Free: Contests & Raffles.
Quote from: Reidus on February 23, 2016, 01:08:45 PMQuote from: Curly on February 23, 2016, 11:58:46 AMQuote from: DaveMonti on February 22, 2016, 11:16:49 AMBobcat,I realize the chronograph will tell you the velocity, but how does it indicate the max load? Do the velocities from shot to shot become inconsistent as you go beyond the "max" load?Just curious, I never heard of using the chrono to determine max load. You could graph velocity vs. powder charge and it should look like a fairly linear increase. Then as you reach max powder, you will see the graph flatten out. There does come a point where more powder does not result in much of a velocity increase. (There may even be a point where increasing powder results in less velocity.)This doesn't make sense to me. With certain powder/bullet combos it may work but in some cases I think you will see flattened primers and a sticky bolt before you see a decrease in velocity gain.You should stop increasing your powder charge once you reach the maximum expected velocity. If you're getting more velocity than the book shows you're most likely also over pressure. If you're seeing over pressure signs with your brass and/or your bolt being hard to open, then you're probably WAY over pressure. Better to stop before you reach that point. This is why a chronograph is very useful.
Quote from: Curly on February 23, 2016, 11:58:46 AMQuote from: DaveMonti on February 22, 2016, 11:16:49 AMBobcat,I realize the chronograph will tell you the velocity, but how does it indicate the max load? Do the velocities from shot to shot become inconsistent as you go beyond the "max" load?Just curious, I never heard of using the chrono to determine max load. You could graph velocity vs. powder charge and it should look like a fairly linear increase. Then as you reach max powder, you will see the graph flatten out. There does come a point where more powder does not result in much of a velocity increase. (There may even be a point where increasing powder results in less velocity.)This doesn't make sense to me. With certain powder/bullet combos it may work but in some cases I think you will see flattened primers and a sticky bolt before you see a decrease in velocity gain.
Quote from: DaveMonti on February 22, 2016, 11:16:49 AMBobcat,I realize the chronograph will tell you the velocity, but how does it indicate the max load? Do the velocities from shot to shot become inconsistent as you go beyond the "max" load?Just curious, I never heard of using the chrono to determine max load. You could graph velocity vs. powder charge and it should look like a fairly linear increase. Then as you reach max powder, you will see the graph flatten out. There does come a point where more powder does not result in much of a velocity increase. (There may even be a point where increasing powder results in less velocity.)
Bobcat,I realize the chronograph will tell you the velocity, but how does it indicate the max load? Do the velocities from shot to shot become inconsistent as you go beyond the "max" load?Just curious, I never heard of using the chrono to determine max load.
If you can safely work up added velocity and not lose accuracy why wouldn't you make it faster? Get all you can. No reason to shoot lower loads of a hotter load is just as accurate and not over pressure for your particular load and rifle. But I agree to keep it conservative so that different conditions won't create unwanted pressure spikes.
Quote from: BULLBLASTER on February 23, 2016, 04:54:14 PMIf you can safely work up added velocity and not lose accuracy why wouldn't you make it faster? Get all you can. No reason to shoot lower loads of a hotter load is just as accurate and not over pressure for your particular load and rifle. But I agree to keep it conservative so that different conditions won't create unwanted pressure spikes. if he is new to reloading he may want to consider atmospheric conditional changes that affect the velocity and pressures. A book that was published shooting in cool and high density air will not be the same as those shot in hot conditions. The temperature of the powder plays a big role too, some powders are fairly temperature sensitive.I stick to suggesting the velocity range that is a known for the cartridge and not pushing it until the shooter knows how to measure the brass for strain.....its not worth it, just hold a quarter inch higher.
I've been loading for my 7mm for over 20 years and bullet seating depth seems to be the biggest factor in accuracy. Measure the lands to ogive for each differerent bullet you want to experiment with. Some like it .020 off and Barnes love them about .060 - .080 off the lands.
If you want to see how recommended maximum loads are all over the place, find some of the old books from the 60's and 70's and see what those maximum loads were.You'll find out maximum load recommendations are way more cautious these days.
