AmericanLongRifles Forums
General discussion => Black Powder Shooting => Topic started by: The other DWS on March 19, 2012, 04:28:55 AM
-
is there a ratio of ball diameter to patch diameter for accurate shooting with pre cut patches.
I have a small arbor press and I am thinking of making a cutter out of steel tubing somewhat like a harness punch that would let me cut patches out of multiple layers of patch fabric.
Since I'll be making patches for .54, .50, .40, and now .29 cal rifles I thought that there might be a rule of thumb for proper patch diameter relative to the ball size.
-
As a minimum size I wrap a ball with cloth and cut it off even with the ball like you were cutting it at the muzzle. then you can figure a patch diameter from that. As long as your making a custom size.
-
I wonder if you could recover one of your shot patches and up that size by half inch or so. Smylee
-
Try ball diameter times 2.57 for the same patch diameter as if you cut at the muzzle.
-
2.57 eh? thats the kind of ratio I was hoping for. How did you calculate that? surface area of a sphere? I recognize it as a topological problem but I'm mathematically challenged---I know just enough to run and hide when I see it coming.
Obviously the patch has to wrap more than half of the ball but how much more that? I suppose the muzzle cut patch has evolved as the optimum.
I guess I could simply buy a selection of factory precuts for different calibers and measure them and calculate from that. .54 .50 .40 are fairly standard I imagine. just wondering about the .29---doubt I'll find many factory cut patches for that.
-
.30 - .39 roundball = 0.75 diameter
.40 - .49 roundball = 1.13 diameter
.50 - .59 roundball = 1.38 diameter
.60 - .69 roundball = 1.52 diameter
These sizes will give inclusive results for the calibers within their range
-
2.57 eh? thats the kind of ratio I was hoping for. How did you calculate that?
If the ball is pushed down even with the muzzle, then the path the patch follows around the contour is: 1/2 the ball diameter down to where the ball is at full diameter, pi/2*diameter around the ball, then 1/2 the diameter again back up to the muzzle. You end up with diameter*(1 + pi/2) or 2.57*diameter. (The numeric value of Pi being 3.14159...)
The thing to keep in mind is that 2.57* ball diameter is the diameter of the patch you'd get if you cut at the muzzle. If you've pre-cut the patches, you need to take some care that the ball is well centered on the patch. Cutting with a knife at the muzzle the ball is automatically centered on the patch.
-
Thanks for the 2.57ratio. I will store that in the old memory bank. Then again, I should probably write it down. The memory bank has a tendency to self-clear these days.
I have been determining the diameter by wrapping patch material in a U around the ball, marking it at the top of the ball and measuring it. That gives me the minimum patch diameter, but I don't hesitate to use patches cut for somewhat larger calibres - doesn't seem to affect accuracy.
I have a small arbor press and I am thinking of making a cutter out of steel tubing somewhat like a harness punch that would let me cut patches out of multiple layers of patch fabric.
I haven't had much luck with the punch type cutters. I had difficulty getting them to cut cleanly. I made patch cutters to fit my drill press, and they will cut very cleanly through a good size stack of material. I understand some folks grind the teeth off appropriate size hole saws and sharpen the edge - a whole lot easier than making a cutter on a lathe. DUH... why didn't I think of that!
Laurie
-
Heck, don't over engineer the thing. Cut in strips, shove one end under your belt to be handy and cut em at the muzzle after applying a good dose of spit. Much less ditzing around....
-
There was an article in Muzzle Blasts several years ago by the Bevel Brothers where they compared pre-cut, square cut, and cutting at the muzzle and there was a difference. Not much and certainly nothing an offhand shooter would notice, but a repeatable difference. Cut at the muzzle shot best. Centering up pre-cut patches is the problem.
-
This is all real helpful and educational. And yeah, I do tend to over-think a lot of this stuff. I get fascinated with the how and why of things.
I like the simplicity of using a strip and cutting at the muzzle. I like knives a whole bunch too, so anything that gives me an excuse for a new one is welcome. HOWEVER, I am thinking about the problems that strips and cutting might present if you were to spend a day at the range. I get dry mouth too easy as it is ;D.
How do you guys handle it when you are doing one of those woods walk/run matches---chaw on a wad of cloth while you are running. with my luck I'd trip on a root, and wind half swallowing it and choke to death.
Since I'll be trying to get the "new-to-me" .29 fired up and running over the weekend--I hope, and of course the smaller the bore the more sensitive guns are to ANY variations. I'm thinking more along the lines of pre-lubed patches I guess the logical thing to do is to prelube strips or larger patches, keep them in a container, and then cut them at the muzzle.