Bridgeport drum ID

[elviejo]

Standard Bridgeport drum but with beautiful deep bluing, excellent condition. All I’ve ever seen were that grayish park.  Can’t find any book references.  Can anyone shed any light on this.  Thanks

[Mike Hammer]

It's got to be a refinish job.

[rpbcps]

Roger Herbst who wrote the book, 'Thompson Submachine Gun Magazines: 1917-2021: Feeding The Dragon For Over A Century', will be the man to answer that one .

Looking at the United Air Cleaner 'U' on the back of the drum, it looks like a fourth generation WW2 AOC L Drum, with the 'wrong' finish. I had a quick look at Rogers book on my bookshelf🤫.

 

Edited February 24, 2023 by rpbcps

[inertord]

You can see rust pitting that wasn’t removed before refinishing 

[rpbcps]

9 minutes ago, inertord said:

You can see rust pitting that wasn’t removed before refinishing 

Well spotted...

Edited February 24, 2023 by rpbcps
Typo, yet again,and with only two words 🙄

[TSMG28]

It appears that someone has stripped the finish, buffed the surface, and re-blued the drum.  The noted pitting is a clue, as are the rounded off tops of stakes in several places, and the uniformity of finsh.  Looks pretty and shiny, but not original.

All of the United Specialties drums were originally grit blasted before being blued. That gives them that rougher finish similar to parkerizing. Seymour drums were not grit blasted, so they are smooth and shiny out of the box. 

Roger

Edited February 24, 2023 by TSMG28

[elviejo]

That is indeed a keen eye.  Never thought it was some “factory presentation drum” or anything like that. Assumed a refinish but why wouldn’t you do an original.  When I was active on this board years ago, the RKI factor was exceptional.  Nice to know nothing has changed.  Much like the Bowers Subguns board was in its day, especially on select fire guns.  My thanks.

[TD.]

elviejo,

Show us a picture of the rotor. Has the rotor been blued too. I want to see the stake ribs on the rotor body. What I see is a shooter L drum...if it runs. That would be the test for me. If it runs, a great shooter L drum. If problematic when the trigger is pulled, a display piece. The Tawain L drums have turned the problem WWII L drums into display pieces. This United Specialties L drum needs to go to the range! 

The TCA Show & Shoot would be a great place to try it out

[elviejo]

TD - last shot the drum at least 15yrs ago and it ran fine.  A couple of rotor pics for you

[BRMCII]

Reblued. You can see the multicolored hues, like the "Newton's rings" easily seen on a molecule thick layer of gasoline or oil on a puddle of water, and which are often present on the surface of reblued guns with slight residue of water dispersing oil, used after bluing to eliminate the water wash last process of bluing.
Not to mention the obvious metal surface treatment and black oxide hot dip color, etc. The face of the rotor boss tells the tale of the condition of the drum prior to refinish.

FWIW