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 Post Posted: Mon Sep 14, 2015 1:34 pm 
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Joined: Tue Apr 18, 2006 6:38 am
Posts: 11644
Location: Coming At Ya!
James Hampton, of M1 Machining in Roseville, California.

I purchased one of their 80% AR10 lowers back in June along with the "Jig" to do the machining. BOTH PIECES WERE/ARE JUNK!! The jig also doesn't fit anything but an M1 lower so don't think you can use it on anyone else's 80% lower.


Second major problem, the aluminum drill jig side plates have NO DRILL BUSHINGS TO GUIDE THE DRILL BITS??

Third major problem is this jig cannot be used to do the machining where the trigger group fits because when it's mounted on the lower there's no way to clamp it up in a vice due to the fact that the two side plates ARE NOT PARALLEL!!! And not only that, but the top plates ARE NOT LOCATED WITH DOWELS and have as much as .030 inch of slop in the bolt holes in all directions!???

In the end I did figure out how to use the jig to drill the fire control group holes but I didn't use it at all to locate and machine out the opening for the trigger group! I did that on my Bridgeport milling machine from dimensions I got from a DPMS drawing!

Next point is the magazine well, which was CNC machined by M1 Machining using an END MILL instead of being EDM cut or broached like it should be. According to the DPMS drawing I have the the mag well is .055 too long at the top and .033 too long at the bottom. It's also .054 too wide at the top and .032 too wide at the bottom?? The mag well is not only way out of the DPMS tolerance but is tapered top to bottom also?? That and the radius for the corners on the drawing is suppose to be .062 and the M1 is .125???? What you wind up with is a sloppy fitting magazine that causes feed problems with the rifle and it jams up!!

Long story short, if you're looking to buy an 80% lower receiver to build your own LR.308 AR10 clone DO NOT BUY FROM M1 MACHINING IN ROSEVILLE, CALIF!!!

In the end I finally just ordered and installed an Aero Precision lower and now my rifle works like it's suppose to!

This is also posted here!

Big Boyz Toyz!


Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)

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