158gr HSM PHP in 9x23 Comp

[zaphar]

Howdy, I'm planning on working up the following load tomorrow, but want to get a second opinion on the matter. The load will be:
158gr HSM PHP (.357)
4.0gr Unique (to start)

Starline 9x23 Comp brass (fire formed to .390 and resized to .383 neck and web)

Wolf SPP

OAL 1.245

lee factory crimp die

The firearm will be a standard steel witness in 38 Super.

This load is based on one listed in the Lyman Reloading Handbook 46th Ed:
#358311
158 gr. (#2 Alloy) 1.245" OAL
Unique start 4.4gr/958fps/20,100C.U.P. - 5.1gr/1058fps/28,100C.U.P.

I haven't used Unique before, it's a bit faster than what I've been using (HS-6/Longshot). Are there any things I should look out for when using it, other than a double charge? Bullet tension seems like it will be OK in the 9x23 Comp brass even though it's being sized with 38 Super dies due to the .3575 bullets being used, I had trouble before with .355 bullets and had to use 9mm dies. Any suggestions would be appreciated if I'm heading in the wrong direction.

Edited June 10, 2013 by zaphar

[superdude]

Not sure why you're using 38 Super dies. The 9mm are more appropriate for the tapered 9X23. The expander die should return the neck to the same dimensions regardless of 9mm or 38 Super, but with the 38 Super sizer, as you've noted, you typically get less neck tension in a 9mm-like case because of differences in case design between the cartridges.

[zaphar]

At first I was planning on using the 9mm dies but figured that if I could effectively use the 38 Super dies, it'd be closer to the actual chamber dimensions of the pistol I'm using, which are .390 at the mouth and web. It definitely wont work with a .355 bullet since it slides right in after resizing, however with the .357 bullet it does not.

[zaphar]

Just a follow up, I switched to 9x19 dies as you suggested. Both dies worked, however after comparing the two loaded cartridges side by side, I see what you mean about case taper. With the 38 Super dies, a taper remains close to the web, with straight case walls from there to the case mouth. With the 9x19 dies, the taper extends from the web to about 3/4ths up the case or to about where the bottom of the bullet is seated.

4.0gr of Unique caused a FTE with one of the rounds so I tried 4.2gr which worked well, although I still need to chronograph it to see where the velocity is at. The OAL of 1.245" was making contact with the rifling, so using the drop test, I found that right around 1.24" was where the bullet started to not stick so the new OAL became 1.235".

[kneelingatlas]

I don't know how relevant this info is, but 5.5gn of Unique in 9mm (1.146" OAL) pushing a 124gn CMJ made 146 PF for me, but is very soft.

[zaphar]

In the few work-up loads using Unique, it shot well, although I now understand why many reloaders here prefer other powders for progressive loading.
4.2gr 14 shot average of 836fps, 132pf

4.3gr 6 shot average of 857fps, 135pf

4.4gr 6 shot average of 873fps, 138pf (one FTE)

There's another six rounds loaded up with 4.5gr but I was unable to test them due to white faced hornets and other wasps swarming me. That'll be the last of the Unique used, the rest went into ~950 rounds of 40S&W practice ammo. I have HS-6 and Longshot on hand, any ideas on which one would perform better (aiming for ~1100fps)? The closest information avalible in the Hodgdon reloading reference is for a 150gr and based on it, I'm thinking Loudshot:

150 GR. CAST LRN Hodgdon Longshot .356" 1.230" 5.0 1076 27,200 CUP 6.2 1162 32,200 CUP

150 GR. CAST LRN Hodgdon HS-6 .356" 1.230" 6.4 1078 25,400 CUP 7.1 1175 30,900 CUP

150 GR. SIE JFP Hodgdon Longshot .356" 1.265" 5.5 1040 26,900 CUP 6.0 1126 31,800 CUP

150 GR. SIE JFP Hodgdon HS-6 .356" 1.265" 6.5 1029 26,000 CUP 7.2 1137 31,200 CUP

I thought Longshot was supposed to be slower than HS-6?