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Can A M1a1 Bolt Be Used In A 1928 Thompson?


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#1 philasteen

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Posted 22 February 2006 - 04:51 PM

Can a M1A1 bolt be used in a 1928 Thompson?
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#2 deerslayer

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Posted 22 February 2006 - 06:11 PM

You need an offcenter buffer pilot/spring guide which Doug Richardson made some of. He didn't recommend using it with anything other than blanks though. I've got one that I picked up by weird circumstane. If you want to try it I's sell it.
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#3 PK.

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Posted 22 February 2006 - 11:38 PM

Do NOT use it with bulleted ammunition, you WILL break the receiver.
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#4 philasteen

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Posted 23 February 2006 - 07:04 AM

PK, would you mind elaborating? I thought that might be the case but wanted to undestand the physics of the problem.
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#5 Z3BigDaddy

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Posted 23 February 2006 - 08:40 AM

QUOTE (philasteen @ Feb 22 2006, 04:51 PM)
Can a M1A1 bolt be used in a 1928 Thompson?

Philasteen,

Not trying to be a smarta$$ but why are you wanting to know this? Economics or some other reason?
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#6 PK.

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Posted 23 February 2006 - 09:19 AM

The M1 bolt weighs much more than a ’28 bolt assy and does not have the Bliss lock to retard the rearward motion and soak up the energy imparted to the bolt upon fireing. This equates to a significant increase in energy that must be absorbed by the rear of the receiver. The ’28 receiver was not designed for this amount of energy and it will break.

This set up has been successfully employed in blank fireing guns because the Bliss lock makes function with blanks problematical. Even so, the blank system must be carefully regulated to ensure the bolt velocity is not excessive or damage will occur here also.

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#7 calibre

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Posted 23 February 2006 - 09:51 AM

How were you planning on operating the bolt?
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#8 Bob

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Posted 23 February 2006 - 02:39 PM

Sure you can...ha ha slap.gif

All you have to do is cut a slot in the side for the knob and ur good to go.
I call this my M1921M1

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#9 philasteen

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Posted 23 February 2006 - 05:30 PM

QUOTE (Z3BigDaddy @ Feb 23 2006, 08:40 AM)
QUOTE (philasteen @ Feb 22 2006, 04:51 PM)
Can a M1A1 bolt be used in a 1928 Thompson?

Philasteen,

Not trying to be a smarta$$ but why are you wanting to know this? Economics or some other reason?

It was a theoretical question only. Someone asked if it was possible; I didn't think so and I suspected it was because it would be destructive to the receiver.

Now I can meaningfully say, in addition to the need for the offset pin and the cocking handle issue, that the rear of the 21/28s are not strong enough to handle the un-blished M1 bolt. Thank you PK for your expertise.
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#10 giantpanda4

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Posted 23 February 2006 - 06:11 PM

Doesn't Richardson's book show/describe this - including adding a top mounted bolt handle?
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