Disclaimer: I am relatively new to reloading.
I've been successfully reloading 38 special with Trail Boss and was looking to try out an HP-38 recipe. I have two different brands of bullets, XTreme and Acme, both 158gr SWC. I went to the Hodgdon reloading site and checked out load data for HP-38. The results were somewhat surprising. (If the cut and paste doesn't show up well, you can just repeat my results at https://hodgdonreloading.com/reloading-data-center : 38 special, 158gr, HP-38.)
158 gr cast LSWC
Manufacturer Powder Bullet Diam. C.O.L Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure
Hodgdon HP-38 BUY NOW 0.358" 1.475" 3.1 782 11,900 CUP 3.7 834 14,600 CUP
158 gr Hornady XTP
Manufacturer Powder Bullet Diam. C.O.L Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure
Hodgdon HP-38 BUY NOW 0.357" 1.455" 3.8 661 12,600 CUP 4.3 779 15,900 CUP
The first thing I noticed is that the max charge for the LSWC (3.7gr) is less than the minimum charge for the XTP (3.8gr). Conversely, the max velocity for the XTP (779fps) is less than the minimum velocity for the LSWC (782fps).
One theory I had is that the larger diameter of the LSWC vs the XTP (.358 vs .357) and lead being not as slick as copper causes the LSWC pressures to build much higher compared to an equal weight copper bullet and therefore less powder is needed to achieve the same pressure (and velocity). Is this correct? Is there anything else going on here that I'm overlooking?
Of course, the golden rule of reloading has been drilled into my head: start low and work your way up. But the physics of what's going on with this published data is very interesting to me if anyone can enlighten me. Is it likely that my Hitek coated Acme bullets would more closely mimic the LSWC and the copper plated XTreme would be akin to the XTP?
Thanks,
Ken
I've been successfully reloading 38 special with Trail Boss and was looking to try out an HP-38 recipe. I have two different brands of bullets, XTreme and Acme, both 158gr SWC. I went to the Hodgdon reloading site and checked out load data for HP-38. The results were somewhat surprising. (If the cut and paste doesn't show up well, you can just repeat my results at https://hodgdonreloading.com/reloading-data-center : 38 special, 158gr, HP-38.)
158 gr cast LSWC
Manufacturer Powder Bullet Diam. C.O.L Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure
Hodgdon HP-38 BUY NOW 0.358" 1.475" 3.1 782 11,900 CUP 3.7 834 14,600 CUP
158 gr Hornady XTP
Manufacturer Powder Bullet Diam. C.O.L Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure
Hodgdon HP-38 BUY NOW 0.357" 1.455" 3.8 661 12,600 CUP 4.3 779 15,900 CUP
The first thing I noticed is that the max charge for the LSWC (3.7gr) is less than the minimum charge for the XTP (3.8gr). Conversely, the max velocity for the XTP (779fps) is less than the minimum velocity for the LSWC (782fps).
One theory I had is that the larger diameter of the LSWC vs the XTP (.358 vs .357) and lead being not as slick as copper causes the LSWC pressures to build much higher compared to an equal weight copper bullet and therefore less powder is needed to achieve the same pressure (and velocity). Is this correct? Is there anything else going on here that I'm overlooking?
Of course, the golden rule of reloading has been drilled into my head: start low and work your way up. But the physics of what's going on with this published data is very interesting to me if anyone can enlighten me. Is it likely that my Hitek coated Acme bullets would more closely mimic the LSWC and the copper plated XTreme would be akin to the XTP?
Thanks,
Ken