I recently bought a 500 with an 8 3/8" barrel. Its still like new (less than 200 rounds), and I'm not independently wealthy so I'm reloading ammo for it. I've shot a few 375 and 440 grain cast bullets through it without a problem. I've also got some jacketed 300 grain Hornady FTX rounds loaded for it. Most of the time they're as accurate and as fun to shoot as anything I've ever had, but the other day I had some that wouldn't extract without breaking them loose with a dowel. The first thing that comes to mind is they're too hot. They're not. I worked up a load using Lee dies, Hornady brass, CCI 200 primers, and Winchester 296 powder. For obvious reasons I don't want to post how much, but it's well within Hornady specs. I forget the exact number but they chronograph somewhere around 1,600 fps. What's happening is I'm getting burned powder, looks just like fine sand, between the case and the cylinder wall on some of them making them stick. It doesn't always happen and it's not always the same cylinder bores. The only thing I can think of is the crimp on the case isn't right. Has anyone else seen this before?
Thanks in advance.

There is no problem with posting your load here,The amount of Powder is the first thing that should be investigated.Maybe the load is too light causing pressure spikes or unburned Powder? 296/H110 are finicky Powders that only perform well on the upper end of the scale.

I figured out early that with full loads of H-110, 296 or MP-300 it really works better to use a Large Magnum Rifle primer. You'll have to make adjustments to your load and work up of course.That will clear up the crystalyzed particles. Also keep an eye on your brass as it will stretch and needs to be trimmed from time to time. Untrimmed brass will also tie one of those guns up tighter than hell.

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As for me....make mine .500

The HDY 300 FTX is the only bullet I've used in our 500. Some of the reduced loads (85% full & ~40K psi) I tried used H110/296, & a CCI-200, which I estimate brackets (no chrono) the 1600fps mark you mentioned & had no problem with them. My thought would be as you suggested, that the crimp wasn't heavy enough on the ones that gave you unburnt powder & extraction troubles. Of course the reduced loads don't burn as completely as a full load but if you had more partially burnt grains with those than the ones that didn't have a problem, that might be worth paying closer attention to.

This isn't a good powder to download with as you may know. Lyman #49 has some reduced load data worth looking at if you have some Unique, which worked well for me.

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Waiting for the break of day

Hodgdon does not specify anything but Large Rife for any powder including H110/296. I’d suspect they know more about reloading than you. Too hot a primer isn’t a good thing.

I’ve been using WLR primers for 11 yrs w/o a single issue with consistency or hard extraction but I use Starline brass. Don

For the OP, I’d strongly suspect that most of your problems are due to using Hornady brass, it’s much softer than Starline and prone to problems. Don

Thanks for all the replies. I'm not trying to shoot reduced loads, 32.5 grains if I remember right. Fairly hot, but nowhere near max yet. And as Don mentioned, I can't find a load chart that mentions magnum primers and I'm not one for experimenting with a $1,200 firearm or my hands. I'll take a closer look at my brass, I'm thinking that may be the problem.
Thanks again for the advice.

Wow that's not even close. I hope nobody takes what I just said seriously, I load cast bullets at 32.5 grains. I don't have my load specs in front of me, but if I remember right its more than 40 for the FTX bullets.