IMR4350 vs. H4350 vs. H4831

[T90]

I will be shooting a 180 gr boattail from my .308 Norma Mag. For years I was using 62.8 grns of 4320 with good results, but would like to make a change and was thinking about making the change to 4350 or 4831. I am looking for some real world input on the differences in your mid range magnums firing these powders. My goal is accuracy. Thanks

 

[Eagleye]

H4831 has always yielded good results in my 308 Norma Mags.
While I actually prefer Norma MRP, or Reloder 22, H4831 is pretty close.
With 180 Flat base spitzers, I usually get the best result right around 74 grains of H4831.
The boattails may tolerate slightly heavier charges, but in any case, start 3 grains lower and work up.
You did not mention which rifle your 308 Norma is, but the S&L, rear locking actions will
have slightly shorter brass life at max loadings.
Regards, Eagleye.

 

[Ganderite]

How much do you shoot? In target rifles, the 4350 is harder on the barrel because of a higher flame temperature.

RL22 is more temperture senetive than, say, H4831SC.

 

[KDX]

That's interesting. If I used about 50gr of H4350 in a .257 Roberts AI with 75gr V-Max bullets, what would my expected barrel life be?

 

[T90]

Thanks for the info. 4831 sounds like the ticket. I don't noormally load hot, I tend to go for accuracy over fps. As for make of rifle, its a gun smith special as far as I can tell with an Enfield 1917 action and a 24" Globco barrel. It shoots extremely well considering the age, so well in fact I just topped it with a new Viper Vortex HS. So I think I will give the 4831 a try as no one in my neck of the woods stocks actual Norma powder.

As for shooting, I love shooting the rifle as much as I can. It is a bit of a beast with recoil, but shoots very straight and I just love shooting Since I have owned the rifle (20 years now) I have put in the neighbourhood of 1500 shots through it and they still all go where I want them to

 

[b72471]

Ganderite I think that your thinking on 4350 requires a little more thinking (thought) there are simple gas laws (P1 V1/t1) = yad yad. That means the spike in pressure with powders of different burning rate will be at a diferent point in the barrel. Therefore there will be no noticeable difference in wear & tear in the barrel should you use either 4350 or 4831.
Enjoy. Bill

 

[Johnn Peterson]

In both the parker Hale I started out with and the 308NM Schultz & Larsen I have now, accuracy always seemed to be a touch better with IMR 4350 than IMR 4831.

I'm working on loads using Barnes bullets but here's results I've posted previously on one of my favorite loads using IMR 4350.

 

[444shooter]

In both the parker Hale I started out with and the 308NM Schultz & Larsen I have now, accuracy always seemed to be a touch better with IMR 4350 than IMR 4831.

I'm working on loads using Barnes bullets but here's results I've posted previously on one of my favorite loads using IMR 4350.

That is a beauty Johnn!

 

[Boomer]

Ganderite I think that your thinking on 4350 requires a little more thinking (thought) there are simple gas laws (P1 V1/t1) = yad yad. That means the spike in pressure with powders of different burning rate will be at a diferent point in the barrel. Therefore there will be no noticeable difference in wear & tear in the barrel should you use either 4350 or 4831.
Enjoy. Bill

Except that it is the effects of throat erosion that is the major contributing factor responsible barrel longevity, and throat erosion is significantly impacted by the propellant flame temperature. This is particularly true in target matches where the shooter is inclined to machinegun his rounds as quickly as possible to beat changes in wind or light; thus not allowing time for the barrel to cool between shots. The accumulated heat build-up in the barrel steel, combined with the hotter flame temperature of 4350, will result in greater throat erosion over a shorter period of time as subsequent shots are fired, compared to a propellant with a lower flame temperature, fired in a similar fashion.