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Posted: 7/18/2011 7:59:17 PM EDT
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My gun is sort of overgassed. It normally throws shells about 10 feet in the 2 o'clock position.
I had just cleaned and lubed my gun and I went shooting with Federal XM193. After about 100 rounds or so, I had a short-stroke which prevented the next round from chambering. Thinking that I had just fired a low-pressure dud, I kept shooting but the short stroking continued. I took the gun apart and a guy and the range officer both suggested that my gun was way overlubed and that gunk was sticking to it. Yes, my gun was overlubed, but I have seen pictures or AR15's after firing 1k rounds of Wolf and they were much dirtier and still functioned. Still, I wiped off the excess lube and tried again. I started having very strange firing sequences afterwards. I would fire one round that was very undergassed. It ejected 8 feet in the 5 o'clock direction. The next shot ejected only about 5 feet in the same direction. The third round would eject only about one foot. The next pull of the trigger was a click and pulling the bolt back showed that the chamber was empty. I then unloaded the weapon and racked the bolt several times, then shot it again - same three shot sequence as previously mentioned where each round was progressively more under-gassed than the previous one, eventually leading to a failure to extract/chamber. After that, my gun was pretty much a bolt gun so I went home to look for a blown primer. I took the gun apart and didn't find anything wrong. I scrubbed it down very thoroughly and even took the gas tube out to look for a blown primer. I used my mouth to blow air through the gas tube and it was not obstructed by anything. I still haven't gone back to the range but I was wondering what could suddenly cause short-stroking if not a blown primer in the gas tube? Also, what could have caused that strange firing sequence where each subsequent round became more and more undergassed? Thanks |
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First off there is no such thing as too much lube...unless the barrel is full of oil or something like that. Now, lets start from the top.
What gas system, carbine, mid, rifle? What type of gas block? What buffer and spring? What trigger group? What type of bolt carrier (M16, semi, half moon, etc)? Did you assemble the gun? How many rounds through the gun before exhibiting malfunctions? |
| Since the rifle worked for 300 rounds before showing problems and you are using a non-pinned gas block, I would definitely check the gas block to make sure that it has not come loose and out of alignment. Same thing with the carrier key. Also check to make sure your gas rings are working properly, by placing the bolt carrier group with the bolt's face on a table; the gas rings should be able to hold the carrier in the extended position under its own weight, if the carrier drops forward to the closed position, then the rings need to be replaced. |
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