DD MK18 begining to keyhole

[GarandThumb]

I've got a Factory SBR DD MK18 that has 6k rounds through it, 5k of those suppressed, none of it full auto. Typical strings of rapid fire were around 6-7 rounds with time to cool off. Just recently (last 300 rounds) I began to see key-holing every 50 or so rounds. Ammunition has been brass cased 62gr freedom munitions the entire time. Changes the rifle has had are a Vltor A5 system with standard weight buffer (since the first round) and geissele G2S trigger. Suppressor is a Surefire SOCOM556-RC with 3 prong mount, mounted by professional gunsmithing shop to ensure it is centered.

I'd be surprised if the barrel was that worn out at this point. But wanted to reach out. A buddy speculated that it may be that the rounds are getting pushed in during feeding and this is causing the key-holing? Any input gentlemen?

[Wake27]

Is the Freedom Munitions new or reman? I've had their stuff keyhole on my OAF Noveske that has less than 2k rounds through it. I think mine was reman, but even if it's new, that'd be my first guess. I'd also be surprised if the barrel is shot out. There are plenty of members here that will be able to give more advice, but many would probably recommend grabbing a few hundred rounds of some other factory ammo to try first.

ETA - good to see you on here, I just found your channel within the last month or so and am a fan.

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[GarandThumb]

Is the Freedom Munitions new or reman? I've had their stuff keyhole on my OAF Noveske that has less than 2k rounds through it. I think mine was reman, but even if it's new, that'd be my first guess. I'd also be surprised if the barrel is shot out. There are plenty of members here that will be able to give more advice, but many would probably recommend grabbing a few hundred rounds of some other factory ammo to try first.

ETA - good to see you on here, I just found your channel within the last month or so and am a fan.

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Thanks brother. I hadn't heard of Freedom munitions key-holing for others. It's just odd it only just started. It is their 62 grain new, non reman

[TomMcC]

Tried that ammo in another gun, or different ammo in the suspect gun?

[GarandThumb]

Tried that ammo in another gun, or different ammo in the suspect gun?

Ah, I have - though not to the extent that I've shot it through that particular upper. It seems to only occur on my SBR's

[P2000]

It might be worth removing all the copper from your bore with something like sweets 7.62. I had a rifle shooting softball size groups at 75 feet once(but not keyholes). Similar round count to yours. After cleaning it was shooting well again. Maybe if I kept shooting it would have eventually keyholed.

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[Wake27]

Thanks brother. I hadn't heard of Freedom munitions key-holing for others. It's just odd it only just started. It is their 62 grain new, non reman

I doubt it's too common but I'd be surprised if many people notice really. I probably wouldn't have but we were shooting one of Redback One's assessments and Jason actually pointed them out. I had just resigned them to misses.


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[signal4l]

Remove the muzzle device. Clean the carbon off the muzzle and comp

[Beat Trash]

Remove the muzzle device. Clean the carbon off the muzzle and comp

Good idea. In addition to this, throughly clean the barrel as well.

[markm]

This shouldn't be happening even if you've never cleaned the barrel. My immediate reaction is to try some DIFFERENT ammo! Perhaps any factory 77 gr to see if those longer bullets remain stable. Are the holes perfect otherwise with an occasional key hole?

I'd expect some egging (partial keyholing) mixed in there too. I can't see that low round count doing that much throat erosion, but I suppose anything is possible.