Imr-7383/imr-4064

[waco]

I have used IMR 7383.
I have an 8 lb. container of it right now.
It reminds me of petting a rattlesnake.
It can be done, but you better be real careful.
I certainly wouldn't recommend 7383 to an inexperienced reloader.

Ben

This is why I am looking for more info. Don't want to jump in blind....

[JonB_in_Glencoe]

I have a full 8 lb jug of the stuff, that I bought from GIBrass about 8 years ago. I've never burned a kernal of it yet, but I've read through every thread I can find, and read most of them a dozen times.
With that disclaimer out of the way, I can tell you the following.


Lot numbers:
post #5 in this thread, summarizes the info I've read about lot numbers.
https://castboolits.gunloads.com/sho...=1#post3581750

[Maven]

All, I've been using IMR 7383 for years, primarily in my .243Win. (now sold off) and .30-06 with jacketed bullets, with nary a problem. My unnumbered lot is ~the same burn rate as IMR 4831 and is much "fluffier" than IMR 4350. Lately, I've been using it with 160gr. cast bullets in my SKS with LR magnum primers and have been very happy with it with respect to accuracy and not tossing the ejected brass a country mile. If you already have a jug, use it, but start conservatively and chronograph your loads: It is a good propellant especially since it was once dirt cheap. Now? maybe not so much (because of its price).

[waco]

I picked up 45 pounds of it for $5 a pound.

[waco]

The stuff I have has hollow sticks like SR4759 only much thinner.

[475/480]

I bought this powder 5 years ago , label say's 4831 less 15% , finally got around to using it.
Gun:
TC Encore pistol 25-06- 15" barrel -shooting Sierra 120g HPBT
IMR 7383- Winchester LR primers
37.0gr = 1895 fps- dirty
38.0gr = 1956 fps- dirty
39.0gr = 2115 fps- a few unburned flakes
40.0gr = 2237 fps - nice and clean barrel.

Sean

[Vettepilot]

I would like to keep this thread alive.

Back during the height of the shortage, in a panic, I bought 24 lbs. of 7383 from Bartlett. I keep looking it up from time to time, trying to accumulate knowledge and load info/data.

I am interested in loading 30.06, .243, 308, 7.62x39, and 338 Lapua with it. I've never heard of anyone using it in 338 Lapua. Anyone here??

So, it seems a bit slow maybe, for our most common uses. So, why would people not trend towards heavier boolits? Like 180--> 200 grain boolits in 30.06 instead of 150's?? Or is it that with it's bulkiness, more room in the case is more important than projectile weight??

Thanks for any info, data, or insights. At some point, I would like to use this up. Any use in pistol calibers is interesting too!

Vettepilot
EDIT TO ADD: Can't believe I forgot, but I would like to also possibly load my 7383 in 300 WSM for my AR10. Anyone load 300 WSM with 7383??

[JonB_in_Glencoe]

Vettepilot,
Have you read this?
https://www.castpics.net/LoadData/7383/default.html
the most important part is this...

I will add to what Linstrum posted by saying that I have found 7383 to burn very dirty below the pressures it needs and that once you find a clean burning load, you have reached the sweet spot. Going beyond the point at which you get clean burn is begging for a pressure excursion and should not be done. 7383 is certainly a powder where too much of a good thing is a very bad thing. I also find that 7383 doesn't like empty space in the case with it nor does it like compression. Best loads are most commonly found between 85% fill and 105% case fill. Below 85% is often erratic and above 105% is usually asking for problems with pressure. available powders and all other currently available surplus powders. It requires special care when loading so has been given a section of its own.

Also, you see the two links at bottom, Jim and Will offer a bunch of data.


Your best loads need to be worked up with your gun. Even when getting load data that someone else worked up, I would strongly recommend not using their data, but drop the charge 10% of their data and work up, because guns and loading techniques vary enough to get you into danger if you just use someone else's pet load.

[JonB_in_Glencoe]

Also, in post #22, I have a link to a thread about the different lot numbers. Do you know your lot number?
The different lot numbers have slightly different burn rates...which is another reason to work up your own load.
Good Luck.

[Vettepilot]

Thanks guys. Yes, I had already found, and read the info you referenced.

My lot is either 48000 or 48001. (Don't remember and don't have access at the moment-- I think 48000.)

Thanks,
Vettepilot

[Moleman-]

So far I've used the RAD-78L-(7383) version for 223, 308, 30-06 and 303. I bought this back in the late 90's and this is the load data that came with it. (you can click on the pic to make it larger) I shot a lot of rounds of 223 with pulled 62gr SS109 bullets for dirt cheap plinking. It would cycle my 20" ar15's but it didn't burn clean and occasionally you'd need to use the chamber brush to clear unburned powder. 308's were underpowdered but the 303's and 30-06 were slower than IMR-4895 but reasonable.

[Maven]

Let me say at the outset that IMR 7383 is better suited to jacketed bullets than cast and has a burn rate somewhere between IMR 4350 and 4831. This varies by lot (mine has no lot no.), cartridge, and possibly bullet weight. I've had no trouble using it in y now sold .243Win., .30-06, and 8 x 57mm Mauser. (It was accurate and clean burning in these.)

Here is another cartridge to consider using it in, with cast bullets and LR magnum primers. To wit, the 7,62 x 39mm in the Type 56 SKS. In my as issued rifle, the C.E. Harris designed, but NOE produced mould, it is accurate, doesn't toss the brass far (100% ejection rate), but throws unburned powder into the magazine. The Harris CB is the one on the right and weighs ~165gr.. I use between 22.0 and 23.0 gr. IMR 7383.

[Vettepilot]

Since the powder is a bit slower than we might like, one would tend to go with heavy for caliber weights, right?

Or would the heavier bullets taking up room in the case be more of a factor??

Vettepilot

[Maven]

Heavier bullets, as long as you don't heavily compress 7383.

[JonB_in_Glencoe]

Since the powder is a bit slower than we might like, one would tend to go with heavy for caliber weights, right?

Or would the heavier bullets taking up room in the case be more of a factor??

Vettepilot

Thanks guys. Yes, I had already found, and read the info you referenced.

My lot is either 48000 or 48001. (Don't remember and don't have access at the moment-- I think 48000.)

Thanks,
Vettepilot

Also from the link I posted, that you've read

"The main thing to remember about IMR7383 is that it is a HIGH ENERGY TRIPLE BASE PROPELLANT that goes by different rules of loading density than the normal single and double base propellants that we are normally used to. The third ingredient is nitro guanidine, which supplies both the increased energy content and confers its flashless characteristics."
...

A triple base propellant that starts getting zippy when it is in it's ideal pressure zone is probably breaking the rule of slower powder-heavier bullet.

[Maven]

Some more points I neglected to mention about IMR 7383. (1) 7383 is best used with a chronograph so you know exactly how it performs with respect to velocity, and maybe pressure. (2) It doesn't like heavy compression or excess temperature. Ergo, don't leave loaded rounds in the sun on a warm - hot day. (3) I've had no trouble with combustion and unburned powder residue when I've used it with standard seating dies, even in the SKS. I.e., no crimp of any kind was used even in the SKS*. Yes, there's unburned powder with the 7.62 x 39mm cartridge, but it hasn't affected accuracy so far as I can tell. OTOH, a crimp degraded it.

*IMR 7383 isn't ideally suited to the 7.62 x 39 cartridge, but neither is Unique or Blue Dot. However, 7383 has the virtue of 100% [gentle] ejection in the SKS whereas Unique and Blue Dot failed in that regard even though they were very accurate.

[Vettepilot]

Well, regarding chrono usage. I think the only useful info would be looking for a "point of diminishing returns" plateau. Being a "too slow" powder, the overall velocities will be slow. Trying to load it up to normal velocities seen for a given caliber would be very dangerous.

Energy is of course, related to both velocity and weight. With a too slow powder, velocity will be low, so hopefully you can get some energy back into the equation with heavier weight projectile. However, there's also the necessity of balancing projectile weight versus available powder room too.

Vettepilot

[Maven]

Not exactly, VP. To wit, I loaded my .30-06 (Mod. 70 Win.) with 55 gr. IMR 4350 and 55gr. IMR 7383 and a Sierra 125gr. jacketed bullet. The chronograph showed very clearly how each load performed. No pressure signs, but 7383 was ~100fps faster than 4350 and took up noticeably more room in the case. As I've written many times before, 7383 is better suited to jacketed bullets than cast, with the 7.62 x 39 mm cartridge being a notable exception.

[Vettepilot]

Well, it's good to know 7383 can be used in 7.62x39, and that it produces enough gas to cycle. I generally use 125 grain projectiles in that caliber though, and I shoot AK, and an AR in that caliber; not SKS. The 16" barrels in those rigs would like the slow powder even less...

:~(

Not that I couldn't do something similar to you, as I do also cast. What velocities did you see, and what alloy did you use? Powder coated or naked? Gas checked? Leading?

Thanks!
Vettepilot

[Vettepilot]

Seems like I see quite a few people using 7383 in 30.06, which is good for me. Not so many in 308 though. Not enough case capacity in 308??

Vettepilot