Post by jimtowns on Aug 7, 2006 4:58:49 GMT 12.75
I was selected to test some bullets for the NAHC field test. Berger has been one of the best long range target bullet companies for many years. Walt Berger came up with a design called the VLD,( Very low drag). It's a long sleek boat tail hollow point match bullet.
Walt sold the company to someone else who wants to expand the business to include hunters who handload. BUT he doesn't want to come out with an exposed lead, or plastic tipped bullet that would work well for hunting. He wants us,(the testers), to hunt with the VLD bullets.
The problem is that match hollow points can either be so fragile that they tend to fragment and not penetrate, causing a shallow wound. Or the hollow point plugs and the bullet goes straight through like a pencil, no expansion.
I'm working with my son's 7-08 Browning A-bolt synthetic stalker. Using R-P cases, federal gold medal match primers and Hodgdon Varget powder. Here's the groups I shot yesterday;
None of the groups were really bad as far as shape or size goes, a few were over an inch. I was running them over my chronograph so I could keep track of the velocities. It has the ability to do extreme spreads,(ES), high, low, and a statistical tool called SD, or standard deviation. The better the ES, the better the long range accurate will be. The best group came with 37.0 grains of varget, it also had the lowest extreme spread of all the powder charge levels. 10.7 feet per second for five shots! It SHOULD be very accurate at longer distances, which I will find out in a few days.
What I did was look up what charge levels were recommended for Sierra match kings of the same weight. They are very similar to the Berger bullets. I then started out at the recommended starting load and went up in 2.0 grain increments to 35.0 grains. Then I went up in 1.0 gr increments to my max level of 38.0. Sierra said I could go up to 39.8, but max charges are seldom the most accurate, and why strain the rifle? Also Sierra's rifle used to test those rounds was a Savage with a 26" tube. My boy's rifle has an 18 inch bbl, so the velocities I got were quite a bit lower. 38.0 grains was supposed to do 2500 fps, I only got 2390 fps!
31.0 av 1947 fps ES 67.3 SD 25.7
33.0 av 2077 31.3 12.6
35.0 av 2204 22.4 8.4
36.0 av 2294 81.9 30.2
37.0 av 2333 10.7 4.3
38.0 av 2390 24.8 10.1
It can be seen that the "sweet spot" is at 37.0 in this particular load combination.
As far as the SD goes, as I understand it, it allows you to forecast how close to the average a bullet's speed will be. In the case of the best load above, you could say with some certainty that any bullet fired would be within 4.3 feet per second of the average velocity of 2333 fps.
Walt sold the company to someone else who wants to expand the business to include hunters who handload. BUT he doesn't want to come out with an exposed lead, or plastic tipped bullet that would work well for hunting. He wants us,(the testers), to hunt with the VLD bullets.
The problem is that match hollow points can either be so fragile that they tend to fragment and not penetrate, causing a shallow wound. Or the hollow point plugs and the bullet goes straight through like a pencil, no expansion.
I'm working with my son's 7-08 Browning A-bolt synthetic stalker. Using R-P cases, federal gold medal match primers and Hodgdon Varget powder. Here's the groups I shot yesterday;
None of the groups were really bad as far as shape or size goes, a few were over an inch. I was running them over my chronograph so I could keep track of the velocities. It has the ability to do extreme spreads,(ES), high, low, and a statistical tool called SD, or standard deviation. The better the ES, the better the long range accurate will be. The best group came with 37.0 grains of varget, it also had the lowest extreme spread of all the powder charge levels. 10.7 feet per second for five shots! It SHOULD be very accurate at longer distances, which I will find out in a few days.
What I did was look up what charge levels were recommended for Sierra match kings of the same weight. They are very similar to the Berger bullets. I then started out at the recommended starting load and went up in 2.0 grain increments to 35.0 grains. Then I went up in 1.0 gr increments to my max level of 38.0. Sierra said I could go up to 39.8, but max charges are seldom the most accurate, and why strain the rifle? Also Sierra's rifle used to test those rounds was a Savage with a 26" tube. My boy's rifle has an 18 inch bbl, so the velocities I got were quite a bit lower. 38.0 grains was supposed to do 2500 fps, I only got 2390 fps!
31.0 av 1947 fps ES 67.3 SD 25.7
33.0 av 2077 31.3 12.6
35.0 av 2204 22.4 8.4
36.0 av 2294 81.9 30.2
37.0 av 2333 10.7 4.3
38.0 av 2390 24.8 10.1
It can be seen that the "sweet spot" is at 37.0 in this particular load combination.
As far as the SD goes, as I understand it, it allows you to forecast how close to the average a bullet's speed will be. In the case of the best load above, you could say with some certainty that any bullet fired would be within 4.3 feet per second of the average velocity of 2333 fps.