compression is a mystery, but not a big problem.. just another factor to figure in in the hell raising problems of black powder.. im finding my best load for 45-70 is using a 500 grain bullet, probably becouse bp gets better cleaner burning for me with a heavy bullet.. i wonder if this is the same thing the us govt found when it switched from 405 to 500 grain bullet in military rounds.. i then use 4 .030 vegi wads under a 500 grain gas check bullet (without gas check) to stop blowby and unkowingly increase compression to make good groups.. how i got this to my advantige is a miricle. the shilo forum guys say compression should be .2 to .3 inch.. not a tough proposition.. what i do now is change the powder load 5 grains an outing with a new bullet to see what load compresson works best.. it seems to come together for the limited time ive used it.. then ill taper this down to the best weight and start changing vegi cards.. on thing at a time. mix this with crimp variences, and types of powder and primers, and its a second full time job..make sure some of the bullets dont poke back out further after loading. weather plays a role here too.. light, wind, and front rest postion, body position etc has taught me that one outing with a load will not reflect a good test for it.. my best load today was off, but i needed to tighten a lawrence sight that i hit pretty hard with the cleaning brush and rod some how,,.. it was cold and i wasnt paying attention. one big help for me is i shoot test loads at 25 yards, it takes very little time to run a target, and make notations on it, and dont have to wait to go up on the 100 yard ranges as the 25 range is less crowded, especailly on snowy mornings like this.. what i do now is put on a firm crimp, not heavy by any means, on a trimed case, cases must be trimed every time. and cleaned with water and brush on drill and flash hole cleaned with drill bit the same size it was drilled at.. then seat the bullet back to where it will load three or four times without blow tube, (for hunting) not much, then vary powder for compressioin to get started.. it seems to be luck as ive only gotten one good load, and as i stated you must not arrive at this with only one group.. bp is the most fickle thing ive ever worked with and once you get a good home base with one good load things start to really come together pretty fast.. as you can use it to see if you ahve other problems than the load.. its taken me over a year and a half to get to this point, and im just tryhing to help, you need alot more infl.. i sugest also reading the shilo page at
http://www.shilohrifle.com/forums/viewforum.php?f=2 they have a black powder page with good natured long range shooters, probably some of the best in the country, and they are very helpfull. lots of fun on a cold night.
ive learned the hardway that black powder is a cold hearted mistress that keeps all shooters hopping and hopeing.. i shoot ducks with a 16 gauge flintlock and have good luck with it and still am still learning after 15 years of shooting trap and winged critters with percussion and flint.. this is the greatness of bp, it gives the game an edge, greatly reduces distances we can hunt at and puts hunt back into hunting.. good luck dave..
