BULLET DIAMETER-SIZE TO?

[THOMAS0001]

I do alot of bullet casting. I like to size my bullets .001-.002 over bore in my centerfire rifles. What is the ideal size for a ML? Under bore-or over bore? And what about lube? Tom.

 

[arquebus]

I size my Minies & conicals about .001" or so under bore size. Though lately have been trying a bullet from a custom mould.....it is a reverse taper with each band .002" bigger than the one below it & the top one being just a tad over bore size, requiring a starter to get it into the muzzle. The idea, I guess, is to make sure the bullet is centered in the bore whereas a straight cylindrical bullet could, feasibly, be loaded a little crooked. Very similar to the tapered breech seated bullets in BP cartridge rifles.....only in reverse!

 

[shmrck1]

Thomas,
Check 'Member Resources' forum...Might help with
your question about PRB size. You don't say but do you have a muzzleloader or just looking for answers to muzzleloading questions.Either way you are surely at the right place to get answers. Don't forget about the "Search" feature of the forum. Lots of information in the archives.
snake-eyes:thumbsup:

 

[boar]

All my Rb are under bore size. Usually .10. 45cal is .440- 50 is .490, some is just .5'th under. I like the .10 as is easier to ajust the patch thickness. Now bullets that don't have a patch could be close or bore size. Depends what you are shooting( bullets) and what gun you are using. My pistol takes a .451 bullet as it seals lead to metal,no patch. Dilly

 

[paulvallandigham]

What kind of ML are you shooting? The answer to your question varies with the gun.

In my first BP revolver, we used oversized balls because they were supposed to shave off a ring of lead as they were seated in the chamber. The .36 Caliber revolver actually had a bore diameter of .375, and we used cast balls that were actually .380" in diameter. Cast balls were oversized, because we used no patching betwen the ball and the chamer wall.

In m Ml RIFLEs, I like the ball to be .010" under bore size, but have had rifles who shoot better with .005" or even more diameter sized balls. Some shooters use oversized balls and patches in their target guns, using a mallet to seat the ball in the muzzle of the gun. Thre are many different sized .45 caliber rifles. They can be .440,.445, .451, .454, and .457, as well as an assortment of custom barrel dimensions. There are also .44 caliber rifles to confuse matters. TYhe only way to know what you have and what components it needs, is to measure the bore and groove diameters with calipers before buying any components.

In smoothbores, with round ball loads, You may want to have a cast or swaged ball that is .020-.-025" under bore size, because you need that room for an adequate cloth patch to fit the barrel, and not burn up. My 20 ga. fowler is .626" in bore diameter( Instead of the nominal .615") , for instance, but I am shooting a nominal .600" ball with .020" patching. Its a bit tight, and I am going to see how .015" patching works. If accuracy goes down, I may try even thicker cotton fabric to see if that will improve accuracy, and just put up with the tight fit.

In a ML rifle, the groove depth is used as a measure of how thick a cloth patch you should start with in working up a load. Once a patch is lubed-- with spit- or grease, or water- it will squeeze down into the grooves off the lands, filling the grooves, and preventing gas blowing by the patching. However, if the width of the groove is narrower than he width of the lands, you may have to use a thinner patching, and seal the bore from gases using a Over powder wad, or a filler to get the best accuracy.

The land to land diameter is the BORE diameter, for clarification. So, a .50 caliber rifle may have a land to land diameter of .500", while the groove diameter may be .512-.528"( groove depth of .006 - .014").