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Navistar82

Not pleased but might be jumping the "gun"

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I built a 308 using a areo precision M5E1 complete 16" mid-length upper and stripped lower. I finished the lower with aero precision LPK, hypertouch 24c trigger. Bolt is aero precision melonite finish with a bcm gunfighter charging handle. Daniel defense stock has an armalite ar10 carbine buffer with an H3 buffer and a Leupold VX3II 4.5-14x40 scope

First time shooting it (and an ar rifle) was this morning. 40 rounds of cheap stuff, a few to get on paper and the rest to break the gun in...or so i thought.  30 rounds of handloads followed that didnt shoot any better than Academy Sports monarch 150gr cheap stuff. Handloads were 150gr nosler accubond with ramshot tac powder with charges from 43gr-45.5gr in half grain steps and cci br2 primers. So, all in all i have 70 rounds down the pipe in 5 shot groups and the best group was around 2.5" at 100 yards.  I shoot off a leadsled that is ratchet strapped to my shooting table so im pretty much just pulling the trigger. I like to take all the variables out when im testing new loads.

Do i need to shoot more to get better accuracy or is something up with the barrel or something else to look into?

I come from savage bolt guns. Am i expecting too much from an ar10 style platform.

Thanks 

Edited by Navistar82

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My Faxon mid-weight 18" barrel at 10:1 likes 165 to 175 grain projectiles - groups less than 1" at 100 yards just off a bag.  With 147 grain factory ammunition I can't get any better than 2."  A lot has to do with your barrel.  With Slash's heavy buffer and a Miculek (sp) brake it doesn't have any more recoil than my AR 15s, which frankly feel like an old .22.

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For curiosity sake and me liking to learn. What is it with the ar platform that makes it not like 150gr bullets? My savage hs precesion 308 with a 1:10 twist, 24" barrel was scary accurate.

Again, not questioning, just like learning new stuff. 

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 I shoot 155's & have no problem keeping under MOA on 16" & 20" BBL's . ,Truth ,these barrels shoot much better at long range with heavies , 500 & above ,but 150's should shoot fine a lower ranges . Just don't expert much from surplus ammo , out of any bbl..

 Also , some barrels require break in round count . A box or two won't do it . The Barrel may not like that Bullet or Powder , hard to say with out a good inspection & more testing with different bullet combos & Powders .

 Even with Shot guns , have to find the Combo the Chamber & Barrel likes & barrel ,as said, may need some break in time . Clean with coper solvent , but remember , you may need another 50-60 rounds to re-season the Barrel , for good grouping .

Edited by survivalshop

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1 hour ago, Navistar82 said:

For curiosity sake and me liking to learn. What is it with the ar platform that makes it not like 150gr bullets? My savage hs precesion 308 with a 1:10 twist, 24" barrel was scary accurate.

Again, not questioning, just like learning new stuff. 

 Cant compare a AR to a Bolt Gun , the Bolt gun will out shot an AR , just the way they are made . Comparing apples to oranges .

 Thats grouping wise , if you want rapid precision shots , the AR will blow the Bolt gun out of the water .

Edited by survivalshop

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2 hours ago, Navistar82 said:

For curiosity sake and me liking to learn. What is it with the ar platform that makes it not like 150gr bullets? My savage hs precesion 308 with a 1:10 twist, 24" barrel was scary accurate.

Again, not questioning, just like learning new stuff. 

I haven't the faintest idea to be honest, but it seems to be a well documented quirk of the platform. My large ARs have always performed well with 165gr and upwards, anything below that tended towards 1.5 MOA accuracy at best.

 

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On 6/26/2017 at 3:13 PM, Navistar82 said:

For curiosity sake and me liking to learn. What is it with the ar platform that makes it not like 150gr bullets? My savage hs precesion 308 with a 1:10 twist, 24" barrel was scary accurate.

Again, not questioning, just like learning new stuff. 

MOST Factory loaded 150gr ammo is moving too slow from a .308AR with a 1:10" twist barrel.  You gotta crank the speed up on the 150s to make them work in a 308AR with a 1:10" twist.  I reload Hornady 150gr FMJ-BT projectiles ALOT, in .308 Win and 300BLK - hell, it's all I load for Blackout. For the .308 Win, crank up the powder charge, with the right powder, and those specific 150s work like a charm through a 1:10" twist.  I've got some 150s loaded for bolt gun only (Rem 700 AAC-SD gun), that wouldn't be "safe" in every semi 308AR.

Edited by 98Z5V

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On 7/9/2017 at 7:19 PM, 98Z5V said:

MOST Factory loaded 150gr ammo is moving too slow from a .308AR with a 1:10" twist barrel.  You gotta crank the speed up on the 150s to make them work in a 308AR with a 1:10" twist.  I reload Hornady 150gr FMJ-BT projectiles ALOT, in .308 Win and 300BLK - hell, it's all I load for Blackout. For the .308 Win, crank up the powder charge, with the right powder, and those specific 150s work like a charm through a 1:10" twist.  I've got some 150s loaded for bolt gun only (Rem 700 AAC-SD gun), that wouldn't be "safe" in every semi 308AR.

Thanks for pointing this out.  I never thought about it.  I never knew nor heard of 150(s) being too slow for that rate of twist.  I'm sure there isn't a whole lot of folks that think about that neither.

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13 hours ago, GRA said:

Thanks for pointing this out.  I never thought about it.  I never knew nor heard of 150(s) being too slow for that rate of twist.  I'm sure there isn't a whole lot of folks that think about that neither.

It's literally gun-by-gun,with the 1:10"s.  For ARs, I've got an 18.5" barrel, 18" barrel, 16" barrel,and 13.5" barrel.  Haven't finished the 13.5", so I can't talk any shiit about that one yet. Then there's the 700 AAC-SD gun with 20" barrel.  Those are all 1:10" twist.  I don't even fuk with the Kimber bolt gun (Clackamas manufacture) with 24" barrel, due to the 1:12" twist rate. It gets it's own loads.  For "range loading" on the 1:10" guns, I had to find a powder and speed that would make the 150s work on all of them, in a general sense.  "Range load ammo" all the same, so it's "decent" no matter which one I take out.

Shiit  'bout drove me crazy, too...   :laffs:

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Some good comments. I'm an AR308 newbie but had a SST AR15 barrel that magically started shooting well after about 300-400 rounds. 

Ammo as mentioned is a huge variable.  

The attached pic shows a lower group with 147 WWB. The upper group was shot with factory federal 175 grain game king or something or another. Guy at the range spotted me 3 of them after witnessing my group. Pretty much one hole at 100 yards with a 1x4 scope and a clean mil spec weight trigger. 

 

IMG_1473.JPG

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Guessing it might have been the Federal Gold Medal Match with a 175 grain Sierra match King BTHP. If it was a game king load, you got the perfect whitetail gun.

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All of my AR-10's have acceptable accuracy with any load I've tried in them.  Groups never go over about 1.5" for any reason.  They do favor heavier bullets, and all three guns shoot the best groups with Barnes 175 grain bullets using Varget power, pretty sure around 41 grains but I'd have to check my notes to be sure.  Even with that said the all do quite well with Hornady 155's but the 175's are more consistent in all three guns showing the 1-10 twist prefers heavier bullets.

I certainly wouldn't give up on the gun/barrel just from a single shooting session.  It also helps to cool things down between groups to keep them as tight as possible.  I try to shoot 5 shot groups and leave the bolt open between shots to let things cool some.  After each group I'll switch to another gun or give the gun I'm shooting half hour or so of cool down time......Cliff

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