Hi Vince,

I have been looking at the various burn rate charts published on the net, especially ADI and Hodgdon. On thing is obvious, none of the charts are in total agreement.

The particular reference we were working on was equivilant of H4227/H110/ADI's AR2205. With the info that H110 is made by St. Marks in Florida it will have a different burn rate but 'similar' (in the ballpark) to ADI's AR2205/Hodgdon H4227. AR2205 and H4227 are the same product.
Hodgden lists the maker of their powders in their MSDS information on their website. You can compare that info to the ADI burn rate chart and eliminate the St. Marks Powders and see which powders are made for Hodgdon by ADI (same powders) but I don't guarantee the info accurate.

Hodgdon = ADI (manufacturer)
Clays = AS-30N
HP38 = AP-50N
International = AS-50N
Universal = AP-70N
H4227 = AR2205
H4198 = AR2207
H322 = AR2219
Benchmark = BM2 (Benchmark2)
H4895 = AR2206H
Varget = AR2208
H4350 = AR2209
H4831 = AR2213
H4831sc = AR2213sc
Trail Boss = AS-25BP
H1000 = AR2217
Retumbo = AR2225
H50BMG = AR2218

popgun,

A long time ago I did some research on burn rates and how they were found.
first, the distributors (Hodgdon, Winchester, etc.) don't test burn rates. The manufacturer does these tests and they publish the results so that ammo manufacturers can order blends for non-canister applications.

The testing is done with a closed chamber bomb that never disintegrates. A charge of powder is placed in a given cavity, the bomb is sealed and the powder is ignited. the internal pressure, temperature rise, and average impulse is measured remotely.

I was told that these tests mean nothing to the reloader because the chamber of the test bombs and the volume of any given cartridge is so different that the pressure rise, burn rate and peak pressures don't even follow the same curve between the bomb and your cartridge.

The bomb is a fixed volume and the cartridge is an expanding volume. Smokeless powder burns faster with an increase in pressure - the bomb does that - the pressure continues to rise for the entire burn time making the powder burn increasingly faster throughout the test. In a cartridge your volume can more than double and may only grow by a fifth during the time the powder takes to burn. That flattens out the pressure rise and slows the burn time of the powder in your gun. We have all seen pictures of what happens when the bullet doesn't move or hits an obstruction and the pressure rises too fast and beyond the design limits of guns.

I am beginning to ramble - my point is that no two testing houses use the same load in the same volume but they do use fixed volume test bombs. When you see differences in burn rate charts you are seeing differences in the amount of powder and / or volume used in the testing. My second point is that a powder listed as #3 in the chart may burn slower or faster than powders on either side of it on the chart when used in different cartridges or with different bullet weights. We have no way to know what changes may be happening in our chambers compared to the results in the tests.

popgun wrote:

Hi Vince, I have been looking at the various burn rate charts published on the net, especially ADI and Hodgdon. On thing is obvious, none of the charts are in total agreement. The particular reference we were working on was equivilant of H4227/H110/ADI's AR2205. With the info that H110 is made by St. Marks in Florida it will have a different burn rate but 'similar' (in the ballpark) to ADI's AR2205/Hodgdon H4227. AR2205 and H4227 are the same product. Hodgden lists the maker of their powders in their MSDS information on their website. You can compare that info to the ADI burn rate chart and eliminate the St. Marks Powders and see which powders are made for Hodgdon by ADI (same powders) but I don't guarantee the info accurate. Hodgdon = ADI (manufacturer) Clays = AS-30N HP38 = AP-50N International = AS-50N Universal = AP-70N H4227 = AR2205 H4198 = AR2207 H322 = AR2219 Benchmark = BM2 (Benchmark2) H4895 = AR2206H Varget = AR2208 H4350 = AR2209 H4831 = AR2213 H4831sc = AR2213sc Trail Boss = AS-25BP H1000 = AR2217 Retumbo = AR2225 H50BMG = AR2218

Gidday Chris. Thanks for the above mate. My contact at ADI didn't want to give me too much info because of the cavaet, which I can understand. However Hogdon being the retailer can provide this info if they wish. Its interesting to see that ADI actually "export" pretty well their entire range of powders.

I am surprised at the way ADI show H110 on their burn rate listing. The way it reads indicates that H4227 and H110 are the same in all respects. Not good. I think I might indicate this to ADI so that they can show it in a more realistic manner.

Again, thanks for that.

Cheers, Vince

popgun wrote:

Hi Vince, I have been looking at the various burn rate charts published on the net, especially ADI and Hodgdon. On thing is obvious, none of the charts are in total agreement.

They never are, and further more powder burning rates change from lot to lot, and always have. That's why you have to rework your load when changing powder lot number .............. !!!!!!!!!!!