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Posted: 5/22/2005 3:42:52 PM EDT
I bought a lower a while ago as a part of a complete rifle. Recently, when I tried to put another one of my uppers, I discovered that the cavity in which the rear take-down pin block sits, is too small. So I am faced with a choice between dremeling the corners of the the rear take-down pin blocks on all of my uppers (see top picture) or milling out the rear take-down pin block cavity on my receiver (see bottom picture - I would actually have to mill out some of the curved area where the threads are). I would appreciate any suggestions as to what my best course of action is. Also, if you think I should mill the lower, who would be the best among our industry partners?

Upper:


Lower:
Link Posted: 5/22/2005 4:12:51 PM EDT
I would work on the UPPER, it is the cheaper of the two and doesnt require FFL to replace.
Link Posted: 5/22/2005 4:24:31 PM EDT
Always work on the upper. I had a similar issue about 2 months ago, I worked the upper lug a bit, and now its good to go.

Just remember to do a few file strokes at a time.
Link Posted: 5/22/2005 6:39:23 PM EDT
Working the upper makes sense. Uppers are relatively cheap and much easier to come by than lowers. Thanks for the input.
Link Posted: 5/22/2005 6:44:57 PM EDT
[Last Edit: 5/22/2005 6:47:42 PM EDT by IceMan_1]
If it's an RRA lower they are supposed to be tight fitting , but some people take a little off of the upper to make it to there liking !

A little CLP there helps .
Link Posted: 5/22/2005 6:51:55 PM EDT
I have had this problem with a few Stag lowers. I don't know exactly how tight the fit is on yours but I was able to persuade them together on mine. After a few assemblies and a few trips to the range they fit together perfectly.
Link Posted: 5/22/2005 8:03:23 PM EDT
Exactly!
Link Posted: 5/22/2005 8:03:45 PM EDT
If his is like mine was, it won't even pound closed.....
Link Posted: 5/23/2005 5:29:18 AM EDT
I'm not an AR expert by any means, but if the lower is the part which is causing the problem I'd fix it. Why take metal off your uppers & potentially cause problems with other receivers if you can fix one part & make them all work. If the uppers fit in other receivers I don't see any reason to do anything on them.
Link Posted: 5/23/2005 7:08:07 AM EDT

Originally Posted By jhereg:
I'm not an AR expert by any means, but if the lower is the part which is causing the problem I'd fix it. Why take metal off your uppers & potentially cause problems with other receivers if you can fix one part & make them all work. If the uppers fit in other receivers I don't see any reason to do anything on them.



Because it's easy to get a new upper, not a new lower. Also, by the shear design of the weapon, it makes a whole lot more sense to work on the upper instead of the lower. Just my thoughts.
Link Posted: 5/23/2005 8:21:04 AM EDT
Personally, I'd try a few other uppers to see where the problem lies. If it IS the upper, by all means, grind it down a tad. If it is the lower, you might consider having the manufacturer stand behind their product. I had this issue with an OLD Oly reciever and they made right by it. YMMV.

ka
Link Posted: 5/23/2005 7:12:01 PM EDT
I’m admittedly kind of fussy, but normally I’d find out which part is out of spec and correct it rather than auguring on an in-spec part (except maybe a minor part like a pin or such).

Still, in this instance it looks like even if the lower is the problem, simply modifying your uppers wouldn’t make them unusable with another lower. That, together with the fact that you can do the repair yourself, would push me towards trimming the lugs (with a file, not a Dremel – it’s just aluminum after all).

Nice Pics!
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