Interesting Keyhole Target From AR-15

[Profreedomokie]

That is a pretty slow twist for that heavy of a bullet.

 

[JEVapa]

See if the rifling is 4 grooves or 6. If it's 4, it's prolly 1-14. If it's 6, it's prolly 1-12.

 

[rc508pir]

Had this problem when we switched from A1 to A2 in Panama. We got the rifles 3 months before the M855 came in.

 

[OKCHunter]

I found this graphic a few years back. You might try 55 gr or smaller in a 1:12 twist barrel.

 

[WoodsCraft]

Actually you can shoot round nose 60 grain bullets and they will stabilize in a 1:12 I have done it many times and they will be acceptably accurate , just not with optimal accuracy. Its not bullet weight causing the key hole issue its bullet length and the bearing surface of the projectile


Keep in mind that M855 is not a pure lead bullet, its bi metal lead shank and a steel nose hence its length.

 

[OK Corgi Rancher]

See if the rifling is 4 grooves or 6. If it's 4, it's prolly 1-14. If it's 6, it's prolly 1-12.

It's 6 grooves.

 

[RustyW]

I've shot 64gr sp in a NEF 1 in 12 and got acceptable accuracy for hunting, roughly 1-1/2-2" at 100 yds. I'm thinking that is a shot out barrel or copper fouled badly

 

[Bahick71]

1x12 or 14 in a bolt rifle is recommended to 52 or 53 grain max. As mentioned the
Bullet shape can cause problems as well. Load works into things as well, like bullet
Speed

 

[Shadowrider]

My BIL has an Anderson build he got from FBT over in Bixby. The barrel is marked 1-7 but the target looks exactly like yours. I thought for a minute you might have snagged a pic of his target but I'm fairly certain we didn't take any.

Anyway green tip is a nogo. I had on hand a baggie full of low powered (2900fps) M193 type reloads with 55gr Hornady FMJBT and they did the same thing. In my rifles with 1-9 twist they shoot one hole groups at 25. Same story as yours, the barrel looks pretty good actually. I can't visually see anything wrong with it, but it won't shoot for ****. He never shoots it anyway so I doubt he ever does anything with it.

 

[okierider]

IIRC the Polish Tantal 5.45x39 we’re infamous for keyholing. Had a chance to get one one time and did my homework luckily.

Hope it’s just an ammo issue, OP.

Hmmm my Tantal 5.45x39 shoots fine, cheap ammo or reloads. It does not matter.