As promised, I went out and ran my own test today to add to the knowledge base. The test guns were a Sig P365 and a Sig P365 XL. I used 124 grain Precision Delta jacketed round nose bullets, 4.3 grains of W231 and mixed brass, loaded to 1.155" OAL. All results were obtained using a Labradar.
The primers were recently purchased Federal No. 100 Small Pistol Primers and some older Federal No. 200 Small Rifle Primers in the old red box. (If I use any rifle primers in my pistols, these would be the ones, so I used those. Sorry.) The results were:
Sig P365
Federal Small Pistol- Average 1017, high 1028, low 1005, extreme spread (ES) 23, SD 7.6. 10 shots
Federal Small Rifle-Average 1020, high 1035, low 1002, ES 33, SD 9.7. 10 shots
Sig P365 XL
Federal Small Pistol-Average 1059, high 1076, low 1042, ES 34, SD 11.0. 10 shots
Federal Small Rifle- Average 1057, high 1084, low 1044, ES 39, SD 12.2. 10 shots
(Also, from notes, using Winchester Small Pistol Primers for Standard Loads-Average 1043, high 1060, low1025, ES 35, SD 13.9. 5 shots.)
There were no malfunctions. I did not test for accuracy, but the velocities are the same and I would not anticipate any difference. I should have compared the primers in the fired cases like Waders did, but I forgot. I will have to do that next time I load using SRPs.
Take care!
