What Patch Thickness?

[Ohio Joe]

Thought the following may be of help to some as a starting point for patch thickness;

With the ball adequately undersize (.005) to fit into the bore we now determine the needed patching thickness to seal the grooves.

Groove ------ .526
Ball ---------- .498
--------------- .028 difference
Now divide the difference by 2 and the minimum patching thickness is determined: .014

Example (You Will Need To Measure Your Barrel Grooves)

Groove ------ .470
Ball ---------- .440
--------------- .030 differance divided by 2 = .015 Patch Thickness (Minimum)


Note;

You can always play with your patch thickness and ball diameter for best results. Most of us do... The above is just a starting point for those who may be scratching their head - wondering where to begin.

[Doc Nock]

Thought the following may be of help to some as a starting point for patch thickness;

With the ball adequately undersize (.005) to fit into the bore we now determine the needed patching thickness to seal the grooves.

Groove ------ .526
Ball ---------- .498
--------------- .028 difference
Now divide the difference by 2 and the minimum patching thickness is determined: .014



Example (You Will Need To Measure Your Barrel Grooves)

Groove ------ .470
Ball ---------- .440
--------------- .030 differance divided by 2 = .015 Patch Thickness (Minimum)


Note;

You can always play with your patch thickness and ball diameter for best results. Most of us do... The above is just a starting point for those who may be scratching their head - wondering where to begin.

Care to elaborate on HOW you measure your Barrel grooves?

[Ohio Joe]

Most, if not all folks use a Caliper. Digital or Dial, at the muzzle.

Groove depths can vary anywhere from .001 to .002 difference in a bore because of the cutting dies wearing before they are changed out.

Round Ball Barrels;  (NOTE: The TC Hawken Barrel will accept "Ball and Conical" with good results most of the time)

Green Mountain Barrels are grooved anywhere from .010 to .012

TC Barrels have always been very consistent at .005 depth (as they were "button" pulled) Don't know exactly what that means - but that's what TC told me 12 - 15 years ago (maybe 20 years ago?)

Lyman GPR will vary from .008 to .010

My old CVA Barrels (which were made by Douglas) all seem to be right at .008 - but it's possible one never passed through my hands with the die cutters worn to a point of less than .008???

My old .50 Douglas X-Stick Rifle Barrel measures .008 in depth. (Very accurate rifle).