Thompson semi-auto .45

[Jack Gilbert]

My brother has a Thompson .45 submachine gun but in the semi auto version. The effort to cock this thing is extreme. Could the spring be lightened in it to reduce the cocking effort without effecting the function of this weapon? 

He is using stick mags because the magazine will hold the action open which the drum magazine won't.

Any help will be welcomed here.

Jack

[Savage]

Jack,
Tell your brother to get out the "Bowflex". The spring rate is set up for optimal operation of the firearm. A weaker spring could cause damage to the gun from battering.
Savage

[Rickk]

I forget where, but there is a guy that that has figured out how to modify the 1927 semi-auto to make it easy to cock and still function. There is a third position on the safety swtich to put it into this mode somehow.

Yes, the drum mags are a hastle to load, and if it jambs, you need about 5 hands to unjamb it.