Square load for 12 ga?

[spurgon]

What weight shot load for a "square" load for a 12 gauge?
spurgon

[Sir Charles deMoutonBlack]

Two rules;

1.  Holland's rule of 96.  The gun should weigh 96 times the weight of shot for reasonable recoil management
    e.g.  gun weighs 6 pounds, shot charge is 1 oz.
              "       "     7 1/2 lbs.   "        "     is 1 1/4 oz.

2.  A "square load" in its strict definition is equal volumes of shot and black powder, with the HEIGHT of the shot column being equal to the diameter of the bore.  The traditional British 12 ga. "game gun" weighing about 6 1/4 lbs, used 1 1/16 oz shot, to give you an idea. That is about as close as you can get to the "square load.", and is bang on the 96 formula.

I would start with the rule of 96 to find your ideal shot weight, and then MEASURE your powder with the same measure..  While 1 1/16 oz shot is the same volume as about 75 grains of powder, it is often found that an effective powder load can be as much as 30% less.  Less powder = tighter pattern.

[Sir Charles deMoutonBlack]

The theory of the square load is based on the observation that the most even patterns happen when the shot column is about the same height as diameter.  Without getting little tubes made up to actually measure, just pick a light load. For 12 gauge pick a load from 1 oz to 1 1/8 oz, and try it out to see if it does the job for you.  If you are going hunting, try 1 1/4 oz, but don't use a greater volume of blackpowder than shot.  It will generally be counter-productive.

The blackpowder I refer to is 2F.  Generally speaking, 3F is too fast for a .730 bore.  For smokeless, there are many loading manuals laying about. For 777 & Pyrodex, see the Hodgdon manual.

Less powder = tighter patterns, so does slower powder, generally speaking.

See the thread below"Anyone Loading Black Powder".  .