12 ga. SxS Shotgun help needed

[patocazador]

I came back from the panhandle to find the shotgun I bought was here. I have never had any dealings with a BP shotgun so here goes.   

Questions:
1) The bore measures .735". What size ball/mold do I need to shoot a patched round ball?
2) If I use a plastic shot cup/wad in place of the fiber one, how do I lube the load to allow for easier cleaning?
3) How do I get tighter patterns in a gun with a cylinder bore?

I think I have the regular loading system down with the over-powder wad, thicker lubed over-powder wad, and overshot-card(s).

* I just downloaded the photos so here's a picture of it.

 

[Spitfire1]

Closest ball to .735 I know of is the .690 but you'll need a thick patch.

From what I understand from the guys shooting BP shotguns you need to lower the powder charge to tighten the pattern.

 

[exMember]

.710 - .715

Looks like a great shotgun!

 

[patocazador]

I shot it today to pattern it at 30 yards. I used 70 gr. 2FG then a nitro wad followed by a lubed wad, 1 oz. of # 7 1/2 shot and an overshot card. It was a real thin pattern at 30 yards with a 5" void right in the center. I moved up to 25 yards and the density was better but the void was still there.
Then I used the same load but inserted a plastic power piston on top of the lubed wad. The pattern tightened up but the void was still there only it was about 3" then.  :x 

Any suggestions to tighten patterns and eliminate the center void? I don't know what, if anything, can be done to shrink the group since both barrels are cylinder bore. I've heard of tricks to do it but don't know any.

 

[exMember]

i'll do some research, but i think you're doing pretty good for just a beginner, just takes time to learn and experiment.

 

[Spitfire1]

Pato to eliminate the void you can try upping or lowering the powder charge as well.

 

[patocazador]

Thanks Spit. I intend to lower the charge to 60 gr. and work up in 5 gr. increments and see if I can get a good pattern.

As far as tightening groups .. do you think that the group (pattern) would shrink if I used the plastic shot cups and encircled the petals with Scotch tape to delay the spreading of the petals?

 

[Spitfire1]

Really don't know . Friend of mine shoot a shotgun and get best results using lubed doughnut wads and card wads.

 

[patocazador]

Someone else told me that the real thick lubed wad makes a center hole in the pattern. He cuts each wad into 3 thinner ones and only uses one at a time. He says that helps. It also makes your wads last longer.

 

[Greybear Jr.]

Pat,
Your friend is correct.  Each gun is different but in all of my shotguns I either use a half of a wad or none at all and just two nitro cards over the powder to get a good gas seal.  On powder and shot, general rule of thumb is equal volume of powder to shot.  In most of my 12's its 70 gr 2f to 1 1/4 oz. 5 shot for turkey.

GBJ