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Posted: 5/22/2011 6:02:39 PM EDT
| I have been waiting over 2 months for my spikes tact ar 15. I went to the range to go try it out. I loaded a mag full of some xm193 and it worked great, then i loaded sone PMC and 3 or 4 rounds into the mag i had a jam. this happened to me at least 3 or 4 times yesterday at the range. i have read some reviews on pmc and couldnt really find any problems with it. Has anyone had this happen? |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. That's not an ammo problem. I agree a true double feed is not....but this particular case sounds like It possibly ammo/short stroking related - its a commonly misdiagnosed one. With weak ammo (and PMC is weak....not usually enough to cause issue though), sometimes the bolt comes back just far enough to marginally pick up the next round, or even manages to move it off the magazine stack by the bolt pushing the round off on its side. What then happens is the bolt either slips off the bit of the round it picked up, and/or starts to override the cartridge, which gives the cartridge an upwards angle and thus jamming it somewhere in/around the barrel extension. The bolt continues to try to close, which gives the round the dent in the side. On taking a look, people think "Doublefeed" - when that is not actually the case, its more of a misguided single feed. If the OP is not having trouble with ammo known not to be weak (i.e. the mentioned xm193), this is what I suspect is happening here. Things I would check (in order) would be - ensure the rifle is clean and well lubed, then I would check to see what buffer/spring is in there and go lighter down to a carbine buffer if possible to see if that cures it....if still having problems with weak ammo only, I would then start to suspect some sort of gas leak at the bolt carrier key/somewhere else in the system, or possibly a misaligned gas block, or finally an undersized gas port. |
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Thank you for the help i will go to the range today and see if it does it again. Could it be cuz its a brand new gun and had only a hundred rounds or so through it? That is a possibility for a few reasons. Sometimes the gas tubes leak a bit where they go into the gas block - normal and nothing to worry about and shooting eventually seals up any leak but might be enough to cause initial short stroking issues with known weak ammo. Secondly, I do personally believe running a good few rounds combined with a very good cleaning and lubing before firing anything (you have done this right?) goes a long way to helping the new parts bed in together. Some people don't think it makes any difference, but IMHO guns are mechanical items and all mechanical items run optimally after they've had a little chance to bed in. So basically I would clean the snot out of it and lube it well before you take it back to the range to try again. Run a couple of hundred more of that xm193 through it and see how it goes; if that continues to cycle fine it would indicate that there is no fundamental or other problem with the rifle. Then switch again to PMC and try again. What kind of AR is it? What length gas system? |
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It is a spikes tactical carbine length. here are some specs from their website.
•Spike's Tactical 16", 1:7 Twist, Mil-spec Barrel •M4 Barrel Profile, Carbine Length Gas System •F-marked A2 Front Sight Base, .750" Diameter Gas Seat •Spike's Tactical Mil-spec M16 Bolt Carrier Group •M4 Double Heat Shield Handguards •A2 Flash Hider •Mil-spec Lower Parts •ST-T2 Tungsten Buffer •ST M4 Stock I had zero problems with xm193 and i even ran 2 mags of tula ammo and had no problems. I ran the tula after i ran the xm193 and the PMC. |
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It is a spikes tactical carbine length. here are some specs from their website. •Spike's Tactical 16", 1:7 Twist, Mil-spec Barrel •M4 Barrel Profile, Carbine Length Gas System •F-marked A2 Front Sight Base, .750" Diameter Gas Seat •Spike's Tactical Mil-spec M16 Bolt Carrier Group •M4 Double Heat Shield Handguards •A2 Flash Hider •Mil-spec Lower Parts •ST-T2 Tungsten Buffer •ST M4 Stock I had zero problems with xm193 and i even ran 2 mags of tula ammo and had no problems. I ran the tula after i ran the xm193 and the PMC. Good to hear it, sounds like you had a case of new rifle gremlins then. Just for future reference, if you do ever find yourself having problems with crappy weak ammo like Tula at any point, and you really want to run it, first thing I'd do is change that buffer out for a carbine one. However, especially with it being a carbine length gas system, I doubt you will ever have any short stroking issues as is. |
| New guns tend to cut a large amount of brass off the cases as they get broken in, and AR's are no different. Look at your empty brass for long scratches and dings, and check inside the rifle for lots and lots of small brass flakes. this will screw up an AR pretty darn fast, especially if a bunch of it gets under the extractor claw and in the chamber. After all the sharp edges are smoothed out from firing a bunch of rounds the problem stops most of the time. I take a Cratex bit and lightly polish out any sharp edges in the carrier where it rides over the cartridges in the mag, and the bolt's barrel locking lugs, especially the backside of the lugs can be sharp, and will cut chunks out of the brass as it ejects. Hope this helps. |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. I have this problem with pretty much any ammo that isn't full power 5.56. PMC sometimes works but it's hit and miss. Dripping wet BCG helps some too. You need either: -Lighter buffer -Lighter BCG -Weaker recoil spring. |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. I have this problem with pretty much any ammo that isn't full power 5.56. PMC sometimes works but it's hit and miss. Dripping wet BCG helps some too. You need either: -Lighter buffer -Lighter BCG -Weaker recoil spring. I was going to ask.... Could it be the buffer? Ammo not hot enough to shove buffer to full cycle? |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. I have this problem with pretty much any ammo that isn't full power 5.56. PMC sometimes works but it's hit and miss. Dripping wet BCG helps some too. You need either: -Lighter buffer -Lighter BCG -Weaker recoil spring. I have a carbine buffer and a semi bcg, how much lighter can I get? I'm all for mil-spec but this daniel defense barrel must have a microscopic gas port. |
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I have a carbine buffer and a semi bcg, how much lighter can I get? I'm all for mil-spec but this daniel defense barrel must have a microscopic gas port. I did hear something about last year about DD releasing a bunch of barrels with undersize gas ports....that could well be the case. If you Google "Daniel Defense small gas port", quite a lot of hits come up. |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. I have this problem with pretty much any ammo that isn't full power 5.56. PMC sometimes works but it's hit and miss. Dripping wet BCG helps some too. You need either: -Lighter buffer -Lighter BCG -Weaker recoil spring. I have a carbine buffer and a semi bcg, how much lighter can I get? I'm all for mil-spec but this daniel defense barrel must have a microscopic gas port. How stiff is you recoil spring? My carbine is way overgassed going from a carbine buffer to a H3 didn't have any effect, but when I got a stiffer recoil spring it slowed everything down. |
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its 55 gr it seems like it wanted to double feel and would jam and put a dent in the cartridge. I have this problem with pretty much any ammo that isn't full power 5.56. PMC sometimes works but it's hit and miss. Dripping wet BCG helps some too. You need either: -Lighter buffer -Lighter BCG -Weaker recoil spring. I have a carbine buffer and a semi bcg, how much lighter can I get? I'm all for mil-spec but this daniel defense barrel must have a microscopic gas port. How stiff is you recoil spring? My carbine is way overgassed going from a carbine buffer to a H3 didn't have any effect, but when I got a stiffer recoil spring it slowed everything down. Just a normal carbine spring. Who makes weaker springs? |
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