Bushmaster xm15 cycling issues

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Bladerunner82
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Bushmaster xm15 cycling issues

#1

Post by Bladerunner82 » January 2nd, 2019, 4:54 pm

Hello everyone, new to the site and figured I would post here since this has been an issue I have been trying to solve for a while now. I have a bushmaster xm15 that has been having double feed and FTE issues. I had a gun smith look at it, he said the BCG looks in great shape along with the springs and has tube. He did machine m4 feed ramps in the rifle which seemed to solve the problem but 100 rounds or so later the issue came back. Just looking for any insight to solving the issue unless swapping the upper is the best bet.

Thank you!



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Harrier
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Re: Bushmaster xm15 cycling issues

#2

Post by Harrier » January 2nd, 2019, 6:31 pm

Are both upper and lower OEM Bushmaster?
Any other mods besides ramps?
Have you tried multiple magazines.

I have a 1999 14.5: A1 bushmaster and don't recall ever having issues with it but I think i did beef up the extractor with a blue insert and O-ring (for more tension).
That's my opinion... and I'm stick'in to it...
but.. I might change my mind.

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Re: Bushmaster xm15 cycling issues

#3

Post by Bladerunner82 » January 2nd, 2019, 6:33 pm

Both upper and lower are OEM Bushmaster. I have Pmags and cheap steel mags, those are the 2 kinds I have tried. Also want to add that I don’t shoot steel casings, only brass. No other mods other than the feed ramp.

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Re: Bushmaster xm15 cycling issues

#4

Post by Harrier » January 2nd, 2019, 7:01 pm

So to be clear on the 'double feed' issue, the bolt is pushing 2 cartridges up at the same time, thus jamming when they start to enter the barrel extension ?
or is some other thing?

A couple issues with making new feed ramps... aluminum is soft and after a while wears with the bullet profile... re-anodizing the new cuts helps alleviate this from happening.
If shooting lead tips, lead can build up after a number of rounds and clog the ramp like it wasn't there..
That's my opinion... and I'm stick'in to it...
but.. I might change my mind.

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Re: Bushmaster xm15 cycling issues

#5

Post by Bladerunner82 » January 2nd, 2019, 9:15 pm

It’s exactly what you explained at the beginning. I get 1 round trying to eject and the other trying to load underneith.

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Re: Bushmaster xm15 cycling issues

#6

Post by sonofbp » January 3rd, 2019, 12:46 am

I think you're describing failure to eject rather than a double feed of two unfired rounds

Is the new round that is attempting to chamber running into the spent casing that hasn't been removed or a 2nd unfired round fed from the magazine popping up and causing a failure?

If it is failing to eject try a new extractor spring or one of those D shaped extractor spring bushings like this one.
https://www.brownells.com/rifle-parts/b ... d9949.aspx
Years ago, I picked up an ar upper of unknown manufacture or round count with an extractor that didnt like to hang onto the rounds long enough to eject them and one of those little D bushing things took care of it.

Or, snag a nickel boron bcg off psa for a cheap upgrade

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Re: Bushmaster xm15 cycling issues

#7

Post by Bladerunner82 » January 3rd, 2019, 7:22 am

Thanks all, yeah you are right I was stating a FTE in my last post there haha. I think I’ll try a BCG swap on it and possibly a barrel swap. Harrier has a good point about the modified feed ramps I had put on mine. I’ll let you all know what happens when I get to the range with it

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Re: Bushmaster xm15 cycling issues

#8

Post by Harrier » January 3rd, 2019, 4:21 pm

I wouldn't spend money on a new barrel just yet.... I only mentioned the things to watch for on 'new' feed ramps because there are a lot of people with dremels... If you notice, the M4 ramps on almost all OEM guns are shiny silver- so it's obvious they aren't anodized either BUT they are made with a standard placement, angle, width and depth - we don't know if that is the case with yours as we don't know who did them. Also if the upper/lower are original to each other, they are designed either to have ramps or not to have them so if you had ramps cut, the should have been made as one unit on both the upper and lower for a smooth transition. If there are any 'ledges' for a bullet to catch on , well.... back to the drawing board.

You also don't need to buy a new BCG either- if you really need to, you can swap the bolt. The extractor comes off pretty easy with just one pin (hold it in good with your thumb and don't loose the spring). Replace the spring with an extra power and a rubber insert or o-ring. Also look at the extractor "hook" where it grabs the rim- make sure there isn't any build up of grime or burrs... test fit it to a case and if needed hand file for a good solid fit. (you can always replace this part cheap if needed).

Since the bolt is going back far enough to pick up another round, look to see what is preventing the fired round from being ejected (your ejector [round protrusion on left side of bolt face) works and has spring tension... right?) - you may have to work the action wit DUMMY rounds to see where the hangup is.
That's my opinion... and I'm stick'in to it...
but.. I might change my mind.

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