PRB Ball Size for .729 Bore?

[hunts4deer]

I am going to ask for Jeff Tanner mold for Christmas. I am having a 12 gauge fowler built for me and the measured bore is 0.729 (standard 12 gauge) I am considering either a .714 mold (.015 under bore) or a .710 mold (.019 under bore). For those who have experience with large bore PRB shooting, what is your preference: Smaller ball/thicker patch or larger ball/thinner patch?

I will likely use a lubed felt or fiber wad under the PRB. What are the trade-offs? Do you have specific 12 gauge experience with Accuracy, ease of loading, optional bare ball loading? &c., &c. Thanks!

 

[Rifleman1776]

I my Ped. Brown Bess I use a .715. Follow up shots can be hard to seat. My (nominal) 20 ga. fowler is using a .600 ball and follow up shots are very hard to load in the field. On the range I can shove a damp wad down first help. But, I would rather switch than fight and will be looking for .595 or possibly .590 mould next.

 

[BEP]

Keep in mind that you'll have a smoothbore to deal with. A rifle's bore diameter is measured from land to land; there are grooves to take up some of the patch's bulk. Your smoothbore is just that - smooth. I would get a .70 caliber mold. That, plus a 15 thousandths patch equals 73 thousandths. You won't be trying to engage any rifling here - the patch's function is just to form a seal and keep the ball centered in the bore. And if you aren't happy with that patch thickness you can always increase it to 18 thousandths. A ball much bigger than .70 limits your options with patch thickness. Good luck and enjoy.

 

[BEP]

Okay, "That, plus a 15 thousandths patch equals 73 thousandths" should have been ".73 caliber" not "73 thousandths". My bad, but you get the idea. :redface:

 

[Britsmoothy]

.690" everytime with a well lubed patch and keep shooting all day if you wish :thumbsup:

B.

 

[flintlock75]

My Pedersoli Bess has a .729 bore. I use a .705 ball with a .018 to .020 patch. A thick patch works great for the first dozen shots, then the fouling builds up so I go with a thinner patch, during a long shoot it comes down to a bare ball over a wad. I can get about 40 shots off before I must swab the bore with a very wet patch to break up the fouling. my standard charge is 90 grs of 3F.

 

[nwtradegun]

mine has a 730 bore bess shoots a 715 and 15-18 thou patch 85 gr swiss 3f. this gives easy loading and 50 yard accuracy for hunting. track of wolf sells them.

 

[hunts4deer]

So far I have recommendations for:
.690 (1)
.700 (1)
.705 (1) (for a.729 bore)
.715 (2)(Pedersoli unspecified bore),(.730 bore)

Here's my thinking:

• A patch that will carry a good amount of lube and give a range of compression would likely be around .015 ??
  A ball of .709 creates a .010 gap all around the ball, to be filled with .015 patch which then must undergo a 1/3 compression down to .010
  If it gets hard to load switch to .010 patch.
  If I want to try to get a tighter fit, go for .020 patch

Does that sound reasonable? What is the most common amount of patch compression for smoothbore, 1/3, 1/2? I welcome more input and opinions on what works best.

 

[Many Klatch]

In my Pedersoli Bess I shoot a .715 ball with a .010 linen spit patch over 90 grains of 2F. I can shoot 20 to 30 shots depending on the humidity level before I need to either swab the bore or beat the ball down with the rammer.

If you switch patch thickness during shooting that will change your point of impact. Keep it simple. Pick one patch ball combination and stick with it. Loose is good.

Many Klatch

 

[Britsmoothy]

A .690 and thin denim over a fiber wad wetted with olive oil=no bad foul issues :hatsoff:

My new trade gun is giving me a headach with ball. The fouling is bad and I do not have any fiber wads to carry the oil so I have stamped some leather and soaked them in olive oil. So a OS card+leather oil soaked wad+ patched ball so far (5 shots) fouling issue seems to be fixed as in soft and not crusty! May do the same with shot too.
The ball in this example is a poor choice...I only have some .562" but the bore is .625"! Doubled up linen patches hold it snug though.....for now!

Use what ever size you wish but with an oiled wad first you won't get a fouling issue :thumbsup:

B.