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Posted: 1/21/2004 10:41:02 AM EDT
| I took my new AR out today and put 70 rounds through it. I had three shells that stuck halfway out of the upper. I noticed the brass on all three shells had a small area smashed down flat around the edge that the bolt grabs on to in order to pull the shell from the chamber. It is Winchester white box 55gr. from wally world. Bolt looks ok I think, anyone have any problems with winchester brass? |
| If the deformation is on the back side then it's most likely soft brass. By saying that the cases were stuck half way out of the upper, do you mean that the cases were sticking out of the ejection port, held in place by the bolt. If so, that would be termed smoke-stacking and is generally the result of a weak ejector. If the brass was soft, bits of it could have flaked off and found their way into the ejector recess thereby gumming up the works. Try lubing the ejector according to the military operators manual and see if that solves your problem. |
| If lubing the ejector doesn't work, it probably means you have brass flakes wedged into the ejector recess which will require you to knock out the roll pin that holds the ejector in place and clean out the recess. To reduce the chance of this becoming a concern again down the road, you can either find ammo that has harder brass or better yet, [b]slightly[/b] radius the edges of the ejector recess hole and ejector (if they are not already), so the edges don't act like a knife and shave off brass from the base of the cartridges. |
| What brand is the upper? If the rounds are stuck in the chamber (which is what I think you meant) your chamber is probably rough or tight. It takes a lot to deform case rims. It could also be that the rifle is trying to extract the round when the pressures are still holding the case walls to the chamber walls. If you have a deep extractor mark (goes to the base of the rim against the wall of the casing) that indicates that your extractor spring is plenty strong enough and that it took significant case deformation to make it slip off. If it's just the leading edge of the case rim that is being scarred and deformed, stronger extractor springs will help. However if the problem is indeed high friction between the casing and chamber you will wear out extractors quicker than normal. So don't consider a stronger extractor spring a correct fix. |
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Quoted: The rounds were sticking out of the upper. Not the chamber. It actually chambered a new round even. Just didnt throw the old round clear. Even though the problem is different from what you stated the problem can still be the same. If the extractor is not holding onto the casing well enough the ejector will not get a good punch on it. If you clean out the ejector area and make sure the spring is good and it still doesn't work you're probably dealing with a rough/tight chamber or an early high gas impulse or both. High case rim deformation indicates that it's not a problem with the ejector but that the extraction process is meeting excessive resistance. I've personally had what you mention happen on my rifle and extraction issues as well. All is resolved now and it runs like a champ. Do the easy thing first and check your ejector but you can't rule out a tight chamber or too much gas yet. You really should tell us the brand of the upper and where you received it from. Certain sources seem to have this issue and it would help us a lot in helping you. |
| Bizbad said the rim deformation was on the outside rear or base of the cartridge, not on the inside of the rim (at least that's my interpretation, could be wrong). As a result, I doubt it's a rough chamber or weak extractor, in fact the deformations might suggest the extractor tension was too high. I really doubt that is the case, more likely soft brass explains the deformations on the outside of the rim. If my interpretation is wrong, then wyv3rn comments would be applicable. |
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Quoted: Bizbad said the rim deformation was on the outside rear or base of the cartridge, not on the inside of the rim (at least that's my interpretation, could be wrong). As a result, I doubt it's a rough chamber or weak extractor, in fact the deformations might suggest the extractor tension was too high. Extractor tension being too high is HIGHLY unlikely. When have you ever seen extractor springs that strong? If extractor tension was too high, you'd see failures to chamber as the round could not be seated against the bolt face. I really doubt that is the case, more likely soft brass explains the deformations on the outside of the rim. If my interpretation is wrong, then wyv3rn comments would be applicable. I've had some very soft brass go through my rifle, and even the softest (PMC, Rem UMC, etc.) did not display the kind of rim deformation (pulling through the rim) to create any kind of problem. Also, he said he was using Winchester White Box 55gr, not known to have soft brass. Distinguishing between the case rim deformation happening deep into the rim, toward the case wall and at the edge of the case rim will help in fixing the problem. If it's at the edge of the case rim (showing the extractor lifting early), a heavier spring will help and may even "solve" the problem. However, if case rim deformation is still happening and it's deep into the rim (that shows your extractor has enough tension) against the case wall, you have a tight/rough chamber or short headspace. If I'm not mistaken, Model 1 does NOT use chrome lined chambers, which are smoother and less prone to extraction problems. Also, since it is not chrome lined, it could be re-reamed or carefully polished. |
| All three cases looked similar. I went out today but was unable to pick up a different brand of ammo. However, I didn't have any problems at all. The only thing I noticed when I was done was that there was a small thread of brass stuck in the extractor area. But the gun performed flawlessly. |
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