IMR-4350 load info for .308


April 22, 2011, 05:53 PM
Down sizing the bench and want to use up a lb of 4350 in my .308 with 175gr fmjbt. Just shootin paper.
I was looking and found a few loads but nothing as trustworthy as the info I get here on the high road.

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April 22, 2011, 06:34 PM
Nothing here at the High Road is any more trust worthy as what you'll find listed at Hogdon's site. Listed loads are SAMMI tested and approved.

April 22, 2011, 06:47 PM

IMR4350 is not a suitable powder for the .308 Winchester, much too slow and you simply cannot get enough IMR4350 in a .308 for normal velocity. So, if you really want to use it, stuff as much in the case as you can and call it good.


April 22, 2011, 07:00 PM
Don i fear im being that cheap sob in your quote

April 22, 2011, 08:19 PM
I have lots of IMR/AA/H4350. And lots of 308 cases. You would think there is a chance for a wonderful match, but not really.

With the cases I have, 47 to 47.5 grains 4350 is all I can get in. So start there. As you can see from my data using 4350 for 155 grains is a waste, they don’t go fast enough. 190’s were not very fast either.

I have a F class champ bud who used to use 48 grs IMR 4350 in thin skinned 308 cases with 185gr Berger bullets. He is a long range shooter and had long, like 28” to 30” barrels. You need barrels that long to get the velocity up. My barrels of 24” and 26”, not enough length.

I have shot next to people who were using 175 SMK and 47.0 grains IMR 4350, I forget the cases and primers, but they were shooting well at 600 yards.

So that is where I would start.

Pre-64 M70
24 " Krieger Barrel 1:10 twist

150 gr Hornady FMJBT 43.5 grs AA2520 wtd Lot 9595 Czech Mixed LC WLR OAL 2.785"

29 May 2010 T = 83 °F

Ave Vel = 2785
Std Dev = 23
ES = 75
High = 2820
Low = 2745
N = 14

155 Nosler 46.0 grs IMR 4350 wtd, Lot 6164 (60's) mixed cases CCI 200 OAL 2.780"

29 May 2010 T = 82 °F

Ave Vel = 2418
Std Dev = 17
ES = 60
High = 2441
Low = 2381
N = 10

155 Nosler 47.0 grs IMR 4350 wtd, Lot 6164 (60's) mixed cases CCI 200 OAL 2.790"

29 May 2010 T = 82 °F

Ave Vel = 2490
Std Dev = 17
ES = 59
High = 2515
Low = 2456
N = 10
best IMR 4350 group

Ruger M77 Tactical, 26” barrel
190 Speer 47.0. grs IMR 4350 wtd Fed210S 161grs ≤ Fed cases ≤ 164.9 grs
17-Aug-06 T = 90 °F
Ave Vel = 2407
Std Dev = 5
ES = 11.24
High = 2414
Low = 2402
N = 4

M70 26" Kreiger Barrel, four groove, 1:10 twist
190 gr Speer Match 45.0 grs H4350 wt'd R-P cases Fed 210S
9 Mar 97 T=70F

Ave Vel = 2301
Std Dev = 24
ES = 65
Low = 2272
High = 2337
N = 5

190 gr Speer Match 46.0 grs H4350 wt'd R-P cases Fed 210S
9 Mar 97 T=70F
Ave Vel = 2382
Std Dev = 17
ES = 36
Low = 2365
High = 2401
N = 6

190 gr Speer Match 47.5 grs H4350 wt'd R-P cases Fed 210S
30 April 97 T=72F
Ave Vel = 2414
Std Dev = 9
ES = 23
Low = 2402
High = 2425
N = 9

April 22, 2011, 09:31 PM
I disagree that IMR 4350 is inadequate for 308. If it was, my Sierra hand book wouldn’t have data for it. I’ve loaded up to 52.0gr using a drop tube. 168 SMK. Had very good results on paper. In fact, if you compare the data according to the Sierra book, the max load for 4350 is 200 fps faster than the max load for Varget or 3031. You can get the velocity from 4350 with a drop tube and a willingness to compress the load. My best groups where with 48.0 gr 175 SMK and 50.0 gr 168 SMK. However, 4350 is inadequate for semi-autos…

April 22, 2011, 11:45 PM
IMR 4350 is not so much "inadequate" as it is "not best suited" for the 308Win
(And was that "52 grains" above a misprint?)

I went to Quickload and set up w/ a 175SMK for which I arbitrarily chose a
55,000psi limit (max pressure ~60,200). Then I ran a powder table search
for best performance as defined by maximizing case fill, velocity, and %burned.
(Note that Quickload's "105% case fill" is about where light compression starts.)

This is the result when using light compression as the upper limit and 99% case
fill as the lower, then sorting on velocity:


IMR4350 fell outside of this window with 109%fill (47.8gr) 2,623fps, 94.4% burn for 55,000psi

BOTTOM LINE: Even for heavier bullets, IMR4350 is not (ballistics-wise) a top choice for the 308Win.
Useful... certainly. And if it shoots well in your rifle, go for it (Unless it's an M1 or M1A).
Velocity/efficiency isn't the end-all/be-all when accuracy is your guiding principle.

April 23, 2011, 08:39 AM
52gr was not a misprint. I've used 4350 in 308 for the last 15 years and I spent years working my way up to it. Started with 45.0 all the way up to 52.0. Yes, the powder was filled all the way to the top of the case and had to use a drop tube to get all in. I found no signs of excessive pressure, but I did drop the charge to 49.0 and 50.0 due too better accuracy. It works well in my rifle, but I will admit that I prefer Varget as my 308 powder of choice...

April 23, 2011, 11:03 AM
God bless, my friend.

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