80% lower, large front take down hole diameter?

[technique]

I was looking to find out how to do like a Colt large hole lower. I was unable to google myself an answer. What is the front take down hole diameter?

Thanks

[ke6guj]

Per KNS, it looks to be .315"

http://www.knsprecisioninc.com/Gun%20Parts.htm

[technique]

Per KNS, it looks to be .315"
http://www.knsprecisioninc.com/Gun%20Parts.htm

Thanks. I had no idea KNS made those.... Back to the drill press.

[ke6guj]

One thing you may need to check on, isn't the hole offset on a large-hole lowers. I seem to recall it needing to be an offset pin or something. I'd hate for you to just enlarge the existing .250 hole and have it be in the wrong spot.

[technique]

One thing you may need to check on, isn't the hole offset on a large-hole lowers. I seem to recall it needing to be an offset pin or something. I'd hate for you to just enlarge the existing .250 hole and have it be in the wrong spot.

Offset how?

[technique]

Also there is no existing .250 hole.

[ke6guj]

Offset how?

Offset in that the center of the normal .250 hole is not the same center point of the .315 hole. I don't think you can just enlarge the .250 hole to .315 and be ok. If you ahve a large-hole uppper, use it to see how the hole is offset.

You may be better served buying a offset bushing to go in the large-hole upper to bring it down to .250 in the correct spot.

http://www.pkfirearms.com/store/get_items.aspx?type=0&term=12

OK, if you have no existing hole, you may be able to use the large=hole upper as a jig to properly locate the hole center.

[technique]

Cool, I'm gonna see if I can upper as a jig.

[ar15barrels]

Upper receiver rear lugs are often slotted.
You can't use them to get a precise location off the rear lug.

John will have the drawing.

[m24armorer]

I do.

Thank's Randall.

BTW, why would you want to mess with a large pin upper. The only reason I can think of is for a correct slabside civilan AR.

[technique]

I do.

Thank's Randall.

BTW, why would you want to mess with a large pin upper. The only reason I can think of is for a correct slabside civilan AR.

I'll show you tomorrow

[ar15barrels]

BTW, why would you want to mess with a large pin upper. The only reason I can think of is for a correct slabside civilan AR.

He probably got one of those $125 A1 uppers...

[ke6guj]

He probably got one of those $125 A1 uppers...

even if that was the case, would he be better served with one of those offset bushings to convert the upper to a small-pin upper? That way, he could use that upper on any lower. I've never used one, so I dunno if they work well, or are a pain to use.

[m24armorer]

A1's are worth a buck and a quarter, HOLY CRA* I'm rich......