New .38 Spl +P Load - 11/06/21
I have been on a quest for a good "+P" .38 Special load. Most published data that I've found is mostly for 110 gr bullets. I wanted to find something that would safely push a 158 gr LSWC through a 4 inch barrel with a muzzle velocity at or greater than 950 FPS. Most data that I have seen, if you read the small print, use 7 inch or such unrealistically long test barrels, and for the most part I'm sure without any cylinder gap. This is just not reality. My .38s and .357s have 4 inch and 2 inch barrels. I am quite sure this is also the case with 75%+ of those that exist. The following loads are what I have come up with that were shot with my S&W M-19 .357 with a 4 inch barrel: All bullets were coated lead 158 gr SWCs and velocities are the average of multiple shots of each loading. Brass is mixed .38 Special. There were no signs of over pressure seen. The fired brass was easily re-inserted into the chambers, no leading, and no deformed primers.
4.3 gr. Titegroup - CCI SP primer - 906 FPS
5.0 gr. Universal - CCI SP primer - 916 FPS
5.2 gr. Unique - CCI SP primer - 957 FPS
5.4 gr. CFE Pistol - WSP primer - 890 FPS
6.7 gr. Vihtavori 3N37-WSP primer - 1007 FPS
I was particularly impressed with the Vihtavori 3N37 load as it produced by far the best velocity. While VV does not list any .38 Spl +P loads per se, this was their max published load using this powder and a 158 gr. Hornady XTP bullet. Unfortunately, they do not list any pressures with their data. I surmised that by using the same weight bullet and it being a coated lead instead of a jacketed bullet, the pressure should be a bit less and therefore safe to use this data. They also list a higher powder charge of 6.9 gr. for a 158 gr. copper plated bullet, so again I felt comfortable with the 6.7 gr. powder charge I tested with my coated lead SWCs. While I really cannot say what the actual pressure of this load is, maybe the pressure level really doesn't get into "+P" territory? The velocity certainly does and I am quite comfortable that pressure is not excessive. JMHO,YMMV
4.3 gr. Titegroup - CCI SP primer - 906 FPS
5.0 gr. Universal - CCI SP primer - 916 FPS
5.2 gr. Unique - CCI SP primer - 957 FPS
5.4 gr. CFE Pistol - WSP primer - 890 FPS
6.7 gr. Vihtavori 3N37-WSP primer - 1007 FPS
I was particularly impressed with the Vihtavori 3N37 load as it produced by far the best velocity. While VV does not list any .38 Spl +P loads per se, this was their max published load using this powder and a 158 gr. Hornady XTP bullet. Unfortunately, they do not list any pressures with their data. I surmised that by using the same weight bullet and it being a coated lead instead of a jacketed bullet, the pressure should be a bit less and therefore safe to use this data. They also list a higher powder charge of 6.9 gr. for a 158 gr. copper plated bullet, so again I felt comfortable with the 6.7 gr. powder charge I tested with my coated lead SWCs. While I really cannot say what the actual pressure of this load is, maybe the pressure level really doesn't get into "+P" territory? The velocity certainly does and I am quite comfortable that pressure is not excessive. JMHO,YMMV