other than the name, load and possible outcome, how much difference in velocity @ max pressure is there? not like it's an accuracy changer, but more of a potential. this is between h1k and grand for comparisons/outcomes? online sources from bullet and powder manufacturers aren't the best to go by compared to the cartridge and firearm you've loaded for. although mmmv and ymmv as they are more productive than produced data from powder and bullet mfgrs.
what's the difference
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MagnumManiac
Well-Known Member
There is only one answer, until you test both in the SAME cartridge, there is no way to know.
Powders do not behave the same from cartridge to cartridge because burn rates are not constant across all cartridge capacities or calibres in the same cartridge.
Cheers.
Powders do not behave the same from cartridge to cartridge because burn rates are not constant across all cartridge capacities or calibres in the same cartridge.
Cheers.
This^
You can have powder-A be faster than powder-B in something like my 300prc. Then the opposite can happen in a 300wsm. Compare 3 burn rate charts and they will all have rifle powders listed in different order.
The only way to know is to test with your equipment
Another criteria for choosing between two powders that are providing the same accuracy & velocity, I would choose the one with the lower temperature sensitivity and then the lower burn temperature.
MagnumManiac
Well-Known Member
Problem is as I stated, burn rates do not stay the same, so these burn rate charts are a guess at best. Have seen many powders ‘flip-flop’ as to what behaves slower in regard to burn rates. Prime example, in 338WM using 225g bullets, RE19 outperforms RE22 by a big margin, but switch to a 250g, normality returns and RE22 outperforms RE19 by 75fps. This happens more than many believe. H4350 often outperforms H4831 in many cartridges and the burn rate swaps…
Cheers.
as usual lighter bullets have more velocity with faster powders than with slower regardless of cartridge. accuracy is a different story if all tested at same atmospheric conditions.
MagnumManiac
Well-Known Member
All tests done on the same day with the same equipment. Regardless, burn rates are not constant…and your statement is incorrect.
Cheers.
Varmintnv
Well-Known Member
Lighter bullets-faster burn rate needed is a myth.
There are very few "hard and fast" rules in reloading. And there are absolutely no "given" factors when it comes to pressures and velocities. Burn rate charts are a "ballpark" at best. Read the disclaimer for each one, it'll tell ya how inaccurate that chart can be.
Bottom line is the available info comes from the bullet mfgrs because they tested with their bullets. And if you don't have any experience loading for a certain car/ridge/bullet combo, start low and slowly work up. Max pressure in one gun may be 2gr light in another. And since I noticed the AR15 in your handle, only use data for a "gas gun" when loading for any semi auto weapon.
There are very few "hard and fast" rules in reloading. And there are absolutely no "given" factors when it comes to pressures and velocities. Burn rate charts are a "ballpark" at best. Read the disclaimer for each one, it'll tell ya how inaccurate that chart can be.
Bottom line is the available info comes from the bullet mfgrs because they tested with their bullets. And if you don't have any experience loading for a certain car/ridge/bullet combo, start low and slowly work up. Max pressure in one gun may be 2gr light in another. And since I noticed the AR15 in your handle, only use data for a "gas gun" when loading for any semi auto weapon.
Burn rates may vary a bit from lot to lot, but you cannot compare or make a judgement on the "burn rate" of a powder in a particular cartridge. Published burn rates are obtained in a laboratory under extremely controlled conditions. How any particular powder behaves with your case, primer, bullet, rifle, temperature, etc., combination compared to another is conjecture at best, especially considering all the variables.
Lefty7mmstw
Well-Known Member
Yup, I've seen the burn rate flip flop a bit over the years.
It also seems some powders are happier in some cartridges than others. I run rl19 in my 338win with 225's but in my 300win I run rl22 with 165.180 grain bullets. My 7stw is happier with rl25 with 140's. I've tried test loads with rl19 in the 300win and 7stw and it wasn't as happy. My 25wssm loves h4895 with 100's; it hates 4064. My 30-06 and 405 win like 4064. My 405win doesn't run h4895 very well.
Croomrider
Member
Barrel length can make a big difference on what works in your rifle compared to published load data. The faster powders can work better in short barrels if they allow for complete powder burn. An incomplete burn may have a detrimental effect on your accuracy even though you get similar or better velocity.
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Likely what is consistent on a large scale is total energy generated. The geometry of the case and restance in the bore/bullet configuration will cause changes in burning rate slightly
^^^^ This…right…here…
And the most important part of what MagnumManiac wrote…”so these burn rate charts are a GUESS at best”
OP, is this thread more based on reloading for AR cartridges?
Thanks
