patch diameter

[twotimer]

what is a good formular for patch size? untill i started using real black powder i had only used the pre-cut,pre-lube patchs that measure almost an inch and a half for .50 calibers.thanks for the help.

[mjm46@bellsouth.net]

Wrap a piece of cloth around your bullet and cut it off flush with the ball. Unwrap it and that's the perfect diameter. A little larger is OK. I usually use precut patches with my .50 cal but I go up a size and shoot the patches for .60 to .69 Cal. You don't have to be so careful trying to center the patch and they are not so large that they get stuck on the rammer.

I guess if you need a fromula, Something like Ball Diameter X 3.14 (pi) = circumferance of the ball or patch diameter.

[twotimer]

micah.thanks for the info.its amazing how the,'my' mind works the older i get.i have done about everthing but that,ie,scribe the barrel on patch materal,make a pattern from that.cut it square,nip the corners,ect,but always seemed to have just a tad to much,or not enough,in my thinking.regards,robert

[SCLoyalist]

Ball diameter time 2.57 will give you the patch diameter as if you'd pushed the ball flush with the muzzle and cut it with a razor or knife.   For a .50 cal, .5*2.57=1.285 inches.     I sometimes cut square patches with scissors according to that formula, and then clip the corners so they're more or less octagonal and a little rounder looking.

[bgf]

Square patches are fine -- every bit as accurate as round when I tested them.  The only drawback is if you want to leave the cleaning jag on your range rod -- the corners can catch on the jag (which can also happen with grossly over sized round patches), but that is not a problem with a regular loading tip on the rod; I use square patches in the woods all the time, and I have shot a good match or two with them when I felt lazy.  Cutting at the muzzle is easy, also, if you are at a loading bench, and every patch is certain to be "perfect".

[Daryl]

I like using pre-cuts merely due to the convenience of pre-lubing. I firmly suspect that cutting at the muzzle is the most accurate or is at least  the method that possesses "the potential" for the greatest accuracy, due to pefectly centering the ball, every time.

Now, how the ball is introduced into the muzzle, is of vital importance- in that it must be pefectly centered or more lead will be pushed by the lands on one side than the other. Those who thumb start probably will not improve accuracy by using a 'straighter' seating method.

We used to merely give the ball a smack with the knob of the starter- one smack - not as using a hammer, but with the starter shaft held in the fist- a pounding blow. The ball and aptch goes into the muzzle with barely marking the sprue- really - virtually no damage. However, if the blow is slightly canted, the ball is pushed to one side or the other slightly, and will lack the accuracy of starting when using the short cupped stud on the ball. I am talking of group shooting, or shooting at a small mark at long range, not shooting 5" gongs at 25 yards. Even a smoothbore can hit those - sometimes.

[jamesthomas]

 Getting the right patch diameter is important, But to me the proper thickness is just as important. On another post I meantioned that I use a .490 and a .24 patch that leaves me .14 pressed into a .12 groove barrel. G.m. Barrels are .12 aren't they? Tight fit to clean the barrel as I load the next shot.

[Daryl]

Yes - GM barrels have .010" to .012" deep rifling, james, with the smaller calibres likely at the shallower number.  Thus with .012" rifling, a .50 cal. barrel would measure .500" + .012 + .-012" = .524" to the bottom of the grooves..

Your .024" (24 thou) patch would make that combo: .490" + .024" + .024" = .538" - .524" = .014" total compression, which is .007" compression per side (in each groove).

With .007" compression, the patch would contain any load that one might even think of using - it's a really snug combination.

Must get those Zero's in place, james as they skew the #'s.