Colt AR Build Question

[glockstar]

So im looking to try my hand at my first AR build. I am in the process of picking up a complete preban lower (colt). This particular lower has the collapsable stock but also has that dreaded over sized front take down pin. The markings on the side of the lower say " AR-15 A2" and below that " Sporter II ) My question is if I buy this and get the front pin adapter can i legally and functionally attach a new post ban colt upper? Also I noticed Daniel Defense make an upper with the oversized .315 Dia. hole, does anyone have any experience with these as Ive heard that with the preban colts the front dia. isnt just larger but also offset. I just dont want to spend good money on a lower thats going to give me a bunch of headaches with little return. Any info is MUCH appreciated!

Thanks, G.S

 

[drgrant]

Yes. The donor gun was preban so whatever you build out of it can have the same "evil features". .

The offset adapter pin thing works, but ifyou are using the rifle for "social work" you might want to loctite the screws into it with some weak locktite at least, so that it doesn't ever unscrew itself.

-Mike

 

[glockstar]

Sounds like a good idea. One of the uppers i was looking at was " LE marked" and i was unsure even with a Preban lower if that was a Mass no no or not? I figured starting with a stripped DD upper and just using good parts from there id be ok but found out that can quickly add up to over $1,000 so maybe just buying a new colt upper would be the way to go?

 

[Another_David]

LE marking on an upper or lower doesn't really mean much. It just has to be Mass AWB compliant (e.g. pre-ban lower or modified to be ban compliant).

Why do you need a new upper--what's wrong with the one you're buying? Can't you just modify it rather than buy a whole new upper?

If I had a colt I'd get a standard sized upper and then buy an adapter pin. That way if you ever want to swap uppers or sell it's the standard size.

 

[glockstar]

Yeah that's kinda my plan. Im just trying to get a little info. Ill be buying the complete lower first then moving onto either a complete upper or building one from a stripped upper.

 

[96cbr900rr]

I have a large hole colt lower, and always seemed to have issues with using the standard small hole upper and conversion pin. I now have one of the DD big hole uppers that works flawlessly and fits well. Since I built the upper piece by piece the increased cost of the upper itself was negligible.

 

[Mike-Mike]

The offset adapter pin thing works, but ifyou are using the rifle for "social work" you might want to loctite the screws into it with some weak locktite at least, so that it doesn't ever unscrew itself.

-Mike

This.

 

[Cabinetman]

I've got a preban EA lower with a Colt SP1 upper (one of the original 16000 made I was told... who knows). Anyway the upper has a large hole and the lower a small one. The clearance of the front hole is crucial for the rifle to work correctly and not chew up the buffer retaining pin. Ask me how I know.

You can find the small barrel spacer that is drilled off center creating an eccentric. Therefore when you insert the spacer into the front hole of your upper you can adjust the eccentric side of it so that it aligns your upper and lower perfectly. (When you close the upper on the lower, the back of the bolt just kisses the buffer.) Once you figure out where that is, you can locktite the sleeve (or super glue it) into place. Mine has lasted over 10 years of regular shooting. Here's a link:

http://www.brownells.com/.aspx/pid=24949/Product/AR-15-M16-PIVOT-PIN-ADAPTER-BUSHING

Notice that one side of this barrl insert is thicker than the other? You can't simply reduce the size of the large hole upper equally. You MUST use this eccentric barrel to have things match up correctly between a large hole upper and a small hole lower. There are no other options.

Just trying to help!

Rome