
Gunmachines Co. Tsmg Enhanced Performance Parts
#1
Posted 20 November 2003 - 04:08 PM
My question is has this body of thought and method of TSMG enhancement been debunked or is any of it valid?
#2
Posted 20 November 2003 - 04:16 PM
#3
Posted 20 November 2003 - 04:27 PM
Both the "speed" bolt (some metal removed) and Blish lock with its ears removed have been addressed many times on this forum, and I can't remember one positive thing ever being said about them. I can definitely tell you that Tracie Hill takes a dim view of these modifications.
Roger
#4
Posted 20 November 2003 - 04:40 PM
#5
Posted 20 November 2003 - 07:03 PM
Didn't make much sense to mess with it.
#6
Posted 20 November 2003 - 10:13 PM
#7
Posted 20 November 2003 - 10:13 PM
#8
Posted 20 November 2003 - 10:20 PM
#9
Posted 20 November 2003 - 11:09 PM
I wonder that's possible? Seems like, by definition, the 21 kit would cause you to run out of ammo sooner.
#10
Posted 20 November 2003 - 11:37 PM



#11
Posted 21 November 2003 - 06:18 AM
Hmmm. Lube differences? Spring tensions? Mine is markedly faster with the 21 kit. I've timed the differences with the video camera and, though far from quantitative, the audio difference alone is significant. CJ, just cut the ears off the Blich lock;-)
#12
Posted 21 November 2003 - 08:38 AM
That said, different guns run at different rates. I have a 28 in the shop that runs almost as fast as a 21 for no apparent reason. I haven’t taken the time to dope out why yet, but it stands to reason that certain combinations of components will run faster and others slower. It’s called tolerance.
When shooting the two guns (21 & 28) there is a noticeable difference however.
On the “performance parts” question; I feel strongly that the parts and practices advocated and sold in former days are pure poison to the Thompson and should be avoided. If the gun is set up as a 1921 model it is plenty fast and within the design parameters intended for it.
#13
Posted 21 November 2003 - 05:58 PM
Decrease the mass or displacement, or increase the spring stiffness or the ammo force and the firing rate goes up, reverse of the same and the rate goes down.
Further, the force generated by the ammo has to be great enough to work the action with a reasonable variety of ammo without bashing out the back of the receiver (i.e., the impulse of the fired round has to be equal to or greater than the momentum of the reciprocating parts). Hence, the component sizes fall within a range of generally acceptable size, weight, spring force, etc. plus a buffer is needed to ensure that the ammo force values that exceed the usual tolerances are accommodated. Go out of the design range with any part in any direction and trouble results. Eichoff and Payne, and the Savage engineers were all very good engineers. Stay with what they put in the original packages.
Comment and/or corrections are welcome.
#14
Posted 21 November 2003 - 06:16 PM

#15
Posted 21 November 2003 - 09:23 PM


#16
Posted 21 November 2003 - 10:06 PM
#17
Posted 22 November 2003 - 12:03 AM
#18
Posted 22 November 2003 - 12:34 AM
You brought back a lot of unpleasant memories of my days in engineering school. I squeaked by in Dynamics and took Thermodynamics three times. Enjoyed your cycling analysis, just the same.
#19
Posted 22 November 2003 - 11:38 PM
I know I forgot all of what you said when I got my two engineering degrees. It's easy to do when you don't use it. But, for alluded to a damn good point - why does the speeded up action cause more wear and tear on the reciever? The input force is the same (same ammo)! So - the reaction force must me the same, right? I think what is going on here deals with energy- same force, less time, more energy. Or something like that - maybe 8 years ofo college went down the drain already.
Does anyone (PK??) have any data (picture or story) of a reciever that failed - especially due to being "speeded up"? And why it failed (history of use/abuse)?
I think we all know that the blish lock was NOT a requirement in the design of the TSMG - Gen. Thompson would not agree, but the M1s work fine without them. If there is an additional problem with just "cutting the ears off", I would like to know why.
#20
Posted 23 November 2003 - 12:17 AM
Are you advocating turning 1921/28 Blish Locks into Vincent Van Gogh's? The reason the M1 SMG's work without the Blish design is because they are as different from a 1921/28 TSMG as an M3 Grease Gun is.