Metalman1 said:
Rem 40 S&W, 180 gr, FN FMJ bullets ... I can't find Starting or Max powder loads for Powder Pistol or Unique.
When the load data lists only max powder charge, many use 10% reduction as start charge.
Lyman #49 lists the following and 10% reduction of 5.6 gr is 5.1 gr and is close to the listed 4.9 gr start charge for Unique. 10% reduction of 6.7 gr is 6.1 gr and is close to the listed 6.0 gr start charge for Power Pistol (Note: Lyman data uses shorter 1.115" OAL so powder charge range will be less than Alliant data that uses longer 1.120" OAL).
40S&W 180 gr Sierra JHP Unique 1.115" OAL Start 4.9 gr (839 fps) 18,800 CUP - Max 5.6 gr (916 fps) 23,100 CUP
40S&W 180 gr Sierra JHP Power Pistol 1.115" OAL Start 6.0 gr (876 fps) 19,300 CUP - Max 6.7 gr (974 fps) 22,900 CUP
Metalman1 said:
FN FMJ ... is the OAL the same as a JHP? I think I can use the same powder loads and keep the OAL at 1.120.
For determining what OAL to use for any particular bullet, you should use the barrel drop test to determine the max OAL and check reliable feeding from the magazine to determine the final working OAL -
http://www.thehighroad.org/showthread.php?p=8864541#post8864541
For most 155 - 180 gr 40S&W jacketed/plated truncated cone flat point (TCFP) / round nose flat point (RNFP) / flat nose (FN) bullets, I have used 1.125" - 1.130" OAL in various pistols but you should use the OAL that will work with your pistol/barrel/magazine.
Since the FN FMJ bullet is shorter than the JHP, bullet base will get seated shallower when using the same OAL which will lower chamber pressures. If your working OAL is longer than 1.120" listed for
current Alliant load data for JHP, I would reference the Alliant load data for powder work up for the FN FMJ bullet but many prefer to use the lowest published load data for their powder work up.
40S&W 180 gr Speer GDHP Unique 1.120" OAL Max 6.7 gr (1,000 fps)
40S&W 180 gr Speer GDHP Power Pistol 1.120" OAL Max 7.2 gr (1,013 fps)
So for 6.7 gr, 10% reduction would be 6.1 gr for Unique and for 7.2 gr, 10% reduction would be 6.4 gr for Power Pistol.