80% 1928A1 Receiver

[dana5901]

I am considering purchasing 80% receivers from Philadelphia Ordnance. I am concerned however, about the broach cut for the extractor. The cut is fully cut in the barrel thread area but not further back. Can anyone point me to a maker who has completed the entire extractor cut? Thanks

[deerslayer]

Assuming you don't have a broach, About 10 minutes with a file takes care of the job finishing out the cut.

[Blanksguy]

Anyone have a clear photo of how far back in the receiver the extractor-slot is made currently on the Phila.-Ord. 80% receivers (?)…….and a clear photo of an original 1928/1928A1 receiver in the same area for comparison (?).

TIA,

RichardS

US Army, RET

[thirtyround]

I'm sure, if you request it, with an additional charge that's acceptable, Philadelphia Ordnance can complete the cut desired. Give it a try. Cheers JB

[reconbob]

The ATF has apparently gone after partially machined Thompson receivers

with the same enthusiasm as if they were AR-15 receivers and will not allow any

machining to take place in what would end up being the pocket for the bolt if you

were to finish the receiver.

The impact of this on the extractor slot is that you can't drive the shaper tool

into a blind hole. You need clearance so the tool does not break and so there is

someplace for the chips go.

We are able to machine the extractor slot in the front part of the receiver

from the front of the ejection port thru to the front. See photo below. We can't do

the part of the slot to the rear of the ejection port because we can't do any machining

back there and as mentioned above there is no place for the tool to go.

But as Dan says, cutting the rear part by hand is quite do-able. The diameter

of the round hole in the receiver for the bolt head is 0.640" The diameter of the bolt

head is 0.600". The extractor sticks out about 0.015" beyond the round surface of

the bolt head. So its not a huge undertaking to cut the necessary clearance with files.

When the bolt head and the extractor is at the rear end of the ejection port, the extractor

is always flat against the bolt head because by the time the bolt has moved back there

the cartridge has been ejected.

It is when the bolt moves forward, strips a round out of the mag, and chambers it that

the extractor needs the clearance to flex away from the bolt head and snap in to the rim

of the cartridge. The extractor cut in the receiver has this necessary clearance.

If you are making a semi auto, you can return the receiver to us after you machine the

pocket for the bolt and we can cut the rear part of the slot. Like wise, if you are a Class 2

manufacturer you can register the receiver on a Form 2 and return the receiver to us

and we can complete the cut.

 

Bob/Phila Ordnance

Edited September 2, 2020 by reconbob

[dana5901]

Bob, Thank you so much for the additional information.