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View Full Version : Thompson M1SB shooting right and low--help!



Tommy Gunr
02-26-2017, 01:03 PM
Hello, guys. New Thompson M1SB with fixed front and rear sights is shooting about 2" to the right and about 1" low at 25 yards from a benchrest. Three experienced shooters are getting the same results. I phoned Auto-Ordnance customer support and they directed me to fill out an RMA request via the Web site to return the gun. I submitted the RMA request but received no response. I phoned again three or four days later and spoke to another representative, who was, it must be said, rather unpleasant. He was discouraging about the possibility of the company providing any adjustment, said he had no way to access a prior RMA request filed via the Web site, and directed me to fill out a second request. I did so, but still no response after another three or four days. The company clearly is not exhibiting a customer service ethic. Does anyone have a suggestion for correcting sights?

Bawanna
02-26-2017, 03:10 PM
The M1SB has a rear sight held in place with 4 screws? I think that anyhow.
The only way I can think of would be to remove the sight and elongate the holes to the left so the rear sight can move to the left.

Without seeing one in person I don't know if that's feasible but I don't see why not. Shouldn't take much.

I don't see a cure for the elevation , might have to just adjust the sight picture.

I may be mistaken but I think there might be an adjustable rear sight available , not sure if they are for that model.

Tommy Gunr
02-26-2017, 07:07 PM
The M1SB has a rear sight held in place with 4 screws? I think that anyhow.
The only way I can think of would be to remove the sight and elongate the holes to the left so the rear sight can move to the left.

Without seeing one in person I don't know if that's feasible but I don't see why not. Shouldn't take much.

I don't see a cure for the elevation , might have to just adjust the sight picture.

I may be mistaken but I think there might be an adjustable rear sight available , not sure if they are for that model.

Thanks for your input, Bawanna. Yes, the rear sight assembly is held in place with four screws and doesn't have adjustability for windage. I'll give it a closer look and see if some adjustability can be created along the lines you suggest. To raise the point of impact, perhaps a thin shim under it could work. The front sight blade is likewise not intended for adjustment. There appears to be at least one windage-adjustable rear sight available, a USGI WWII Lyman model not strictly correct for the Thompson M1SB/M1A1 but very nice. Some Web surfing suggests it attaches with four screws that could very well align with those on the factory sight. Who's to say an enterprising G.I. might not have swapped out his as-issued sight for a scrounged Lyman? I see them online for $250 and up, so not exactly an impulse purchase. Need to investigate further. Perhaps in the meantime Auto-Ordnance customer service will surface.

Bawanna
02-26-2017, 07:13 PM
I don't recall what the front sight looks like. Might be possible to file it down a bit.
The shim idea is sound, that would be pretty easy.