the Modern symbol of the right of the individual to be armed
with an effective rifle capable of Defending Liberty. Discuss anything
related to the AR15 and other arms of this nature herein
Did you say that you never cleaned it before firing it? If so, anything could have been in the chamber from the manufacturer. The ammunition you chose could also be dirty, although I doubt if it would do that by itself.
I'm no AR guy, but I do remember the mess back in the Vietnam era.
The chamber could be a little too tight, too....
I had a Springfield XD9SC, which is a small pistol, that occasionally, with range ammo, would about half extract a spent case, and then just sit there. If I backed the slide up a bit, and then let it go into battery in an attempt to get the extractor to do the work, the slide would seize up.... Took a hammer and cleaning rod to clear it.... Locking the slide back and using a fingertip to flip the round out worked all the time.... I don't think you have same problem, but a tight chamber and a bit of crud from the ammunition can cause all kinds of issues.... WWB or virgin factory loads never had a problem....
Enjoy the new Sig!
(Why write a quick note when you can write a novel?)
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That said, it could be any number of things.
1. Overgassing - This is typical of Carbine length gas systems. It may help to put a heavier buffer in to slow down the bolt.
2. Make absolutely sure the chamber is clean. Get an ar-15 chamber cleaning brush if you don't already have one and give it a good scrub. Also, inspect the chamber and make sure it's smooth. I would go so far as to remove the upper receiver from the lower and take the bolt carrier group out. Drop a dummy round in the chamber and see if it hangs up. It should be able to move freely in the chamber. You may have to push it out with a cleaning rod, but it shouldn't be difficult.
3. Check the extractor and extractor spring. If the extractor isn't able to move, that could explain everything.
I agree with ConcealCinci in terms of what might be the problem. If it's visibly ripping the brass, that's ridiculously over-gassed...something that Sig is definitely liable for and needs to fix.
Have you cleaned the gun since you bought it? Grease should be used during barrel assembly and some can seep in the chamber area. That shouldn't be the lone issue but it can contribute to it.
End of the day, it sounds like an issue Sig needs to fix. If we can isolate the problem and articulate that concisely to Sig, they're more likely to fix it without griping or telling you some stupid crap about 'your gun has a break in period'. This is case in point why I buy their shit anymore.
The moisture ammo I knew was trash but I was messing around to see what kind of problems it might cause and I ended up with some stuck cases torn rims. Just a couple additions to your troubleshooting list.
I see a lot of ar's and I shoot them a lot, don't start doubting your choice of the M400. I. Agree it is a great rifle for the price and ease of acquisition. My opinion, of course, is worth what you paid for it!
Self-Defense/CHL Law, BP, HFS, PPIH Instructor
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