I finally tried Hodgdon 4350 for 180 grain loads in my 300WSM and found a great, accurate load. Now I notice that it is several bucks a pound more than other 4350's. Since the more I save, the more I shoot (and I like to shoot!) I was wondering how much difference there really is under real world conditions (not temperature controlled test labs).

Basically, H4350 is touted for high uniformity over temperature changes. Soooo.....

How does the termperature effect compare to the others?

How does the shot to shot variation (and lot to lot) compare to the others?

IMR is the other 4350 I see everywhere, by I think there is 1 ot 2 more out there. Anyone seen or done a comparison?

I can partially answer your question.

In our town, IMR and Hodgdon powders are the same price. I got lucky a few months ago, and snagged an old 5 pound keg of H4350 for $65. Usually, it is $17 per pound.

The Hodgdon temperature stability claim is only partly true. It does work well in specific cartridges. In other cartridges the same lot of powder will show considerable variation with temperature. For example, 46 grains of Varget in my 308 is practically dead stable from FYBO to uncomfortably warm. Same lot of Varget is is less stable in my 223 than commercial mil type ammo. I think Varget is tailored for the 308, and H4350 is tailored for something close to the '06.

I have a few pounds of AA4350, and, in my Swedish Mauser, it works great. It seems to be just a trifle faster than the other two, and I generally get slightly lower MV's at maximum pressure than I do with IMR or Hodgdon, in my 30-06.

Hope that helps.... good shooting!

All the 4350's are very similar. I've found that there is as much lot to lot variation, as some times there is between manufactures.

Treat each lot number of each manufacturer as a separate item. Start a few grains low and work up.

In the 243win. i find IMR is better then H. I have to use more H to get the same vel. Accuracy is also better with IMR.

I could be wrong, but: isn't IMR4350 a single-base powder, whereas H4350 is double?

Anyone confirm?

RSY

RSY,

You are wrong.

It really depends greatly upon the individual cartridge / bullet being used as to the actual performance of one brand of 4350 versus another. I fear you won't get a 'real' answer to your question.

Generally speaking, all single base powders are more thermally stable (less temperature sensitive) than double base powders. Double base powders, typically have more energy per unit mass than single base powders do. This energy increase is due to the introduction of nitro glycerin, which is incredibly temperature sensitive. In most modern double base powders retarders are introduced to reduce the temperature sensitivity of the powder, which in effect, reduces the powder's energy content per unit mass making it perform more like the single base powder. Regardless, the double base powder will be more temperature sensitive than the single base, and as the retarders are reduced in the double base powder the more temperature sensitive this powder will be.

Scott

I have tried both in my .338-06/250gr bullets & my .338mag/225gr bullets. H4350 seems to be a bit slower tahn IMR4350. I can get a bit more vel. from the H4350 w/ 1-2gr more.

I tried all three, head to head, in a 338 Jamison using 225 bullets. The differences was exactly 1g of powder from the fastest, AA4350, middle IMR4350, to the slowest H4350. Two grains difference for the same velocity between AA4350 and H4350. Without looking, I believe the loads were 67g AA, 68g IMR and 69g Hodgdon.



And, PS, I also find the H4350 IS affected by temperature in everything in which I've shot it, particularly above 70�.

Interesting then that Vihtavouri says (in reference to their 500 series double based powders compared to their 100 series single base) "N500 series powders work well at differnet temperatures, even better than the traditional N100 and N300 series." (Reloading guide to centerfire cartridges, 1-2004, downloaded from the Vihtavouri website.)

I have no doubt that nitroglycerin is very temperature sensitive, but your statement and Vihtavouri do not agree. Also, they are adding nitroglycerol, not nitroglycerin. I'll have to dust off my old organic chemistry books to find the difference, but it might be significant. It seems like lots of powders are going double base, and I can't see that as a step backwards.....

In the same cartridge mentioned above I also tried Vihtavouri N550 and N150. The N550 was faster than the N150 and it was equally subject to change in heat. No real difference, and that was the principal reason I tried it.



I was told at the the time that the "temperature tolerance" was better with double based propellants and that is the reason they are predominant in the military cartridges that must be used by our military in all types of climates. Most are loaded with double based ball powders. The only place I've seen much difference is using H4350 is in extreme cold. It doesn't seem to lose as much velocity around zero degrees as other propellants, including the double based powders.

glycerol = glycerin

One disadvantage to double base powders is that above 135 F, the nitro evaporates out of the powder. When the cartridge cools, the nitro does not go back to exactly where it came from. The results are fairly unpredictable.

Merck Index, page 644, 4347 Glycerol. 1,2,3-Propanetriol; glycerin; trihydroxypropane

Double base powders also burn hotter = more throat erosion and have a greater muzzle flash.

N550 roughened the throat of my 6.5x55 in 500 rounds. Shooting other rifles with the same make barrel with 100 series powders has resulted in no appreciable wear. Not scientific but I'll pass on the 500 series.