Starting load data question

There is often fluctuation between manuals, but after reading this, I'm interested too. My older Speer manual lists 4.0 - 4.5 gr as well, Lyman 48 lists 3.9 - 4.4, Hodgdon online lists 3.9 - 4.4 Lee #2 lists 4.2 - 4.5, Hornady Handbook #3 lists 3.9 - 5.2, and Hornady Handbook #4 lists 4.7 - 5.3. That's a lot of fluctuation, but most overlap in a significant portion. I'd go with the data from Speer, Lyman, or Hodgdon online. That Hornady Handbook #4 seems dangerously high.

A little bit of COAL difference in 9mm can change pressure significantly.

Also different test equipment. Some use a actual pistol most use a test chamber. So leads/lands are all over the place.

Zendude said:

A little bit of COAL difference in 9mm can change pressure significantly.

Click to expand...

Different COLs was my first thought too.

I just started reloading 9mm and noted the plethora of load data, many of which use similar components but different charges. COL seems to be the biggest difference.

Never forget the golden rule of reloading. Reduce 10% and work up, so 4.1 sounds like a safe place to start.

Some Chrono data, might or might not be helpful
S+P SP, mixed range brass, 5" 9mm 1911
Charges as thrown after setting measure

String: 3
Date: 10/29/2017
Time: 10:04:31 AM
Grains: 124
Hi Vel: 995
Low Vel: 962
Ave Vel: 986.2
Ext Spread: 33
Std Dev: 14
RMR 124 MPR JHP 4.0 HP38 1.08 5inch 1911
Velocity Power Factor Ft/Lbs
991 122.884 270.378
993 123.132 271.47
990 122.76 269.832
962 119.288 254.785
995 123.38 272.565

String: 2
Date: 10/29/2017
Time: 9:42:14 AM
Grains: 124
Hi Vel: 1068
Low Vel: 1004
Ave Vel: 1034
Ext Spread: 64
Std Dev: 24
RMR 124 MPR JHP 4.3 HP38 1.055 5inch 1911 (shorter OAL than above)
Velocity Power Factor Ft/Lbs
1046 129.704 301.222
1021 126.604 286.995
1004 124.496 277.518 This one messed up the numbers
1068 132.432 314.026
1034 128.216 294.35

String: 2
Date: 7/23/2017
Time: 10:44:23 AM
Grains: 124
Hi Vel: 1046
Low Vel: 1003
Ave Vel: 1026
Ext Spread: 43
Std Dev: 16
RMR 124 MPR-HP 4.5 HP38 1.08 OAL Longer OAL than above, .2gr more powder
Velocity Power Factor Ft/Lbs
1003 124.372 276.965 Another one that seems like the charge was a little light....
1036 128.464 295.49
1022 126.728 287.558
1025 127.1 289.248
1046 129.704 301.222

Wildbillz said:

I understand that the type of bullet used is going to change things a bit, but a FMJ should be the same no? Color me confused.

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There are different reloading variables such as bullet type (plated vs jacked), bullet diameter (.355" vs .356"), OAL/COL, primers, case used, etc. that will effect chamber pressures and start/max charges.

Speer load data for Speer 124 gr TMJ (Thick plated RN .355" diameter) - https://www.speer-ammo.com/download...m_caliber_355-366_dia/9mm_Luger__124_rev1.pdf

• Speer 124 gr TMJ W231 1.135" COL Start 4.0 gr (887 fps) - Max 4.5 gr (998 fps)

Hodgdon load data for Berry's 124 gr HBRN-TP (Thick plated hollow base RN .356" diameter) and Sierra 125 gr FMJ (Jacketed RN .355" diameter) - http://www.hodgdonreloading.com/data/pistol

(NOTE: Since many jacketed/plated bullets can vary by 1.0 gr, I often interchange load data for 124 and 125 gr 9mm bullets)

• Berry's 124 gr HBRN-TP 1.150" COL Start 3.9 gr (920 fps) 27,400 PSI - Max 4.4 gr (1,037 fps) 31,900 PSI

• Sierra 125 gr FMJ 1.090" COL Start 4.4 gr (1,009 fps) 24,600 CUP - Max 4.8 gr (1,088 fps) 28,800 CUP

So, depending on bullet type, sizing and OAL use, reference appropriate load data.

FYI, for most plated 124 gr RN bullets, I reference Speer TMJ (max 4.5 gr) and Hodgdon Berry's load data (max 4.4 gr) of W231. For most jacketed 124 gr RN bullets, I reference Hodgdon Sierra load data (max 4.8 gr).