I can confirm that XcountryRider's (XCR) Liberty barrel rifle achieved higher average velocity than my Satern barrel and the .264 LBC BHW barrel. We all shot commercial 123 gr A-MAX from the same box, lot #8150. As XCR pointed out, it was very hot yesterday in the Southern CA desert - 97F, and we were at 3400 ft elevation. So all of our velocities were higher than advertised.
We shot through three chronographs simultaneously and the fps results for 5 shots were:
rickOshay - Satern 24" 5R cut rifled:
Magnetospeed: 2639 average, ES 10
F1 Chrony: 2636 average, ES 28
Beta Chrony: 2633 average, ES 19
XCR - Stoner/Liberty 24" 5R button rifled:
Magnetospeed: 2673 average, ES 53 (he had one shot that measured 2701 fps)
F1 Chrony: 2666 average, ES 43
Beta Chrony: 2647, ES 37
.264 LBC 24" 3 Poly BHW barrel:
Magnetospeed: 2641 average, ES 21
F1 Chrony: 2622 average, ES 15
Beta Chrony: 2615 average, ES 12
XCR's barrel is faster, but does show more ES.
None of the spent brass showed ejector marks. Many of them from all three guns had flattened primers which was expected given the conditions.
We have eliminated one of the three possible reasons for XCR's high velocities - his chrony readings are in agreement with others.
XCR is aware that his rifle may be producing higher pressures and may run into pressure issues earlier in load development, especially under extreme heat conditions. But there was no evidence on the spent brass of any higher pressures than generated by the other two barrels.
We shot through three chronographs simultaneously and the fps results for 5 shots were:
rickOshay - Satern 24" 5R cut rifled:
Magnetospeed: 2639 average, ES 10
F1 Chrony: 2636 average, ES 28
Beta Chrony: 2633 average, ES 19
XCR - Stoner/Liberty 24" 5R button rifled:
Magnetospeed: 2673 average, ES 53 (he had one shot that measured 2701 fps)
F1 Chrony: 2666 average, ES 43
Beta Chrony: 2647, ES 37
.264 LBC 24" 3 Poly BHW barrel:
Magnetospeed: 2641 average, ES 21
F1 Chrony: 2622 average, ES 15
Beta Chrony: 2615 average, ES 12
XCR's barrel is faster, but does show more ES.
None of the spent brass showed ejector marks. Many of them from all three guns had flattened primers which was expected given the conditions.
We have eliminated one of the three possible reasons for XCR's high velocities - his chrony readings are in agreement with others.
XCR is aware that his rifle may be producing higher pressures and may run into pressure issues earlier in load development, especially under extreme heat conditions. But there was no evidence on the spent brass of any higher pressures than generated by the other two barrels.