Why not 4350 for the .308?

[Wannashootit]

Want to experiment with something other than Varget for my son's LR-308.
Consensus seems to be that 4350 (whether H or IMR) is too slow for this chambering- especially the heavier 175 grain pills.

What I don't get, it that I shoot 162's from my 7-08 with 4350.

Same case, just necked-down. Bullets are pretty close in weight.

So what accounts for the unsuitability- is it the smaller bore diameter of the 7mm?

 

[HodgdonExtreme]

Burn speed must match the relationship between case capacity, bullet inertia (and friction to a lesser extent) and bore diameter.

This balance is quite a bit different between a 7mm08 w/ 162s vs a 308 with 175s.

A decrease in only bore diameter requires a slower powder. A decrease in only case capacity requires an increase in burn speed. An increase in only bullet weight/friction requires a decrease in burn speed.

Usually, when working with stick powder slower than ideal for a given application, you'll be case capacity limited, not pressure limited, meaning even a compressed charge won't generate enough pressure fast enough to achieve good velocity.

Mind you, while H4350 is suitable for heavies in a 7mm08, it is MORE ideally suitable for a 260 with heavies. Frankly, H4350 is really a bit slow for a 7mm08, which is evidenced by the fact you can usually match the performance of a compressed load of it with a light charge of Varget. 7mm08 would prefer something in between. Most likely, that in-betweener burn speed would achieve a higher velocity than either Varget or H4350 can produce. Usually, an ideal powder will have a load density of ~100%.

H4350 will "work" in a 308, but performance will be weak.

 

[gstaylorg]

If you want to try something "different" you might look at H4895, IMR4064, IMR4320, or IMR8208 XBR, depending on the bullet you want to use.

 

[Sniper260]

burn speed must match the relationship between case capacity, bullet inertia (and friction to a lesser extent) and bore diameter.

This balance is quite a bit different between a 7mm08 w/ 162s vs a 308 with 175s.

A decrease in only bore diameter requires a slower powder. A decrease in only case capacity requires an increase in burn speed. An increase in only bullet weight/friction requires a decrease in burn speed.

Usually, when working with stick powder slower than ideal for a given application, you'll be case capacity limited, not pressure limited, meaning even a compressed charge won't generate enough pressure fast enough to achieve good velocity.

Mind you, while h4350 is suitable for heavies in a 7mm08, it is more ideally suitable for a 260 with heavies. Frankly, h4350 is really a bit slow for a 7mm08, which is evidenced by the fact you can usually match the performance of a compressed load of it with a light charge of varget. 7mm08 would prefer something in between. Most likely, that in-betweener burn speed would achieve a higher velocity than either varget or h4350 can produce. Usually, an ideal powder will have a load density of ~100%.

H4350 will "work" in a 308, but performance will be weak.

boom!

 

[gewehr]

If you want to try something "different" you might look at H4895, IMR4064, IMR4320, or IMR8208 XBR, depending on the bullet you want to use.

+1 on the imr 8208 xbr for the 308


Sent from my iPhone using Tapatalk

 

[ridein4life]

Alot of people say its temp sensitive but here in Washington state ive never had any issues with H335. I run 40.7grs of H335 over 175gr SMK's and love the load all the way to 700 meters(never shot farther yet). Also run the 178gr AMAX over Varget.

 

[81Z4ME]

The most accurate loads I've ever fired in my .308 were with IMR4350 powder and Sierra 180 grain match bullets. It was a compressed charge and I don't remember the amount. Federal bench rest primers. Never any sign of pressure at the case. It just broke my M1A operating rod, twice, before I gave up on it.

 

[Road_Clam]

I've been working several "other than Varget" .308 powders. Here's my top favs' shot out of an R700 .308 26" bbl 1-12" Varmint. All shot between .390"-.780" groups at 200 meters in ideal conditions and doing my part :

Benchmark 39.9 , 168 smk
Win 748 41.9 168 Nosler CC's
2000MR 43.5 168 smk
Win 748 42.9 155 smk
2000MR 46 155 smk