I use 777 in my Swede's all the time. Case capacity will never be up to original black powder capacity so even given the 15% reduction Hodgen recommends, it's not a problem. I basically fill the case to a point where a veggie wad on top of the powder will give slight compression and the bullet will seat to where I cannot see the uppermost lube. I am casting a .512 bullet using mostly wheel weights. I lube with a 50/50 beewax/lard mix. One of my Swede's, the Remington made one, will print a 2-3 inch group at 100 yards with the iron sights. The throat on this one is very liberal and I have no problems chambering. I use reformed .348 Win brass, and also I use .50 Alaskan trimmed down with a tubing cutter. I bought some of the Bertram 12.7 x44R brass, but found it not very uniform as far as rim thickness, or diameter. It is also thinner than the other brass and tends to collapse easier. I'm down to three rounds of it now and will not purchase more. The .348 and .50 Alaskan is slightly smaller in diameter than original brass so you have to let the breech pull the bullet in or you may "miss" the extractor and will have to force the shell out of the chamber with a rod. I am considering having someone rechamber one of my Carl Gustav's to a .50-70 or .50-90 chamber, using the same barrel, and just use the .512 bullet.