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4/7/2008 10:40:40 AM EDT
Switched lower recievers and buttstocks (inc buffer spring and tube) and now having all sorts of problems with my M-4rgery... light primer strike misfires, and failure to fully extract , leaving the spent casing jammed in the top of the reciever and the newly unfired cartridge halfway into the chamber... Using Guat surplus.. tried 2 diff mags, same problem.

I dont see how it could be the carrier because it worked fine with the other lower...

I'm leaning toward the buffer/spring, but neither explains the light primer strikes

Ideas?

Jeff
4/7/2008 10:59:44 AM EDT
[#1]
is this the same ammo you were usin before with the other lower?
4/7/2008 11:02:59 AM EDT
[#2]

Quoted:
is this the same ammo you were usin before with the other lower?


I have shot this ammo before with no problems in several guns... it does not do this just occasionally either... practically every round...
4/7/2008 11:07:56 AM EDT
[#3]

Quoted:
Switched lower recievers and buttstocks (inc buffer spring and tube) and now having all sorts of problems with my M-4rgery... light primer strike misfires, and failure to fully extract , leaving the spent casing jammed in the top of the reciever and the newly unfired cartridge halfway into the chamber... Using Guat surplus.. tried 2 diff mags, same problem.

I dont see how it could be the carrier because it worked fine with the other lower...

I'm leaning toward the buffer/spring, but neither explains the light primer strikes

Ideas?

Jeff


All else being equal except for changing the lower reciever, buffer spring and tube is one a regular buffer and the other an H buffer?  Is it safe to assume you've not fired this particular lower before?   Was the bolt carrier different?  Lots of variables here.
4/7/2008 11:08:16 AM EDT
[#4]
if its a common upper then.....

light primer strikes to me would be weak hammer spring.  is this a factory lower?  a self assembled?   does the hammer bind?  i binding hammer could cause the weak hits and if bound enough could drag the BCG enough to slow extraction.  
4/7/2008 11:23:35 AM EDT
[#5]

Quoted:
if its a common upper then.....

light primer strikes to me would be weak hammer spring.  is this a factory lower?  a self assembled?   does the hammer bind?  i binding hammer could cause the weak hits and if bound enough could drag the BCG enough to slow extraction.  


Self assembled lower, I will check for the hammer binding, sounds like a possibility that might cause both symptons..
Thanks
Jeff
4/7/2008 12:08:01 PM EDT
[#6]
Had a problem with the hammer binding when I put a Bushmaster 2 stage trigger group into a S&W M&P15.  Replaced it with a RRA 2 stage trigger group and it works beautifully.  I put another RRA 2 stage into a RRA lower and it feels a little sticky.  Go figure.  I guess all these standard milspec dimensions are not so standard?
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