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Posted: 2/17/2003 6:18:08 AM EDT
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I have just reloaded the first batch of cases that I shot from my Bushmaster AR-15. I have noticed that all of them have a pronounced dent on the shoulder of the case and a lot of them have a smaller dent at about the midpoint of the case. It appears that the shoulder dent might be caused by the case flipping sideways as it exits the chamber and impacts the inner side of the upper receiver. The other dent might be caused by the case deflector, I'm not sure. Is this type of case damage normal in an AR-15? I know that HK91's and their cousins mangle brass pretty good, but I haven't noticed any complaints about abused cases from AR users. Could it be that the ejector spring is a little over-active? Should I clip a few coils off the ejector spring to reduce the case damage or get a lower force spring? Thanks. |
| Had the same problem but even more severe. First get spare ejector spring(s). Then cut a coil or two from your present ejector spring (I used a Dremel with a cutting disc). Test and recut as necessary (or install replacement spring and start over). My brass is now unpunched and is at 2:00 in front of me and three feet out. |
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ks_shooter, Regarding ejection distance(force) and path, on a normally functioning rifle, the path will be at the 4:00 position and around 10/15 feet out. The path/distance is determined by the case being stripped out of the chamber, connected to the bolt face via chamber pressure/momentum force, until the buffer strikes the back of the receiver extension and stalls, due to the weight in the buffer, and allows the spent case to clear the bolt face/action before the bolt starts it's forward stroke. A ejection path that is forward is a sign that the case is still attached to the bolt face on the return stroke, and can be caused by a weak ejector spring (clipped) or a buffer that is not stalling out and lacks the time needed to allow the case to clear the bolt before the forward movement. In general, having the case still attached to the bolt on the forward stroke can lead to jams due to the possibility of the spent case mouth can jam into the front of the ejection port and reek havoc. Granted that high power shooter will tune the ejection spring, and/or use an adjustable gas tube to limit the amount of barrel pressure gas to the B/C to function the action to dribble the spent rounds out of the rifle. But, these tweaks should be left until you have a true understanding of the rifle, and it's operating functions. Dano |
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Dano, My cases do, in fact, collect at about 4 o'clock. I do a lot of shooting prone so they only travel about 5 feet before they land. I usually just open up my hardcase and 80% will land inside. They others are usually very close. The rifle is very new. I have only shot a few hundred rounds through it, so I don't think a weak spring is an issue. I think that I will buy a spare ejector spring and lighten it up a little. I will try putting some padding on the case deflector too. |
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