Short barrel 308, fast bullet, what powder?

[meles meles]

Seeing as this thread http://ukvarminting.com/forums/topic/37853-los-solid-brass-bullets/ - hasn't gone far, we've out and bought ourselves a copy of Quickload and starting running a few 'what if' scenarios. Our objective is to develop a SAFE, moderately high velocity (2,500 fps or thereabouts) load for the LOS 165 grain bullet.

 

We chose a basic SAAMI COAL of 2.8 inches and that gave a useable case volume of 2.834 cc

We chose powder next - RS50 and entered a recommended charge weight from Lyman’s 49. That gave a result that was average for calibre in terms of velocity and pressure. The Quickload results were actually in close agreement to the Lyman published data, which we thought was A Good Thing. However, we noticed that the % powder burn was poor (We hate not burning every grain of powder we’ve bought) and also the ballistic efficiency was only 24%.

So we started playing….

The DTA barrel is short, and so we thought “Why not use a faster burning powder ?” We may get full combustion…

We then looked at RS 40 and even RS30, which both burn faster and apparently contain more energy per grain. From the Quickload data these seem better loads by far. Using considerably less powder we appear to get 100% powder burn in the barrel, velocity that seems more than acceptable and the pressure isn’t frightening. So why is RS50 the recommended powder for .308 rather than RS30 or 40 ? Does the pressure build unacceptably quickly ? (It doesn’t appear to) Is it fear of burning out the throat ? Are we missing something else? We don't plan to use these loads because they don't correspond with any data published in reloading manuals but it is making us think that a fast powder might be a good idea if we aren't missing something critical...

[JSC]

I can't see how you're getting acceptable pressures in QL with RS30 and that bullet if you're aiming for 2500fps.

 

I just ran it and even for QL it was scary! 16" barrel, 2.8 OAL, 31gn of RS30 is showing 2379fps at 65463psi! Maybe I've missed something with your set-up, but what are you getting?

 

In any case, unless you begin by measuring a few start loads with a chrono, you're playing a guessing game, as the powder data in QL is a starting point only and very rarely accurate enough to work up a load with.

 

Personally, I'd try RS50, 52 or H4895 but you can run a report in QL which will list all the powders in the right ball-park for your particular bullet/barrel/MV combination, so that would be worth trying.

[dannywayoflife]

Ramshot wild ore was the powder I developed a spectacularly accurate load in that rifle buddy. It would also work very well with the 165-168 grain projectiles. As it's a ball powder it nesters like silk as well

[dannywayoflife]

Ramshot wild ore was the powder I developed a spectacularly accurate load in that rifle buddy. It would also work very well with the 165-168 grain projectiles. As it's a ball powder it nesters like silk as well

 

With the faster powders mention I would bet your hit pressure before your specified velocity

[Chris-NZ]

What does QL say about H335 for that config?

[marty]

155gr scenar -44gr ramshot tac.

[BlueBoy69]

meles meles,

I'm not sure if you are aware of this, but you can use QuickLOAD to access its complete powder library and assess the most suitable ones for the bullet, cartridge and gun combination.

You can choose stuff such as what gives: a certain velocity; pressure level; pressure range above and below Pmax; case fill level; barrel time (ignition to bullet exit); etc..

For the powder, you just pick two burn rates limits, a min and a max.

Once that's all in, you let it calculate and it displays the data sorted by the muzzle velocity (MV).

Going by what I put in, here's a suitable list of US and European powders (all right, some are rebadged Australian powders). This is with; a 16" barrel; a COAL of 2.800"; a 165 gr LOS Tactical bullet; max pressure of 55000 PSI; max load fill of 105%; min load fill of 85%; and the min and max burn rates of 0.45 and 0.65.

 

Shows powder type first, then powder charge (grains), MV (fps), filling (%) and pressure.

Hodgdon CFE223 44.9 2501 95.8 55000
Winchester 748 42.5 2496 97.9 55000
Hodgdon BL-C2 44.3 2493 96.8 55000
Alliant AR-Comp 39.6 2484 100.0 55000
Lovex D073.6 43.0 2484 98.5 55000
IMR 4895 42.3 2481 95.4 54013
Hodgdon H4895 41.1 2472 96.2 55000
Ramshot Big Game 45.0 2470 94.6 53345
Ramshot Wild Boar 43.2 2468 95.4 55000
IMR 3031 39.5 2464 99.7 51670
Norma 202 40.9 2459 99.0 55000
SNPE Vectan SP 9 42.8 2459 95.4 55000
Hodgdon H335 40.8 2459 99.0 55000
ReloadSwiss RS 52 43.6 2458 96.5 50524
SNPE Vectan SP 10 39.8 2454 99.0 55000
Vihtavuori N530 39.8 2450 97.1 55000
Alliant Reloder-15 42.3 2449 94.3 52765
Vihtavuori N540 42.7 2445 98.8 54015
Norma 201 40.8 2444 97.1 55000
Lovex D073.5 41.7 2444 97.9 55000
IMR 8208 XBR 40.4 2442 97.0 55000
ReloadSwiss RS 40 39.4 2440 98.3 55000
Norma 203B 42.3 2436 94.7 51624
SNPE Vectan SP 7 43.7 2435 92.8 55000
Lovex D073.4 40.9 2431 97.8 55000
Vihtavuori N140 41.4 2431 99.2 54326
Ramshot TAC 43.2 2424 92.1 55000
Ramshot X-Terminator 41.6 2418 95.3 55000
Norma 200 36.3 2413 100.0 55000
Somchem S335 40.4 2401 99.5 55000
Lovex S062 41.1 2400 96.3 51009

Sorry for the poor formatting, Seems to be a problem with the message editor. The list created by QuickLOAD displays fine in Excel, Word and Text editors I use, but not here. I'd put it in a Excel table and paste it in, but that does seem to work here and there doesn't seem to be a table creation function in the editor. For note all non-available powders (not those affected by REACH) were taken out and the list was cut off at 2,400 fps. There were even more powder combinations below that velocity figure, but I didn't see the point of putting them all in

 

Be aware, as always that QuickLOAD is just a model, a guide. The list above is just an example of what powders are likely to be suitable for use with that component combination. It is not reloading data. So it would be best to look at what powders are listed and then cross reference these with commercially released data (don't get me going on Beger's data). Personally I've never had any problems with using QuickLOAD as I guide, as long as you start low and use standard safe reloading practices.

 

Neil

[meles meles]

Hmmm, we have a tub of Wild Boar as well as several different flavours of ReLoad Swiss... Time to try those we think, starting low and working up....

[dannywayoflife]

Badger to give you some idea of the performance I got from that DTA I was sending a 155 Optimus HBC at 2730 fps using wildbore. Athe lapua scenar is also an excellent bullet with the same BC but I never tried it in that barrel as I came into them after I sold it. What I did find was that to get that speed and consistency (i.e. Single digit ES and SD) I had to use specific primers CCI 250 mag primers were what I found worked for me.

[gbal]

Commercial ammo, SAAMI Specs,24 inch barrel (so will be about 200fps less at least,with a 16" barrel,ball park):

 

155g:

Cor bon scenar. 2900

Lapua scenar. 2822

Hornady TAP. 2785

Black Hills A max. 2750

 

165g

Hornady BTSP. 2880

Federal SGK. 2700

Fed Nos Ac-B. 2700

Fed Trophy B. 2700

HornadyIntLoc. 2700

Norma Swift A. 2700

Rem AcTip. 2700

Black Hills BTSP 2650

Rem Scir. 2700

Umax Nosler BT. 2680

Umax Speer BT. 2680

Fed Barne TS. 2650

 

All 24" barrel,remember,so

2500 for 165 and 16 inch barrel seems about on spec

 

gbal

[deadcenter]

I have some of the brass solids but not had the chance to experiment yet.

 

From the research I did when I first got them, they will tolerate a faster powder as they run on the bands around the bullet and are very low friction.

 

I think the idea to finding charge weights with your chosen powder was to keep increasing weight (while keeping a close eye on pressure signs of course) until velocity stopped increasing. The max velocities reached were before any over pressure signs were evident. I can't remember what velocities or powders were quoted, or even where I read the info now. On the net somewhere obviously.

 

Hope this helps in some way.

[Andrew]

You really shouldn't jilt established load data for Quick Load. Even quick load says as much.~Andrew

[meles meles]

Andrew,

 

Read the last sentence of our very first post.

 

 

Thanks to all who have contributed usefully to the question. The plan is to start working up some loads with Wild Boar and possibly an RS powder, comparing them and seeing which combination best suits this rifle and bullet. We'll put the results up as we get them.

[gbal]

Meles,by all means try and see-it looks like there is very little differnce in velocities-on both Blue boy's and SAAMI data-2440 fps/ish.

 

50 fps either way isn't likely to be critical.

I'd go for accuracy.

Remember some of these powders may not have been cleared (yet) for future sale by REACH (Vihtavuori and RS are OK)...

 

gbal

[meles meles]

We're just back from the range, oomanses, and here's how things panned out.

 

We loaded once fired and neck sized cases (available powder volume measured at 55 gns of water) with the 165 gn LOS Tactical bullet set to give a COAL of 2.953 inches. That seated the bullets 5 thousands of an inch off the lands in our DTA. We used RS52 powder and began at 40 grains, increasing in increments to 44.5 grains. We fired 5 rounds of each increment at 100 yards. The load which worked best was 43.5 grains, giving a group measuring just under half an inch. Loads higher and lower than that gave increasingly larger groups, the upper and lower bounds of the charge weight spread both increasing to 0.75". At the upper charge weight tested we were still seeing no signs of overpressure.

 

So...

 

Powder: RS52

Charge weight: 43.5 grains

Bullet = LOS solid brass Tactical at 165 grains

COAL = 2.953"

[ejg223]

What does QL say about H335 for that config?

 

I'd give that a go too.

Recon you mean the good results your buddies at New Zealand Hunter had with 130gr /16" 308 Barrel and H335.

edi

[deadcenter]

Sounds good. Any idea of velocity?

[ejg223]

Just looked up the pic of the article that I took a few years ago.

 

308, 16" barrel. 20 thou jump. 130gr. ttsx

 

H335 48gr 2850 fps

H335 49gr 2896 fps

H335 50gr 2965 fps

H335 51gr 3035 fps

 

edi

[meles meles]

Yes, most interesting. A lighter bullet and a bigger load of powder does that sort of thing...

[dannywayoflife]

What's the speed with that load badger?

[meles meles]

What's the speed with that load badger?

 

Not sure.

 

According to Quickload it is around 2450 fps, and at only 45,500 psi so potentially some scope for raising the velocity. However, it was a small group and seems to be in the centre of an accuracy node so we're not too fussed about going faster. We may be able to borrow a chrono soon and if so we'll update the post with some real world speed data. We haven't tried Wild Boar yet but it looks to give a slightly higher velocity at similar charge weights (but the pressure is considerably greater). Given that, it seems that RS52 may be the better option in terms of barrel life... A second point was that after we had finished testing the barrel was very clean. Those brass bullets seem not to leave much if any, fouling at all.

[dannywayoflife]

Ramshot powders are engineered to burn cool so wouldn't put much weight into the barrel life situation being significantly different either way......

 

45,000psi seems very low for the 308....... there will be further nodes higher up.

[Laurie]

 

Not sure.

 

According to Quickload it is around 2450 fps, and at only 45,500 psi so potentially some scope for raising the velocity. However, it was a small group and seems to be in the centre of an accuracy node so we're not too fussed about going faster. We may be able to borrow a chrono soon and if so we'll update the post with some real world speed data. We haven't tried Wild Boar yet but it looks to give a slightly higher velocity at similar charge weights (but the pressure is considerably greater). Given that, it seems that RS52 may be the better option in terms of barrel life... A second point was that after we had finished testing the barrel was very clean. Those brass bullets seem not to leave much if any, fouling at all.

 

 

Do NOT believe QuickLOAD results for RS52 - they are way out and invariably present a 'wrong-side failure' (ie understate pressures and velocities). You really must chronograph your actual MVs now, otherwise you have no idea at all as to the sort of pressures you're running.

 

Given the paucity (often complete absence) of tested data for Reload Swiss powders, it is unfortunate that for this grade at any rate, that QL is so unreliable. I quickly realised something was far out in the State of Denmark (sorry Ovenpaa!) with RS52 in early tests where I obtained substantially higher MVs than predicted in 308 Win amongst others and some serious over-pressure indications on or just above my QL obtained starting loads. (It does tick me off substantially to have to take ammunition home at the end of a 120 mile round trip to the range still intact and have to demill and subsequently reload with lower charges!)

 

So far in three or four cartridges, I've found RS52 works very closely to H. VarGet performance in terms of starting loads and resulting MVs, One can usually work up to slightly higher charges than are comfortable with VarGet (about the same as Re15 actually) for slightly higher MVs (30-50 fps depending on cartridge / barrel length).

 

Moreover, the likelihood of actual pressures being higher than the computed 45,500 psi PMax is actually no bad thing providing they're not too high. RS52 is a 'high-energy' propellant made with an improved version of the techniques that Viht uses to turn base N100 grades into N500 equivalents. (Nitrochemie sold the techniques to Vihtavuori Oy many years ago, but whilst the Finnish company hasn't developed them much if at all, Nitrochemie claims to have made substantial refinements/improvements to the process in the intervening years.) You often find that under-pressure loadings of so-called doubled-based (or in this case added nitroglycerin 'high energy') types results in inconsistent performance - large MV ES/SD values, horrendous muzzle flash and blast, and undesirable habits like shooting tiny groups this week but refusing to repeat the performance next week.

 

Conversely, I've found QuickLOAD predictions to be pretty close to actual results with Ramshot powders - Tac, Wild Boar, Big Game, and Hunter in the loads I've tried in a small selection of suitable cartridges for members of this quartet.

[Laurie]

To give an indication of how QL may deceive on this, here are the results of one of the very first tests I did on RS52 using a sample lot provided by Nigel Cole-Hawkins under the manufacturer's OEM description of Nitrochemie EI-N130 in December 2013. There was no loading data available, and QuickLOAD hadn't been updated with it at that time, so the advice was to use Alliant Re15 data as a guide.

 

This had been done from very low levels initially, then a second and even third stage tests were run with higher charge weights once a 'feel' had been obtained for the powder's characteristics. Parallel loads with H. VarGet and Re15 were run alongside in the same sessions using identical components to provide comparisons.

 

The rifle was a Savage PTA based FTR rifle with a 32-inch 1-12 twist Bartlein barrel, minimum SAAMI chamber dimensions and freebore cut to suit long 155s such as the 155gn Scenar seated slightly shallow in the neck.

 

With the short-shank (low barrel friction) Sierra 155gn Palma MatchKing (#2156, later model), loads for all three powders were worked up to 47.4gn in Winchester brass (57gn water capacity = +1gn on Lapua) with Federal 210M match primers. 15 thou' jump. MagnetoSpeed V3 chronograph used.

 

QL prediction for H. VarGet .......... 59,840 psi / 3,024 fps MV .............. Actual MV ............... 2,997 fps

 

......................Alliant Re15 ......... 57,428 psi / 3,042 fps MV ............................................... 2,999 fps

 

..................... RS52 .................. 47,934 psi / 2,925 fps MV (not available then, run today) .... 3,039 fps

 

Great powder though RS52 is and no matter how much benefit the patented EI deterrent infusion process gives, it simply cannot provide another 40 fps over VarGet and Re15 whilst running at 10,000-12,000 psi lower pressures. It almost certainly produced similar peak pressure values to the others, but gave the usual 30-50 fps extra MV I mentioned.

 

Incidentally, the trio produced near identical MV spreads / ES values for 5-round strings, all good with the top 47.4gn charge weight, rather higher with lower charges - 11 fps for RS52, 12 fps spreads for Re15 and VarGet; SD of 5 for RS52 and Re15, 6 for H. VarGet.

 

'Playing' with QuickLOAD to match that 3,039 fps actual MV, the program says RS52 produces that at 49.4gn - ie exactly 2gn 'out' on the wrong side. I regard that as a quite unacceptable margin. The two 'right side' errors for Re15 and VarGet are within typical accuracy levels for what as others in earlier posts point out is a model, and in % variation terms are quite close, VarGet's actual being 0.89% 'out' on the predicted MV, production lot variations often accounting for this sort of deviation.

 

 

VERY IMPORTANT NOTICE. These charges were worked up in a dedicated longer than SAAMI freebore competition rifle with a top-grade match barrel. They may produce excessive pressures in other rifles. DO NOT USE THE CHARGE WEIGHTS SHOWN FOR THESE THREE PROPELLANTS WITHOUT EXTENSIVE WORK-UPS FROM MUCH LOWER CHARGES WHILST MONITORING MVs AND PRESSURE SIGNS SUCH AS HARD BOLT LIFT, EJECTOR MARKS ON CASE-HEAD AND SUCHLIKE.

[meles meles]

Many thanks for your input Laurie, it's truly appreciated !

 

We plan to measure the velocity of the rounds we make to this recipe and will post the results. The pressure is almost certainly under-calculated by Quickload but, be that as it may, we're likely to stick with his load. It's accurate, shows no signs of over pressure and shoots to the same point of aim as German MEN 7.62x51. It meets all our needs.

 

We'll probably look at Wild Boar too. We have used Ramshot powders for other cartridges and like them: if they can also give 1/2 MOA groups with our LOS solids then that's a useful thing to know in case of any supply issues with RS52.