Kahr/AO TM1 Bolt and Spring Tension question

[Bad Gambler]

Hello guys. New poster here from Wyoming. I'm a M1 Garand and Carbine collector so naturally I needed to add a Thompson into my collection. Wish I could afford a real one.

 

Before I purchased my TM1, I did several hours of research. I knew the spring tension was going to be strong but I never expected it to be that strong. I have to pull the bolt back with a towel just to get it to lock.

 

Has anyone purchased the longer bolt handle? I would rather go that route then a spring kit if it works. Unfortunately I don't shoot much so running a few thousand rounds through it isn't going to happen anytime soon.

 

Any advice would be great.

[Adg105200]

I think most people here would advise a EZ-pull spring kit. But I've always wondered why Kahr hasn't fixed the problem themselves. Seeing that it is a real issue with every one.

 

Andrew

[dokkerdam]

Kahr won't fix the problem because the gun is a simple blowback operation and it needs the strong springs to operate. The original Thompsons had a "Blish" lock that functioned as a mechanical locking device (using friction) and thus didn't need the strong springs.

 

I have kept my bolt locked back (until the locking mechanism started to fail) as often as possible and found that the spring tension though still stupidly strong did weaken quite noticeably. The only problem I see know is that the bolt wouldn't always strip a round from a 30 round stick until four or five of the 30 were gone.

 

dokker

[brassmagnet]

I did a spring and buffer replacement with Mcmaster Carr springs. Worked great... gun runs great...very easy to rack the bolt now....there is a thread on it somewhere here on the forum.

[Bad Gambler]

I was hoping that just the longer bolt would do the trick so I can keep the original springs and not change them out. I guess if guys are having good luck with ez pull springs, maybe I should go that route.

[Bad Gambler]

 

I did a spring and buffer replacement with Mcmaster Carr springs. Worked great... gun runs great...very easy to rack the bolt now....there is a thread on it somewhere here on the forum.

[Bad Gambler]

I did look at the macmaster carr website but didn't really know what to buy. will have to look again.

[Merry Ploughboy]

Kahr won't fix the problem because the gun is a simple blowback operation and it needs the strong springs to operate. The original Thompsons had a "Blish" lock that functioned as a mechanical locking device (using friction) and thus didn't need the strong springs.

 

I have kept my bolt locked back (until the locking mechanism started to fail) as often as possible and found that the spring tension though still stupidly strong did weaken quite noticeably. The only problem I see know is that the bolt wouldn't always strip a round from a 30 round stick until four or five of the 30 were gone.

 

dokker

 

With all due respect, I disagree with your analysis. While the 21 and 28 Thompsons had the Blish device, the M1 and M1A1 did not. The reason for the much heavier recoil spring force with the semi auto Thompsons is because the full auto Thompsons fire from an open bolt. The semi auto 27A1 and M1 Thompsons fire from a closed bolt. The open bolt operation requires that the ammo overcome not only the recoil spring force, but also the substantial forward inertia of the bolt. In contrast, the semi auto design has a stationary, light bolt and thus needs a heavy recoil spring.compared to the recoil spring for the full auto, open bolt design.

 

FWIW, the Uzi full auto and semi auto firearms have the very same situation.

 

While I do not have an M1 semi auto Thompson, I do have a 27A1. To ease cocking, I slide on the bottom a spare AR-15 A2 pistol grip over the Thompson cocking knob and pull back using the added gripping area to enhance my grasp. I do much the same thing with my semi auto Uzi, but I have to turn the A2 grip sideways to fit over the Uzi charging knob.. I do not know if the AR-15 A2 pistol grip will fit over the M1 charging handle. There is another thread from some time ago where a board member discussed and had pictures of a very nice looking custom grip aid that he made for his M1 semi auto Thompson.

 

MHO, YMMV, etc.

[Joe H]

Gambler,

 

Ez pull springs for the Kahr semi have been discussed here on the Board at great length. There have been virtually no complaints about them.

 

To get a set check with "Deerslayer" (Dan Block) here on the Board.

 

Here is recent discussion you may be interested in:

 

http://www.machinegunboards.com/forums/index.php?showtopic=18312&hl=pull

 

Joe

[Bad Gambler]

Gambler,

 

Ez pull springs for the Kahr semi have been discussed here on the Board at great length. There have been virtually no complaints about them.

 

To get a set check with "Deerslayer" (Dan Block) here on the Board.

 

Here is recent discussion you may be interested in:

 

http://www.machinegunboards.com/forums/index.php?showtopic=18312&hl=pull

 

Joe

Thanks for the link Joe.

 

I did read many threads on the ez pull kits, I was wondering if anyone went with a longer bolt instead of the ez pulls.

[vanvock]

I ( being a frugal type) tried epoxying a spent 45acp case in mine which worked but not for long till the (old) epoxy let go.. The extra length does make a big difference when you can get 2 fingers on it instead of just the pinky. What I do now is use a 1/2" wooden dowel shaved to fit in it long enough to get a 3 finger purchase & it works well. Just stick it in there when you need it. I put it on a key ring & a small carabineer so I can hang it on the sling swivel to keep it handy. I just don't see 40-50 $ for a little longer metal button that should go for 5-10.