9mm 124gr FMJ + HP-38: What's the recipe?

[UpTheIrons]

Greetings, all!

Having figured out the whole reloading process with .45 ACP, it's time to move to 9mm to keep my wife from shooting up all my ammo! I'm loading for an SR9c with about 400 rounds down the pipe.

I've got Zero 124gr FMJ bullets and HP-38 powder along with Winchester SP primers and mixed once-fired brass.

Hodgdon's site only has HP-38 listed with 125gr FMJ bullets (4.4gr to start, 4.8gr max load and a min. OAL of 1.090").
Lee's manual lists the same starting, max, and min. OAL numbers for a 124gr FMJ.
Lyman (49th) has nothing for 124gr bullets, and uses Win 231 for a 125gr JHP (3.9 to start, max of 4.4, 1.075" OAL).

Since the bullets are within 1 grain of each other, do the Hodgdon and Lee numbers look like a good place to start? Or should I be more conservative and use the Lyman numbers, since HP-38 and Win 231 are identical?

I'll run 10 rounds of the starting load and creep up from there with other batches of 10 until I hit the sweet spot.

Thanks!

 

[noylj]

Yes. 124=125gn. Also, 231=HP-38 Also, in almost all cases, FMJ=JSP=JHP, except the COL will vary. Loading manuals reference the shortest recommended COL.
Start with the lowest starting load your manuals show and work up. This is why I made up a compilation of all the referenced loads in reloading manuals I have come across.
Bullet Weight Powder Weight Velocity Start/Max Power Factor COL
JSP 125 231/HP38 3.2 901 Start 113
JSP 125 231/HP38 3.2 910 114 1.120
FMJ 124 231/HP38 3.9 950 118 1.040
FMJ 124 231/HP38 3.9 950 118 1.090
Speer SP, GD-HP, TMJ 124 231/HP38 4.0 887 Start 110 1.120-1.135
FMJ 124 231/HP38 4.1 Start 0
FMJ 124 231/HP38 4.2 1005 Start 125
FMJ 125 231/HP38 4.2 1000 125 1.090
FMJ 124 231/HP38 4.3 1000 124 1.040
Sie FMJ 125 231/HP38 4.4 1009 Start 126 1.090
J-all 124 231/HP38 4.4 1008 Start 125
FMJ 124 231/HP38 4.5 1060 Max 131
Speer SP, GD-HP, TMJ 124 231/HP38 4.5 998 Max 124 1.120-1.135
FMJ 124 231/HP38 4.5 1099 136 1.110
FMJ 125 231/HP38 4.5 1050 131 1.090
JSP 125 231/HP38 4.6 1099 Max 137 1.120
JSP 125 231/HP38 4.7 1022 Start 128
FMJ 124 231/HP38 4.7 1025 127 1.150
FMJ, JHP 124 231/HP38 4.8 1050 Accurate 130 1.040/1.100
Sie FMJ 125 231/HP38 4.8 1088 Max 136 1.090
FMJ 125 231/HP38 4.8 1100 138 1.090
JSP 125 231/HP38 5.1 1108 Max 139
JSP 125 231/HP38 5.1 1059 Start 132
FMJ 124 231/HP38 5.1 1150 143 1.090
FMJ 124 231/HP38 5.2 1100 Max 136 1.040
FMJ 124 231/HP38 5.3 1125 140 1.150
FMJ 125 231/HP38 5.4 1200 Max 150
JSP 125 231/HP38 5.6 1149 Max 144

 

[Jim Watson]

My test:
9mm Para 5" Springfield
124 gr Remington FMJ
4.4 gr HP38
1064 fps
That worked for Herr Luger in 1903, it is good enough for me at power factor 131+.

Sorry, I don't have OAL but it was probably more than you show.
Start around 1.14" and see if it chambers

 

[LiveLife]

With 124/125 gr jacketed/plated RN and W231/HP38, I typically load them with 4.3 gr at 1.125" OAL.

 

[rfwobbly]

I'm with BDS.

4.3gr does fine for a jacketed or plated 124gr anything from 1.125" to 1.169".

 

[UpTheIrons]

Thanks for the info!

I worked up a dummy round to get the turret all ready to go, and have a COL of 1.115" and it chambers fine in the gun. I may tweak that out a bit to 1.125" before I load up a few tomorrow and see what happens.

My Lee Auto Disk throws odd weights. I'll get 4.1 from one cavity, then 4.5 from the next, 4.7 from the next one up, and 5.1 from the next. I'll experiment with a few from the three lower volume cavities to see which one works best. It looks like the 4.5gr throw will be the one to run with, though, unless I can tweak that Auto-Disk a little.

 

[LiveLife]

My Lee Auto Disk throws odd weights. I'll get 4.1 from one cavity, then 4.5 from the next, 4.7 from the next one up, and 5.1 from the next.

The Auto Disk holes will drop 0.2-0.3 gr (up to 0.4+ gr) average between holes depending on the powder used. Many reloaders "customize" disk holes so they get the powder charge they want.

Lee Double Disk kit is about $10 and comes with two sets of 4 disks. I drill out the holes so I have "in-between" sizes for 0.1-0.2 gr increments.

FYI, here's the Lee Auto Disk chart PDF.

 

[UpTheIrons]

Funny. That chart doesn't match up, even when I look at the HP-38 numbers. They are + or - 0.1gr in either direction of what I get out of them.

Anyway, here's what happened this morning. I loaded two sets of 10 rounds as follows: 124gr FMJ, Win SPP, 1.124" OAL, one set had 4.5gr HP-38, the other set had 4.7gr. Hodgdon lists 4.8 at the max load, so I was a bit hesitant to be so close to the top, but that's what my Auto-Disk choices were.

The target on the left was the 4.5gr rounds, the target on the right was from the 4.7gr ones. Two hand stance at 7 yards. I could definitely feel the power difference between the two, and the 4.7gr load felt more like a factory round. I think I'll continue with that load, since the accuracy was so much better. Didn't think it would be that much, but it is what it is. I could have tightened the groups up a little more, but it was a rushed range trip and I was really there to function test the loads more than anything. I didn't expect so much of a difference.

 

[LiveLife]

Funny. That chart doesn't match up

Well, it wasn't funny when I first used the chart and powder charges did not match! I thought "what the heck?" and must have reweighed my charges about 5-10 times and even thought my Lee scale was broken (it almost got thrown out the window) Yeah, my reloading mentor had a good laugh on me when I told him about it. For me, W231/HP38 comes fairly close to the chart, varying about 0.1 gr. If it's off by 0.1 gr, I just use the charge as it won't make that much difference.

The target on the left was the 4.5gr rounds, the target on the right was from the 4.7gr ones.

Powder burn will become more consistent as you go higher on the load data and accuracy will often improve with increasing recoil. For me, with the 4.3 gr loads shot out of G22/G27 with LWD conversion barrels, I usually get 1" shot groups at 7 yards, which is good enough for me.

 

[rfwobbly]

Two hand stance at 7 yards.

You really need some sand bags or other type of hand steady. This because most people shoot better after they "warm up". Your test won't be conclusive until you shoot the higher load first next time.

 

[ArchAngelCD]

My son's favorite practice 9mm FMJ load is a 124gr FMJ bullet over 4.4gr W231/HP-38 with an OAL of 1.115". With a 124/125gr LRN bullet I drop the charge down to 4.0gr W231/HP-38.

Neither load is a barn burner but they work and they accurate.