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Re: Trouble with upper reciever

PostPosted: Sun Dec 17, 2017 12:52 pm
by commander faschisto
Cross Machine Tool makes a big-bore AR slick side upper: https://www.cmttac.com/AR-15-Receivers/ ... pper-upur3

Currently out of stock with them, but they're making more soon.

Meanwhile, Ranier Arms has them in stock now: https://www.rainierarms.com/cmt-tact-up ... ust-cover/

Also: https://www.nokick.com/CMT_UPUR_3_AR_15 ... upur-3.htm

And a side charger: https://www.rainierarms.com/cmt-tact-up ... e-charger/

Re: Trouble with upper reciever

PostPosted: Mon Jan 15, 2018 7:41 pm
by carpenterminator
I got lucky in my first 450 build- I was reusing a Seekins upper that used to be part of a 6.5 G. When I learned about this problem, I measured the height of the port, and found that it was exactly .55", centered on the ejection angle. I ordered some rounds, and it hand-cycles perfectly without nicks. I'm not ready to shoot it yet (still some parts on order), but it seems that I "Forrest Gump'd" my way into something that doesn't need mods!