Aluminum Receivers On Thompsons?

[maverick4440]

How durable are the lightweight alloy receivers on the lightweight thompsons?

Thanks

maverick

[Samslack]

if you want a display reciever try a Richardson. I'm not sure if he is still making them. anyone know if he is ?

[Sgt]

I think Maverick is talking about the live Kahr semi Thompsons, right? I haven't heard anyone on this board recommend them. On the contrary, several suggested that they wouldn't trust them. Maybe someone who owns one will comment.

[Grey Crow]

I've always steered clear of them with the thought of the steel bolt sliding against the softer aluminum that it just wasn't a good combo for longevity.

 

I could be wrong, but I feel better with the steel receivers.

 

Just my .02

[Kevin]

I had one once- the feed ramp seemed to be wearing at an alarming rate http://www.machinegunbooks.com/forums/invboard1_1_2/upload/html/emoticons/ohmy.gif . My brother has it now and since he doesn't shoot it, it should last a long time. Kevin

[PK.]

It is my understanding that the alloy used in the aluminum receivers is 7075 t6, and hands on experience would seem to verify this (as far as that goes).

 

This alloy is actually stronger than the steel (12L14) believed to have been used in WH & Kahr receivers (73 ksi vs. 70 ksi yield), but is slightly softer at Bn 150 vs. Bn 163. However, the anodic coating is as hard or harder than the heat treated steel receivers of GI guns. If this coating is not disturbed, feed ramp and bolt pocket life should be very good. The geometry of the Thompson feed ramp design is such that wear should be minimal.

 

Here’s the rub (pun intended), if the geometry of the feed ramp is not correct, the anodizing will be removed in the machining to establish the correct geometry or the impacting bullets during feeding will wear it prematurely.

 

I worry a lot more about the frame latch area that I do feed ramps or bolt pockets; if there is any axial play between the frame and receiver, the frame latch hole in the receiver and the seat in the frame will wear quickly.