All,
I have just recently gotten three 6mm BRX rifles up and running. They are NRA Prone guns to be used at 600 and 1000yd competitions.
The load development has been with 105-107 gr bullets along with Lapua brass,Varget,VV140,and RL 15. Bbl lengths are all 29-31 inches.
Two different Oehler 35P chronographs have been used in the development process. All barrels are SS,.236 bores, 8 twist, and custom made. Two are button and two are cut rifled.
Now here is what has made me very curious. On this site, shooters are claiming to get velocities of 2900+ fps out of standard 6mm BR cases. Shooting a standard case at 2950-3000fps seems like an awful lot of velocity to me. The BRX rifles that I have tested will start to experience stiff bolt lifts at 3050 fps or there abouts with the 105-107 gr bullets.
I am beginning to question just why I would want to fool around with a Dasher or BRX if it is only worth 100 fps over a standard case? My experience is that one is no more accurate than the other, the little case if incredibly accurate in any of it's forms.
To my thinking, either the std. BR shooters are loading to very high pressures at the expense of case life, or their chronos need to be calibrated. Are the 5R or 5C barrels worth that much extra velocity over standard rifling? Can button or cut rifling make that much difference? How about .236 vs .237 bores?
What is the real velocities that a std 6 BR can achieve without risking life and limb.
Bob
I have just recently gotten three 6mm BRX rifles up and running. They are NRA Prone guns to be used at 600 and 1000yd competitions.
The load development has been with 105-107 gr bullets along with Lapua brass,Varget,VV140,and RL 15. Bbl lengths are all 29-31 inches.
Two different Oehler 35P chronographs have been used in the development process. All barrels are SS,.236 bores, 8 twist, and custom made. Two are button and two are cut rifled.
Now here is what has made me very curious. On this site, shooters are claiming to get velocities of 2900+ fps out of standard 6mm BR cases. Shooting a standard case at 2950-3000fps seems like an awful lot of velocity to me. The BRX rifles that I have tested will start to experience stiff bolt lifts at 3050 fps or there abouts with the 105-107 gr bullets.
I am beginning to question just why I would want to fool around with a Dasher or BRX if it is only worth 100 fps over a standard case? My experience is that one is no more accurate than the other, the little case if incredibly accurate in any of it's forms.
To my thinking, either the std. BR shooters are loading to very high pressures at the expense of case life, or their chronos need to be calibrated. Are the 5R or 5C barrels worth that much extra velocity over standard rifling? Can button or cut rifling make that much difference? How about .236 vs .237 bores?
What is the real velocities that a std 6 BR can achieve without risking life and limb.
Bob