Data chart for IMR 7383

[Jim]

I know this horse has been beaten to death for years. I just came from Castpics and noticed there's no data posted on this powder.

Would y'all be interested in submitting established load data and compiling a chart?

7383 is still out there and is still available. I've got some data, but I know others have loads I don't.

I admit it is a very tricky powder and things can go south quickly if it's over charged. However, if it's used with a good starting reference point, it can produce some decent shooting.

What say the court?

[felix]

It is good, Jim. Speed can range from 4064 to about 4350, depending on bore size in particular. Best used in case full allotments as usual, which is 38 grains in 308, 41 grains in 8mm Mauser. Maven has used it in 243 with some reasonable success as well, and I think he was using condoms to build the required pressure to burn the stuff cleanly. ... felix

I do think someone researched the formulation of this powder to being of triple base design. Therefore, I would NOT jump start a load using a faster normal powder with this powder. The reason being the burn-at- pressure balance will be upset and very well make the whole power composition loose its normally designed progressive curve and go bananas. ... felix

[Jim]

Felix, I'll admit I wouldn't make a pimple on your back side for what I know.

However, I've loaded this stuff in rifle calibers from .223 all the way up to .45-70. It took me a long time, but I found loads for several calibers and several boolits in each. I even worked up a load for .45 Colt, if you can believe that.

I was just thinking if each member that has successfully developed data submit their records, maybe we could establish a chart, of sorts, for others to refer to.

As for a write up, well, that's been done a thousand times over.

[felix]

That is OK by me, Jim. You can include both of those loads contributed by me above. They will work for any medium thru heavy boolit in the two bore sizes. Adding more powder in bigger cases would be OK as far as the powder alone is concerned in those two bore sizes. ... felix

[Jim]

I sent a list to Wiljen. He said he may add some of his own to it and publish it on Castpics.

[TCLouis]

when I read that it gets pressury fast towards max loads I sit back and did nothing.

Fast as in 0.1 grain increments, 0.5 grain, 1.0 grain ? ? ?

Compiling a chart would be very appreciated by me.

When I applied the percent reduction mentioned by Bartlett, it ended up matching 4064 in every cartridge/bullet combo I was interested in.

[MT Gianni]

Please include lot numbers when submitting loads. They seemed to vary a lot.

[hicard]

I've used 40 grs with a 245 gr bullet in a 358 Winchester and 45 grs in a 35 Whelen with good results.

[Ben]

I use 40 grs. of IMR - 7383 in commercial .308 Win cases formed into 358 Win. with the Lyman 358318 HP, weighing 262 grs. with lube and g/c.

Shoots great.

You have to " settle " the powder a bit to get the bullet seated without compression. I've always read that compressing IMR - 7383 isn't good, so ..........40 grs. is as far as I've taken things.

Ben

[wiljen]

Sometimes very mild compression is acceptable, but not more than that. My finding is as soon as it burns clean, quit upping the charges. At lower pressure than it likes, you get unburnt garbage. The minute you don't get that garbage, you have hit the sweet spot and any further increase only serves to get you in trouble.

[Ben]

wiljen

Yes, you're " on target " with everything that you're saying. I'm in full agreement with you.

Ben

[sundog]

30-06 / 168 SMK or Hdy BTHP / 50.0 gr of IMR 7383 / 2395 fps (chrono'd) and deadly accurate at 200 yards. SD in single digits and ES in the teens.

powder needs to be 'settled' (tap the case several times) just a little so it will not compress.

In the several rifles in which I have used this load little or no copper fouling was found, even after 80 plus rounds for high power. What I did get though was the first several patches coming out extremely black. This powder leaves a different kind of residue then 4895/4064.

[MT Gianni]

I have a lot of notes by Roger Bartsche from Accurate reloading about '03-04. They are not mine and I have not been at that sight often enough to know if he is still around. They could go on cast-pics but it is a collection of data complied by someoneelse. I don't know how the intellectaul properties run with that.

[Jim]

Wiljen and Sundog, obviously, like me, have shot a lot of this powder. Both know what they're talking about.
As for Roger, several years ago, he went on a rant about how dangerous this powder is. He even stated that he would like to see it outlawed.
Like Wiljen and Sundog, I've been burning and experimenting with it for years.
I have about 45 lbs on hand. That oughta' last me a coupla' more weeks.

[Maven]

MT Gianni, Roger and I corresponded with each other about IMR 7383 on the AR Forum years ago, mostly because of the lack of [reloading] data provided by its milsurp distributors. I know he wrote to them complaining of that and the liability issue it posed. However, once the AR Forum became a subscription only website, I stopped posting there and have since lost touch with Roger. Be that as it may, here is some loading data for milsurp 7383 (no longer have the lot no.):

.243Win.: 7383 isn't a candidate for CB loads in this cartridge. However, it works extremely well with Hornady 87gr. BTSP's and 85gr. Sierra SP's. If you're not sure of the "speed" of your lot of 7383, start with Lyman et al., starting loading data for IMR 4064 or H 380. Chronograph these if possible. Actually, it's imperative to do so. I did and found that my 7383 was closer to IMR 4350 and used that data as a basis for load development with those 2 j-word bullets. 39.5 -41.5gr. worked perfectly: At least 3,000fps and better than m.o.a. accuracy from my Ruger #1. In warmer weather, cut back to 40.5gr. as 7383 is sensitive to high[er] ambient temperatures.

.30-06: Using 7383 as IMR 4350 with 125gr. Sierra SP's, I chronographed 55gr. IMR 4350 against 55gr. IMR 7383. The former -> a mean vel. of 2,545fps +-23fps, whereas the latter -> 2,697fps +-22fps. I never tried IMR 7383 with CB's in this cartridge. Accuracy, btw was outstanding.

7.5 x 55mm Swiss (K-31): My friend Vly tried 7383 in his K-31's, but we had only a small no. of chronographed loads to work with. Some time later I decided to try 38.5gr. 7383 with Ly. #311466 (sized to .309" and seated to the rifling). Mean vel. (n = 20) was 1,967fps +-21fps. Accuracy was as good with this powder and CB as it has always been. In short, you can adjust this powder charge down to 37gr. or up to ~40gr. if using different weight CB's.

8 x 57mm Mau.: I tested Hornady, Sierra, and Speer 150gr. SP bullets with 50gr. 7383 (heavily compressed!) While accuracy and velocity were excellent, I DON"T RECOMMEND that charge. Mean velocity was 2,449fps +-17fps, which is essentially the same as I've obtained using Ken Waters' "pet load" of 48gr. IMR 4064. IMR 7383, however, IS quite user friendly with heavy (195gr. - 205gr.) CB's in this cartridge. 38-40gr. works quite well for me.

[Jim]

Thanks, Maven! that's good data.
Y'know, I forgot to credit you with your knowledge of this powder. Do forgive me!

[Jim]

Thanks, Maven! that's good data.
Y'know, I forgot to credit you with your knowledge of this powder. Do forgive me!

[Maven]

Jim, No offense taken/not a problem at all!

[rongaudier]

Sometimes very mild compression is acceptable, but not more than that. My finding is as soon as it burns clean, quit upping the charges. At lower pressure than it likes, you get unburnt garbage. The minute you don't get that garbage, you have hit the sweet spot and any further increase only serves to get you in trouble.

This is interesting. I ordered a case (42 pounds) of 7383 to use in my 30-06. Today I fired some of my cast bullets (powder coated and gas checked) over 40-43 grains and 1980-2050 FPS. Plenty of unburned powder on my cleaning patch after each shot. I'm thinking of bumping the load up to 46-47 grains and see what happens. I'm looking for that "sweet spot" you are talking about.

[Yodogsandman]

Please be careful. Use good safe loading techniques like working up slowly.