Handloading, consistency and accuracy

[The Gun Pimp]

Well, Stuart at Osprey Rifles has been making them in various sizes mainly at the request of the FTR shooters loading 308. I've made my own but I think they do a couple of sizes.

[Big Al]

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.

 

 

I can understand that Brillo, sometimes things seem like they will make a difference to some people while not to others, I guess the proof is in the actual measurements.

 

In theory both methods will leave the same internal neck diameter assuming that the expander ball and mandrel are of the same size, In practice I have found that it doesn't make much difference. Its just a case of which route you want to take to get to where your going.

 

I have started to use the mandrel method like Vince, I make my own mandrels to suit the amount of neck tension I want. Although the results end up the same and it becomes an additional operation within the process I find the effort required on the down stroke of the press handle preferable to the up stroke to do the internal resizing. The mandrels for the method I use are also easier to make than turning a different size/profile expander. Doing it this way takes less effort as the press is working for you on the down stroke and with suitable lube it feels very easy indeed, much more pleasant than dragging a less than perfectly shaped expander back back out on the up stroke, even if the ultimate result isn't measurably more accurate. I dont want to neck turn unless I have to (other than a cut into the shoulder to prevent doughnuts) and so working from the inside outwards with a mandrel (rather than with neck bushes on unturned necks) will always give more consistency in neck tension.

 

I use the housing from my K&N neck turning mandrel set up to do this and then make a mandrel to suit, the one on the right is .2235 which gives me 0.001" neck tension for my .224 cases after the brass has sprung back a little, the one on the left is the standard K&N one for .224 cases. The longer tapered lead on these mandrels compared to that of an expander ball is what makes things so smooth and the larger surface are contact for longer should in theory make things a little more consistent although again not easy to measure any real differences.

[Brillo]

Many thanks AI. Great explanation.

I have a K&M mandrel housing for my .7mm expander. I didn't realise the mandrel itself was so inexpensive and it won't be too difficult to turn down to give me the desired neck tension.

 

Time to give Spud a call.

[Big Al]

Many thanks AI. Great explanation.

I have a K&M mandrel housing for my .7mm expander. I didn't realise the mandrel itself was so inexpensive and it won't be too difficult to turn down to give me the desired neck tension.

 

Time to give Spud a call.

 

 

An electric drill and some 240 & 600 grit emery cloth, maybe some scotchbrite if you want and a micrometer is all you need, a lathe would make work holding more convenient but its far from essential.

 

Be careful, your probably only going to need to polish 0.001- 0.0015 off a standard K&M insert, this can happen quicker than you might expect.

[Brillo]

Thanks for the tips guys.

[MTLEADFARMER]

Out of curiosity do any of you try to duplicate factory ammo, or do you instantly apply all these methods when loading for a any firearm? At one point in time I applied most of these methods but do not anymore, now I uniform primer pocket, debur flash hole, aneal, full length size, trim to factory spec, prime, weigh powder, seat bullet to factory spec, and lee factory crimp. I have seen no loss in accuracy. I have rifles that shoot in the ones and twos consistently with this ammo. I do agree with the above statement about the wind, anybody can run the numbers on a ballistic calculator but if you can't call the wind your going to miss. anybody wanting to shoot LR/ELR must learn the wind and have as much time behind the trigger as possible. I know it's different for you folks but where I live I can shoot everyday at whatever range I want, even if it's only one shot, I fire at least one round out of whichever rifle I'm packing for the day sometimes only 100yds sometimes 2000yds. hit or miss spend the rest of the day thinking what I did right or what I did wrong. I think spending more time behind the trigger and less time at the loading bench will improve your groups more than anything.

FTW not f##k the world but Fundamentals,Trajectory,Wind

[VarmLR]

Out of curiosity do any of you try to duplicate factory ammo, or do you instantly apply all these methods when loading for a any firearm? At one point in time I applied most of these methods but do not anymore, now I uniform primer pocket, debur flash hole, aneal, full length size, trim to factory spec, prime, weigh powder, seat bullet to factory spec, and lee factory crimp. I have seen no loss in accuracy. I have rifles that shoot in the ones and twos consistently with this ammo. I do agree with the above statement about the wind, anybody can run the numbers on a ballistic calculator but if you can't call the wind your going to miss. anybody wanting to shoot LR/ELR must learn the wind and have as much time behind the trigger as possible. I know it's different for you folks but where I live I can shoot everyday at whatever range I want, even if it's only one shot, I fire at least one round out of whichever rifle I'm packing for the day sometimes only 100yds sometimes 2000yds. hit or miss spend the rest of the day thinking what I did right or what I did wrong. I think spending more time behind the trigger and less time at the loading bench will improve your groups more than anything.

FTW not f##k the world but Fundamentals,Trajectory,Wind

 

Horses for courses. I think that for the guys who shoot competitively, it's no bad thing understanding the nuances of detailed ballistics and applying them as it's a chance to remove or at least control known variables and make for best practicable consistency. The wind seems to be the only variable that one cannot invent a widget for controlling and is therefore the black art/skill for long range shooters. I would guess that guys regularly achieving high scores at distance already have this down to a tee.

 

For many others, including myself, such additional measures at the reloading stage are not only considered unnecessary, but unwelcome. They add cost, complexity and time to the reloading process which for hunting and long range vermin control just seem an unnecessary encumbrance. I tend to do as you do and now that I have found bullets that my rifles like and my pet loads have been perfected, am regularly shooting in the 0.2s and 0.3s which seems pretty good enough for my purposes, out to 400 or 500 yards. I had some 400 yard practice yesterday in gusting wind coming from my 3 O'clock with some shear causing a few issues but a few sighting shots and learning the wind for that particular spot saw some very tight groups, all sub moa. Like you, all I do is resize, deburr the flash hole, clean out the primer pockets, anneal every 3 or 4 firings, trim to SAMMI spec length and through load development find the optimum seating depth which isn't always at "book" seating depth for my rifles.

[Brillo]

Ok, I've bitten the bullet, so to speak and bought a .308 expander mandrel from Spud.

 

I needed to find out for myself which is best, expander ball or mandrel.

 

Following the advice from Big AI I polished this down with 180 grit paper and finally fine wire wool until I got the desired neck tension. This is half thou less than that with the Redding expander ball.

This took a bit of time because I didn't want to take too much off the mandrel in one go. Once it's gone, it's gone.

 

Although logic tells me there shouldn't be a difference between pulling and pushing a mandrel I must admit it did feel different. And, although it's an additional operation it doesn't take that long.

 

My next step is to make up two batches; one lot with the neck expander and one with the mandrel method.

 

I've got an open mind on this so the results will be interesting.

[apexi]

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

 

 

I'm shooting a TRG22 for FTR and regarding headspace found the TRGs to have surprisingly tight chambers out of the box. With Lapua brass:

- headspace measurement on virgin unfired brass 1.614"

- after 2-3 firings requiring bump 1.616-1.617"

- 0.002-0.003" difference indicating the Sako TRG has a relatively tight chamber...not a custom match build but can hold its own!

[Martin52]

I have a 0.307 K&M mandrel and found run out increased on many cases probably due to inadequate support of the case body. The cases were first full length sized in either my Forster FLS die (0.3345 neck) or my bushing die and there was minimal run out present (<0.001) before the mandrel was used. After the mandrel, run out was up as much as 0.004 (similar to past results neck sizing only, which I gave up on some time ago).

 

I reverted to a body die and a Lee Collet.

 

I then bought a Hornady New Dimension bushing die that came with a 0.306 expander ball and tried again. Using a 0.334 bushing, the neck (turned) experienced minimal expansion and run out. This made me rethink that discarding the expander ball should perhaps be reconsidered.

 

The general problem that leads to removal of the expander ball is where a standard die is used that reduces then expands the neck considerably more than with the above methods.

 

Interesting that Whidden Gunworks in the USA are on to this and now sell expander balls of various sizes so that the bushing and mandrel can be closely matched to minimise the amount the case neck is worked.

 

Now, whether this is better than the body die/Lee Collet combination or just using a FLS bushing die I don't know. However, assuming correct matching it does seem to work in favour of retaining the expander ball, perhaps contrary to general opinion.

 

I have yet to try the Whidden product but have this on order along with some carbide bushings.

 

Martin