Brethern,
I have a 264 Sendero II that's been worked over by a very qualified BR mechanic. Action was trued, all the other good stuff. It's sitting in a Bell&Carlson fiberglass stock and it's torqued down correctly. Still using the factory barrel and I've shot probably...400 rds at most out of the gun. ALL of it was simply load development. I've settled on two possible loads - 140 AMAX over 66.0 Retumbo or 140 SMK over 58.5 I4831. I use a caliper and Stoney Point device to measure off the ogive. I won't mention those dimensions but they're accurate. I've chronoed it using a MagetoSpeed and it looks like a little over 3,000.
First shot is typically right on the money. And when I say right on the money, I'm talking about shooting at an aiming point on the target smaller than a dime at 100 yards. I aim small to hit small. Anyway, the second round is usually good. And then...things go crazy. The bullets start dropping and the group opens up. While it varies, I'm allowing between 3 and 5 minutes per 3 shot string - and between those 3 shots I'm allowing a minute. Today for instance, temperature was in the low 50s so I think I'm allowing the barrel to cool adequately. I cannot for the life of me, figure out what this rifle is going to do from shot to shot. I'm going to try to post photos of the targets for your analysis. I could understand impacts rising as the barrel heats up, but not impacts dropping. And it's always been consistent - after the first 2 -3 shots the rest always drop.
So I'm asking you guys, what's up with the drop?
After MUCH experimentation, I managed to get the scans of the groups posted. They appear below. The 140 Amaxes started low and I came up about an inch. That where shot 2 begins. The Amaxes didn't give a bad group. Not a great group by any means but it shows promise. Your learned insight is appreciated.
I have a 264 Sendero II that's been worked over by a very qualified BR mechanic. Action was trued, all the other good stuff. It's sitting in a Bell&Carlson fiberglass stock and it's torqued down correctly. Still using the factory barrel and I've shot probably...400 rds at most out of the gun. ALL of it was simply load development. I've settled on two possible loads - 140 AMAX over 66.0 Retumbo or 140 SMK over 58.5 I4831. I use a caliper and Stoney Point device to measure off the ogive. I won't mention those dimensions but they're accurate. I've chronoed it using a MagetoSpeed and it looks like a little over 3,000.
First shot is typically right on the money. And when I say right on the money, I'm talking about shooting at an aiming point on the target smaller than a dime at 100 yards. I aim small to hit small. Anyway, the second round is usually good. And then...things go crazy. The bullets start dropping and the group opens up. While it varies, I'm allowing between 3 and 5 minutes per 3 shot string - and between those 3 shots I'm allowing a minute. Today for instance, temperature was in the low 50s so I think I'm allowing the barrel to cool adequately. I cannot for the life of me, figure out what this rifle is going to do from shot to shot. I'm going to try to post photos of the targets for your analysis. I could understand impacts rising as the barrel heats up, but not impacts dropping. And it's always been consistent - after the first 2 -3 shots the rest always drop.
So I'm asking you guys, what's up with the drop?
After MUCH experimentation, I managed to get the scans of the groups posted. They appear below. The 140 Amaxes started low and I came up about an inch. That where shot 2 begins. The Amaxes didn't give a bad group. Not a great group by any means but it shows promise. Your learned insight is appreciated.
Last edited:
