If you switch to Blackhorn 209, I strongly recommend you weigh out each charge with a powder scale, not use a volume measurement. BH209 burns hotter, faster, and creates more pressure than traditional black powder. If you're not careful, it can be dangerous. There are formulas on various forums that can assist in converting grain weight to volume measurements but keep in mind, these are not 100% accurate. One lot of BH209 may convert 77 grains by weight to 110 grains by volume but a different lot may only produce 100 grains by volume for the same grain weight. Add too much by volume and you may end up with a different bang than you expected.
For example, a muzzleloader rated for a 150 grain charge WILL NOT safely shoot 150 grains by volume of BH209. It can shoot 3 x 50 grain preformed charges, sure, but not 150 grains of BH209.
I have two muzzleloaders that I use BH209 in, one is a Paramount HTR which is rated for magnum loads, and the other us a Accura MR-X which is more of a standard muzzleloader.
I shoot 98.1 grains by weight of BH209 out of my Paramount HTR (.40 cal, 225 grain bullet) and get muzzle velocities similar to a .308 WIN. I zero it 2.1" high at 100 yards, it's dead on at 200, and drops 9.2" at 300. This load is on the low end of "magnum loads" but it's where I started, had excellent accuracy and velocity, so I never increased to heavier loads. I've shot deer at 200 yards with it and it's wicked. Of the 2 bucks I shot with it, one at 194 yards and the other at 206 yards, neither ran. Both dropped on impact with hits in the vitals. I absolutely love that gun but toting a 10+ lbs muzzleloader around isn't always fun.
However, with the Accura MR-X, 77 grains by weight of BH209 is the top end of the BH209 charge the gun will safely handle. Breach action muzzleloaders simply cannot handle the pressure that a bolt action muzzleloader can.
Strongly recommend reaching out to muzzle-loaders.com (they have a customer service line you can call) to help you dial in a safe load. They are extremely helpful and knowledgeable but most importantly, will help keep you safe. No, I am not affiliated with them whatsoever but whenever I've had a question, they have always steered me in the right direction.
Sorry for the long message. Just thought it was worth sharing because I went through this same process a few years ago and almost learned the hard way.
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