Advice and comment, please. Which would you go with and why? Am I likely to have longer barrel life with the Varget load?
These are with 155 A-Max bullets out of an M1A with a new barrel.
Load #1 tests quite accurately, .5 MOA for 4/5 and a called flyer, still under MOA with the flyer and it was NOT the steadiest bench that day.
It's 1/2-grain under the Sierra Max for their older Palma bullet, but about 30 fps faster than their max speed for their 26-inch barrel. The M1A is a 22-inch barrel, so I'd expect about 75-100 fps less
I get 2930 fps at about 90 degrees F.
Sierra shows 2900 fps max with Fed primers and a 26" Savage. My WLRs would be expected to boost velocity 20-40 fps anyway based on mine and others' experiences.
With Varget, I'm almost exactly 100 fps less at 2835, and the groups +.4 gr and -.4 gr from there are hitting the same at 100 and are only about 20-30 fps away as well. Haven't tested it for accuracy yet but it shows promise.
Sierra shows a max speed with Varget of 2800 with 155s, but with .4 grain less than what I'm using. Again, my shorter barrel would be guessed to be about 75-100 fps slower, so that "danger sign" on the load-to-velocity rationale is about equal with the 4064 load. Since so many people are running Varget loads and 155 SMKs to 2950, I wonder if the Sierra data for Varget is not quite realistic.
I'm inclined to go with the Varget load because I suspect slower will = maybe a bit less pressure and definitely longer bore life. BUT, the barrel life spreadsheet passed around here a few months ago shows Varget as burning noticeably hotter than 4064, shortening accuracy life.
I *could* test for a 2830 node with 4064, but the OCW startup down there wasn't giving great groups and they were not that close vertically.
These are with 155 A-Max bullets out of an M1A with a new barrel.
Load #1 tests quite accurately, .5 MOA for 4/5 and a called flyer, still under MOA with the flyer and it was NOT the steadiest bench that day.
It's 1/2-grain under the Sierra Max for their older Palma bullet, but about 30 fps faster than their max speed for their 26-inch barrel. The M1A is a 22-inch barrel, so I'd expect about 75-100 fps less
I get 2930 fps at about 90 degrees F.
Sierra shows 2900 fps max with Fed primers and a 26" Savage. My WLRs would be expected to boost velocity 20-40 fps anyway based on mine and others' experiences.
With Varget, I'm almost exactly 100 fps less at 2835, and the groups +.4 gr and -.4 gr from there are hitting the same at 100 and are only about 20-30 fps away as well. Haven't tested it for accuracy yet but it shows promise.
Sierra shows a max speed with Varget of 2800 with 155s, but with .4 grain less than what I'm using. Again, my shorter barrel would be guessed to be about 75-100 fps slower, so that "danger sign" on the load-to-velocity rationale is about equal with the 4064 load. Since so many people are running Varget loads and 155 SMKs to 2950, I wonder if the Sierra data for Varget is not quite realistic.
I'm inclined to go with the Varget load because I suspect slower will = maybe a bit less pressure and definitely longer bore life. BUT, the barrel life spreadsheet passed around here a few months ago shows Varget as burning noticeably hotter than 4064, shortening accuracy life.
I *could* test for a 2830 node with 4064, but the OCW startup down there wasn't giving great groups and they were not that close vertically.