Oh, I so do hate to get into this thread...makes me feel kinda dirty if you know what I mean. But, amongst other things properly black, I load for my 470NE double. Like many contemporary doubles, it was regulated with Federal ammo. Now, I bought a box of that stuff when I was new to the gun to prove its accuracy. The two barrels shoot to one ragged hole at 50 yards.
But, the Federals cost $7 per bang so hand loading is mandatory. Problem is, I had to duplicate the Federal load and if any of you have ever done either, I reckon it's easier to regulate barrels to a load than finding a load which matches the regulation parameters of the barrels. I, therefore, did the only proper thing and pulled one apart to examine the charge under the microscope. It was 84 gr of a medium length tube powder with no wad
. The load rattled around like a spoon of salt in a coffee can. Seriously, that case is less than half full.
So. there I was out at the Safari Club convention in Reno where I hounded the Federal guys to give up the recipe. "Oh, my dear fellow, no...secret...tripple secret and arcane knowedge...even we do not speak of it...we would have to kill you...please go away or buy something." Finally - I'm a most tenacious fellow - they said that it was a proprietary canister powder not available to the marketplace. "Now, go away or buy something."
Later after the 12 bars opened - SCI is a very civilized place - I found noted African writer, Craig Boddington, and told him the story. After spitting his scotch half way across the room, he said, "B*** S***! It's 84 gains of RL15!" The difference, and the thing we reckoned allowed all that air space without an explosion, was a truly proprietary primer hotter than the 215, a 216 if you will.
How to overcome the problem? A trip over to the Kynoch booth yielded up some 1" black foam wads. It's very open celled and squishy and, according to Kynoch, completely obliterated in the ignition sequence.
Loaded 'em up, shot the range at 50 yards and they cut one ragged hole. Sweet success.
The point is, Federal got it done with a huge
airspace and I got it done with a foam wad. It seems there are no absolutes.
Regards, and Damn All Chickens,