Max load of 4350 in .308 win

[sam700]

For about the last year my target load in .308 was a 168 grain sierra match king over 49.5 grains of IMR 4350. The max load listed in the Lyman manual for a 168 grain bullet is 50 grains, so I figured I was good being ½ grain under the max.

Recently, I looked at the Sierra manual and saw a max load of 47.4 grains of powder for this bullet. I was a bit concerned as it is quite a bit less than what I’m shooting, but I’ve shot nearly 500 rounds of this load with no problems, so I figured I was fine.

Recently, I bought 300 pieces of Remington brass as I was unable to find the Hornady brass that I was previously using. I was shocked that the 49.5 grains of powder that I have always used filled the case all the way to the top, when the Hornady brass I normally use only fills to within 1/8 inch of the top or so. This indicates to me that the Remington brass has a significantly lower case capacity than the Hornady.

My question is this. Is the 49.5 grains of 4350 still safe in this brass if it fills the entire case to the point of nearly overflowing? Obviously, I’ll have to start 10-15% less than the max load and work back up as I’ve switched brass. Should I even bother working up to 49.5 with this brass? How big of a POI difference you think I'd see at 600 if I used 47.4 grains instead?

 

[oldgold]

A chrony is your friend. Less capacity equals more pressure [and velocity]. Chronograph your Hornaday brass loads then work up the Remington brass to match the velocity you have with the Hornaday brass.

I just ran into this with some 30-06 loads I was making up. Different cases gave different velocities. Lake City brass gave much higher POI than my R-P loads.

Be safe,goldy

 

[USSR]

sam700,

Yes, Remington brass has a smaller case capacity than Hornady Match brass. That being said, IMR4350 or H4350 is too slow of a powder to use with the .308. You simply cannot get enough powder in the case to generate enough pressure to drive a bullet at a decent velocity, let alone have to worry about a "max" load.

Don

 

[NCsmitty]

I believe if you weigh the cases, you'll see the Remington is heavier which equates to a smaller capacity due to the thicker brass. You do need to start from scratch with the new cases. USSR is correct about IMR4350 not being a good powder for the 308. There are many, more efficient powders available, and I'll bet you're giving away a lot of velocity by using IMR4350 unless you have a 32" barrel. Hodgden, the owner of the IMR powders, does not even show a load for IMR4350 at their web site data base for the 308. If you are going to start fresh with the new cases, I would rethink the powder situation. BLC2 or Varget are favorites, and others could chime in with their favorite powder for the 308 with the 168 Sierra for 600 yd shoots.

NCsmitty

 

[Slamfire]

Most I could get in a case, and stuff a 190 in, was 47.0 grains of IMR 4350. And then, the velocity was 2473 fps, not fast enough. I would crunch down the bullet into the powder, and then I would see the bullet rise as the powder pushed back!

I will bet that if you chronographed your load, it would be barely above 2500 fps.

I assume you are using a bolt rifle, go get some Varget. With a 168 SMK your best load will be between 43 and 44 grains. The velocity will be around 2650 and 2700 fps.

Varget also works very well with 190's, which is what I mostly shoot at 600 yards in the 308, and I have shot nice groups with the 175 SMK at 600 yards.

If you plan to get a M1 or M1a, I would recommend using IMR 4895 with a 168 SMK. That powder shoots outstanding groups with 168's and 175's, but is too fast for 190's.

 

[Doug b]

Sam IMR 4064 is another good powder for your 308.

 

[sam700]

Sounds like I'll be buying a chronograph!! I'd switch powder brands, but for whatever reason, my gun seems to shoot 4350 the best, although I have no Idea what velocity I'm getting. I have yet to try Varget though so that may be worth a try.

Anyways, anyone have any recomendation for a chronograph. I'm looking to spend around $150. I don't need a lot of fancy features, but I do want something that is as accurate as possible and something that will last.

 

[climbnjump]

There are other threads for info on chronographs, of course, but I have a Competition Electronics ProChrono. It's easy to use, works great and I wouldn't handload without one. They can be had at Midway for about $100.

I agree with the other posters on IMR 4350. It's great in my .270 WSM, but you can't get enough of it in a .308 load to get good velocities. I use either BL-C(2) or IMR 4064 in my .308.