Thompson 56 smoothbore loads

[brokenarrow]

I just got a T.C. 56 smooth bore and wad wondering what anyone is using for a round ball load.  Thompson recommends a 550 round ball with a .015 patch was wondering if anyone uses 530 or 535 instead. Any help with round ball loads would be appreciated. Thanks. Bob

[Maven]

I have a .56cal. T/C SB and a Lyman .550" RB mould for it.  With a proper patch, i.e., a thinner patch* than you mentioned, I get decent accuracy (from a rest) @ 25 yd. with 70 - 80gr. FFg.  A tow wad fore and aft with  that true ..550" RB is also accurate or at least is worth trying (I had a limited sample size).  Lastly, although many use a .535" RB with a thicker patch and claim "laser like" or "rifle like" accuracy, I haven't found that to be true.  I.e., the .550" RB works better in my gun.

*.0111" - .012" 100% cotton patch material (Sew Classics brand at Jo Ann Fabrics)

P.S.  T/C bbl. dimensions vary a bit with the SB.  While a .550" RB fits my bore, it may be too large for yours.

[Daryl]

I would use a .535" ball and a patch suitable to take up the windage, likely 10 to 12ounce denim.
That mould size is easily found.
I assume it is a .560" bore. A .550 ball would be way to big for me, as I like a substantial patch to hold lube.
I do not wipe the bore at any time, while shooting.
Like Paul, I have never seen rifle like or laser accuracy from a smoothbore shooting round balls.

[utseabee]

I would use a .535" ball and a patch suitable to take up the windage, likely 10 to 12ounce denim.
That mould size is easily found.
I assume it is a .560" bore. A .550 ball would be way to big for me, as I like a substantial patch to hold lube.
I do not wipe the bore at any time, while shooting.
Like Paul, I have never seen rifle like or laser accuracy from a smoothbore shooting round balls.

I agree with Daryl. Use a .530-.535 ball and .018-.020 patching.

[Daryl]

This target was just outright luck from a 20 bore.
5 shots at 28 yards


These are quite consistent and more normal, for me with no rear sight.
5 shots each, from 25 yards, same rest.

[Maven]

Here's is a photo that I took 15 mins. ago of a target using the T/C .56cal. smoothbore with a .550" patched RB @25 yd.  (I have a second target that's essentially the same, but in a different location on the target.)  You may be able to read the data, but if not here it is:

75gr. GOEX FFFg + .550" RB (Lyman mould) + .011" - .012" [Sew Classics] patch.  All shooting done from a rest.

Btw, my 20ga. GRF trade gun (no rear sight) will group like Daryl's @ 25 yd., but with a different diameter RB and thicker patch.  The second image (the lower one) is from the trade gun