Due to very limited selections of available powders I decided to try some 4320 for the first time. I wish I would have a long time ago. I am curious about burning rates of this powder. I have found conflicting claims from a few manuals that I have. One claims it burns faster than 4064 and two others say it is slightly slower. Curious what the AR consensus might be.

Also curious if anyone here uses it for 308 Win loads?

According to IMR and quite a few other charts.

Fast to Slow
IMR, Co IMR 3031
IMR, Co IMR 4895
IMR, Co IMR 4064
IMR, Co IMR 4320

http://www.imrpowder.com/burn-rate.html

Great powder useful for a lot of medium bores. Check your data for applications. Certainly could be used in a .308, if a bit on the slow side for that but will work fine. I have never seen it listed as faster than 4064.

quote:

Originally posted by richj:
According to IMR and quite a few other charts.

Fast to Slow
IMR, Co IMR 3031
IMR, Co IMR 4895
IMR, Co IMR 4064
IMR, Co IMR 4320

http://www.imrpowder.com/burn-rate.html

Yes it is slower than 4064 and 4985. The big jump in burning rate is from 4320 to 4350 which is a good bit slower.

To fill that gap they brought out IMR4007 SSSC.
4007 is about half way between 4320 and 4350.
You might consider 4007 insead if you can find enough data to make you happy.

I got great velocity in my 458 Lott with IMR4320 and reasonable groups.

Thanks Guys. That is what most of the sources I have say as well with the exception of a relative burn rate chart in the Hodgdon #27. It shows 4064 as being the slower one.

What I find perculiar though is that a lot of data I have for same case/bullet loads lists many max charges for 4320 being slightly less than 4064, as would be common if 4320 were in fact the faster of the two..

I wonder if they are so close that the actual rate could vary from lot to lot?? Or perhaps some of the 4320 data is just outdated..

It does seem when comparing loads for various cartridges using these medium burning rate powders that the relativity between these three powders in particular does vary depending on the cartridges they is used in, or the apparent effects vary.

IMR3031 is definitely the quickest of the four powders seemingly in all cartridges but there can be apparent differences when using IMR4064, IMR4895 and IMR4320.

Sometimes 4064 and 4320 are interchangeable and sometimes 4895 hops about either side of these two powders.
I have found you can generally kick off with the same starting load for each powder and then build from there in a given cartridge as these three are pretty close.

quote:

Originally posted by Wstrnhuntr:

Also curious if anyone here uses it for 308 Win loads?

No not 308 - But like it in my 9.3x62.

I noticed 45 years ago that the data flips flops depending on the cartridge and bullet weight.

I attribute it to 2 primary reasons

1. The manuals were not always good about defining which loads were at 100% loading density, which were less than 100% and which were compressed loads.

2. The companies didn't and probably still don't have a pressure gun test barrel for every last round loaded in the manual. Without the test barrels, pressures are estimated by throwing darts and chicken bones.

3. And maybe you can add this last one. Some of the data in a modern manual may be old data carried forward because the company does not want to waste precious resources on reshooting all data. Especially data for uncommon and dying rounds or rounds that give poor accuracy and poor case life in the best of conditions.

quote:

Originally posted by eagle27:
I have found you can generally kick off with the same starting load for each powder and then build from there in a given cartridge as these three are pretty close.

That is what I am seeing too. Especialy between 4064 and 4320.

quote:

Originally posted by SR4759:
2. The companies didn't and probably still don't have a pressure gun test barrel for every last round loaded in the manual. Without the test barrels, pressures are estimated by throwing darts and chicken bones.

3. And maybe you can add this last one. Some of the data in a modern manual may be old data carried forward because the company does not want to waste precious resources on reshooting all data. Especially data for uncommon and dying rounds or rounds that give poor accuracy and poor case life in the best of conditions.

Ill bet you are right on the money!

The time we spend just to develop a single load kind of puts into perspective the work involved in compiling a manual.

I saw in a couple manuals that 4320 was designed for match shooting (back in the day) and also that it was once used for factory 308 ammo. That is why I was wondering if anyone might have any pet 308 loads with it..

quote:

..... anyone might have any pet 308 loads with it .....

Got stuck in the same situation you're in ..... didn't have anything else to use and a Buddy needed some .308 Winchesters.

Used a grain less than the top load manuals called for and teamed IMR-4320 with a 130 gr. Barnes TTSX; shot wonderfully in his rifle; a Browning Short-Trac.

It does well in the 9.3x62 & 5.6x50R, too.

A buddy just gave me 1 1/3 lbs of IMR 4320. The full can is still factory sealed, both look good. They were from an elderly relative of his.

Doing some research it does seem like a useful powder, very close to 4064 in burn rate.

quote:

Originally posted by Gerry:

quote:

..... anyone might have any pet 308 loads with it .....

Got stuck in the same situation you're in ..... didn't have anything else to use and a Buddy needed some .308 Winchesters.

Used a grain less than the top load manuals called for and teamed IMR-4320 with a 130 gr. Barnes TTSX; shot wonderfully in his rifle; a Browning Short-Trac.

It does well in the 9.3x62 & 5.6x50R, too.

Apparently it is supposed to be a winner in the 35 Whelen as well, I will have to try that for sure. I am suprised that more people havent used it in the 308 as it should be very close to Varget.

quote:

Originally posted by SR4759:
To fill that gap they brought out IMR4007 SSSC.
4007 is about half way between 4320 and 4350.
You might consider 4007 insead if you can find enough data to make you happy.

Intresting.. That must be a pretty new powder because I cant find any data at all on it. That could be the ticket to getting an 8X57 to get up and dance with some 196 gn slugs..

I have used IMR 4320 in 308,30-06 and 375H&H.
It is my go to powder for lighter bullets in 30-06 and all 308 because I have lots of it.
It doesn't give the fastest velocities out of a 308 but they are adequate. Mrs Blacktailer took a zebra with 165 TSX with her 308 and if we decide to take only 1 rifle to Argentina next year I will use it for red stag.

quote:

Apparently it is supposed to be a winner in the 35 Whelen as well

W-Hunter,
I agree, if it works as well as it does in the 9.3x62; ought to be right at home in the 35Whelen - be sure to check a manual though.

Also IMR 4320 seem to be somewhat "twitchy".

I have never loaded it, but from what I have read over the last many years...
In some cartridges and in some loads it can suddenly pressure spike.
And in some cartridges it is never recommended.
IMR 3031, IMR4895, and IMR 4064 do not seem to have this problem.

Twitchy one word for it. Temp sensitive is another. Many powders are. Be careful with 4320. Max loads made up in the spring means blown primers in the summer. Don't ask me how I know that. I have had good accuracy with 4320, but I tend to shy away from it, because it is a bit sensitive.
I have a AR-10 in .243 that really likes imr 4320. I guess I'm going to use it again, and be a little more careful.

quote:

Originally posted by da_sidewinder:
Twitchy one word for it. Temp sensitive is another. Many powders are. Be careful with 4320. Max loads made up in the spring means blown primers in the summer. Don't ask me how I know that. I have had good accuracy with 4320, but I tend to shy away from it, because it is a bit sensitive.
I have a AR-10 in .243 that really likes imr 4320. I guess I'm going to use it again, and be a little more careful.

Military specifications for ammunition involves testing at various temperatures. The tests gather data on the variations in the pressures. Using the data, safe limits for the ammo are calculated. Without that data it is easy for us to load into the region that is close to blowing primers.
In loading data, you will often find that the max permissible pressure for one powder is higher than another. You can bet the powder with the higher pressure is much more consistent so that it does not exceed the upper limit at maximum variation.
The greater the variation the lower the acceptable maximum pressure will be.

quote:

Originally posted by da_sidewinder:
Twitchy one word for it. Temp sensitive is another. Many powders are. Be careful with 4320. Max loads made up in the spring means blown primers in the summer. Don't ask me how I know that. I have had good accuracy with 4320, but I tend to shy away from it, because it is a bit sensitive.
I have a AR-10 in .243 that really likes imr 4320. I guess I'm going to use it again, and be a little more careful.

Is IMR 4350 suitable for a 243 AR10?

I know on a bolt rifle and a single shot I had excellent accuracy at long range, with the 95gr Partition and the 100gr Sierra with 40gr to 42gr of IMR 4350.

Always got good results with IMR4320 in my 7x57 and 7mm-08.

Speer 145gr bullet and 45.0grs in the 7x57 for 2864fps from a 24" barrel.

Same bullet and 44.0grs in the 7mm-08 for 2800fps from a 22" barrel.

Our climate is quite temperate so don't have issues with temperature spikes.

quote:

Originally posted by eagle27:
Always got good results with IMR4320 in my 7x57 and 7mm-08.

I hate hearing about it being temp sensitive, Im trying to get away from such powders.. One thing that really sucks about this current component shortage..

Lyman shows a 7X57 load of a 139 gn Hdy @ 2898 fs.. That is runnning with 280 Rem territory. May have to play around with that a bit as I have a couple boxes of those. Your Speer 145 load looks great too. Ive taken a lot of deer with that bullet.

I like to try to work up loads with temp sensitive powders in the summer for saftey. The downside is they aint the same on opening morning..

I recently came across a pile of 4320 at a price I couldn't turn down. Never made a powder order that came on 2 pallets before

Anyway, I've been useing it in the 30-06 for with 165 bullets and it shoots as well as the Varget I've useing. The data on the website seems about grain or so too hot in my rifles.

In a truely bizare coincidence the load I settled on for the house general practice/plinking/economy/hunting load is the exact same powder measure setting as I was useing with the Varget load.

I came across this article about the powder in .308, you may find it interesting.

http://riflemansjournal.blogsp...oading-imr-4320.html

Interesting article Dogleg. I had forgotten that 4320 is fine grained and does meter well.

The loads I listed above for the x57 and -08 were not hot but gave good velocities, good performance on game with the Speer bullet and importantly were very accurate for hunting.

I think 4320 has been under-rated a bit by other more 'well known' powders.

it did ok, it had the slowest volasity with so-so accuracy in the .308 & 7-08 i tried one bottle but if IMR-4064 or RL-15 are avablible those are my choises. but with todays sale of powder you better get whats there..

Ive been using IMR 4320 for many years in my .308 Model 760. Tried IMR 4064 and RL-15 but never got accuracy that matched the 4320. It's pushing a 150 Gr. Hornady Interlock. It works great for Whitetails. I only shot one large Black Bear with this load and he went right down as well.

4320 is da bomb in my wife's 6mm Remington. Works in a pinch for .375 Wby or whatever if you have data...

4320 Is a powder that has worked well in calibres as varied as a .17 Remington, 22\250, 250 Savage, .308 Winchester, .35 Whelen, 9.3x62 Mauser, .416 Remington, and last but not least, it was the original powder of choice in the .416 Taylor and the .458 Lott. 47 grains of 4320 with a 150-155 grain pill in a .308 will usually be a very accurate load. 35-36 grains of 4320 with a 52-55 grain bullet in the 22\250 is usually a tack driver.

You should invest in Ken Water's Pet Loads. He had some very good loads with this powder in the 22\250 Remington, the .250 Savage, and the .308 Winchester with hunting bullets. It is a superb powder in the .338-06. It was with IMR 4320 that Ken Water's had his most accurate load with 250's in the .35 Whelen. In my own .308 Husqvarna Lightweight, a 150 grain Speer Grand Slam with 47 grains of 4320, Remington brass, and a Federal 210 match primer is an outstanding load. A stout load(1-2 grains above some books) of 4320 with 165's has been known to drive tacks as well.

My personal experience with this powder is that it drives home a Grand Slam home run, or leads you to the bench in shame. It can be hit or miss. When it does hit, it is out of the park.

I forgot to mention in my earlier post that IMR 4320 works well in the .303 British. In my Ruger #1, 44 grains of it push a 174 grain Hornady into some good groups off the bench. This load came from an old Lyman manual, where it was described as a factory duplication load. It is not mentioned in today's Lyman manual. It is 3-4 grains hotter than the new material. I figured the Number One could handle it and was right.

I used to use a lot of 4320 however it is not available downunder anymore.
http://www.adi-powders.com.au/...uide/equivalents.asp

My most accurate 32 Special load using the new Hornady rubber tips is with 4320 based on data from Pet Loads for a 170 cup and core.