The gun shop got in some 300 grainers. I loaded some with 19 grains of H110 and crimped with a taper on the lowest crimp ring. They barely fit in the cylinder and it rotates fine. My question is will they jump and lock up? My tapercrimp has held effectively on everything else.

I've never taper crimped any revolver cartridge for fear of bullet jump. .45ACP is the only round I use a taper crimp on. Good luck.

I started taper crimping a few years ago with 38 and 357 because the cases were never exactly the same length and some would crease with a roll crimp. I have not had amy issues once i taper crimped but habe not shot the big boys in 300 grains. I guess we will see.

I think that you could be asking for problems with that load. The 50AE has similar issues in the BFR for the same reason. Jumping crimp is why you typically don't see big bore handgun cartridges with taper crimps.

So my first question to you is why don't you trim your brass to ensure consistent length? About every 2nd or 3rd load I will run my 44M brass through the trimmer just to ensure things are still consistent. I can't remember the last time I actually did take anything more significant than the slightest amount off the case, probably .0005" or less. Were it not for the fact that I tend to be a bit on the anal retentive side I could probably abandon that step altogether and not see any adverse side effects. The pressure loss as the bullet jumps the B/C gap will pretty much nullify the slight variability that you might see due to the slight differences in seating depth.

Even then, good neck tension and a nice deep roll crimp keeps my hottest fire breathing 44m loads secure. I have not had a single one jump crimp yet.

I think you'd be better off using a roll crimp, but if the taper crimp works, go for it.

The only way to know is shoot them and let us know what happened....

They worked well. No jumping, no binding. I think that i found my new favorite load.

The 300 XTP on the second crimp line in my 44 mag is my favorite jacketed load for my SRH in 44 Mag.