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Posted: 5/24/2010 7:06:39 PM EDT
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I'm trying to figure it out.
The upper is a Larue stealth, with roughly 1.5 to 2k rounds through it. The barrel and crown look fine. Though I'd take some advice on what more to look at. Ammunition is American Tactical 62gr (ss109). I have used close to 600 rounds of this with no keyholing. I can manage 1 MOA groups with the combo. Yesterday, I fired about 55-60 rounds, all at 25m. 5 ended up keyholing. 2 of them keyholed pretty sideways, so I can see the bullet appears intact. They keyholed rounds did not go where it was aimed, some were 8MOA off or so (as expected). Not all of the keyholes were in a row (first 30 didn't, last 10 didn't), I didn't get to notice them until I was done shooting and picked up the target. I didn't get to try another ammunition type. The rifle always functioned after each shot, always locking back on an empty magazine. A couple months ago, I was at an appleseed and was in the rain for 9 hours, the rifle and ammunition were soaked. This is that same ammunition, though I'm not sure if it matters. I can't really think of anything that could cause it, I think I'm running out of places to look. |
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At 2k,
Either the barrel is copper guilde to the point that the grooves of the rifling are built up the lands, The bullets are striking the FS/Muzzle device on the way out of the barrel, Or the bullet is self is undersized and not making contract with the grooves of the rifling. So check the muzzle device for bullet strikes, Clean the bore with Sweets or another aggressive copper solvent and keep at it until the patches are no longer coming out blue, and mic the bullets to confirm that they are .224 across and not undersized at .223 or smaller (read pull one and mic it). |
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Thanks for the suggestions.
Before this shooting outing, I had applied 2 soaks of wipe out and patched it out. There was blue, mostly blue and some black. After shooting these rounds there was some more blue (I let it soak for 24hrs). I ran some hoppes and some MPro 7 down the barrel with a brush after soaking with some more wipe out and patching it, not in that order. I would feel confident eating off the insides of the barrel, it's pretty clean and it doesn't seem too dirty. The only blue I can get off of it now is off the front of the barrel / back of the flash hider, on the inside away from the crown, where the wipe out has collected. I assume this will blow away after a few shots. I don't see any striking of the flash hider (A2). I'll pull a bullet when I can. I thought I had a bullet puller around here but it's gone. I did mic the bullet at the top of the case, it came out the same as my other types of ammunition. (.222 or so, depending on the crimp grooves) I'll be taking it out again this weekend. |
Here's the targets, shot top left to bottom right minus the zero check in the top right. The keyholes are on 6 (2 of them, sideways) and 8 (3 of them, the ones not on target).
(offhand, sitting in 35s with pos change on the next two, then the rest are sitting 5 each) |
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Quoted:
By chance, are you bouncing things off the dirt 458 If that was the case i think there would be shrapnel all over the place on the paper. IM thinking it may have been a couple bullets out of spec considering you shot so many, and only had 2-3 go in sideways, not bad! |
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Quoted:
Quoted:
By chance, are you bouncing things off the dirt 458 If that was the case i think there would be shrapnel all over the place on the paper. IM thinking it may have been a couple bullets out of spec considering you shot so many, and only had 2-3 go in sideways, not bad! Ah.. Okay..... They only time I've ever seen a sideways key hole was from a 1x12 marked as a 1x9". At 100 yards. Very frustrating, until you check the rate. To key hole at 75 feet, I'd think you might have a smooth bore 458 |
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Behind the target was nothing for another 55meters or so, a large dirt berm.
The target backing was plywood, but down the center of the target (about 1/3) was emptiness. If you look close, you can see the perfect (plywood) holes compared to the paper only holes that will show where there is nothing. I'm close to chalking it up to bad bullets, like you mentioned. Let me mic the paper... :) |
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Ok, I went to the range again yesterday. I had just reorganized everything in my utility room and range bags... and I FORGOT TO BRING A MAGAZINE!
So, I shot singles, which is probably a better test. My first 2 shots were wolf polymer (base - has never keyholed). Then I shot 3 of the same that keyholed. The third shot keyholed. I shot 20 more wolf, no keyholes, and with no magazine, that was enough! Next, I pulled 6 of the bullets. All of them measured .224, have very uniform bases and look great except......... 
There are 7 bullets there. The one with a red ring is a wolf 55gr, I pulled as a base. The other that is separated from the next 5 is pulled from what I think is a box that was not drenched by rain. I must stress that I "think" it wasn't. The other 5 all came from 2 boxes that have keyholed. So... the powder residue (or... black stuff) that is on them, is that normal? It doesn't wipe off. I don't normally pull bullets from factory loads. Is this the cause? |
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Quoted:
Ok, I went to the range again yesterday. I had just reorganized everything in my utility room and range bags... and I FORGOT TO BRING A MAGAZINE! So, I shot singles, which is probably a better test. My first 2 shots were wolf polymer (base - has never keyholed). Then I shot 3 of the same that keyholed. The third shot keyholed. I shot 20 more wolf, no keyholes, and with no magazine, that was enough! Next, I pulled 6 of the bullets. All of them measured .224, have very uniform bases and look great except......... http://farm5.static.flickr.com/4023/4657447427_b58203e428.jpg There are 7 bullets there. The one with a red ring is a wolf 55gr, I pulled as a base. The other that is separated from the next 5 is pulled from what I think is a box that was not drenched by rain. I must stress that I "think" it wasn't. The other 5 all came from 2 boxes that have keyholed. So... the powder residue (or... black stuff) that is on them, is that normal? It doesn't wipe off. I don't normally pull bullets from factory loads. Is this the cause? Do you mean the messy black rings? that's tar sealant for waterproofing, not powder residue. completely normal on most mil/NATO ammunition, and most likely NOT the cause of the problem. |
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Yes, tar,
But the better question is does the case mouths also have the same tar marking, or are these pull down bullets, stuffed into new cases. If pull downed and re-sized, it could explain the few tumblers that you are getting since they may have been .222 instead of .224. And before anyone gets there panties in a bind, Wolf some times will pull down loaded ammo if if is found to be out of spec when imported, and reuse the components. Lastly, nothing wrong with loading the ammo back up so it does not go to waste. |
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It's tar, I wasn't aware. There's a very uniform tar on all of the case mouths.
This will still be a mystery then. After that most recent 1 in 3 keyhole, the barrel was beyond spotless. This is american tactical 62gr (not wolf). So, I can't find anything wrong with this, should I pull 30 more and look for a .222? I think I'll try it in another AR, I don't have another 1/8, so 1/9 will have to do. |
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Quoted:
don't bother pulling any more down. remove the muzzle device and try shooting without it. Ditto, and if you are sure that you don't have a 1-12 barrel (you did check with a cleaning rod right?), then get the supplier on the phone if FS strikes are not the problem. |
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Try using these patches.
You will be AMAZED at what comes out of your barrel! I used some Kleen-Bore patches after a 20 minute workout with solvent, patches and bronze brush... and I got COPPER CHIPS on the patch! Regular patches & chemicals do NOT leave a clean bore! |
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Ok, I can try removing the muzzle device. I'm not sure how much that will eliminate here, because the first keyholes from the first range session were with an A2 Flash hider, and before the second range session here, we swapped it out for a YHM I was meaning to put on (very glad I didn't do it before this keyholing appeared, it would have looked like the problem!) I also checked out the crown with it off, it looks nice and uniform.
So, in short there, it keyholes with either flash hider, but I will try it without one. I can check the twist with a cleaning rod when I get home. It's a Larue barrel, and it's marked 1/8. It shoots 77 SMKs fine. (though I haven't shot any since this problem started, that might be something to check as well) As far as clipping something, it's at 25 yards, and the first session I wasn't using a bench (who shoots that crappy off a bench!). I was just using myself in a sitting or offhand position. For solvents, I had used wipe out before both of these range outings, and EXTENSIVELY before the last one, along with the other cleaning solutions I mentioned. I wish the barrel was dirty, even a little bit. Lastly, the target backer was plywood, or empty space, depending on where it was shot at. |
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Huh... I was butt raped for saying in my review that this ammo could achieve 1MOA! Anyway, measure a projectiles and tell use what you find. Then it's just me and you... hehe I did it before I realized it said it on the box. I just went shooting this stuff in my new 1:8 upper w/ a Lothar walther barrel, it doesnt like the ATI ammo. I'm honestly not sure what is up with this ammo, my armalite 16" loves this stuff, i had <1MOA groups with it, but with a 12x scope and a 18" precision barrel my results were horrible. I shot 2 5 shot groups, giving me a 3.5" group, and another 2.9" group. Either this stuff is rediculously inconsistent from box to box, im not sure, I also had 5 failures to feed when i only fired 15 rounds, i shot 100 rounds of heavy OTM fine with the same mag. Honestly I have lost faith in this ammunition. I have 300rds of it in my SHTF supply, and right now silver bear seems more reliable. If i were you, i would see if another rifle likes it, because im not sure if this ammo is worth your time. |
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Ok, the 6 bullets weigh in between 62.6 grains and 63.6 grains, depending on how much tar and the variance...
The barrel is definitely 1/8 twist. So, I'll try without a flash hider, and with a heavier bullet of different brand. This is really odd. Is going without a flashhider necessary since it has done it with 2 different ones? |
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Quoted:
Ok, the 6 bullets weigh in between 62.6 grains and 63.6 grains, depending on how much tar and the variance... The barrel is definitely 1/8 twist. So, I'll try without a flash hider, and with a heavier bullet of different brand. This is really odd. Is going without a flashhider necessary since it has done it with 2 different ones?[/quote] Well, on the off chance that the threads on the bbl. ,in some way are out of spec. |
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Quoted:
To keyhole at 25m, you're definitely hitting *something*, if not bouncing them off the dirt. Are the keyholes only on the very low targets? No. If you could see my shooting setup, this would be out of the question. For the target that is posted, I was shooting in a sitting position, not near a bench, with nothing in front of me. My ankles were crossed and elbows on the inside of my legs with the sling wrapped in a hasty hasty. Rifle barrel was floating out in front of me in front of the firing line. Berm is 55 yards behind the target. On the second outing, the keyhole was on the top right target (same target type). I was shooting from a bench without a magazine single loading. |
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Last update:
Went to the range for about an hour in a hurry before my weekend trip. I brought an additional AR that is a 1 in 9 SS barrel to test with. I tested both guns, in the 1 in 9 alternate AR, I shot only the ATI 62 stuff, about 60 rounds or so. On my other gun, the one that had been keyholing with the ATI 62 grain ammunition, I shot lots of different ammunition: 69 grain prvi S+B 62 grain SS109 (almost identical to the ATI, but has a green tip) 55 grain prvi Winchester 5.56 white box I did not remove the muzzle device, but being that it had happened with 2 of them, and the YHM flash hider is almost 2x as long as the older A2, I didn't think it was necessary if I was just testing if the bullet was striking it. There was no keyholing in either gun, at least 120 rounds total. The only thing I can think is what was previously mentioned, some of these were undersized, and I just happened to grab those couple boxes in my previous outing. Thanks for the help. |
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