AR stock issues

I bought a cheap lower a few years ago with the intention of building a stock super simple 20 inch A2 out of it. I never built it and it sat in my safe this whole time. A friend a work came to me wanting help building his 1st AR. I helped him find all the parts he needed on BCM and all he needed to complete the rifle was a lower. I told him I had a lower I would sell him for $100 so he bought it.

He came back to work a few days ago and said his reciever extension would not thread into the lower, just about 2.5 turns and it binds up. He had googled the manufacturer of the lower and found numerous complaints of out of spec lowers, mainly take down pin holes and reciever extension threads.

I didnt know about these problems with the manufacturer when I sold it to him but I went ahead and bought it back from him. Since the threads appear to be smaller than the buffer tube I figured I would either have to take it to a smith and have it tapped or buy a tap myslef and do it. I figure the gunsmith route would most likely be cheaper than buying a $70 tap that I will only use once.

I was talking to another friend at work about this and he said it could possibly be machined for a commercial buffer tube. I have always used milspec ones so I was not familiar with the exact differences with them, and I dont have any way to test it out. I was under the impression that the commercial buffer tube was only different after the threads, and that either one would work and any lower as long as you matched it with the correct buttstock.

Short of buying a commercial buffer tube is there any other way to tell if its threaded for commercial or milspec? I wouldnt hesitate to buy a comemercial tube but with the info my co-worked found on the manufacturer on the making so many out of spec lowers I afraid I would end up wasting even more money on a worthless lower.

Are the threads different on a lower if it was made to milspec's or commercial specs? or do I just have a lemon lower?

Any info or advice would be appreciated...

Also if it turns out it is a commercial spec lower does anyone make an A2 stock that will work with them?

Wow just realized this is a huge post...sorry :o

It would help if you staid what lower it is. Shy of that, I'd say your post is pretty useless to the rest of us. Sorry.

(I'm not trying to be condescending or rude, just matter of fact. Please don't take offense.)

I've never heard of a lower made for "commercial tubes". I've installed commercial and milspec tubes on the exact same lowers in the past.

Sounds like an out of spec lower.

http://www.ar15pro.net/2008/09/milspec-buffer-tubes-vs-commercial.html

It is a roggio arsenal lower...

I thought they were all had the same size threads as well..

i found a diagram that said the comemrcial buffer tube is slightly smaller diameter than the milspec on the threaded portion...that and talking to my co-worker is what gave me the hope that a different buffer tube might actually fit on this lower

at least it looks like the commercial is smaller at the threads, but larger further back where the stock rides...

It would help if you staid what lower it is. Shy of that, I'd say your post is pretty useless to the rest of us. Sorry.

by type do you mean what brand? the manufacturer of the lower is roggio arsenal..not sure on the buffer tube..but it was out of the box from bravo comapny

Commercial and military have the same thread size. The buffer tube diameter is different due to the different way they are manufactured. Sounds to me like your problem is the receiver.