patch for colerain .40cal?

[LH]

I'm building a rifle now and am using a Colerain .40 cal. barrel with round bottom riflings.  I have never used a roundbottom barrel before and am just curious what patch thickness I might have to use for a .395 ball.  I have three other  square groove .40 caliber rifles, and they all like .014 twill but I'm wondering if this Colerain might shoot better with a thicker patch.  Anyone shooting this combination?   

[roundball]

I think your right on track with your thoughts...

In changing from .45/.50/.58cal square bottom groove barrels to .016" round bottom grooves, they were so much more "roomier" that I had to bump up from .018" to .022" in all of them.

[Daryl]

LH - Taylor shoots a couple rifles with rounded grooves. He uses a ball that is .005" smaller than the bore along with a .022"(10oz denim) patch. How the patch is measured - technique and tool, makes a BIG difference on what that measurement reading is. 

Best to test a range of thicknesses of tightly woven 100% cotton material, and record or remember which one worked best - measure it with your tools for reference. What someone else gives a a thickness, might be no where near what your calipers or mic. indicates.

The material runs from duck, twill, denim, ticking - all different weaves.

[bob in the woods]

I have a 42 in A weight swamped Colerain barrel on my .40 cal rifle. It shoots .395 balls with .020 to .022 patches.  I usually load 45 gr of 3 F .

[cahil_2]

I have a 45 with a colerain barrel and I use .023 patches with a .445 ball.

[Wolf Eyes]

Cahil_2, what patch material are you using to get .023?   

[LH]

Daryl,  you're perzackley rite about measuring cloth thickness.  Seems like we could come up with a standard or some way of communicating patch thicknesses, but I dont know how that would be possible.  I'm probably a month away from being ready to shoot this gun and was just wanting some reference as to which way (thinner or thicker) it might go.   The stuff I call .014"  is sold by Jo-Anns fabrics and is called "bottom  weight twill"   I think.  Its a twill weave like denim but comes in solid colors.  Some of the "duck" or canvas cotton they sell mic's about .025 to .030 by my method, and there is a bolt of pillow ticking that mics about .021 in that store.  I'll pick up an assortment of stuff thats thicker than what my square groove guns shoot and see what develops.   Thanks for the reply's fellers

[excess650]

The smaller than 40cal Colerains are supposed to have shallower (.012") grooves than the larger calibers (.016").  My .62 Colerain seems to prefer cotton duck(.023-.-025")  over even the heavy pillow ticking(.020"). 

[Gene Carrell]

LH---   Jo Ann fabrics sells 10oz denum  that I meaure at .022-.023. Be sure to read  carefully, some  is not pure cotton.

[cahil_2]

wolf - just ticking that  I have won at blanket shoots.  I measured with a mic.