You probably know this but those charts are just generalities. You really can't take much else from them as there are several factors that can effect burn rates. One such example I'll give, because I'm quite familiar with both powders and their characteristics is n120 vs h4198. A few charts show h4198 as being faster and that might or might not be true in some cartridges. I have used a lot of both in 30BR and 30 Major(grendel) cases. In every instance n120 has been faster, considerably so. In those two cartridges, it's about 2 full grains faster on average. That's not a small amount when you consider the case capacity involved here and that the chart would imply that a safe charge of h4198 would be safe with n120, but that is NOT the case. With the light bullets typically used in those two cases, it's hard to get enough h4198 in there to be dangerously hot but with n120, that's just not true and this is just one example where if you put 35.0 grains of n120 in a 30BR case, I'd pretty much promise extreme pressures or worse yet, it comes unwound on ya. I'm sure there are other examples but I'm just very familiar with this one.
I understand what you saying,and I agree I have seen the same issues with powders for .308 and 6.5cm.....I actually am working on loads for my 30 br at the moment. I'm using LT30, but was looking at different options for powders. Not that the LT30 doesn't perform, but looking at different options for if and when LT30 can't be found,like H4198.
N130 is a good one but so is n120 ime. If you'r gun likes it, you'll love that powder. The old stuff was even better but it's still a great powder to work with and it will shoot. Meters fantastic too....Probably better than any powder I've ever used in anything. It just has limited use or I'd use it in everything possible.
Hodgdon is a distributor and retailer of powder. They do not to my knowledge manufacturer the powder they sell.
No but they test it all and that's what counts
Never used a burn rate chart. I look in the reloading manuals and see which powders give the highest fps for my bullet weight for a 6BR. I assume they are the most efficient powders for my cartridge. Also see what powders they are using at high levels of competition. Speed doesn't guarantee accuracy but that’s what I do.
Thank you Webster. I'd add that bore to capacity ratio can make a huge difference. Your post may indirectly indicate that too. I've literally seen people believe that a 6br and a 30br data can be interchangeable. This is very far from true, even with the same bullet weights, or close. Big difference. Most of us know these things but I thought that guy knew better too, until he proved me wrong. He didn't underway he had to beat his bolt open every shot.
Thank you for the information. Good to know.
Comparing a 6BR to a 30BR. As the bullet moves forward the cylinder that the powder burns in increases. The powder doesn't burn in just the case volume. The hole that the powder burns in increases at a different rate with a bigger diameter and wt. bullet. The burn rate should change from initial ignition to max pressure.Thank you Webster. I'd add that bore to capacity ratio can make a huge difference. Your post may indirectly indicate that too. I've literally seen people believe that a 6br and a 30br data can be interchangeable. This is very far from true, even with the same bullet weights, or close. Big difference. Most of us know these things but I thought that guy knew better too, until he proved me wrong. He didn't underway he had to beat his bolt open every shot.
I agree and I look at it like the chamber is from bolt face to the point where peak pressure happens, maybe 3 inches down the bore for example. And yes, 3 inches of 30 cal bore has a lot more expansion area vs 3 in of 6mm bore.
