8 replies to this topic

[marks]

Picked up a WH M1 semi destined as an SBR project and noticed fore and aft play between the upper and lower receivers. The little button near the back of the receiver looks kinda shiny (worn?) too and is not holding the two pieces tight together. Is this a common problem? Hard to see why or how the button could ever get worn out. Maybe out of spec to begin with? Should I be looking in other area's for the cause? Haven't had a chance to field strip the weapon or even shoot it for that matter although cosmetically the gun is in great shape.

Idea's?

Edited by marks, 27 April 2004 - 09:09 AM.

[Motorcar]

Pretty common on Westy or Kahr, has no effect at all on performance of gun. If it bothers you PK can fix you up along with any other mods you may wish for.

[TN.Frank]

I've got a 1995 AO 27a1, it's not got any front to back play but has got alittle bit of up and down play, not much, just the slighest bit. I don't think up and down play is as critical as front to back play, I'd have it looked at before I shot it just to be safe.

[PK.]

Fore & aft play is not good; the parts will eventually beat themselves up pretty good. If it is more than .010, I’d have it fixed. The frame latch is the weakest part of the Thompson design in my opinion.

A little up and down is normal, but can be removed.

[TN.Frank]

I guess the up and down play would be fixed like you'd fix the slide/frame fit on a 1911a1 pistol. You'd have a tool that would go between the matting surface then you'd peen it and lap it for a zero tollerence fit, I had a gun tighten a slide on a 1911a1 years ago and that's how he did it, it looks kind of harsh seeing him hit the frame with a ball peen hammer and all but it did fix it and tighten the slide/frame fit.

[TAB]

I did something similar with a ball peen hammer, then tried to hide it with a dremel before I sent it to PK.

Yes I know I'm full of sh...

[marks]

Update to original post...........

Measured the fore & aft play and found it at .067. Removed the upper from the trigger group and found the pin in this condition. It's the pin pictured on the left................................



Obviously, the spring is broken. I changed out the pin (with the one pictured on the right) with a replacement I had in a box of parts and the play went down to .057 which is still more than the .010 PK suggested as a max.

The gun is going to a smith eventually when the SBR paperwork clears so I guess it can get looked at then.

[Wes]

My M1 Auto ord semi had a lot of slop too. I took the groups apart and peened it. Leave the button and bolt out, peen it a little then try for fit over and over till it tightens up. It doesn't feel right to beat on it with a hammer but it works and doesn't show when back together. I have no slop at all now. I also polished the feed ramp and put on a US GI mag catch and now it runs like a sewing machine. My rivits on the rear sight were loose too, I took an metal awl and gently hammered it into the holes and the rivets tightened right up.

[prairiefire]

My Savage 1928a1 had a lot of front-back play too. Fixed it up by carefully fitting a very thin steel wire in between the upper and lower halves on the left side. Had some difficulty sliding them back together, but once done, zero slop! I was thinking that this method can't hurt since the upper and lower receivers are not reciprocating together and so can't wear themselves out, but i'd really like to hear PK's opinion on this.