Paper patch bullet

[Maineshops]

[could I paper patch a .380 pistol bullet to try this old .40cal barrel to see how it is going to shoot before I buy a mold for it? It would be more like a sabot. Most information I find is for onion skin paper. I don’t have enough experience with this subject to make an informed decision. I have several .38 molds . Wad cutter etc. thanks .....Dan

[Bob McBride]

Any ball smaller that the bore can obviously be fired from your rifle, as can any lead bullet, just don't expect any accuracy as the ball will not be formed to the rifling and a ball gun has a different twist than a bullet gun, but, yea, have a ball, or a bullet....

Just don't expect much..

[snapper]

Give it a try and see what happens.  I can tell you that I have tried 5 different kinds of paper.  Each gave different accuracy results.  4 of the papers were terrible groups.  Wads and combination of wads make a difference under a PP bullet as well for accuracy.

Sizing is also a possible issue for you.

Also, it depends on what your opinion of shooting well is?

Fleener

[Hungry Horse]

If I’m not wrong the bullet you are talking about is .357 diameter, which is way undersized for a forty caliber. I would get some bullets cast for a .36 caliber cap and ball revolver, they are .375 which is still undersized. But, not so much that you need to make your paper patch from a grocery bag.
 The optimum would be someone that has a mold for a 38-40 which is a 40 cal. Bullet.
  Hungry Horse

[D. Taylor Sapergia]

A cast slug for paper patching should just slide down the bore naked.  Your bore must be in very clean and shiney condition for paper patching to work.  Otherwise, the patch will be ruined sending it from the muzzle to the powder charge.  Paper patching bullets and achieving decent accuracy, is a science unto itself.

[Daryl]

Deeper grooves common to round ball guns will usually not do well with grooved lubricated bullets, let alone paper patched ones.
As Taylor has noted, paper patching is a skill and process unto it's own.  Let's assume your bore is .400", with grooves .010" deep
making a groove to groove diameter of .420".  About the only bullet that I can think of to work, would be the .38/40 bullet, which is
nominally .408", but likely cast .410" in pure lead. Th is bullet would have to be pre engraved in the rifling - using a section of the barrel
as a 'form die'. I've done this and it worked well, however takes some experience in this sort of thing.
I cannot 'see" this paper patching experiment proving anything about this barrel.
What the guys said about the bullets is spot-on. .38 bullets are .357/8" in diameter. 9mm bullets are .356".  Bullets and round balls for
a .36 cap and ball pistol are usually .375". All of these are way too small to to patched to fit the .400" bore. With a .375" bullet, double
wrapping in heavy .003" paper will only bring them up to .387". Triple layer wrapping with .003" should being them to .399".
If you used a tight fitting wad underneath, THAT might work, but I doubt it. 
You should be trying cloth patched round balls IF the rate of twist is 38" or slower.

[smylee grouch]

If it were mine I would slug the bore. Oil the bore real good, drop a 6 inch chunk of 3/8 brass rod down the bore and drive a 440 ball into the bore at the muzzle, up end the barrel once or several times and the brass rod will drive the sized slug out and you can measure it.

[Oil Derek]

Might consider a .405 Win. bullet which should be .412 dia.

[Smokey Plainsman]

A .380 “Colt’s Automatic” bullet shall be too small a diameter for even a thick paper patch to give any hope of accuracy.

[Maineshops]

Thanks much for all the input. I did slug the barrel and it measures.400. It is 100 yrs rough. {old barrel} so paper patching is probably not a good idea. I think I’ll order a ball mold. Rifling is pronounced and deep. Should I go with a .390 or.395? Dan

[snapper]

I think you are on the right track with a round ball.

I would go with the .395 ball and a .015" patch.   You can go to a thinner patch if needed.

Fleener

[Maineshops]

Thanks I’ll get one ordered . Still in the white but coming along


photo hosting sites

[Daryl]

If the barrel is as rough as you indicate, a .390" ball and thicker patch might be the better way to go
as in 10 oz. denim from Joanne's Fabrics or other fabric store.  That's 10 OZ, not .010".