AR lower receiver front pivot plug


November 2, 2012, 12:18 AM
Hi I was just wondering if anyone with a machine shop could fabricate me some Large hole AR-15 front pivot plugs or knows where I can get them? I would preferably like the same type of metal used on a lower for weight and durability. 7075 or whatnot. I am converting my Large hole lower to regular size for modern uppers. I need .315in in diameter. .270 in length. I am willing to pay but not a finger and a toe.. Thanks in advance!

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November 2, 2012, 06:49 AM
Why not use an adapter pin like this one? Hard to beat for $6.

November 2, 2012, 09:40 AM
Because I do not want to use an adapter pin or a sleeve.

November 2, 2012, 12:11 PM
You are going to have to use an adapter pin or offset bushing anyway, as the large pin Colt lower hole spacing is not the same as a small pin upper hole spacing.


November 2, 2012, 01:14 PM
No one makes a bushing for the lower receiver holes. They are all for the upper receiver hole or at least they are to my understanding. The diameter is the same, however the length is to long for the lower pivot holes. I am seeking solid plugs of the specified dimensions so I can drill them out and make my own offset bushings. If the upper receiver bushings are the right length, that would make me very happy because all I would need to do is time them correctly and pin them. But like I said before I believe they are for the upper receiver hole and are longer because of that.

November 2, 2012, 01:26 PM
So could you shorten a couple to the right length for the lower?

November 2, 2012, 02:06 PM
Sure could! But I don't have anything to cut it with, unless I want to grind it for a while.

November 2, 2012, 08:36 PM
IMHO: If you have enough machinery to accurately drill your own offset bushings in solid plugs the right length?

You probably have enough machinery to custom make them from scratch out of whatever you want.

But thats just my humble opinion.


November 2, 2012, 09:29 PM
RC I have valued your knowledge in the past and probably in the future. In this case however your opinion is a little out of line and rude in my humble opinion. How do you know what equipment I have? All you need, and I know this from past work, to accurately drill an offset bushing is a drill press with the right size bit, locked into the exact place you want to drill. In this case you pin one of the plugs in place, attach the upper receiver and secure it onto the lower ensuring it cannot move. Drilling from the side without the plug through the upper receiver hole and into the plug you achieve a perfect offset bushing. (So long as nothing moves.) Then you pin the other plug in place and drill through the hole you just drilled and the upper receiver hole into the blank plug. Voilla, offset bushings. Not that hard.

You know what is hard? Machining down 7075 aluminum rod down to .315x.270 without a lathe and something to cut it with.

November 2, 2012, 11:29 PM
O.K. then.
My apologies!

No disrespect, but I used to make simple stuff like that 50 years ago with a hacksaw, a hand drill, a file, and some emery cloth when thats all I had, or could afford.

Sorry I bothered you.
I won't do it again.


November 2, 2012, 11:35 PM
RC, I didn't mean to offend. Like I said, I value your opinion most of the time. I am just getting really frustrated over finding someone who can make me these damn plugs!:banghead: Sorry for the grumpiness.

November 3, 2012, 01:19 AM
not sure where to get the alloy, but ive had good luck convincing machine shops to make some odd stuff. Try an auto shop that does major engine overhaul stuff. they usually have the equipment to make inserts. Napa auto's sometimes are so equipped.

November 4, 2012, 04:41 AM
D51208, can you send me a sketch of what you want, I may be able to help you out.

November 4, 2012, 11:05 AM
if all you need is a .315x.270" long plugs i can make them.
only problem is i don't keep aluminum on hand, got plenty of crs, 1018 & 4140.
also the motor in my lathe died but the new one is supposed to ship monday.

your best bet would be to but some 5/16" aluminum rod on ebay and part it off to length.
all you would need would be a hacksaw, a file & a pair of calipers

November 4, 2012, 11:19 AM
Is there anything keeping you from running a newer lower?

State AWB, is it a registered MG, ect...

My thought process says you can buy a lower for less than $100 these days and you'd have that into time/frustration/machine work by the time you find what you want....

December 15, 2012, 04:28 PM
Hi Guys, Thanks for responding. I never got the notification that the thread was responded to lol.

What I ended up doing was buying a couple of the upper receiver offset bushings and ground them down to length. There not as tight in the lower as I would like them but they'll do for the time being.
I am using a KNS pushpin, as it is a slab side lower. The push pin holds both sleeves in without permanent modification, although if I take the gun down I have to rearrange the sleeves so it will close ok because they rotate offsetting the alignment. I havent shot it yet though, waiting for my hand guards to come in the mail!

I have thought about putting them in there permanently by blind pinning them or glueing or expoxying them in. I would like to avoid that though so long as having some very slight wiggle room from the sleeves rotating during firing doesn't cause a malfunction. Thoughts? It is a Colt slab side sporter 2 lower, s my goal is to not mess it up lol.

If these sleeves don't work out I'll keep you all in mind, thanks for the offers! :D

UNKA BOO, I am in New York where we still have an AWB. I could get a new lower but then I'd have to lose my bayo lug, permanently attach a brake or a comp, and pin my stock. All of which I dont want to do lol.

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