7.5" Pistol key holing at 25 yards??

[TerdFergison]

I built a 7.5" AR pistol and while zeroing it at 25 yards I noticed that some of the rounds were key holing the paper at 25 yards. Most of the rounds hit the paper as normal but a handful hit the paper sideways making a perfect shot hole the shape of the round. I have a Ferferans CRD muzzle break on the gun. Anyone seen this before??? Thanks.

[TerdFergison]

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[Kain]

what barrel do you have. what is the twist? what ammo were you shooting?

[TerdFergison]

7.5" Radical Firearms M4 profile 4150 CMV Steel Barrel, I believe it's 1/9 twist. Shooting 62 grain American Eagle green tip.

[TerdFergison]

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[daniel87]

Bad crown???

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[TerdFergison]

No, the crown is mint. I was thinking it could be due to the muzzle blast but that doesn't seem possible.

[lunchbox]

Try differ ammo and if it still is happening, barrel might be the problem.

[pubb]

Possible issue with the rifling or muzzle break?

1:9 seems pretty slow for a really short barrel to me.

FF

Try differ ammo and if it still is happening, barrel might be the problem.

[Iraqgunz]

Try another muzzle device to rule it out. I assume that you understand how twist rate works? If so, then you should understand that the round isn't really stabilized with a 1/9 twist and a 7.5 inch barrel.