How to determine the powder load?

[oldracer]

Some years ago I was shooting black powder cartridges and they were 45-70. I spent 6 months getting the right powder load, 68 grains FFG, wad, ETC for the cast bullet I was shooting. Since switching over to muzzle loaders exclusively I find I have to use more powder to get the same grouping as before. As an example with my latest 45 caliber slug gun I use 90 grains of FFG and get about the same grouping at 300 yards as I did with 68 grains in the 45-70's? I wipe between shots and see NO unburned powder particles on the patch so I am figuring all the powder is burned? A few weeks ago I stayed later then normal and the sun was going down and I shot several times and got very large fireballs out the muzzle but I used to get them with the cartridge guns too?

Thoughts anyone? Thank you

[jdfoxinc]

Try FFFg in your .45. It will still have muzzle flash, but more rapid burn.

[waksupi]

Check your nipple.

[mazo kid]

You will get pressure drop shooting a muzzle loader flint or cap lock as opposed to the closed system of a cartridge gun.

[oldracer]

Thanks for the replies guys. I tried several different nipples and also tried one of the Mag Fire adapters which I setup my under hammer for in the beginning. I think in the muzzle loaders system it is not what would be called a "closed" system which is one of the reasons that the patent breech was started. In looking at my note book I find that the velocity of the 540 grain grease groove bullet is the same from the 45-70 and also the muzzle loader, 1255 FPS give or take a couple? Just sort of curious about this stuff.

[charlie b]

What bullets are you shooting from both?

For my conicals in the ML I use bore size. To get a good group they have to be 'bumped' by the powder charge to get good accuracy. For a cartridge I'd be using groove dia bullets. No 'bumping' required so charges can be less.

Velocities. Are the barrel lengths the same? And as stated, the ML has a 'leak' at the back end so pressure drops a little quicker.

[jime444]

well, your bullet in the 45-70 was groove size and the bullet in the muzzleloader is smaller........therefore, the gas seal created by the bullet in the suppository rifle is much superior. without this good gas seal, including the percussion nipple vent; you may require significant more powder to achieve similar velocities.

[Rattus58]

well, your bullet in the 45-70 was groove size and the bullet in the muzzleloader is smaller........therefore, the gas seal created by the bullet in the suppository rifle is much superior. without this good gas seal, including the percussion nipple vent; you may require significant more powder to achieve similar velocities.

That clearly depends upon the barrel... doesn't it? My guns could be engraved to seal with a .457 bullet easily.. but I've not the patience for that , do .452 sizing and an over powder card wad...
Much Aloha...

[maillemaker]

I shoot N-SSA competition. I find the proof is in the grouping off a bench. I don't care how much powder is or isn't getting burned, or the size of the fireball - all that matters for me is the grouping off a bench.

I do load workups in at least 5-grain increments until I find the magical combination for any particular bullet - assuming I find one. I use 3F Goex in everything these days.

Steve

[rodwha]

I use a felt wad under my rifle conicals as the grooves are deep and meant for PRB. This wad helps seal the gasses even though my Lee REAL is almost groove diameter. Without the wad I saw keyholes at 50 yds with hits a foot to the left and a bit low. With a wad they were nearly touching and just below the bull. It seems many use a felt wad under a conical/bullet.

[charlie b]

I use veggie wads, then lubed felt wad, then the bullet.