Re: Thompson "L" drum questions


Dave Hinz wrote:
# Question about the Thompson 50-round "L" drum. Picked one up yesterday
# (the gun for it is on order). Trying it out, I'm a bit confused by the
# "wind 9 or 11 clicks" instruction. It "clicks" a lot when I'm winding
# the spring/key, with more than 11 click-like noises per turn. Not sure
# which of those clicks I'm supposed to be counting, lots of stray noises.
# Obviously, it has to turn further than one turn, to push out almost two
# rows of cartridges.
#
# So - can someone tell me how many _rotations_ I need to make with the
# crank, or how many "clicks" per turn I should be hearing?
#
# On a side note - I'm surprised at how heavy this magazine is. It's
# about 2 1/4 pounds empty, and 4 1/2 pounds loaded. Wow...
#
# Thanks,
# Dave Hinz
#
First one(9 clicks) is for the 1928, the second one is for the 1921.
More tension needed for the 1921 since it had a higher rate of fire and
needed the cartridges moved into position faster. For the semi-auto,
start with 9 and add more if you get failures to feed. For my Numrich
drums I need about 10. A lot depends on the state of lubrication in
the drum itself. Inside the spring case, it takes grease, for the
tracks and outside, use light oil. The Thompson isn't meant to be shot
"dry", anyway, it takes oil and plenty of it.

Without digging mine out and looking, I'm pretty sure there's 4 detents
on the drum, so there's 4 "clunks" per winding key revolution. On
mine, they're pretty obvious. You'll get some noise from the innards
while winding when the thing is loaded but nothing as noticeable as
when you pass a detent. Try winding it when it's empty to get a feel
for it. Look at the back of the drum, there will be a number of
circularly spaced small indentations pressed into the drum, IIRC, four,
about 3/32" or so wide. These are the detents.

If you want more on care and feeding, pick up the latest copy of Small
Arms Review, it has stripdown and lubrication instructions, something
I've seen nowhere else. Follow them if you want to avoid gouging up
the outside. It was recommended to strip a new Numrich drum and relube
before using, apparently they aren't lubed correctly from the factory.
If you're really interested, pick up the previous 4 issues, there's
been a series running about Thompson drums, who made them, markings,
more than you probably want to know. Back issues are on their web
site.

Stan



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