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Posted: 1/14/2012 5:04:24 PM EDT
[Last Edit: 1/22/2012 12:40:54 PM EDT by h2oskier]
I took my just built Ar15 out to the range today. I shot about 150 rounds through it dialing in the aimpoint ML2 and then just having fun. The target was at 50 yards. I noticed that 5 of the bullets keyholed the target or went sidewaysd through the target. My upper is a Larue DMR 16" stealth with 1:8 twist. I unfortunatly used 4 different types of ammo so I am unable to pinpoint if it was a ammo issue. Any help would be appriciated.

Ammo used:
Remingtom UMC 55gr
Black Hills 55gr FMJ
Winchester 62 gr FMJ
ASYM 75 gr tactical match grade (tightest grouping)

http://i1052.photobucket.com/albums/s450/h2oskier1/bulletkeyhole.jpg
Link Posted: 1/14/2012 5:15:49 PM EDT
not sure could be bad ammo but that is weird
Link Posted: 1/14/2012 5:17:23 PM EDT
A 1:8 twist with 55 gr. bullets is a very marginal combination. It is a whole lot better than a 1:7 but still, a 1:8 is pretty fast for a 55 gr. bullet. A 55 should stabilize OK in a 1:8 but a 1:9 or 1:12 would be better, and with UMC being reportedly slightly under powered, my money lies with the UMC ammo being the culprit.
Link Posted: 1/14/2012 5:17:59 PM EDT
Crooked barrel
Link Posted: 1/14/2012 5:23:39 PM EDT
Originally Posted By Big-Bore:
A 1:8 twist with 55 gr. bullets is a very marginal combination. It is a whole lot better than a 1:7 but still, a 1:8 is pretty fast for a 55 gr. bullet. A 55 should stabilize OK in a 1:8 but a 1:9 or 1:12 would be better, and with UMC being reportedly slightly under powered, my money lies with the UMC ammo being the culprit.





That is what I suspected also. I need to go back and be more specific with ammo during each 20 minute shooting session.
Link Posted: 1/14/2012 5:24:34 PM EDT
Who was shooting next to you?
Link Posted: 1/14/2012 5:32:33 PM EDT
Originally Posted By 458winmag:
Who was shooting next to you?


Pistols shooting 25 yard targets on both sides directly next to me. It was a miss mash beyound that.
Link Posted: 1/14/2012 6:44:03 PM EDT
Link Posted: 1/14/2012 6:46:23 PM EDT
[Last Edit: 1/14/2012 6:48:56 PM EDT by iNeXile556]
55gr is just fine for 1:7, instability is from too slow a twist not too fast. I shoot 40-80gr from my 1:7 without a problem.

I'll wager, and this is no reflection on you, that the keyhole rounds are more likely from ricochet round off the ground.
Link Posted: 1/14/2012 7:16:18 PM EDT

Originally Posted By iNeXile556:
55gr is just fine for 1:7, instability is from too slow a twist not too fast. I shoot 40-80gr from my 1:7 without a problem.

I'll wager, and this is no reflection on you, that the keyhole rounds are more likely from ricochet round off the ground.

Ricochets would leave more deformed holes than that.
Link Posted: 1/14/2012 7:16:30 PM EDT
Originally Posted By Dano523:
Double check the FS being loose, with possibly a loose FS that was causing bullet strikes to the FS, with and end result of a few tumbled rounds.

Short of that, funky ammo with some of the bullets a tad cross width under sized, barrel fouled with too much copper to cause the problem, or 5 stray rounds from another shooter.


So on that note, double check the FS to make sure it tight, has no bullet strike, and even check the amount of copper that you are pulling from the barrel rifling when using something like sweets bore solvent to see if the build up is abnormal for only 150 rounds (us did clean the barrel fully before shooting, correct?).


I did not clean my new barrel before shooting.....Is that a problem?
Link Posted: 1/14/2012 7:17:04 PM EDT
Originally Posted By Dano523:
Double check the FS being loose, with possibly a loose FS that was causing bullet strikes to the FS, with and end result of a few tumbled rounds.

Short of that, funky ammo with some of the bullets a tad cross width under sized, barrel fouled with too much copper to cause the problem, or 5 stray rounds from another shooter.


So on that note, double check the FS to make sure it tight, has no bullet strike, and even check the amount of copper that you are pulling from the barrel rifling when using something like sweets bore solvent to see if the build up is abnormal for only 150 rounds (us did clean the barrel fully before shooting, correct?).


Did you meen FH?
Link Posted: 1/14/2012 7:20:27 PM EDT
Originally Posted By markfall:

Originally Posted By iNeXile556:
55gr is just fine for 1:7, instability is from too slow a twist not too fast. I shoot 40-80gr from my 1:7 without a problem.

I'll wager, and this is no reflection on you, that the keyhole rounds are more likely from ricochet round off the ground.

Ricochets would leave more deformed holes than that.


We have a winner
Link Posted: 1/14/2012 7:27:04 PM EDT
Link Posted: 1/14/2012 7:38:17 PM EDT
Amazing, when it's a Larue upper, the problem is everything but the rifle. Ricochets off the ground?? .....
Link Posted: 1/14/2012 7:42:59 PM EDT
[Last Edit: 1/14/2012 8:00:16 PM EDT by Big-Bore]
Originally Posted By iNeXile556:
55gr is just fine for 1:7, instability is from too slow a twist not too fast. I shoot 40-80gr from my 1:7 without a problem.



I would not say a 55 gr. bullet is "just fine for a 1:7" because all of my 1:7s do not shoot their best with anything less than 69 gr. Even the 1:8s do not like them all that much, preferring the midweights the best. My 1:7s shoot 55 gr. bullets within MOGrapefruit but they certainly do not shoot their best with the lighter bullets. But still you are correct, over stabilized bullets may not be as accurate as heavier bullets but it is under stabilized bullets that will tumble.

As far as ricochets off the ground. Could be. I have seen some pretty queer things happen from ricochets. Look in the last issue, the NV2011-04 match, issue of the Fifty Caliber Shooter's Associations VHP magazine. There is a picture of a bullet shot at a 1000 yard match that landed short, ricocheted off the ground and stuck in the target tip first like an arrow, not penetrating the target and the bullet was not deformed much at all. They cannot nickname the shooter Skip (already taken and retired) but they did suggest calling him "Stick."

Link Posted: 1/14/2012 7:43:29 PM EDT

Originally Posted By 35mm_Shooter:
Amazing, when it's a Larue upper, the problem is everything but the rifle. Ricochets off the ground?? .....

The ammo is a paradox. Underpowered enough to strike the ground in front of the target, yet tough enough to not deform before ripping through the target.



Link Posted: 1/14/2012 7:56:36 PM EDT
Damn.
These 55 gr's really get long when they key hole!
Link Posted: 1/14/2012 8:08:22 PM EDT
1:8 and 1:7 shoot 55gr just fine.

What type of muzzle device are you using ?

take a good look at it, and the crown
Link Posted: 1/14/2012 8:21:42 PM EDT
It's either the flash hider, or there was a problem with the barrel, or, one of the ammo types in question is undersized. Remove the flash hider, then, one by one, fire a box of each ammo at a separate target. If only one ammo brand shows the problem, bingo. If they all do, it's the barrel.
If none do. Reinstall the F/H, and repeat the test. If they all do it. It's the flash hider. If one does it, it's that ammo.

55gr will shoot fine in any 1/7 twist. It is overly long bullets that have stabilization problems with 1/9-1/12 twist barrels. It's the length and not the weight, but since the heavier bullets are normally longer, weight is associated with the symptom. There are heavier, shorter bullets that stabilize in the slower twist barrels just fine. What you have with a fast twist like 1/7 is over stabilization. Normally this tends to cause a round to self destruct if it's construction is like that of a varmint round.
Link Posted: 1/14/2012 9:40:00 PM EDT
Sounds to me you have a very dangerous barrel the needs to be disposed of. Send it to me for proper disposal....

Seriously, though, most likely the problem is bad ammo. From what I've heard, Larue barrels are top-notch and most likely NOT the problem.

Also, could be somebody else hitting your target at the range.

Next time you go to the range, test the differenct ammo on different targets. And try to pick a lane away from other shooters.

Link Posted: 1/15/2012 6:09:23 AM EDT
Link Posted: 1/15/2012 6:31:34 AM EDT
[Last Edit: 1/15/2012 6:33:25 AM EDT by iNeXile556]

Originally Posted By Big-Bore:
Originally Posted By iNeXile556:
55gr is just fine for 1:7, instability is from too slow a twist not too fast. I shoot 40-80gr from my 1:7 without a problem.



I would not say a 55 gr. bullet is "just fine for a 1:7" because all of my 1:7s do not shoot their best with anything less than 69 gr. Even the 1:8s do not like them all that much, preferring the midweights the best. My 1:7s shoot 55 gr. bullets within MOGrapefruit but they certainly do not shoot their best with the lighter bullets. But still you are correct, over stabilized bullets may not be as accurate as heavier bullets but it is under stabilized bullets that will tumble.

As far as ricochets off the ground. Could be. I have seen some pretty queer things happen from ricochets. Look in the last issue, the NV2011-04 match, issue of the Fifty Caliber Shooter's Associations VHP magazine. There is a picture of a bullet shot at a 1000 yard match that landed short, ricocheted off the ground and stuck in the target tip first like an arrow, not penetrating the target and the bullet was not deformed much at all. They cannot nickname the shooter Skip (already taken and retired) but they did suggest calling him "Stick."


Skip!


I agree about the light rounds not being optimum in the faster twist, but it will still stabilize and as you agreed, not keyhole.
I have had keyholes from ricochets on numerous occasions. I've even did the ricochet shots for fun, (my own range, no danger) try for 10 ring off the ground!. They can and do keyhole.

You can damn near aim ricochets off water.
Link Posted: 1/16/2012 7:09:54 AM EDT
Originally Posted By pavlovwolf:
It's either the flash hider, or there was a problem with the barrel, or, one of the ammo types in question is undersized. Remove the flash hider, then, one by one, fire a box of each ammo at a separate target. If only one ammo brand shows the problem, bingo. If they all do, it's the barrel.
If none do. Reinstall the F/H, and repeat the test. If they all do it. It's the flash hider. If one does it, it's that ammo.

55gr will shoot fine in any 1/7 twist. It is overly long bullets that have stabilization problems with 1/9-1/12 twist barrels. It's the length and not the weight, but since the heavier bullets are normally longer, weight is associated with the symptom. There are heavier, shorter bullets that stabilize in the slower twist barrels just fine. What you have with a fast twist like 1/7 is over stabilization. Normally this tends to cause a round to self destruct if it's construction is like that of a varmint round.



+1
I've never encountered a 1-7 that would not shoot 55gr OK. I do get key holing from longer (heavier) bullets in my 1-9 barrels.
Link Posted: 1/16/2012 8:00:35 AM EDT
Link Posted: 1/16/2012 8:08:08 AM EDT
My money is on the ammo; try it again with some more "quality" ammo, like Hornady for example; see what happens.
Link Posted: 1/16/2012 8:09:56 AM EDT
Originally Posted By Big-Bore:
A 1:8 twist with 55 gr. bullets is a very marginal combination. It is a whole lot better than a 1:7 but still, a 1:8 is pretty fast for a 55 gr. bullet. A 55 should stabilize OK in a 1:8 but a 1:9 or 1:12 would be better, and with UMC being reportedly slightly under powered, my money lies with the UMC ammo being the culprit.


I don't see how that can be the case with hundreds of thousands of rounds going downrange per year out of 1:7 twist M4's and M16's as well as civilian AR15's.

I'm not saying that the UMC ammo is the issue just that I doubt that the twist is the culprit in this case. I have shot thousands of reloads with 55gr bullets in my 1:7 and 1:8 twist barrels without any keyhole issues.

Link Posted: 1/16/2012 8:16:46 AM EDT
What kind of flash hider are you using?

I would check the clearance on the flash hider to verify you aren't getting bullet strikes.

Verify the flash hider is tight on the barrel as well.

As for the ammunition did any of it "sound" different? Any functioning problems (short stroking/feed jams)?

Do not fire the weapon again until you diagnose what is going on.
Link Posted: 1/16/2012 8:25:06 AM EDT
I bought an M1A ( M14 ) once and the bullets were striking the flash suppressor

Post picks of your flash hider, or muzzle brake, and if possible, your barrels crown.


Link Posted: 1/17/2012 7:21:38 AM EDT
Personally Id remove the flash hider and test again to see if the rounds are not hitting on their way out. other than that I have only seen this on worn barrels....
Link Posted: 1/22/2012 1:00:35 PM EDT
[Last Edit: 1/22/2012 1:01:48 PM EDT by h2oskier]
Here is an update from my session today. Target at 50 yards and ammo was isolated on each target. I shot 30 plus rounds of each of my ammo types listed in my original thread. Gun was cleaned of all shipping oil including barrel and then lightly oiled. Flash hider is what came from Larue and is tight. There was no one next to me and there were no known ricochets

Shocking Results:
Remingtom UMC 55gr ............................................................1 sideways out of 50 shot
Black Hills 55gr FMJ ...............................................................4 sideways out of 30 shot
Winchester 62 gr FMJ .............................................................5 sideways out of 40 shot
ASYM 75 gr tactical match grade................................ ..........2 sideways out of 20 shot

Keep in mind this is a brand new (shot twice now) Larue DMR upper with a 1:8 twist. The cheaper Remmington UMC actualy had fewer sideways shots which is opposite what most people thought including myself. The remmington shot sideways was out of the last 10 round clip out of 50. If I had stopped at 40 rounds with this bullet, it would have shown none. I am going to email Larue to see what they have to say. I had my buddy shoot some of the ASYM out of his BCM upper with a 1:7 twist and he had no issues with that ammo.
Link Posted: 1/22/2012 1:36:39 PM EDT
[Last Edit: 1/22/2012 1:40:31 PM EDT by tamu94]
Something is very wrong to keyhole that bad at 50yds. A 1:8 twist barrel should stabilize everything you were shooting with an issue.

Edited to add:

The only thing that I can think of that hasn't already been mentioned is your bore is way oversized and the rifling isn't engaging. Its that or you don't have any rifling. Did you look through the bore when you cleaned it?

Regardless, if there is something wrong with the gun Larue will make it right.
Link Posted: 1/22/2012 2:10:32 PM EDT
did you also bring a 5.45x39 upper to the range that day?
Link Posted: 1/22/2012 2:16:29 PM EDT
[Last Edit: 1/22/2012 2:22:18 PM EDT by Aimless]
I edited your post, do not repost. this is a techinical discussion about why these rounds are keyholing-Aimless
Link Posted: 1/22/2012 2:24:30 PM EDT
[Last Edit: 1/22/2012 2:25:22 PM EDT by bloodsport2885]
Originally Posted By h2oskier:
Here is an update from my session today. Target at 50 yards and ammo was isolated on each target. I shot 30 plus rounds of each of my ammo types listed in my original thread. Gun was cleaned of all shipping oil including barrel and then lightly oiled. Flash hider is what came from Larue and is tight. There was no one next to me and there were no known ricochets

Shocking Results:
Remingtom UMC 55gr ............................................................1 sideways out of 50 shot
Black Hills 55gr FMJ ...............................................................4 sideways out of 30 shot
Winchester 62 gr FMJ .............................................................5 sideways out of 40 shot
ASYM 75 gr tactical match grade................................ ..........2 sideways out of 20 shot

Keep in mind this is a brand new (shot twice now) Larue DMR upper with a 1:8 twist. The cheaper Remmington UMC actualy had fewer sideways shots which is opposite what most people thought including myself. The remmington shot sideways was out of the last 10 round clip out of 50. If I had stopped at 40 rounds with this bullet, it would have shown none. I am going to email Larue to see what they have to say. I had my buddy shoot some of the ASYM out of his BCM upper with a 1:7 twist and he had no issues with that ammo.


Bad barrel or flash suppressor strikes. I'm betting Larue wants their hands on that upper post-haste because they're probably wondering "wtf" like the OP is too.
Link Posted: 1/22/2012 3:23:43 PM EDT
Link Posted: 1/22/2012 7:44:23 PM EDT
If I have a problem with a rifle that I can't figure out.
I have someone else shoot it
Link Posted: 1/22/2012 7:49:56 PM EDT
Looks like 62gr ammo was the issue, but put a ruler up to the longest one and see how long it is.
Link Posted: 1/22/2012 7:50:35 PM EDT
Originally Posted By 35mm_Shooter:
Amazing, when it's a Larue upper, the problem is everything but the rifle. Ricochets off the ground?? .....


Key holing is a very common AMMO problem.
Link Posted: 1/22/2012 7:50:57 PM EDT
Link Posted: 1/22/2012 7:53:00 PM EDT
Originally Posted By h2oskier:
Here is an update from my session today. Target at 50 yards and ammo was isolated on each target. I shot 30 plus rounds of each of my ammo types listed in my original thread. Gun was cleaned of all shipping oil including barrel and then lightly oiled. Flash hider is what came from Larue and is tight. There was no one next to me and there were no known ricochets

Shocking Results:
Remingtom UMC 55gr ............................................................1 sideways out of 50 shot
Black Hills 55gr FMJ ...............................................................4 sideways out of 30 shot
Winchester 62 gr FMJ .............................................................5 sideways out of 40 shot
ASYM 75 gr tactical match grade................................ ..........2 sideways out of 20 shot

Keep in mind this is a brand new (shot twice now) Larue DMR upper with a 1:8 twist. The cheaper Remmington UMC actualy had fewer sideways shots which is opposite what most people thought including myself. The remmington shot sideways was out of the last 10 round clip out of 50. If I had stopped at 40 rounds with this bullet, it would have shown none. I am going to email Larue to see what they have to say. I had my buddy shoot some of the ASYM out of his BCM upper with a 1:7 twist and he had no issues with that ammo.


Didn't see this update. Definetly a rifle issue, LaRue will take care of you.
Link Posted: 1/22/2012 8:00:10 PM EDT
Wow!
Tag for outcome
Link Posted: 1/22/2012 8:01:16 PM EDT
Link Posted: 1/22/2012 9:35:17 PM EDT
Now that's customer service.
Link Posted: 1/23/2012 12:22:44 PM EDT
[Last Edit: 1/23/2012 12:28:54 PM EDT by silentblades]
All I shoot is 55 gr in my 1/7. Zero issues
Good on LT standing behind their product. Which is a no brainer considering its LT and they are great.
Link Posted: 1/23/2012 2:36:15 PM EDT
Sounds likea bad crown or bad flash supressor to me.
Link Posted: 1/23/2012 4:48:12 PM EDT
i have this same upper, and have shot around 200 rounds of ammo through it. most of which has been a mix between Hornady .223 55gr FMJ, Federal 5.56 M193 Ball 55gr, and a about 15 rounds of V-max. None of my rounds keyholed or anything... All targets showed nice roundlittle holes. Just chiming in to let you know what I have been shooting with no problems.

Link Posted: 1/23/2012 6:08:21 PM EDT
Just to update....Alfred at Larue is sending me shipping labels to send the upper back for a look. Thanks for all the positive feedback and thanks Larue for standing by your products!!
Link Posted: 1/24/2012 1:36:22 PM EDT
Originally Posted By h2oskier:
Just to update....Alfred at Larue is sending me shipping labels to send the upper back for a look. Thanks for all the positive feedback and thanks Larue for standing by your products!!


Wouldn't expect anything less.

You probably accidentally got one of their uppers with "machine gun barrel steel" and its made for better area suppression.
Link Posted: 1/24/2012 1:45:18 PM EDT
[Last Edit: 1/24/2012 1:46:27 PM EDT by LaRue_Tactical]
Link Posted: 1/24/2012 1:48:47 PM EDT
Originally Posted By LaRue_Tactical:
Originally Posted By WI57:
Originally Posted By h2oskier:
Just to update....Alfred at Larue is sending me shipping labels to send the upper back for a look. Thanks for all the positive feedback and thanks Larue for standing by your products!!


Wouldn't expect anything less.

You probably accidentally got one of their uppers with "machine gun barrel steel" and its made for better area suppression.


I'm getting it back for Close Quarters Hog Huntin'.


Please let us know the results when you guys figure out what the problem is. (I'm betting damaged/bad crown or flash supressor strikes).
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