IMR 4320 in .308

[Stats Shooter]

My LGS had IMR 4320 on sale for $21/lb. So I bought 8x1lb jugs to do a 1k round batch of .308 plinking ammo using CCI-200's and LC mixed year brass. 147 gr BTFMJ bullets.

The round is seated to canelur giving an average OAL of 2.765". I also applied a slight crimp.
Partially I bought the powder because it was on sale, and I have used it before a while back for a .30-06, but I remember reading a German Salazar article about his palma loads using 4320 and 155 gr Palma bullets.

Anyway, I decided to try it in my ball plinking ammo. I didn't do a total work up, I started low , but only in pressure testing. I didn't shoot groups with the minimum charge rounds, only varified they were safe....I didn't start shooting groups or loading 10 round batches until I safely hit 45 gr., And Worked up to 47.

For the chroney'd rounds. I threw and weighed the powder by zeroing the scale to the case/primer,threw it, then re-weighed it. Also, 4320 is a short cut Powder and my Uniflow with baffles and micrometer kept each thrown within 0.1 gr. But I dumped anything and rethrew it if it was off at all. The gun is a gas piston AR-10, 16.125" barrel.

I'll skip to the best load....
46.3 gr 4320 .
Best group (5 shot) .54"
Worst group (5 shot) 1.1"
Warm barrel velocities
2689
2694
2680
2699
2682
2694
2689
2693
2702
Cold bore velocities
2681
2695
2677
2691
2684.
2680
2675
2673
2686
2684

I then load loaded up 40 more rounds at the above specs. All shot through the Chroney.
Avg velocity 2694
SD 11 fps
ES 36 fps

All magazine fed, and, as a side note, I have to hand document each round and aim while that round Cooks in the chamber. So if I had single shot it, the SD and ES (and avg velocity) would be lower.


I think 4320 will replace Varget as my lighter bullet plinking load due to cost,and metering, plus good velocity and accuracy in mixed brass.

Another note, 4320 in .308 fills the case up beyond the base of the neck. 147gr FMJ'S have a relatively short bearing surface and boattail section so the 46.3 gr load was lightly compressed. But the max .308 load of 49 would do some serious crunching.

Also, I tapped each round several times and in many rounds the powder settled down right at the base of the neck. Otherwise some loads had Powder half way up the neck with 46.3 gr.

FYI 4320 is a single based short stick powder about the diameter of 4064 but short, like RE 15. It is in the burn rate range of Varget .

I will still use 4064 for heavier bullets, but 4320 seems a great option with 155 gr and below bullets that aren't required to be seated too deeply. And the metering advantage will be helpful in my new Dillon XL 650

[Sure Shot Mc Gee]

If given some thought. Dupont 4320 became available in the mid 1930s. Since that time its been the #1 choice of (stick) powder for the venerable 300 Savage and others.

Although there are claims by other powder manufactures their powder is a direct replacement for & better. Maybe equal too. But as of this day I have never ever found a (stick) powder surpassing or more forgiving than IMR 4320 is for 300 308 and others having similar cartridge brass.

[Dufus]

That is funny in a sort of way.

You told me in another thread that IMR 4320 was for naught in the 308 Win when I mentioned using it. You were complaining about the velocities until you read the article that I posted written by German Salazar. I am guessing that changed your mind.

Regardless, I have been using IMR 4320 since the mid 60s with good results. I don't shoot as much as I used to, but I do still have a good supply on hand. And, for the record, I have never owned any Varget. I don't need it.

[Stats Shooter]

You told me in another thread that IMR 4320 was for naught in the 308 Win when I mentioned using it. You were complaining about the velocities until you read the article that I posted written by German Salazar. I am guessing that changed your mind.

What I said can be found in this link here....post #20

I said I got good accuracy, but not the velocity of some powders....like CFE .223, and I got as good or better accuracy, and better velocity with heavier bullets with 4064. But that was in an AK, so not a very good benchmark of accuracy,. Varget works great on small pill .308 also, but 4320 seems so far to be temp stable too, and meters better

I the Salazar article, and the sale on powder, did combine forcing me to give it a look in my much more accurate AR-10 though, and I am sharing my positive feedback

[Dufus]

Mississippi, I am not chastising you, just that I was surprised that you splurged for 8 lbs when you didn't appear to be that thrilled with it.

I am most appreciative that you posted your data so that others could share in your experience.

I started loading in April '63, and IMR 4320 was the first powder that I bought to use.

I think maybe IMR 4350 was the second some months later that year.

As I said, it gives very good performance accuracy wise in several cartridges that I use it in. I shoot for accuracy first and do not regard velocity until I get a decent load. Most times, the only reason that I chronograph is for downrange usage.

I'm guessing that is the reason Mr Salazar called it the "forgotten powder". You just don't read that much about it nowadays.

[Stats Shooter]

Mississippi, I am not chastising you, just that I was surprised that you splurged for 8 lbs when you didn't appear to be that thrilled with it.

I also load for accuracy first....a powder I am less than thrilled with is CFE 223. Great velocity, but poor temperature stability and thus, poor accuracy aa conditions change.


My other motivation for revisiting IMR 4320, as I illuded to, was getting a 650 xl. I said a while back I had an rCBS pro 7, but mostly all I did on it was pistol ammo. Now that I am shooting xtc matches, F-CLASS, AND field precision AR-10, I need to make more ammo, that is about as accurate, and all of it being thrown.

So I am trying to o find a good metering powder that meets or exceeds some of the loads I made before when metering wasn't as big of a deal because I weighed all match loads.

And it appears 4320 is in the running using bullets 155 or less in my AR10

But worry not, I took no offense.

[jmr40]

I've never used 4320 and it isn't one of those powders I see suggested a lot for 308. But looking at load data it seems velocity is comparable to most of the powders that I use and see suggested.

One thing that I've learned about 308 is that it is easy to load for. I don't think I've ever read about anyone getting poor accuracy with any powder or charge weight. Some give better speeds and some are more temp resistant, but it seems most anything you pour in a 308 case shoots accurately.

At that price, and if it's working for you, why not. Good to know. I'd never considered 4320, but might have to give it a try.

[hounddawg]

never tried 4320 in my .308 but those are some excellent range results Mississippi, I have a tactical style .308 I have yet to get below 1" with and might have to pick up a pound to try. Ken Waters has some loads for it in his Pet loads book.

[Stats Shooter]

never tried 4320 in my .308 but those are some excellent range results Mississippi, I have a tactical style .308 I have yet to get below 1" with and might have to pick up a pound to try. Ken Waters has some loads for it in his Pet loads book.

I've never used 4320 and it isn't one of those powders I see suggested a lot for 308. But looking at load data it seems velocity is comparable to most of the powders that I use and see suggested.

One thing that I've learned about 308 is that it is easy to load for. I don't think I've ever read about anyone getting poor accuracy with any powder or charge weight. Some give better speeds and some are more temp resistant, but it seems most anything you pour in a 308 case shoots accurately.

At that price, and if it's working for you, why not. Good to know. I'd never considered 4320, but might have to give it a try.

The thing Salazar mentioned, and my results seem to also suggest, is that IMR 4320 gives best results near MAP. I was using Lake City Brass, Quickload says MAP is 46.5 gr in LC brass. In commercial .308 brass, MAP is around 49 gr.
But Honestly, 49 gr is an almost completely full case.
I think the vibration and movement of a progressive press is enough to settle the powder, all I did was tap each round twice and some of the cases went from full about half way up the neck, to just at the base of the neck.

I also think that the case being that full is a big benefit. It means that once you seat the bullet, there won't be a whole lot of shifting going on. Also, with the BTFj's, there isn't a lot of seating depth movement to be had since you want to keep at least a caliber's worth of bearing surface below the rim.

Another good thing about this load is it was done with el-cheapo 147 gr FMJ's. Im sure 150's would work too.

But I only have $0.29 into each round (given that the brass is range pickup LC). Tell me where you can get MOA or Sub MOA, brass cased, higher velocity, .308 ammo for $290/1000 rounds?

[Dufus]

That makes good reloading sense.....the cost effectiveness of match quality ammo.

I use a drop tube most of the time.

Your progressive press should make the most of your selected components.

[Metal god]

The reason you don't see a lot of 4320 talk in 308 is because there are many others that do as well or better and those powders are more temp stable . It is how ever one of my secret powders I like but never tell anybody about because it's often one of the last to go when times are tough . Hmm maybe that's why I'm talking it down .

[44 AMP]

I began reloading with the .308 Winchester, back in the early 70s. The first two powders I used were IMR 4320 and IMR 4064. I had good results with bullets ranging from 110gr to 180gr.

However, the rifle I was loading for was a Remington 600, which never was, never will be, and was never meant to be anything near a match rifle.

while I use other powders more often, these days, there has always been a can of 4320 on my shelf. Not the newest, not the best for some things, a bit better metering than longer stick powders. No where near as good metering as a ball powder.

One other thing, for me, about 4320 is personal nostalgia. It's the smell.

Every time I open a can of 4320, I am, once again (briefly) that 16 year old, given his first deer rifle by his dad, along with 10 live rounds and a couple boxes of empties, and who's grandmother gave him an early birthday present of $40 to buy a Lyman Spartan press, (came with dies) and a Lyman scale, and a manual. I spent more than that tonight at the Olive Garden (wife loves their salad), so it doesn't seem like much today, but back then $40 was a grand gift, and one I know my grandmother sacrificed to make, though she would have denied it, if you asked.

Today, I'm set up to load for over 30 different rifle and pistol rounds, ranging from .22 Hornet to .458 Win Mag.

I'm sure the health Nazis would say its bad for me, but when I open a can of IMR 4320 (or any IMR, really) I take a deep sniff. Lets me go back, and briefly touch well loved things, now long lost.

[Scoits]

I use and prefer IMR 4320 in my 458 Lott.

[Stats Shooter]

The reason you don't see a lot of 4320 talk in 308 is because there are many others that do as well or better and those powders are more temp stable

I beg to differ on this. I don't know if I just got a temp stable batch....but I was testing on an 88-90 degree afternoon. The first few groups had ammo fresh out of the air conditioning and I shot over the croney....then I purposely had several sit and cook in the hot chamber and didn't find it anymore temp sensitive than most non- extreme powders.

Then, as far as perfomance, the velocity and groups speak for themselves. Then there is the fact it is 25% cheaper than most "premium" powders.

I have never been a man to believe the hype companies make about new products.... Probably because I am from a large family farm where seed, fertilizer, chemical, and equipment dealers are always trying to sell you something whether you need it or not.

Anyway, I encourage folks to try things for themselves as your results may differ from the "popular" opinion.

[Metal god]

I beg to differ on this. I don't know if I just got a temp stable batch....but I was testing on an 88-90 degree afternoon. The first few groups had ammo fresh out of the air conditioning and I shot over the croney....then I purposely had several sit and cook in the hot chamber and didn't find it anymore temp sensitive than most non- extreme powders.

Shoot it at 20* then again at 100* and check back with us and tell us how temp stable it is compared to Varget , 8208 xbr , AR-comp , 4064 , H-4895 I could go on but you get the picture I did not say it has the worst stability . Just that there are many powders out there now that are better . I read somewhere it was once the go to powder for 308 but that was a loooong time ago .

[cw308]

44 AMP
Very Nice Post. I have nice memories also. IMR 4064 is my powder for my 308 RL-15 s second.

[T. O'Heir]

"...was getting a 650 xl..." The press used makes no difference whatsoever. Warm or cold barrel velocities don't make any difference either. The only thing that matters is accuracy. Not that el-cheapo 147 gr FMJ's are made for accuracy.
49 grains of IMR4320 is a compressed max load. Compressed loads are nothing to worry about, but should be reduced by 10% for use in a milsurp case.
Temperature sensitivity isn't about highish temperatures. It's about extreme differences in temperature. Like Metal God alludes to. Some powders give different results at your 80/90 than they do at Winter/Fall temperatures.
Forget the cannelure. Load to 2.800".
Forget German Salazar's Palma loads too. A Palma rifle typically weighs 14 or 15 pounds, is single shot and has a 32" or so barrel. What works with one of them doesn't apply to a carbine length AR-10.
"...health Nazis would say..." Sooner or later everything is or will be bad for you. And there's more that is bad for you the older you get. snicker.

[44 AMP]

A friend of mine had a coffee cup with penguin cartoons on it, under the words, spaced around the rim...

Eat right!

Exercise regularly!

DIE ANYWAY!

[kennyfixer]

Trying to post 1st post in reply

I shoot DPMS LR 308 --100 rounds now, and subscribe to the 4320 powder with 150 gr FMJ BT Hornady and Fed LR Match primer. Making load development as in 1st post of Stats Shooter.

Best factory ammo to date with MOA Fed 308 150 gr soft points
and Hertenberger 147's are surprisingly accurate.

IMR 4320 now $35 a lb.

Thank you …..

[RC20]

Interesting, not one on my radar at all other than a few vague reference.

Looked it up and in the 130 to 168 grain range it pops up and more so in Sierra than Hornady (my two go to books).

Worth buying a can sometime.

As well as 06 it pops up in 7.5 Swiss.

[Dufus]

It works nice in the 8x57 too. At least it has for me.

[Guybo]

Works great in my daughter's model 7 .260 rem

[Bart B.]

In the heyday of the 308 Win in competition, 44 grains of IMR4320 was used with 190's in 7.62 Garands. Tested well under MOA at 600 yards. Bolt guns rarely used that powder as others were better for accuracy with all bullet weights.

I don't think Sierra ever used IMR4320 testing 30 caliber match bullets in 308 cases to get sub 1/4 MOA test groups consistently.

[Don Fischer]

I have never had good luck with 4320 powder in anything. Don't recll trying it in a 308 but then in a 308, a full case of cow dung and a CCI primer shoot's great! Seem's like pretty much everything shoot's well in a 308!

[Bart B.]

Originally Posted by Don Fischer

Seem's like pretty much everything shoot's well in a 308!

.....except ball powder when best accuracy is the first priority.