I'm having a few problems with my Razorback 10mm

[chutestrate]

I'm using Lee's truncated cone mold and the slugs are dropping at 180gr. I lubed with them with a 50/50 alox and mineral spirits mix with a coal of 1.258. The cartridges fall freely into the chamber.

Problems I'm having:

I will have 5-10 trouble free rds. Then the cartridges begin to not fully chamber and have to pushed in. If I use a brush to clean the chamber then the cartridges will feed smoothly again.

I am also having failures to feed. The boolit will get caught at an angle with the nose jammed at the top of the chamber and the bottom of the case in the magazine.

What am I doing wrong? Am I loading too long? Is the truncated cone a problem? The lube? I don't have the same problems with fmj's of the same design.

thank you for any advice given.

[Adam10mm]

Little long. 1.245-1.250 is plenty. Seat the bullet so the shoulder where the cone starts is just about the height of the case. You want to see a sliver of lead between the mouth and bullet cone.

[chutestrate]

Thank you for the advice. I'll seat some to 1.250, and try again.

[fredj338]

Try paying with oal, but I would look at your mags. Bullet designs for the 10mm are pretty much the same across the 180gr wts. My Delta only likes Colt or Tripp mags for 100% feeding.

[Blackwater]

There's another possibility too. I've found that most folks who seat AND crimp rounds for autos in a single step tend to have the 1st problem you're experiencing. What happens is that the ctg. is still going upward into the die as the bullet is seated and the crimp begins to take effect, and with that slight movement, a very slight "ring" of lead is pushed up in front of the case mouth, thus effectively causing that tiny ring of displaced metal to act as a lengthening of the case, and preventing fully chambering. This is why I've taken to crimping in a separate step for all auto ctgs. It worked, and it works consistently.

The second problem may well be one of charge wt. or powder selection. Autos feed well only within narrow windows, and the time/pressure curve must be within a narrow range. Too fast or too slow a powder, and I think this is more true for hotter rounds like the 10mm., can cause the problems you describe. More or less powder, or a change of powders may be in order. If you've got an extra power recoil spring installed, you're probably going to have to use a tad more powder, or maybe a slower one that'll keep the slide's impetus within the range best suited for your gun as it's set up. Some just don't LIKE having to do an "extra step," and I know everybody's in a big hurry to git-r-done these days, but you ALSO have to remember that the small amount of time spent in crimping as a separate step comes back to you in not having slow-downs in your pace of fire at the range. It also allows you to achieve perfect functioning, which ain't no small thing in semi-autos, ESPECIALLY if you ever get caught having to use it in earnest while it's loaded with your reloads. There are a number of real advantages in having ammo that simply WORKS in a semi-auto, or any other kind of gun for that matter. In our haste to git-r-done ASAP, we sometimes set traps for ourselves, and get caught in problems we really don't need, and don't have time for either. Something to think about?

[chutestrate]

Thank you to all for the advice. I have reseated the bullets to 1.247, and I will start there. If I continue to have problems then I will address all of the other pieces of advice one at a time. I am also tumbling my boolits with walnut media. I think the residue from loading or firing is gumming up the chamber. I'll see what happens.

[fredj338]

You tumble brass or bullets or loaded ammo in walnut? If you are tumbling brass I walnut, I don't see the issue.
Are you sizing he bullets? If they vary much from bullet to bullet, that could be an issue.

[chutestrate]

I tumble brass in walnut, but this time I'm trying some of the loaded rounds