AR15: Major Keyholing Issues

[turnerdye1]

A friend and I went out to Atterbury today and had some fun. Overall it was a good time. Shot about an hour and half on the pistol side and about half an hour on the rifle side. Things were great until we checked our targets. Ill post a pic of our targets to show you.

The ammo being used were Brown Bear 55g FMJ.
I have used this ammo before. About 1000rds of it and havent noticed any keyholing before. Today obviously has been differant.

The first mag at 50 yards i completly missed the paper. Thats my fault: I aimed at the wrong white paper.

The second mag my friend shot and had 1 keyhole but the others were fine. He used a GI Mag

The third mag my friend shot and almost all of them keyholed. He used a PMAG

The fourth mag I shot and all of them but one keyholed. I was using a PMAG.


I havent had any issues with this ammo in this gun before until today. The wind was 10-15 with gusts to 20 but I wouldnt think that would affect them that much.
The gun being used was a Delton 16" carbine with a 1:7 twist.

So what is the problem? I have no idea what the issue could be.

 

[esrice]

Its not a mag issue, its a barrel issue. Its screwed.

 

[Indy_Guy_77]

Are you absolutely 100% sure that it was 55gr ammo?

-J-

 

[elpenguin0717]

check your bore....... if its good could be the ammo you were using was too light cause 1/7 twist handles a good variety or ammo weight but if less then 55grns no good

 

[Mr. Habib]

By any chance have you shot a lot of M855 or SS109 mil surp ammo through this gun?

 

[jblomenberg16]

Suggest trying some heavier / longer bullets. It may be that you found the point at which the 1/7 couldn't stabilize. Most will shoot 55gr ok, so either the ammo was light, or the barrel is in bad shape.

 

[MarlinMan68]

Next time out try a minimum of 62 grn. ammo.I know some people here have 1in7 16" barrels that shoot 55 grn. fine but every gun is different.I'm not saying there are no exceptions but most .223 and 5.56 reloading data usually starts at 69 grn. and goes up for a 1in7 twist.I think you would do better with a heavier and longer bullet as far as longer range accuracy.If you do a search on 1in7 twist barrels you will find all recommendations lean towards a heavier bullet.

 

[abnk]

It's odd that it should happen out of the blue. Is the ammo you are using from a different batch than the first 1,000 rounds?

 

[turnerdye1]

Are you absolutely 100% sure that it was 55gr ammo?

-J-

Im 100% positive. I still have the boxes that it came in.

Its not a mag issue, its a barrel issue. Its screwed.

I sure hope not. Ive only put about 1200 rounds through it.

By any chance have you shot a lot of M855 or SS109 mil surp ammo through this gun?

I have not. Steel cases is the only stuff if shot out of this. All of it being 55g Brown Bear or Wolf.

Suggest trying some heavier / longer bullets. It may be that you found the point at which the 1/7 couldn't stabilize. Most will shoot 55gr ok, so either the ammo was light, or the barrel is in bad shape.

I was gonna try this...but i have about 1500 rounds of this stuff.

It's odd that it should happen out of the blue. Is the ammo you are using from a different batch than the first 1,000 rounds?

Nope all this ammo is from the same lot. All from the same case that i ordered online from. Same number and everything.

 

[esrice]

I sure hope not. Ive only put about 1200 rounds through it.

Purchased new?

So far this really doesn't add up.

 

[turnerdye1]

Purchased new?

So far this really doesn't add up.

Yes i bought the thing brand new from Atlantic Firearms in November '10.

Im a bit worried to be honest.

 

[BGDave]

Check your muzzle device or flash hider for hits or brass shavings. Sorry about this, but have you cleaned the bore in 1500 rounds? Had to ask. Sorry.

 

[esrice]

How does the bore look? Rifling look good?

 

[Fargo]

Suggest trying some heavier / longer bullets. It may be that you found the point at which the 1/7 couldn't stabilize. Most will shoot 55gr ok, so either the ammo was light, or the barrel is in bad shape.

In my experience, it is going with a too heavy/long bullet where you get keyholing.

Going too light causes the bullet to disintegrate shortly after leaving the muzzle or just really poor accuracy after a certain point.

I see one of three possibilities here:

1. You have run into a bad batch of russian bullets which are spec'd a few thousandths below .223.

2. You had something between you and the target that was disrupting the bullet's path.

3. Your barrel has given up on you. Specifically, what does the crown of your barrel look like? Is it so dirty you can barely see the lands? How much copper buildup is there>

Best,

Joe

 

[turnerdye1]

Check your muzzle device or flash hider for hits or brass shavings. Sorry about this, but have you cleaned the bore in 1500 rounds? Had to ask. Sorry.

I checked the barrel and flash hider at the range and there were no fouling or shavings anywhere. The barrel looked pretty clean as well. And yes i have, i clean the gun after every range trip.

How does the bore look? Rifling look good?

The rifling looks great. Just as it did when i bought it. I brought it home and i checked the rifling before i cleaned it and the grooves look just fine. Barrel is still shiny also.

In my experience, it is going with a too heavy/long bullet where you get keyholing.

Going too light causes the bullet to disintegrate shortly after leaving the muzzle or just really poor accuracy after a certain point.

I see one of three possibilities here:

1. You have run into a bad batch of russian bullets which are spec'd a few thousandths below .223.

2. You had something between you and the target that was disrupting the bullet's path.

3. Your barrel has given up on you. Specifically, what does the crown of your barrel look like?

Best,

Joe

1. Idk why it would be a bad batch. Ive shot 800 rounds of this stuff and have had 3" groups at 200 yards with it. So idk why these mags would be doing this at 50 yards.

2. There wasnt anything between us and the target other then air lol. We were the only ones at the range as well.

3. I really hope not. Idk why it would give up on me because i shot this same gun with this same ammo back in January and it shot fine on paper at 100 yards. So idk what happened between January and now.

 

[esrice]

The target marked "2nd" looks fine, with the exception of one keyhole. The targets marked "3rd" and "4th" are full of keyholes. Did anything happen to the gun itself after target 2? Did it fall off the table? Did you take it apart for any reason? Swap muzzle devices?

 

[BGDave]

Only other thing I can think of is when you clean the rifle tonight see if the patch hits a real easy place in the bore. Maybe a swelled spot in the barrel?

 

[jblomenberg16]

In my experience, it is going with a too heavy/long bullet where you get keyholing.

Going too light causes the bullet to disintegrate shortly after leaving the muzzle or just really poor accuracy after a certain point.

Good point...I had it backwards. Too long out of a too slow barrel and it wouldn't stabilize. Too short from too fast means disintigration.

 

[turnerdye1]

The target marked "2nd" looks fine, with the exception of one keyhole. The targets marked "3rd" and "4th" are full of keyholes. Did anything happen to the gun itself after target 2? Did it fall off the table? Did you take it apart for any reason? Swap muzzle devices?

No nothing happened to the gun between magazines. My friend shot the 2ng mag and layed the gun on the bench because of of the range sieze fire and it didnt move. Then he fired the 3rd mag and layed it down. I walked up and fired the 4th mag and layed it down. At the sieze fire we walked down and saw the keyholes. The rifle was never taken off the bench and nothing was done to it in that time.

Only other thing I can think of is when you clean the rifle tonight see if the patch hits a real easy place in the bore. Maybe a swelled spot in the barrel?

Well i use a bore snake...so i didnt feel anything. I did just run a patch and a cleaning rod through to check it and it ran fine and came out clean. I didnt feel anything abnormal

 

[Panama]

How do you clean your barrel?
Cleaning Rod or Bore Snake?

How to Break-in a Barrel

OR NOT................
http://www.6mmbr.com/gailmcmbreakin.html