Converting M1 to full-auto only

[Lazyace]

I recently purchased an AO Thompson M1 from Rock Island Auctions. NFA transfer is in process. My issue is that in Connecticut, any select-fire capability has to be removed so that it is full auto ONLY. (Yes, I realize my state laws are ludicrous but that's another topic entirely.) My question is how to remove the select fire capability without doing any permanent damage? Do I need a new rocker pivot selector switch? Can this be done without welding any parts?

 

My class 3 dealer will have to do the modification but I want to make sure that I give them explicit instructions. I don't believe that they have done one before and not sure how much Thompson expertise they have. Bear in mind that since this is my FIRST Thompson, my technical knowledge is extremely limited so please keep it elementary.

[cubguy]

I know you can't help it, but that's a crazy law!

[jim c 351]

If you remove the rocker it will shoot FA only, but I have no idea if that will satisfy the law.

Jim C

[ron_brock]

Those 10 round mags are going to empty pretty quickly on full auto only.

 

Ron

[Motorcar]

Or the top of the rocker could be just ground off a bit so it no longer contacts the bolt in semi auto position. That way the selector (rocker pivot) stays in the gun and has no effect on fire control in either position. Buy a spare rocker for a few bucks for the day you need to sell and restore it to full operation.

[laurencen]

just take the rocker out,

[mnshooter]

Move.

[Sandman1957]

Move the gun to another state and visit it on occassion.

[reconbob]

A few years back I looked at a Thompson for sale in CT and could not believe it had

no selector/rocker pivot. The guy explained to me about this law. He had the rocker pivot

In the case with the gun, it just was not assembled into the trigger frame. I would take a

close look at the law or better yet talk to other guys to see what they do. If the law bans,

for example "selectors" then removing the rocker would still leave the selector in place

and would not be legal. You get the idea.

Yes, this is one of the dumber laws...

 

Bob

[jim c 351]

While the law might appear stupidly written be thankful for the way it is written.

I don't doubt the original intention was the outlaw FA guns and they just screwed up.

Jim C

[OCM]

you can thank Mr. Dillinger & the 1934 law for your 200 tax stamp. The Al Capone boys just set the stage.

He paid the ultimate price so we could own a Thompson , for only 200 bucks now.

 

Actually I think I may be mixed up on this or something.

[DINK]

Who is doing the transfer?

 

As usual, there is no written guidance from CSP on this, but I have always done these conversions in a way that does no harm to the major components of the firearm and have never run into a problem. I have had substitute selectors made up that eliminate the rocker and the selector lever on the outside, but you could probably get away with just removing the rocker and leaving the selector in place.

 

I just did a Thompson and an UZI a couple of weeks ago at NGX.

[TD.]

I remember a collector from Connecticut that displayed four or five of his Colt's at the All Thompson Show & Shoot several years ago. During our discussion he mentioned the full-auto only aspect of Connecticut state law. He told me he simply removed the rocker from each Thompson to comply with the state law. He stored the rockers, marked for each gun, with a friend that lived out of state.

 

Removal of the rocker would prevent a Thompson from firing in semi-automatic mode. I don't believe the fire control lever or rocker pivot, without the rocker installed, would need to be removed or modified. It is not what it says but what it actually does. Of course, I have not read the Connecticut statute - but the removal of the rocker certainly makes a Thompson full-auto only.

[DINK]

You are entirely correct in that a simple removal of the rocker will bring the gun into compliance with stupid CT law. Removing the selector or replacing it with a part that doesn't look like a selector may be helpful if the owner ever finds himself in the unenviable position of trying to explain the mechanism of the Thompson to a State Trooper or local cop who's experience with them is confined to reruns of "The Untouchables".

 

You may beat the rap, but you want to beat the ride, too.

[1921A]

In working with police Thompsons over the years I occasionally found guns with the rocker installed backwards (hook point forward). The telltale sign of this condition was that the gun fired automatic in both selector positions - no semi-auto function. I don't recall any damage caused by this condition but I think there would have been eventually. This was the case with a 28A1 used in a Detroit "gang" murder back in the early '80s. The gun was kept in the Michigan State Police arsenal in Lansing for a time. It was an interesting piece because the receiver was very crudely welded together from 2 or 3 badly demilled parts yet it worked flawlessly once the rocker was installed correctly.

 

M1 rockers and rocker pivots are cheap and readily available. If the "selector lever" is the legal issue you might try machining off the top (lever part) of a spare original rocker pivot so that it resembled an M14 "selector lock." I would opt to machine off the top hook area of the rocker rather than just remove it from the gun. This is good question for reconbob.

Edited July 12, 2015 by 1921A

[Paul in PA]

Having come from the Crazy State of Connecticut. I thought their solution required a "weld" to make it permanent? But again, there is nothing that precludes having two lowers. one with permanent modifications and the other, the original for the gun, stored out of state.

[laurencen]

only the rocker sits on the selector lever,

[RandyM]

Those 10 round mags are going to empty pretty quickly on full auto only.

 

Ron

LOL, for sure

[shadycon]

Take an extra selector switch and grid/mill the head to look like a rivot [round], install in full auto mode. No full auto/semi switch lever visiable.