yeoman

Patches have long been the traditional "sabot" substitute for roundballs. Why are patches not used with under-bore-sized conicals in slow twist, deep grooved guns?

geoffh

I'd say maybe if shooting a soft lead(patch needs to bite the bullet) with a light load(fast twist at speed would be harder to transfer spin to the bullet). The high end charges would probably burn through a patch unless using a wad/buffer material. I think it would pretty hard to find a patch/bullet combo that would load easy enough with a large bearing surface of a bullet compared to a ball where just the line around the circumference is wedging the patch in the rifling
sorry justcaught the slow twist part

lemoyne

They do use cross shaped paper patches on slug guns. Lee

cayugad

The reason most times, patches are not used on conicals are conicals are bore size. For instance a .50 roundball is actually a .490 diameter. A conical on the other hand is .503 or bigger. The patch would add to the diameter of the conceal and make it almost impossible to load. Now I have wondered what if a conical was say a .490 anda patch was used. Would this be the same as the paper patching that used to be used in some of the old conicals and Minnie ball rifles?

The conical is meant to engage the rifling of the bore to get the correct spin. Whether going down or on the rider out.Do to the large chunk of lead, this might be necessary for extended accuracy ranges with them. Otherwise what you would have would be comparable to a shotgun slug. Even now some of the siugs are made to try and get them to spin for additional accuracy so I was told. Its been a long time since I shot any modern rifles or projectiles.

yeoman

Cayugad,

This was my thinking: is it possible a combination of a .490 "bullet" with patch might produce better accuracy results ina slow twist gun than your basic .503 maxi-ball? I question the expansion of maxi-balls into the grooves of slow twist guns. Not that some doesn't happen, but I doubt the spin achieved is anywhere close to that of a round ball, partly due to added weight and therefor added slippage. Further, I suspect there is material damage to the all lead conicals which might be eliminated as the patch would take the abuse and drop away. Similar to employing a card or wad, but the patch would, I think, impart far greater spin. Dunno.

nchawkeye

For a couple of reasons....Conicals or Minis came out a few years before the Civil War...They were made to be able to load the gun quickly, so they are made just smaller than bore size and have a hollow base...Upon firing, this base flares and that's what engages the rifling...For this reason the rifling is shallower than a deep groved round ball rifle...Also it takes a faster twist to stabilize a conical than a round ball, due to the conical being longer....

My 54 caliber flintlock has a Ed Rayle barrel, cut rifling, .012 inches deep and a twist of 1-72...Your typical conical rifle will have button rifling .006 deep and a twist of 1-48 or so...A conical would have a hard time filling the deeper rifling of a round ball barrel....

Make sense???

Pglasgow

I've often wondered about how well conicals fill the grooves when the rifle is fired. I think they do a pretty good job. Lead is pretty soft and when a rifle fires, the bullet is accelerated on the order of over 1000 g's. Thats alot of force. I would think more than a hammer blow. A hammer blow could do it so I suspect that the charge could also.

In my Sidekick, I got leading at 1550 fps and above with some conicals, for example, the 385 GP. The sidekick has deep grooves and they are cut. I figured that the rifling skinned the bullet as it expanded becauseit was accelerated down the bore so fast.

Of interest, my BPI rifles have shallow grooves and the grooves occupy twice the surface as the rifling does. This increases the shearing surface of the bullet (between each rifling) by 33%. The barrels are designed for the Powerbelt conical so I think it is intended to better grip highly acceleratedbore size conicals. The rifling is definitely cut, not buttoned.

For grins and giggles, I plan totest how patched roundballs shoot out this kind of barrel/rifling design. I haven't an opinion as to what the outcome will be, but will report what doeshappen when I test.

yeoman

nchawkeye,

I'm familiar with the mini-ball flaring base concept. Are you saying that a few years before the civil war rifling groove depth was reduced and twist rates increased? I thought both those barrel attributes were relatively new to the MZ world. My history is weak, for sure.

From what I gather thus far in replies, no one has tried patching any projectile other than a round ball?

cayugad

I have paper patched and teflon tape patched minnie ball, and a couple conicals for some different tests. It really did not produce the results I wanted from the projectile.

yeoman

Cayugad,

Why did you not try a cloth patch?