[Poof38]

I set up my used Dillon SD for .380 auto rounds using W 231, a 115 gr Hornady HP, Starline brass & a Winchester primer. I monkeyed with the OAL, since my manual said to keep it shorter than maximum with HP bullets, but the cases bulged a bit. I ended up going up around the maximum cartridge length which minimized the bulge. I tried a few in a magazine in the garage and they chambered properly when the slide was released. I took the first hundred to the range and despite the varied lengths, I only had one stoppage. That one hung up on the ramp, but promptly chambered with one more slide pull & release. They all went bang. My Beretta 85FS seems to be fairly straight from magazine to chamber, so it may be more forgiving than another gun.

[noylj]

You are shooting a rather heavy bullet for the cartridge.
As such, you should be loading as long as possible (given magazine fit, feed, and chambering) to maintain some case volume.
If you load so long that the bullet hits the lede/rifling, at that point the JHP would have a shorter COL that a FMJ-RN. Any shorter COL, and you need to find the COL that works best in your gun.

[robocop10mm]

I have never tried a bullet that heavy in a .380. The problem is you have to seat the bullet too deeply to get a decent OAL and the base of the bullet gets into the thicker web area of the case. I would stick to 80-90 gr bullets