New AR10 in 260, need reload info

pinzmann

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Just got my Krieger 260 barrel and mated it up with a new Armalite upper. I will be utilizing my existing lower. Looking for some good loads to try. Have 139 Lapuas and 140 A-maxes. I currently shoot 260 in a bolt gun but don't know if I have to load down the the AR10. Whats working for you guys?
 

Rovieairto

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Re: New AR10 in 260, need reload info

42.5 H4350, 139 scenar or 140 amax, CCI BR2, RP case.
2600 ft/sec in a 20"
Good to 1250 yards at that velocity.
 

ply1951guy

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Re: New AR10 in 260, need reload info

May or may not be useful to you, but I shoot 123 A-max over 45.4 gr of IMR4350, Win cases, CCI 200 primers. Gives me 2972 fps out of a 24 inch DPMS upper.

I am currently doing load testing with the 140 Amax. I can let you know what I get after I finish the testing.
 

bignada

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Re: New AR10 in 260, need reload info

You don't want to be using any slow burn powders. IMR4064 is about the slowest you should be using. Varget, Reloader 15 or IMR4895 are also good choices. Bolt rifle max loads will beat-up your gun. Sierra has a section on match loads for semis, might even call their 800 number and talk to a tech there.
 

bohem

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Re: New AR10 in 260, need reload info

My advice is close to BN's above. Tame the bolt loads down and treat this as a new set of loading data and workup. I just watch the brass and rifle behavior with slower powders like IMR4350 and RL22 for indicators that it's beating up the rifle.

For the 140 Amax I would suggest starting around 40.5gr of H4350 or I4350 or 41.0gr of RL22 and work up from there.
 

ssgp2

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Re: New AR10 in 260, need reload info

I have a GAP upper in 260 and can't shoot the 42.5grs of 4350 that a lot of shooters recommend on this site.
Blowing primers every time...

So far the N550 is my best load for the 139grs @ 39grs/2.810", Rem brass,CCIBR primers.

Vel = 2650fps
 

michael_aos

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Re: New AR10 in 260, need reload info

I've got a custom upper with a 22" 1:8" twist Lilja in 260 Remington on my Armalite AR-10.

I haven't done anything with it in a while, but back when I was shooting it, it liked VV N540 / N550 & 120gr SMK.
 

Casey Simpson

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Re: New AR10 in 260, need reload info

Hey guys, one possible reason for blown primers in our big chassis AR's is too large a firing pin and hole in the bolt face. They need to be bushed. Originally, as for DPMS, the pin is about .078" at the tip. It needs to be about .010" smaller and a hole to fit.
 

ssgp2

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Re: New AR10 in 260, need reload info

Thanks for the info, but I believe I have a shorter throat than what is common.

Since I get the same velocity with less powder, it's not a problem.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Casey Simpson</div><div class="ubbcode-body">Hey guys, one possible reason for blown primers in our big chassis AR's is too large a firing pin and hole in the bolt face. They need to be bushed. Originally, as for DPMS, the pin is about .078" at the tip. It needs to be about .010" smaller and a hole to fit. </div></div>