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buffer tube madness!

558 Views 1 Reply 2 Participants Last post by  jrs
anybody had any really odd problems with buffer tubes?

i am asking cause of this little episode.

My otherwise excellent TNW lower had some problems when test firing the xm-177e2 replica. what would happen every so often the bolt carrier would stick open without the bolt hold open being engaged. and when cycling the unit by hand it would sometimes feel sticky with the bolt-carrier pulled to the full back position.

now this exact same lower unit worked perfect with the CDD upper unit, the new 7.62x39 unit , the old 7.62x39 unit and the middy, the LMT's and every other upper set up i have. it just wants to stick sometimes "hard" with the brand new 177 upper?!

so i tried the new 177e2 upper unit on my other lowers and the upper ran fine. never stuck open and felt slick as greased owl-shit when pulling the bolt back and letting it slam home.

i put the "retro/nam like" 4 position stock and tube on the double star lower which runs fine with the 177e2 upper. so i put the stock and buffer tube from the double star on the TNW and tried the 177 set up --and now it runs perfect on the TNW.

what i can't figure out is why this 177 seems to hate this one buffer tube--that all the other uppers seem to have no problem with.

the tube shows no scoring, it is not tapered, the buffers seem to go the full length of the tube without binding. there is absolutely no damage to the inside of the tube anywhere. and it runs fine on anything other than the brand new 177e2--

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I ran into a similar situation on my M4. Buffer tube was causing drag on the lower part of the bolt. Swapped lower assembly with another AR I have and both worked fine. I think it's just a combination of those particular parts that caused it. But the swap cured it so no bad.
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