1471 - you appear to be spot on about the fed match primers!!

 

I think the Laurie Holland who wrote it is a contributor here - I'm hoping that he is right on the Fiocchi's and they will perform better in fired brass - I have loads of them

[Laurie]

There will be a follow-up later this year on Small Rifle primer performance in a 308 Win Lapua Palma brass load. SR primers have far less variance than LR between makes and models, yet another good reason to switch to Palma cases.

 

15 primers tested - Vihtavuori even (bet most people don't know that you could once get Viht brand caps). As with the LR models, a surprise, out of left field 'winner', and one or two other interesting things came up.

 

On the original observations, an additional factor is the bullet / barrel marriage. Even though 308 is pretty unfussy, any given action / stock / and particularly barrel will have likes and dislikes. If the barrel doesn't like a bullet, you can play with primers and powders until you shoot it the barrel out and still struggle to get a good result. This is more marked yet in 6 and 6.5mm. There are a lot of variations in bullet diameters, both along the general length of the bearing surface ('shank') and also on the marginally larger dia. 'pressure ring' which many bullets have on the shank / boattail junction.

 

Chamber form can have a significant effect not just on pressures / MV but on precision and velocity spreads. By that, I'm talking primarily about the throat and leade, but also the case-neck to chamber fit and clearances.

 

Case consistency, and within that neck thickness consistency as well as concentricity are very important, Most modern cases are much better than those of a generation ago, but some animals are more equal than others in this which is why people use RWS, Norma, and particularly Lapua and even then give necks a 'clean-up' neck turn to get variations both in a single case and between cases in the ammo box down to a couple of tenths of a thou'. Bushing dies, no expander or a mandrel expander replacing a drag-through 'ball' and new brass or regularly annealed brass all improve grouping consistency and reduce ES values. Relatively rare today, but no doubt still appearing in some makes is the 'banana case', thicker on one side of the body than the other so the case bends under firing pressures. The key value is 0.003" - if the lower case body walls vary by more than that around the body, that case will never produce a good round (unless you measure the case and mark the thick or thin sides on the case-head and always chamber that at say 6 o'clock).

 

........... and so on and so forth. If you want to really find out what affects long-range grouping, get a 223 Rem rifle built with a suitable twist rate and chamber throating to suit 90gn VLDs. If everything isn't 100% 'right' and consistent. (eg charges weighed to within plus or minus 0.02gn, the weight of a single powder kernel) you won't get ES values under 20 fps, and may struggle to get them under double that.

[Hobbit]

Laurie

 

Thank you very much for that - worth the admission alone!

 

a lot of useful pointers there to mull over - three I have immediate questions on

 

1, neck turning - what is this and how do you do it well (said I was a newbie)

 

2, "Bushing dies, no expander or a mandrel expander replacing a drag-through 'ball' " - whose / which dies would you recommend

 

3, Annealing - I get the materials science (studied mechanical engineering so know enough to be dangerous) but the execution looks like black magic - how do you personally anneal and get the timing and localisation on the neck right??

 

Thanks again

 

Hobbit

[LR Chris]

Laurie

looking forward to the SRP follow up but where can I find the LR Primer review?

 

Cheers

Chris

Hobbit do a search on here re annealing :-)

[gbal]

Hobbit- you seem to be in a pretty good place-if you want to go more of the full monty,"Lord of the rings 'trilogy looms- it gets detailed,and much more difficult to substatiate with good evidence-opinion intrudes.

NO harm in pursuing more precision,but Bryan Litz is a breath of oxygen on this-and how to prioritise effort.

What do you want to get from your rifle,and how critical is it for the shooting you do.-as you mention.WEZ analysis reveals much.

Mainly that calibre matters if you want distance performance,and way way more than almost anything else (assuming near equal reloadng etc etc).

AND,given that -wind reading is the big skill.This isn't always seen as good news,since such skill isn'r readily bought,unlike ever more 'accurate' equipment-but fromwhat you say you have realised that having a powder dispenser accurate to 1/20 of a kernel,simply begs the question as to how you can slice up kernels to that degree of accuracy...let alone any on-target effects :-)

Every very little can help,but much is totally swamped by the wind error factor.-I don't mean wind error is just another factor-it is by far where you will get much bigger returns for investment-but of time and skill development.Not of reloading gear,however nice it is to have good stuff-and it has 'feel good' advantages too.

The wind won't care.Its pretty much brute physics.

Note,much of the performance (three shot done once only 'groups' shot at relatively short rangewhen wind has not had so much time to mess ,are usually misleading. Distance performance is not pro rata simply on 100y low dispersal.

If you can read more of Bryan Litz,it's reality checking.IF distance shooting is on your menu.

Of course,this all assumes a reasonable level of reloading (and shooting)-precision-is the gear,accuracy -add the shooter .

Get the best must have gear you can-but don't agonise on extras/upgrades.Get good components-as you say,Lapua brass is probably worth it's small premium,if only because you can skip most prep stages and not see uch performance effect (and you can prep to the nth degree and not see much performance increase...fine if you enjoy doing it.

If it's easy-eg Laurie's sound advice/findings with small primers,do it.If it's £250 meplet uniforming,wait til next year-or get plastic tipped bullets...assuming ball park BC coparability etc.

 

OK,you get the drift- examples below-precision can become a reloading room obsession (I got a bigger room!) but the reality is decent gear/components gets you to where performace is good enough and consistent enough,for you to be able to notice sustained improvement on the big factors-how well you read the wind,over a course of fire.Then you can think of investment-it becomes asymptotic as far as measureable returns go.

 

It's often a revelation eg to find that the %hit on a 10 inch 1000y gong for a 30 cal 175 SMK @2600, 10 fps SD,changes thus:

.5moa rig 40%

1moa rig 35%

1.5moa rig 25%

sobering indeed,as its 100% at 400y for all of 'em.And that's for really good wind reading (1% error).To a good approximation,SD of 10 for MV,and .5 moa evidence pretty good reloading/rig ,too! Cartridge choice is probably more important-again,next time....5000 rounds of 308 could be a wind learning master course..

 

How about one of the specifics you mention-SD of MV? Probably worth some care,as data below:excellent conditions.5moa rig,hit % on 10 inch gong at 1000y:30 cal,175 SMK@2600:

SD10fps 39%

SD15fps 32%

SD20fps 24%

 

Worth a bit of effort,but not split kernal stuff (powder weight especially to .01g isn't the only variable)

 

AT 600y,it's 99,98,and 96% -probably need to shoot hundreds to see this difference-it's small.

 

For small targets ,of course,under 500y the % differences would be considerable-that's why precision reloading matters critically to varminters-a crow is a skinny target even by 300y.

And at the competitive level,a little can nudge you up a winning point-a shot just clips a score up line.

 

300y for score Bench Rest shooting went over big time to 30 BR-reloading expertise was already extremely high,but that 308 hole just cut a few more lines than the 6mm/264 hole had done-switch.For 100y BR,the 6PPC still rules-almost certainly since at the highest level,very fine wind judgement interacts with vey fine cartridge precision-and it's group not score,so line cutting is irrelevant.

 

What the bottom line seems to be coming out at,is for the reasonably competent/consistent reloader-especially with a 308 class rifle-and medium/longer range ambitions,learn the wind.

Until you do,most of the smaller gains elsewhere will be errr blown away! And worse yet,you won't even know if they were there or not.... when you can suss the wind,then they should show up,and even small individual improvements can be significant, cumulatively.... 'cost/effort' returns remain somewhat subjective,especially under field conditions-vulpicide is not a matter of splitting kernels...never will be.

 

All subject to what you feel about your hobby ,of course-and probably your 'personality' :-)

 

gbal

 

ps- Vince gives some excellent advice,on 'upgrades' that are actually counter productive,and some for essentials that are good from the get go.

 

Annealing can prolong the effective life of brass;you can pay for it to be done;all this may well be cost effective.

 

Quite a lot of advice is given from one shooting perspective,but does not acknowledge that it may well be specific and only elevant,to that discipline (and best practice changes). Wind practise is never wasted,just not done enough.

[The Gun Pimp]

Laurie

 

Thank you very much for that - worth the admission alone!

 

a lot of useful pointers there to mull over - three I have immediate questions on

 

1, neck turning - what is this and how do you do it well (said I was a newbie)

 

2, "Bushing dies, no expander or a mandrel expander replacing a drag-through 'ball' " - whose / which dies would you recommend

 

3, Annealing - I get the materials science (studied mechanical engineering so know enough to be dangerous) but the execution looks like black magic - how do you personally anneal and get the timing and localisation on the neck right??

 

Thanks again

 

Hobbit

Neck-turning? Only relevant for extreme accuracy stuff - like benchrest. Plus you need a tight-neck chamber to go with it. If you don't have a tighter chamber, neck-turning will merely increase the 'slop' between cartridge and chamber-neck - which is the exact opposite of what you are attempting to achieve with neck-turning.

 

Bushing dies? - No. Get a set of Forster dies, remove the expander ball and up-size with a mandrel (from Brownells/Sinclair) - from the inside of the neck - so inconsistent neck brass thickness won't be as relevant to doing it from the outside with a bushing die. Use bushing dies ONLY if you are neck-turning. Ditch the Lee press and get a good quality single-stage press. Or, you could try a Lee Cast Classic - they're OK and good value.

 

Forget annealing for the time being - there are lots of improvements you can make before resorting to annealing.

 

Finally - always use good brass - from Lapua and change it as often as you can afford to (six reloads max.)

[Laurie]

There's plenty on UKV about neck turning including a pinned thread on 'how to do it'. I don't agree 100% with Vince (The Gun Pimp) on its value only being for undersize neck chambers, but I certainly do with a rifle such as the TRG. Buy Lapua and it's more than good enough.

 

One thing often overlooked for rifles such as the TRG and AI models is that they often have relatively 'long' (in headspace terms) chambers having been designed to be ultra reliable and reasonably accurate with 7.62 Nato milspec ammo which is not quite the same thing as 308 Win. The result is a slight headspace 'issue' with out of the box 308 ammo or brass and conventionally FL sized handloads. It's important to match post sizing shoulder positions to the chamber in any rifle, but if the TRG is like AIs, even more so for this type. In an ideal world there is one thou' clearance between the chambered round's case shoulder at its 'datum line' and the matching point on the chamber. In practice 1-3 thou' is good, but often there is a great deal, and moreover clearances vary from round to round after sizing. (Why is a subject in itself, but acquiring a good single stage press is an excellent start in obtaining consistency here.) This (clearance) issue is important to ballistic consistency as if there is excess clearance, much of the striker assembly / firing pin energy is dissipated on moving the case forward so it contacts the chamber giving inconsistent primer strikes and hence MVs. There are various ways of ensuring the sizer die is set correctly to give the correct amount of shoulder 'bump', but the Hornady comparator body plus appropriate 'headspace gauge' for the cartridge is the easiest to get and use. Some die makers such as Harrells and Whidden include a little collar to slip over the case to measure this with calipers - no comparator body needed, IMO every die maker should include one such with a FL sizer with instructions on use as it's really quite important.

 

Going back to your basic premise though, the link between ballistic consistency and 'accuracy' (actually 'precision' to be precise!) and getting improvements to the former and thereby in turn the latter, this always so in practice. Take the 'most accurate' shooting combinations on the planet, a seasoned BR shooter, a specialised rifle, and the 6PPC cartridge all optimised for 100/200 yard BR competition and capable of putting 5 shots into under 0.1-MOA on a good day and their ES range is often very large indeed.

 

On the other hand, the 1,000 yard TR, Palma, FTR, F-Class prone or L-R BR competitor wants something that is capable of very tight grouping at all distances, uses very high BC bullets to reduce windage effects and which has small ES / SD MV values to reduce L-R 'elevations'. That's what Bryan Litz is talking about with his Palma or FTR ammo. If you're only shooting out to say 600 yards, you can virtually ignore ES variations (within reason) as they barely affect 'elevations' at 100-600 yards. The size of the maximum score ring also influences this - 'Match Rifle' shooters who shoot at out to 1,200 yards here with 308 and maybe out to much more in Australia, have a 2-MOA 5-ring. They will trade some group dispersion and some increase in 'elevations' against maximum velocities, a tactic that would be disastrous in 308 Win FTR ammunition with the F-Class target's 1-MOA 5-ring and 0.5-MOA V-Bull ring.

 

Grouping is much more important than tiny ES. Everybody who is a keen handloader and owns a chronograph sees the phenomenon whereby four shots have identical MVs with the fifth a mere two or three FPS different, but the combination doesn't group for toffee. Barrel doesn't care for that bullet; the pressure / speed combination is all wrong for the barreled action harmonics ..... etc, etc. Logically one could go for the smallest ES/SD available and use a barrel tuner to get the required small groups rather than looking for small groups and then trying to reduce ES. (This is what rimfire BR competitiors do - ie tune the barrel to the ammo.) However, tuners have not so far 'caught on' as a rule in centrefire precision disciplines despite much discussion and experimentation and this is usually instructive - ie if something really works and gives a genuine and significant benefit, somebody will sooner or later try it and win lots of matches, then everybody else follows.

 

A forum thread simply cannot cover the issues here - they are to many and too complex. There are several books around on super precision shooting from BR competitors and others. Precision Shooting magazine used to have a good little primer on this, but it's long out of print

 

http://www.amazon.com/Precision-Shooting-Reloading-Guide-Brennan/dp/1931220123

 

(Bejasus!!! I never knew how much my copy was worth. I'll have to lock it away!)

 

https://www.amazon.co.uk/Handloading-Competition-Making-Target-Bigger/dp/096269259X

 

This is still in print and worth getting a copy.

 

Metallic Cartridge Handloading by M L McPherson 2013 Safari Press is a good handloading primer but also delves into advanced stuff in detail

 

To get an engineering and highly technical insight into what determines a rifle and ammunition combination's precision, another out of print book, Rifle Accuracy facts by Harold R Vaughn

 

http://www.amazon.com/Rifle-Accuracy-Facts-Harold-Vaughn/dp/1931220077

 

(Bejasus yet again - I need to turf my guns out of their cabinets and put my shooting books in instead!)

 

Going back to the ballistics equivalent of Newton and his Philosophiæ Naturalis Principia Mathematica, there are more than a few copies of the original seminal work - Franklin Mann's The Bullet's Flight around.

 

The Gun Pimp can no doubt advise on the latest top US BR competitor to go into print. Mike Ratigan's Extreme Accuracy is the last I've seen.

 

Bryan Litz is going well beyond bullet performance now and his two latest books should be acquired by anybody wanting to take a rigorous scientific approach to shooting success.

[Panda]

Neck-turning? Only relevant for extreme accuracy stuff - like benchrest. Plus you need a tight-neck chamber to go with it. If you don't have a tighter chamber, neck-turning will merely increase the 'slop' between cartridge and chamber-neck - which is the exact opposite of what you are attempting to achieve with neck-turning.

 

Bushing dies? - No. Get a set of Forster dies, remove the expander ball and up-size with a mandrel (from Brownells/Sinclair) - from the inside of the neck - so inconsistent neck brass thickness won't be as relevant to doing it from the outside with a bushing die. Use bushing dies ONLY if you are neck-turning. Ditch the Lee press and get a good quality single-stage press. Or, you could try a Lee Cast Classic - they're OK and good value.

 

Forget annealing for the time being - there are lots of improvements you can make before resorting to annealing.

 

Finally - always use good brass - from Lapua and change it as often as you can afford to (six reloads max.)

I have to admit, I wish I'd known about mandrel up-sizing a few years ago when I started handloading, however, as I replace brass I'll certainly be using that system of case preparation rather than spending hours neck sizing.

[Laurie]

On bushing dies, they don't provide any great improvement in concentricity (or even any at all) with out of the box brass and unless an expander of one sort or other is also used they can produce poorer grouping ammunition (as they transfer any variations in neck thickness effects from the outside of the neck to the inside, seeing the bullet then forced into a non-concentric hole).

 

They do have one great advantage though - they substantially reduce the amount of working of the case-neck thereby extending its life and also retaining consistent neck tension for a greater number of firings if annealing isn't employed (which for most people is the case).

 

Some years back doing some simple testing / research on this for a feature in the old 'Target Shooter' magazine, I measured 308 Win case neck O/Ds throughout the firing, sizing, bullet seating cycle. Crucially, this involved removing the expander button from the sizer die. Firing Lapua brass in a good quality factory rifle - an FN Special Police Rifle - starting with a loaded round, expansion on firing, sizing down, expansion, bullet seating, I got IIRC some 44 thou' of brass movement in total with a standard factory FL sizer, a huge amount. That is because standard dies massively (and deliberately) size the neck down far, far more than needed then expand up to give a consistent (and usually heavy) amount of neck tension on the bullet. This is because there are a lot of thicknesses of necks in factory brass - I have 308 Win cases whose necks mike out a 12 thou' thickness to around 16.

 

Change to a bushing die + mandrel expander and you work the brass a LOT less. I can't remember the amount in my FN SPR, but it was halved or thereabouts. Moving to a 'minimum SAAMI' type chamber in a custom rifle as in my 308 FTR jobs sees the amount of brass movement in a cycle almost quartered. After acquiring a bushing die, you should also buy (no cheap matter) bushings to suit different makes of brass if that applies. I use bushings from 0.330" up to 0.336" sizes in 308 for the maybe six makes of brass I might use from the famous 1980s Norma 168 cases (so named after their weight in grains) whose necks run from 0.0120" to 0.0128" up to some of the thicker Lapua brass that can exceed 0.0150". Bushings also allow closer control of neck tensions on the bullet as even when a mandrel type expander is employed, the resulting neck tension varies according to the amount of prior sizing and hence the pre-expand diameter as well as other factors such as brass thickness and hardness.

 

To show a simple demonstration of the difference this can make, here is a tale of two rifles. One, a semi-custom 223 chambered with a Wylde chamber (Service Rifle comp orientated), thin Winchester brass conventionally sized with an off the shelf FL sizer die. Life around 7-10 firings with ~55,000 psi loads due to neck splits. After firing number five or six, the differences in neck hardness showed up plainly on press 'feel' during bullet seating. Rifle two, a custom 308 with 'minimum SAAMI' chamber which sees the chamber neck section cut to 0..344-0.345" using aforementioned thin Norma brass that sees case-neck O/Ds at 0.332" in loaded ammunition, a large clearance by precision rifle standards, sized in a Forster Bushing-Bump die (bushing neck sizer that also sets case shoulder back) with a 0.330" bushing and expanded with a Sinclair E30 mandrel. Light to moderate neck tension, computed 60,000 psi + chamber pressures, case-life around 10 firings and that from expanded primer pockets. No subjective signs of serious work hardening, but that would need a proper lab analysis to know for sure.

 

Incidentally, that brings us back to neck turning and clearances. This is a thing The Gun Pimp and I agree to disagree on in a friendly fashion. Our 0.344" chamber ideally needs a round with a case-neck O/D of 0.340 to 0.341", three to four thou' aggregate clearance, half that at any single point on the neck. Subtract 0.308 or marginally above (bullet diameter) from that 0.340 figure and we get 0.032" for total case wall thickness, ie walls that are 0.016" thick. Lapua 308 brass as an example runs at 14 to 15 thou', sometimes exceptionally 0.0155" so as TGP points out we don't want to thin those walls any more as we're already at the maximum clearance we want. My thinnest Norma 168 cases were a fraction under 0.0120", so loaded rounds had a neck O/D of 0.308 + 0.012 + 0.012 = 0.332" tops or total clearance of 12 thou' compared to the desirable four or five. The ammunition loaded with these cases produced every bit as good results in 1,000 yard FTR shooting as with out of the box Lapua and I regarded them very highly. It's only the arrival of the far superior to everything else Lapua Palma case with its small primer and 1.5mm flash-hole that has seen the Norma brass put into retirement. So, to be honest, knocking up to half a thou' off Lapua neck diameters in a mild clean-up neck turn reducing some batches to 0.014" and others to 0.0145"certainly doesn't cause me any sleepless nights about the effects on precision. But if others want to keep the neck walls up to the highest available thickness, that's their judgment and they achieve as good results as I do and often better.

[Hobbit]

gbal, Vince, Laurie

 

Thanks for the thoughtful input - a lot there - I need to digest for a bit!

 

Taking a step back - I completely agree with the point made on Litz and WES

 

The biggest return on effort for LR is going to be improving my wind calls and general shooting and to be fair - if I wanted to be the best that I could be at long range then I probably should have chosen a custom FTR rig rather than the TRG in .308 or, as you say, chosen a better calibre and gone F-class. I do want to push the distance and the reloading side is to reduce my scope for excuses ;-)

 

On top of this - the questions on precision (thanks laurie) are, to some extent, an end in themselves - I am enjoying the learning aspect here - the combination of solid science, a pinch of 'dark art' and a lot of myths to trip up the credulous makes reloading compelling fun!

 

Thanks for the advice - very helpful cutting through shaggy dog stories

 

Cheers

 

Hobbit

[Hobbit]

Laurie

 

On the point you make on TRG headspace

 

"One thing often overlooked for rifles such as the TRG and AI models is that they often have relatively 'long' (in headspace terms) chambers having been designed to be ultra reliable and reasonably accurate with 7.62 Nato milspec ammo which is not quite the same thing as 308 Win. The result is a slight headspace 'issue' with out of the box 308 ammo or brass and conventionally FL sized handloads. It's important to match post sizing shoulder positions to the chamber in any rifle, but if the TRG is like AIs, even more so for this type. In an ideal world there is one thou' clearance between the chambered round's case shoulder at its 'datum line' and the matching point on the chamber. In practice 1-3 thou' is good, but often there is a great deal, and moreover clearances vary from round to round after sizing."

 

Does this mean I should expect lower case life in the TRG if I FL resize - given the headspace will cause stretching? Does neck sizing avoid this and is it actually desirable?

 

Thanks

 

Hobbit

[VarmLR]

If I may add a few points from my own limited experience, having just started going down the longer range route in .308 myself, I'd only echo Laurie and gbal's points. From my own experience, until I can reliably hit a target in varying conditions at 600 yds in spite of wind conditions, then trying to prise the ultimate precision from the re-loading process is almost worthless without mastering both the reading of wind and accounting for it. Where I shoot, the range is across a valley, and this has thrown up a few complexities with judging winds due to shear effect but just starting to get the hang of it.

 

To give myself the best starting point, as well as learning from the wisdom of people like Laurie and gbal, I have read standard texts such as Litz's advanced ballistics for LR shooting but his latest works, as Laurie suggests, go well beyond this and once reading wind/thermal effects are mastered as far as they ever can be (!) then Brian's latest works make compulsive reading. For my part, until I get better at reading and compensating for varying environmental conditions, my own nod to reloading consistency is to start with the best brass (within reason and affordability!) so I use Lapua, and anneal after 4 firings to try and keep a relatively consistent neck tension. I am not planning to neck turn nor to use specialised dies until such time as consistency is achieved in varying conditions at varying ranges. Sounds odd to say that I wont be taking the reloading any further but until I know that with each range in varying conditions, I can consistently return similar grouping precision then there's no base from which to measure progress.

 

In the reloading process itself, I think the most important part is choosing the right bullet to begin with. Following that, consistency in everything from case length to powder charge comes before more advanced case-prep (turning for example). I keep reminding myself that until relatively recently, some world records were set with a simple Lee loader kit!

 

Best of luck with your adventure!

[Laurie]

Does this mean I should expect lower case life in the TRG if I FL resize - given the headspace will cause stretching? Does neck sizing avoid this and is it actually desirable? [Hobbit]

 

 

 

Not if you have your sizer die properly adjusted for your chamber so you only set the shoulders back ('bump') a thou' or three. If the rifle has a 'long' chamber, the default die setting of its bottom edge in hard contact with the shellholder may set them back too far creating a mild 'headspace condition' which not only affects the rifle's performance, but causes excessive case stretching and reduces life.

 

Neck sizing obviously removes this risk. The problem with neck sizing alone is that unless the load being used is mild generating low to modest pressures, the shoulder moves forward under firing pressures and the case quite quickly becomes a crush fit in the rifle chamber longitudinally. Load / pressures aside, how prone the case is to this depends on its shape, longish fairly heavily tapered etc designs seeing it occur more quickly than short, fat types with steep shoulder angles. Some people shoot happily with a slight crush case to chamber fit all the time, but there is evidence around that it often enlarges groups. Eventually the case becomes very hard to chamber (and obtain initial extraction of the fired case too) and the bolt-face starts rubbing a lot of brass off the case-head. Using a Lee Collet die on 260 Rem with full-pressure but still 'sensible' loads, I see slight chambering resistance on the second loading with neck only sizing and it would start to produce downsides on the third.

 

The Collet die is actually a very efficient and cheap way to size cases very well indeed and is a viable alternative to a good bushing neck sizer and separate expander / mandrel die type operation. It works the brass a minimum amount, needs no lubrication, and produces very concentric necks. In the US and Canada, many top level FTR and TR shooters use the Collet die as a first choice, especially in 223. However, to address the 'shoulder bump' issue, they also use a separate 'body die' as a matter of course set up to just bump them back. (A body die is a full-length sizer that is cut oversize in the case neck area and doesn't touch the brass there. Redding makes very good body dies for most popular cartridges and they're not particularly expensive.) Unfortunately, Lee Precision has let its Collet die manufacturing standards drop rather in recent years - the collet tines often need a bit of needle file and steel wool work to smooth them out, other bits of polishing too so the collet slides easily in the die body. Also lube the top of the collet, don't run it 'dry'.

[Brillo]

This thread is proving to be an interesting read and an education in itself.

 

When it comes to to sizing the neck (and I don't mean neck-sizing the case) I must admit to not understanding the difference in internal neck size quality between upsizing the neck with a mandrel and doing the same in one operation with a good expander on the decapping rod.

 

To elaborate: I use Redding bushing dies and for my Lapua Palma cases I use a 0.336" bushing and on the decapping rod I have a Redding expander. This expander is not an expander ball but a stainless steel bar type expander not dissimilar to a mandrel.

 

I resize the cases by lubricating the brass body with imperial sizing wax and then lub the neck by dipping it in Redding dry lub beads, which coats the inside and outside of the neck with very light film of graphite.

 

With this the full length sizing operation is very smooth and on the upward stroke I can feel the neck being internally sized consistently by the expander with just slight resistance on the ram.

 

What I don't understand is what is the difference between pulling out and expander and pushing one in?

 

Since I've adopted this method every bullet I seat feels the same seating tension.

[The Gun Pimp]

OK - let's be silly and say that the brass thickness in the neck of two cases varies by 5 thou. Run both through the full-length die and, the 'hole' in one will now be made ten thou. less in diameter than the other on the down-stroke of the press handle. On the upstroke you will be dragging the expander-ball through a 10 thou. smaller hole. You'll feel that - if you're careful.

 

Do you think this will make any difference? Could it stretch the case? Will both necks be the same diameter?

 

If your answer is "Not a bit" then carry on using the expander-ball method.

 

If your answer is "Maybe" then use a mandrel to upsize!

 

Yes, the difference is going to be very small in the real world - where brass is very consistent. But, most case-prep operations fall into this category - like batch weighing for example. I never do it but you might.

 

A lot of shooters use the mandrel method because it allows them to vary neck-tension a little. Again, does neck-tension bother you?

 

If you shoot in high-level competition, you do everything you can to ensure that your ammunition is as good as it can be and at least as good as everyone else's! Why wouldn't yer?

[Brillo]

Thanks Vince but it still doesn't help me understand what the difference is between pulling a rod that is the same size as a mandrel through a hole that's been sized down by 0.336" and pushing a mandrel down a hole that's been sized 0.336". Surely the effect is exactly the same??

 

If an expander (upwards mandrel) can stretch a well lubricated case, surely an mandrel could compress the same case?

 

The Redding expander is very similar to a mandrel in shape and the correct size to give me the neck tension I need so what is the difference?

I am genuinely puzzled.

[The Gun Pimp]

Brillo - stay puzzled and let the mandrel users choose their way to up-size. I've just always hated the expander-ball method and then learned about using a mandrel - which also has the bonus of controlling neck-tension.

 

It's like meplat trimming, bullet-pointing, primer-pocket uniforming, ultra-sonic case cleaning etc. - some shooters swear by it. Others don't bother.

 

If your 'creaming' everybody in competition - you're doing it right. If you're not - that's when you try to improve your reloading.

[Brillo]

I was actually hoping for a scientific/technical explanation as to why pushing something of a known dimension and material through a hole of a known size is better than pulling something of a known dimension and material.

 

Can anyone else offer an explanation other than suggesting I stay puzzled?

 

I have a science/ engineering background and that is why it puzzles me. It just makes think this is one of those things that seems to work and no one can explain why.

[jcampbellsmith]

Brillo

 

When using a mandrel, the exterior of the case neck is not constrained by anything. When using a resizing die, the exterior of the case neck is constrained by the die walls. It depends on the die design and setup, just when the expander ball passes back up through the case neck.

 

I've tried using mandrels with limited success. I prefer using an expander ball.

 

Regards

 

JCS

[Brillo]

Thank you JCS. That explanation makes sense.

 

My expander set up-up is such that on the upstroke the case neck passes free of the bushing before the expander passes through the neck.

 

I guess I'm going to have to find a fellow shooter who's prepared to lend me a mandrel so I prepare a comparison batch of cases and observe the results for myself.

 

I won't be be surprised if discover the same as yourself.

 

Regards

 

Mark

[The Gun Pimp]

Brillo - benchrest aside, I know a lot of F Class shooters who use the mandrel method. To me, it just seems the right way to do it.

[Brillo]

Vince. I'll canvas my F Class friends to see if someone would lend me a mandrel to make a batch of cases.

 

Do they come in a range of sizes within a bore size, or is that something the shooter does himself by whatever method?