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Posted: 3/18/2007 10:45:18 PM EDT
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I've got a sabre defense upper on a Bushmaster lower, with carbine stock. Every AR I've seen, except this one, ejects the cases behind the gun. This rifle, for some reson, is ejecting the empties slightly to the front. It has run probalby 300 rounds without a single failure but I'm concerned about the abnormal ejection pattern. ETA: The bolt hold open funtions fine as well. |
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Case deflection off the upper defector can be forward or rearward. As long as the cases are making contact with the upper defector, and the bolt is being locked back after the last round, every may be fine. As for the maybe, the last check is to pull all the way back on the charging handle and confirm that the face of the bolt is not retracting back past the back of the ejection port. If you do find that the bolt face will retract back past the back of the ejection port, then the receiver extension will need to be threaded in a few more winds into the lower receiver. |
| On alot of AR's the deflector doesnt work. on the range we use an attachment to make sure it works so the other guys dont get shells in there collar from your gun. if yu ask me it sounds like your deflector is actually working. my ar doesnt work like most ive seen but my buddies works too. sounds like you got a good working gun to me. |
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This Tech Note from Armalite should answer your questions. It applies to the AR-15 as well as the AR-10: www.armalite.com/library/techNotes/tnote34.htm "These ejection patterns are common to all AR-15/M16™ pattern rifles. They are more noticeable on the AR-10® because the heavier cartridge case mars the finish of the receiver easier. "The ejection pattern of a rifle is created by a complex interplay of the opening velocity of the carrier group, and the extractor, ejector and their springs. In general, the faster the carrier group opens, or the stronger the extractor and ejector springs, the farther toward 12:00 (looking down on the rifle) the case is ejected. The weaker the springs are, or the slower the carrier group opens, the farther toward 6:00 the case is ejected. "ArmaLite® seeks an ejection pattern between 1:00 and 3:00, and inspects for this characteristic during inspection. Obviously, the carrier’s opening velocity is subject to differences in ammunition. Springs can take a set over time, and the ejection pattern eventually shifts toward 5:00. This is normal, and readily adjusted by extractor spring replacement and ejector spring timing." Your new rifle is functioning exactly as it should. Thank you, Mark Westrom and Armalite, for providing this valuable information! |
The bolt face does retract all the way past the ejection port. The rear of the ejection port is brass colored as is the very foward edge of the case deflector. I will try putting some more turns on my buffer tube. ETA: I was able to put one more turn on the buffer tube. At two more turns, the buffer tube interfered with the buffer retaining pin. The front of the bolt went from slightly behind the rear of the ejectro port to slightly in front of the ejector port. |
That is some good info. Thanks! |
Please remember on the 308's rifle systems, some have a working buffer, and some just a carrier extension (piece of solid plastic). Without a working buffer (dead blow effect) to stall the B/C at the rear of stroke, all the spent cases will be ejected forward!!! |
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