Best groups for my AR10- load worth trying

[Manzgear]

Recently loaded up some more 308 for my AR10 and here's how they shot today. Mild conditions- temp 60's- wind- N/A- rifle AR10 in 308 pictured below my profile- 18inch barrel- DPMS platform- lower from tacticalmachining.com - ok loads are- target 1- 40grains of Reloader15- 175grSierra bullets in all..target 2- 41grains- target 3 - 42grains- 3/4 inch group- my best so far.
target 4- varget- 42.2 which did well before but still is on the fence...
all are 5 shot groups. anyways I just wanted to put these up.
if anyone has a good load for a gas gun- for 175's that include varget, reloader 15, IMR 4895 let me know. if you have one that is worth trying cause you have a similar gun- let me know. I am up for buying more powder... and my rifle is my own custom job...bought all the parts and considering it was my second AR- I am very happy with it..

 

[RH4540]

Re: Best groups for my AR10- load worth trying

If you can lay your hands on some Lapua, 155 grain, Scenar bullets, and some once-fired brass, out of your rifle, put 46-47 grains of Varget behind them. That has produced sub, 1 inch groups out of all the .308s I've put them in at 200 yards.

 

[Wolf22]

Re: Best groups for my AR10- load worth trying

tag

 

[lsm62]

Re: Best groups for my AR10- load worth trying

i worked up a load for my dpms 308 24 in barrel that worked well.

175smk
43gr varget
2.8 coal

the 168 hornady hpbt gave me a better group at 100 though

168 hornady hpbt
44.4gr varget
2.8 coal

i hear guys do well with the 168 a-max as well

 

[Manzgear]

Re: Best groups for my AR10- load worth trying

ok sounds good guys thanks for the info.... and I checked it and its not 3/4 its 1inch but still not bad for me since I just started reloading...

 

[ClayDirt]

Re: Best groups for my AR10- load worth trying

It looks as thought your rifle is grouping as the bullets are staggered in the mag. Two bullets grouped here three over there or vice versa. This is a fairly common thing among auto loading rifles and especially ARs chambered in 308.

You can single feed the rifle, if it helps it you can do several things to help it. One, continue single feeding and disregard you have a autoloader. Two, polish your feed ramps. Three, sell it and buy a Armalite and keep sending it back to them until it does finally shoot a MOA.

 

[Manzgear]

Re: Best groups for my AR10- load worth trying

thanks Claydirt - I will try that..... although I dont think I will ever buy an armalite. maybe its time to get into a nice custom bolt gun. Probably less variables to account for lack of extreme accuracy. So because the mag feeds them it makes the rifle group differently? trying to understand this cause they are all going in the same chamber?

 

[Lima Bravo]

Re: Best groups for my AR10- load worth trying

It seems that he is saying the feed ramps are scratching the bullet as it is loaded out of the mag, I have an LR 26O that shoots a wide group most of the time, decent group but mostly staggered wide. I never have thought about this causing the problem, thanks for the info.

 

[Manzgear]

Re: Best groups for my AR10- load worth trying

ok so polishing the ramps can help?

 

[ClayDirt]

Re: Best groups for my AR10- load worth trying

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cash6220</div><div class="ubbcode-body">It seems that he is saying the feed ramps are scratching the bullet as it is loaded out of the mag, I have an LR 26O that shoots a wide group most of the time, decent group but mostly staggered wide. I never have thought about this causing the problem, thanks for the info. </div></div>

I belief there are many variables that cause the rifle to shoot staggered groups.

One variable being the blemishes done to the bullet by the feed ramps, barrel extension, and mag feed lips. Second variable being the violent cyclic action possibly seating the bullets deeper into the cartridge. This making slight variations in the gas pressure which causes more deviation between shoots in a autoloader than it would say a bolt gun.

I am not claiming to be right, this is just my opinion. I welcome any friendly debate.

 

[Queequeg]

Re: Best groups for my AR10- load worth trying

I think you need to bump up both powder (RL-15 and Varget respectively)charges as they are both on the low side. Additionally, a larger sample size of targets would be advisable before making statistical inference.

I don't see anything in the targets that could not be attributed to operator error as the AR-10 is a little more difficult to master. How about 5 groups of 5 shots of each load?

I think you are on the right track with those powders. My AR-10 really likes;
44.5 grains of Varget,
168 grain Nosler CC HPBT,
2.810 COAL and,
either BR2, GM210M or WLR primers.

 

[BCP]

Re: Best groups for my AR10- load worth trying

Well, 44 varget win brass 175SMK 2.81 and 43 LC brass 2.81 were good in mine. 178amax shoots better than the SMK for me though. More consistent.

 

[armorpl8chikn]

Re: Best groups for my AR10- load worth trying

Well claydirt I would say it is a great theory but fairly wide of the mark. I have owned several AR15's in both 223 and 300Whisper and they grouped the same from the mag or single loaded. The groups I see pictured in this thread look like normal "not quite there yet" groups from any rifle including a bolt gun. I have NEVER had a bullet driven back into the case from any of my rifles bolt or gas and I do not crimp, but I usually run a compressed load. Maybe I have great feedramps who knows. A scratched bullet will fly plenty true. A bullet with a buggered soft tip will fly plenty true as well. It may not be great for long range accuracy but all the things you mentioned would not amount to much at 100yds.

 

[Manzgear]

Re: Best groups for my AR10- load worth trying

queequeg i did go up as far as 45grains with the varget and I didnt do so well. but now that I mention that I remember that I had a stock trigger when I fired those groups and now I have since replaced it with a timney 4lb drop in. which has been a lot better. maybe I will go back and shoot them again. I pulled the loads I made off of 6mmbr.com and whatever the powder was I went about 2-3grains lower just cause I have a gas gun. Is it ok to run a gas gun at loads that I know are used in bolt guns? I was taught to start low and work my way up. Cause I dont want to exceed the pressure curve and have a load that causes the gun not to function or have sudden catastrophic disassembly....
but aside from that. this forum is addicting and also thanks to all who have responded.

 

[Queequeg]

Re: Best groups for my AR10- load worth trying

Always good to work your way up. Just suggesting a bigger batch of rounds, and shots, before you make a conclusion.

Personally, 45 grins of Varget under the various 175/178 grain match bullets in Win/Hornady/Black hills brass is outstanding in my bolt guns. Don't recall ever trying them in my AR-10.

 

[bunsen27]

Re: Best groups for my AR10- load worth trying

If you are trying to find an optimized load for <span style="font-weight: bold"><span style="text-decoration: underline">your</span></span> rifle I would suggest a bit more methodical approach than trying other random people's load recipes. Keeping all variables consistant (primer, case, bullet, powder lot) incrementally (0.3 or 0.5 grains) load 10-15 rounds at each powder increment and fire at minimum two 5 shot groups. That being said; Varget and 175gr SMK typically display a nice accuarcy node between 42.0-44.5gr. That should help narrow down your powder increment range for the components you have on hand.

 

[ClayDirt]

Re: Best groups for my AR10- load worth trying

I have gotten good results at times with:

155g Lapua Scenars
43.2 IMR 8208 XBR
Win brass trimmer to 2.005
CCI # 200 LRPs
2.840 COL

I have shot under .75 MOA but typically just at 1 MOA @ 100 yrds. With AR10T 20" 1-10 twist.

 

[Manzgear]

Re: Best groups for my AR10- load worth trying

thanks Bunsen. I was asking for loads to see if they are the same ones I have been trying. or the same ones I have seen on 6mmbr as loads that work for the 175gr bullet- people keep telling me to try the 168 but I want to use this for long range shooting and have my heart set on the 175... but what you are saying makes sense. thank you- and thanks to everyone else

 

[colt933]

Re: Best groups for my AR10- load worth trying

Come up to 42.5 to 43 Varget and put a slight crimp on the bullet and I think you will be happy.