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Posted: 2/6/2006 9:34:47 PM EDT
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I have a Bushmaster carbine. 14.5 inch barrel. It was bought new. Now has about 2500 or 3000 rounds through it. Had previously been very reliable. Had a hiccup here and there with Wolf. Was at a indoor range yesterday and had 4 or 5 jams of this type. One was a stuck round in the chamber with a fresh round attempting to load behind it. It was easily cleared by taking the mag out.Letting the bolt close and slamming the buttstock on the floor. The other jams were like this. Bolt 1/2 way forward with empty on bolt face. Fresh round stripped of mag and pressed up against bottom of empty. Some cases were seriously gouged and on one the bullet was bent a little. The only thing I did different was as I was in a hurry loading I didn't smack the mags to seat all the bullets. Could it be this simple. It was a very clean rifle, the ammo was PMC 55 grain FMJ. There was some ultra max remanufactured in the mix but it failed the same with both kinds. Any suggestions or ideas. All other previous failures were of the FTE variety with a stuck case usually wolf.This is the first time I've ever had FTF. Mags are old but previously had been 100% |
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Check the key screws to make sure that they are tight (35 inch LBS). Wolf ammo round sticking in the chamber as the rifle/chamber begins to foul, not out of the norm. The ammo does burn on the dirty side, and with the poly case, add powderized poly fouling to the mix inside the chamber. As for what you are describing, either a leaking gas system or a fouled chamber will both cause the problem with short stroking. Since you did state the bolt had not expelled the spent brass, you can weed out mag problems (unless you were getting double live round feeds). At this point with the broad range of variable ammo being used, give the rifle a good cleaning, check the key to make sure it's correctly tightened, and if you are going to run wolf ammo, remember to keep the upper bearing surfaces well lubed with CLP (it really helps). |
| My friend who was a marine advised to look into the gas system. He said the gas tube needed cleaning. I said I doubted that was it but he said he'd cleaned more m-16's than I had seen which is probably true. He then offered to clean the rifle for me!!I'm going to let him. |
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I will say this, the pipe cleaners that are offered to clean the inside of the gas tube have caused more problems then good. Really they were semi-needed items back in the LSA lube/ dirty recycled gunpowder from surplus days. Given now that CLP is used to clean and lube the rifles, a quick shot of CLP down the gas tube is more than enough to clean even worst of gun powder fouled tube (really doesn’t happen since for the most part, the tubes are self cleaning). Like on other parts, the CLP will dissolve the gun powder fouling and it be blown out of the tube on the first shot fired after cleaning. Now to take cleaning the gas tube one step farther, when there is a barrel gas port entry bur, or you do use the barrel with the 22LR kits, the gas system can get clogged with copper or lead fouling. If something like this is the problem, then really the gas tube needs to be pulled, instead of just ramming a pipe cleaner into the end of gas tube, and just totally blocking the gas tube/ FSB gas channel at the 90*. As for his statement of "he said he'd cleaned more m-16's than I had seen", I wouldn't doubt it, since during boot camp, you spend a great time cleaning your issue more than a few times daily until you get it right. Real question just comes down to how many showers he is going to take with the rifle until he feels it's military acceptance clean. 
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Scrub the chamber with a chamber brush to ensure the chamber & lug area is free of heavy fouling. If you decide to torque the gas key screws, be sure to stake them. It's preferable to use new screws if they are loose. Do not (I repeat...do not) try stuffing things in the gas tube to clean it out. Gas tubes are cheap and easy to change. In the event that you suspect it is blocked (which is not that likely) just swap it out. Also run you next test with a known good USGI mag. Does it lock open with one round loaded in the mag? |
I'm pretty sure the gas tube is fine. I will check the key when he gives it back which should be Monday. I told him it wasn't a gas tube issue but didn't want to bust his balls about it. He's pretty great with guns actually but if he gets an idea in his head nobody gets it out but him. The good thing is he is loaded so anything he messes up he can afford to have fixed for me. 
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