12 Gauge BP

[Mako]

Bob,
Your biggest problem is almost certainly mass on target. As others have pointed out you need to pattern your shotgun at those ranges and see what your pattern looks like.  You really don't want a big open pattern, merely a 6 to 9 inch mass of pellets.  Adding more pellets will be more beneficial than adding powder.  Velocity doesn't transfer a moment, mass at a velocity does.  So it is extremely important you don't blow a hole in your pattern and you need to keep the mass central.

Let's look at your load; Double AAs with a red wad over 3.4cc (54.2gr FFFg)and 7/8oz of shot will barely (actually it doesn't) give you a decent crimp.  This is if you limit your wad seating pressure
to 30 lbs. (more pressure than 30lbs compresses your wad too much to get a good crimp with 7/8oz loads)  I know because I have used that load for my daughter.  It works better with FFg because you get to use 3.7ccs of FFg (or 54.4gr.)  When you fill the shot cup and crimp you will almost always have a hole in the middle which is one sign of an under compressed load.  I used this load for her because it doesn't develop pressure well and because of that will have relatively low velocities.  You on the other hand probably don't want more velocity, but you want a better pressure build up and a better crimp over all.

One simple solution is to seat your wad to 35 lbs over a minimum of 3.7 ccs of FFg or Fg (note that 3.7 cc of FFg is 54.4gr and Fg is 51.5gr. ) Then throw 1 oz. of shot and you should get a good crimp.  The additional mass and compression to the powder, the column and the crimp will help the load develop a bit more pressure before the leaves the hull.  You will probably get approximately the same velocity with an 1/8th ounce more shot.   Your column should be dense and not strung out which promotes a tighter pattern if your choke is more open or non-existent.

A second probably better solution would be to use 4.0 or 4.3 ccs of Fg powder, 40 lbs of wad pressure and 1 oz. of Shot.  What you are doing here is actually filling space and packing your black powder.  If you want low velocities and low recoil, think coarser, bulkier powder and tight crimps.

I currently shoot either an STS or AA Hull, Red Wad at 40 lbs., 4.3cc of FFg with 1 oz. of shot and get very dense patterns out of my '78 double.  At CAS ranges I can get 100% of the mass on target if I do my job and center the pattern.  Knock downs slam back and rockers swing as if hit by a prize fighter.
I am planning on getting a half case of Fg just for shotgun and using 4.3 oz. with the above mentioned combinations.  I was given a partial can to try and I like the fact I will actually be using less powder by weight which means more reloads per pound and I get more fire and streaming smoke (still burning powder bits) heading towards the target.  I don't plan on chronographing, but expect it is a slightly lower velocity, but it showed no detriment to my pattern.  Lower velocities normally generate a tighter pattern with correctly built columns, BUT the pressure needs to build with a fast ramp rate under a tight column. A poorly compressed load gives you low velocity, but it is a ragged column with an erratic pressure curve.   There will be holes and odd shaped patterns with poorly compressed loads.  With the test loads in Fg I saw no increase in plastic residue, but there may have been more residue in the chamber and throat area to be cleaned during the match. I use a chamber brush every third stage.  Unlike some I haven't had a problem cleaning barrels after using plastic wads. I soak them with moose milk or hot soapy water and use a 12 gage Jag with a patch; it pushes out like a snake skin.  Three different shotguns, same results.  I am persnickety about the cleanliness of my weapons and I can guarantee you there isn't any residue after I clean.

So take it for what it is worth, but I recommend a tad more shot and a smidgen more (but coarser) powder.  I don't think you'll notice much more recoil but you will have some steel stomping loads.  If you are worried about recoil add the shot and go with an equivalent volume of a coarser powder (to what you are using now).  Your goal is to try and get at least 40 lbs. of wad pressure but watch those crimps.  If you stay on the ragged edge of minimum powder and minimum shot you need to monitor your crimps. 

Mako's  axiom is "Tight compressed loads make Black Powder happy..."

Pack 'em tight, crimp them hard,
Mako

[Dalton Masterson]

My loads seem to work pretty good for me in my unchoked TTN 78.
I use AA hulls, 70gr 1F skirmish, AA red wad (with as much wad pressure as I can get) and 1oz #8 shot. It crimps nicely, and takes down knockdowns with ease.
Cleanup is as easy as a squirt of moosemilk, then a quick pass with a tornado brush. Then a quick oily boresnake and I'm done.

I recently was working up a load for my wifes 20, and ended up cutting the shot cup out of the wads, and using a nitro card and felt wad over 48 gr. 1F powder. Then the shot cup and 7/8 oz #8 shot and the star crimp. Seems to work good, and doesnt leave near as much plastic. Am gonna try it with 12s after Hell on Wheels and see what happens.
DM

[Jefro]

Hey Dalton, that should be a good 12ga 7/8 load. For Heather I've been loading 45-47gr ffg with Federal 12SO wads and STS hulls. They do the job, KDs or poppers. I just loaded a batch of 7/8 46gr ffg with BPI  HELIX CUSHION DRIVER 24 wads. They match better than the Feds, gonna give them a try in the morning. For my 1 1/8 load BPI has another wad I'm gonna try in place of the  Remington SP12 I've been using, it's about 1/8" shorter OAL and should be perfect for 55 to 58gr ffg. It's the  HELIX CUSHION DRIVER18 wad. I haven't had any problem with clean up either, squirt the pipes down with Murphys mix and push a piece of paper towel through. Finish up with Balistol and the bore snake. Good luck at Hell on Wheels.
http://www.ballisticproducts.com/

   Jefro,  Relax-Enjoy

[Dalton Masterson]

Well happy to report that the 20s worked well at HOW for day one. There were a few edgers that took an extra round, but...
My 12 loads happily flattened all k/ds with ease. Hope it happens tomorrow too. DM