AR10 Specific Loads Needed

[19Scout77]

I started to review the .308 load section above for AR10 specific loads, for 175gns and up, but filtering through 9 pages of posts wasn't in the cards!

I'm looking for a decent starting point for heavier bullets for a 10 twist AR10 (mine is a 20"). My rifle likes 175s and up, so I'm going to test 175 smks, 178amaxes, 185 Scenars and 190 smks. Most likely using Varget, as that is what is on hand.

Please post up your recipes WITH CHRONO DATA PLEASE! Thanks.

 

[Bongos]

Re: AR10 Specific Loads Needed

I have a MWS with a 1:10 twist barrel, currently developing loads, using Nosler 175gr Competition, Win Brass, WLR, 2.8 OAL..
Started out with Varget 44gr in .5gr up to 45gr. At 44 gr it was about 2" @100 yards. At 44.5gr and 45gr it dropped down to barely MOA. I'm going to try 44.4, 44.6, 44.8,and 45 tomorrow and advise. But I think this should give you a starting point.

All were 5rd shots, single feed into the chamber then releasing the bolt from retracted position, front is harris bipod and rear is sand bag

Don't have a Chrono as my buddy whom borrowed it, shot it!!!

 

[raptor99]

Re: AR10 Specific Loads Needed

I have an Armalite AR10 with a stock 20" barrel and mine shot around 1.5 to 2"s at 100yds with whatever I shot in it. I put the free floating handguard on it and that really seemed to help with my accuracy.

Mine also seemed to prefer the heavier bullets and I settled on 42grs of Varget with the 175s. It also shot well with RL15 I am not sure on the charge but I think it was 42.5 but like I said "NOT" sure.

I then discovered by accident that it shot 46grs of Varget with the 168s pretty damn good too. All of my groups are now close to MOA. If I shoot 5 rounds 4 will be under MOA or 8 out of 10 will be sometimes all will be MOA or just under. I have it set up to shoot out to 700yds and it will pretty much do the 4 out of 5 thing to 700yds. This is shooting out of the mag no special treatment. Hope this helps!!

 

[clay_breaker]

Re: AR10 Specific Loads Needed

X2.That is almost exactly what I got out of my AR10, 20". Bad thing about it, I didn;t very much better than that out of 24" AR10T.

 

[19Scout77]

Re: AR10 Specific Loads Needed

Thanks guys--but Please do not post anything without chrono data as it is effectively useless.

 

[BCP]

Re: AR10 Specific Loads Needed

178 AMAX 2.8COAL LC brass 1X 42.5 Varget CCI LR = 2466 out of my 18", 44 grains gave a little over 2500, both were MOA or better out of my rifle.

Same as above except 43 varget and 175 SMK loaded to 2.795 COAL also gives me MOA or better, velocity is just under 2500. 175SMK I have found to be a bit pickier than the 178 AMAX. I tried the 190SMK w/41.5 varget in LC brass, velocity was ~2400 and good accuracy but the 175 weight stuff seems to be better overall.

If you're trying to figure out a load for your rifle you are better off loading up a bunch in .5 grain increments, say 3 of each from the weights of 42 to 45. Shoot carefully and watch for pressure signs after 44 grains. You should find at least one good load (probably 2).

 

[k2peaker]

Re: AR10 Specific Loads Needed

Bullet crimp: are you AR10 reloaders performing any bullet crimp as compared to your bolt gun loads?

I tend to crimp my .223 AR15 loads ever so slightly to smooth out the case mouth to bullet transition, are you finding that step necessary?

 

[19Scout77]

Re: AR10 Specific Loads Needed

Anybody shooting 190s in their AR??

 

[BCP]

Re: AR10 Specific Loads Needed

If you read my post I said I used them - they aren't that great. I mean if I had a bunch I'd keep using them, but I'd rather save a couple bucks and go with a 175 as the 190s seem to be more costly.

If I wanted to go heavy I would use a 208 AMAX.

 

[BCP]

Re: AR10 Specific Loads Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: k2peaker</div><div class="ubbcode-body">Bullet crimp: are you AR10 reloaders performing any bullet crimp as compared to your bolt gun loads?
</div></div>

I don't crimp anything. I do "test" loads to see if the bullets are jumping when chambered - sometimes the force of the bolt carrier will cause the COAL to go from say 2.8 to 2.805-2.81 or so. SMK's do this to me all the time, but after seating them slightly deeper they stopped. Crimping can sometimes prevent that, sometimes not.

 

[19Scout77]

Re: AR10 Specific Loads Needed

BCP- When using the 190s, did you bump it up past 41.5 and try to get the velocity up?

My rifle seems to favor heavy bullets and a 190 at 2500fps gets me to 1000 with only 11.8 mils. Hard pressed to do that with a 175 out of a 20" gas gun.

 

[Unknown]

Re: AR10 Specific Loads Needed

I have a 24 inch barreled DPMS LR308 with a 1-10 twist, Miculek comp on the end.
I'm shooting 43.2 grains of Varget, 170 Lapua Lock Base, CCI BR2 primer, match prepped, and weight sorted Federal GMM cases that weigh 181 grains (nominal) including the primer. I sort cases by weight with primer seated. Bullets are also weight sorted. Length overall is 2.820 as that is as long as the DPMS mags allow.

The rifle was originally returned to DPMS because it had too short of a throat, and although they said they did nothing, when the rifle came back, the excess pressure signs and sticking cases were gone. However, it didn't begin shooting well until around 400 rounds later. Now, the rifle shoots between .75 and 1 MOA at 200 yards. Most of the stringing appears to be vertical. Groups are 1.5 to 2 MOA tall, by 1 MOA wide. Velocity is 2648 FPS average.

The only 308 I have that doesn't like this load is my FNAR..

In my Sako TRG22, the bolt lift is occasionally sticky if I go to 43.5 grains, and primers begin flattening about 80% of the time. The primers aren't smashed, blown, or flowing, but about 80% of them loose the rounded appearance of the edge. So, I believe that in my rifles, I have found the max load. I won't go any higher than 43.5 even thought the Varget powder container's max load is quite a bit higher.

As we know, all rifles are different, and as another member put so very well; "Excess pressure WILL eventually be released in a most unprofitable manner." I would rather not bear that expense.

 

[19Scout77]

Re: AR10 Specific Loads Needed

Unknown- My bolt rifle loves the 170LB, but they SUCKED out of the gas gun. I shoot them at 2900fps from the bolt which makes for a formidable .308.

I started with 185 Scenars over 42.5 and 42.8 gns of Varget. Single digit sd, es around 20 and velocities of 2405 and 2425 respectively. Nothing in the way of pressure signs. Just too darned slow for a sub-optimal slug. Get it over 2550 and it gets interesting.

Next comes some 178 amaxes, 175 smks and 190 smks. Just need to find find the right combo of speed and BC without slaming a BCG through my forehead.

 

[Unknown]

Re: AR10 Specific Loads Needed

My DPMS LR308 seems to have either broken in about 400 rounds after sending it in for a too short throat, and now it is shooting between 1.5-2 MOA at 200 yards. With some loads, it is even outshooting the Sako, with other loads, the Sako wins.

I would be most pleased to find a load that both rifles like reasonably well though. I don't want to have different loads for every 308 in the rack.


With a velocity of about 2648 out of both 24 inch barreled rifles, I think I have enough velocity to quit. Federal says that their goal with their famous 168 match load is right around 2600 FPS for best accuracy. So it looks like I have found "the node" for these two rifles anyhow.

 

[Unknown]

Re: AR10 Specific Loads Needed

19Scout,

at 2900 FPS out of your bolt gun, I would be a bit timid of shooting the same load out of any gas gun.

I sent my DPMS rifle back for having a short throat. It was flattening primers, cases were sticking, and a few other classic short throat signs. Although DPMS said it was fine, and that they did nothing, the problems were gone after the rifle came back. I suspect that they cut a few thou more out of the throat, and didn't want to admit to quality control issues.

I'm just glad that it finally started shooting well. I think the 400 more rounds since return wore the throat out a bit more, and whatever goobers, roughness, burrs, or gremlins were in the throat are now gone. The last trip to the range, the rifle really shot well. Very consistent.

Although not as accurate as the Sako overall, the LR308 is now consistent. I'll take consistent groups of 1.5-2 MOA at 200 yards over groups ranging from 80% at 1 to 20% at 3 moa any day.

 

[19Scout77]

Re: AR10 Specific Loads Needed

I've been doing this a little too long to run my bolt load in an AR

 

[leadbullet]

Re: AR10 Specific Loads Needed

in my Armalite with a novesky 21" 1-10 twist, I run 175SMK with 42 gr of varget, don't know the speed but 10 shot groups at 200yds are rarely over .9 inch. I tried the same load as my TRG 22 with 44 gr of varget and blew all the primers off the winchester cases, with good accuracy also.
hope this helps.

 

[Queequeg]

Re: AR10 Specific Loads Needed

Don't know the velocity but the 168 gr. Nosler HPBT over 44.5 grains of Varget, in Rem, Win and Hornady cases, 2.825", BR2, 210M and WLR Primers, all fell into .75 MOA at 100 yards in my AR-10A4. This is not a heavy barreled rifle nor does it have a match trigger.

Pretty surprising to me as I had previously found that the loads I ran through it were in the 1.5 -2.00 MOA range suggested by Armalite. This particular load is much loved by me in this rifle! And it's damn good in my bolt guns.

 

[CTone03]

Re: AR10 Specific Loads Needed

I have a LR308 with a 20" Krieger Criterion heavy barrel that I've done all sorts of load testing with 155, 165, and 175 grain bullets. So far it likes the 175s best. Here is a recent load up that I did while pressed for time, but I think I'm in the right ballpark:

175 grain Nolser Custom Comp.
New Winchester brass FL sized
CCI BR2s
2.227" COAL to ogive, 2.798" COAL to tip
Reloader 15
43.1 gr
*2,515
*2,501
*2,482
*2,501
*2,510 [av - 2,502 / es - 33]

43.2 gr
*2,520
*2,534
*2,515
*2,496
*2,525 [av - 2,518 / es 38]

43.3 gr
*2,554
*2,534
*2,544
*2,539
*2,534 [av - 2,541 / es 20]

I shot some 43.4 grain charges as well, but didn't get velocity data as it was getting dark and the chrono quit. I shot about fifty of the 43.3 grain charges out to 514 yards with decent results. My first five round group measured 5 3/4", with best four into 3 1/8".

I've also tried Varget with mixed results.
175 grain Nosler Custom Comp
New Winchester brass
CCI BR2s
2.227" COAL to ogive
42.8 - av 2,410
42.9 - av 2,412
43 - av 2,436
43.1 - av 2,492
43.2 - av 2,506

There's an accuracy node in there somewhere, but I couldn't find it under the cercumstances. Had nothing to do with the loads though.

Same exact load with 45 grains of Varget gave me averages anywhere from 2,550 to 2,640 fps depending on the temperature; I gave up on that one as I started wrecking new Winchester brass when the temperatures got really hot. Anywhere from 55 - 75 degrees though gave me a consistent 2,604 fps average, and as long as I used good cases with some neck tention it stayed sub-MOA (.600ish") groups at 100.

I completely agree with BCP about crimping: cases with good neck tention are all you need. You can't load rounds very long and be able to load them into a magazine, so I keep mine around 2.800" OAL as that keeps as much of the bullet in contact with the inside of the case neck. When you drop the bolt on a loaded cartridge and then eject it and measure, the round generally grows around .005" or so, which isn't a big deal.

 

[BCP]

Re: AR10 Specific Loads Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">BCP- When using the 190s, did you bump it up past 41.5 and try to get the velocity up?

My rifle seems to favor heavy bullets and a 190 at 2500fps gets me to 1000 with only 11.8 mils. Hard pressed to do that with a 175 out of a 20" gas gun. </div></div>

You could do that with one around 2550ish depending on altitude etc. I like the 190's just fine, the thing is I didn't get any more use out of them than with the 175s. If I start shooting my 300 win mag more I'll switch to the 190s or 208 amax though so then I can use them in my 30-06, 308 and 300 win. 208 is hard to pass up since they are 27cents a bullet (I'm a penny pincher) and to me they are better than the 190smk.