A Little More Dope on 7383

Just wanted to add to the knowledge base here, as there are quite a few opinions on this powder, with all of them being right, from a certain point of view. First, for those who don’t know, there are at least three lots, and the one I am shooting is a “fresher” one from GI Brass (48000). I’m still doing load development on this powder in the 358, and so far, a couple things “seem” to be the case. In this rifle - which is a Turk Mauser 98 - it seems as though you cannot get enough powder into the case to run into pressure issues. I’ve run this load “hot” into the higher published 4064 data with cast and jacketed (both 200 grains) and still not had “full” combustion of the powder. Quit a few unburned or charred kernels left in the bore after firing.

Now, on a whim, I loaded up 7383 with some old 175 grain round nose jacketed bullets in my 7x57 (also a 98, with a post-WW2 Belgium stepped barrel) and ran them downrange today. Combustion was much more complete, although there were still some unburned kernels, and accuracy hovered ran 1-1.5 in all six weights loaded. It’s important to note, this was simply a first run at the powder and bullet combo, using starting and lower-end published 4064 data, but several of the different powder weights showed promise. My observations with these would indicate you could run into pressure problems with the 7x57 case towards the max loads of 4064, unlike what I (and some others) have noted with the 358 case.

Based on what I’ve observed so far, this lot of 7383 MIGHT be optimal in certain cartridges and cases where a heavy bullet (or boolit) is being pushed, using the lower end of published 4064 data. I am going to move to a heavier boolit in the 358, as there are several members on here - Ben, I think, is one - who have fired some very fine groups with 7383 and the 358, with far heavier boolits. Perhaps this is a key to using this powder optimally. Bullshop has also used 7383 in 308, 35 Whelen, and (I think) 30-06 and reported it worked well.

As to the accuracy of the two guns, both have shot well with other powders, the 7x57 keeping a stout load of 4350 and these same bullets inside an inch at 100, and the 358 and these same boolits shooting into 2 inches at 100 with 19 grains of 2400.

I have had some good results with 7383 in my 35 Whelen
But I was using a 275 gr GC and 300 gr GC cast bullets
Lubed with Carnauba Red

I did get better results with a Mag primer and a HEAVY crimp
But I have to single load the 300 gr load
As they are loaded to long to fit in the mag well of my Savage 110 Rifle ( Old style with the smaller barrel threads )

John

I had decent results with the 35's and 7383. It might be a bore ratio issue.

Johnch - Good point I’d forgotten to mention, all the data, such as it is for me, has been with regular LR primers - an ancient lot of Winchester Staynless and very little crimp to the bullet/boolit.

MT Gianni - I think the 358 is going to work well with 7383, but the test projectiles for me have been too “light.” I believe there’s an unknown pressure variable in here regarding projectile weight still to be uncovered, and until I can get my hands on some heavier 358s, I can only extrapolate (which can be very dangerous in handloading) that the heavier bullets in the 7x57 pushed pressures “up” a bit and allow for a more optimal burn of the powder charge. I gave away all my 140 grainers, since purchasing several hundred NOS 175s, so I’m not able to test that angle easily, either, lol. Most of the successes posted here in the forum have “heavier for caliber” projectiles as a common - and mentioned - variable. Using that logic, though, can lead down rabbit holes and unknowingly run us into twist rate issues (My 358 is 1-16, so “too” heavy is useless) or case capacity challenges when we get to, say, .243 and bullets over 100 grains, even though my 243, an old Model 70, loves a higher end load of 4350.

Some have reported duplexing 7383, but I’m not ready for that in my journey, and from posts here, the jury seems about 50/50 about using magnum primers. I’m enjoying this so far, as it does make me think about variables I have not considered. As I said in the first post, I believe this is a useful powder, but one that doesn’t have reams of data and posts about it - at least not that I have found.

I appreciate you both sharing some of your thioughts.

Cree

Quote:

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Originally Posted by MT Gianni

I had decent results with the 35's and 7383. It might be a bore ratio issue.

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Yes, it is. 8mm seems to be right in the sweet spot as far as bottlenecks go, owing to volume vs neck restriction. I found 7383 perfect for 45/70 just as Jim did many years ago. The tighter the bore constriction to the higher the case capacity is when you begin to over do it. What I have read over the years, 9.3x72, 35 Whelen, all the 9’s seem to do very well with cast and this powder.

Gianni, I seem to remember you posting about it years ago, or am I misremembering?

Cree, I don’t know how much of the old posts by Jim, Ricochet, and the other old timers you have read on 7383, but it’s all well worth perusing.

Some of Jim’s off-CB stuff:

https://floydpics.wordpress.com/2014...-for-amatuers/

As always, do your homework with this powder, it ain’t like WC870 where if you load it in something silly like .243 you end up with a rifle full of unburnt granules,,,,,

Hamish I have a file from Roger on the old Shooters site that runs about 7 pages. The best thing to remember with 7383 is "If we ever get all the powder to burn, this could be peaky".

Quote:

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Originally Posted by MT Gianni

Hamish I have a file from Roger on the old Shooters site that runs about 7 pages. The best thing to remember with 7383 is "If we ever get all the powder to burn, this could be peaky".

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I remember reading this and later thinking, “peaky”, that’s an interesting way to put it,,,, :smile:

Quote:

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Originally Posted by Johnch

I have had some good results with 7383 in my 35 Whelen
But I was using a 275 gr GC and 300 gr GC cast bullets
Lubed with Carnauba Red

I did get better results with a Mag primer and a HEAVY crimp
But I have to single load the 300 gr load
As they are loaded to long to fit in the mag well of my Savage 110 Rifle ( Old style with the smaller barrel threads )

John

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I played with the 235gr Thor in an H&R single in 35 Whelen to fun effect using SRP. Very tame recoil, but never got good burn with that light a bullet.

Hope you’ve had relief from the headaches of years past John.

Hamish - I agree - words like “peaky” often give us pause, especially when handloading. Since I first found this forum several years ago, I can say I’ve gone through many of the subforums, especially gunsmithing, factory rifles, and military rifles several times, both as something to do in the evening before bed as well as to add to my knowledge.

I’ve been fortunate to have found a lot of what I feel is good info on 7383, and like your signature says, “This is what happened when I…” was sort of the reason for this thread. The downside, of course, is someone can take a singular post, or comment, and run off and make a … shall we say, “error in judgement.” But, I think when we set ourselves up carefully, use good reloading bench safety, take copious notes both at the bench and on the firing line, we can find examples of a LOT of “wrong” powders working well. (Of course, we can also make tragic or costly mistakes, too.) When we do this, we can add value to the forum, and encourage some dialogue as well as move things forward.

I’m not sure I’d go down this road without confidence in both the rifles used as well as my experience as a reloader, and certainly without the shared observations I’ve found here. I can say without hesitation that I place a great deal more stock in what I read in Cast Boolits versus many other forums.

Well said, very well said!

This is the lot# of 7383 I have. I’m not sure what I can do with it yet but I bought 45 pounds of the stuff for only $5 a pound.Attachment 312440Attachment 312441

A former member here was having good success with this in straight wall cartridges, 38/55 and 45/70. Then one day he wasn't. It all ended up on his lawn. I am careful to rememer that is was designed for 37,000 PSIg cartridges.

I have been very Leary to work with it. I’m not sure I even have any suitable cartridges that would be a good choice. I am thinking about having JES rebore one of my .308’ to .358

Waco - you’ll be a happy fellow with a JES rebore and a 358, no matter what powder you use!

Quote:

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Originally Posted by Cree

Waco - you’ll be a happy fellow with a JES rebore and a 358, no matter what powder you use!

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Nice thing is he is only about an hour up the road from me.

IMR 7383 certainly performs well in my 358 Win.


https://castboolits.gunloads.com/sho...8-Win-IMR-7383

Well, a bit more to add, even though this thread has a little age on it. With the 358 I’ve been working with, and based on some other 7383 users’ data and posts (Ben, notably), I’ve gotten some solid groups between 1-1.25 inches with a 255 round nose boolit (from Matt’s - his copy of the Lyman 358318) using 40 grains of 7383 and some ancient CIL LR primers.

In other news, though, this spring, a Type I Carcano that Bubba had chopped up - the rifles the Italians built for the Japanese in 6.5x50 Jap - fell into my hands, and I’ve been fooling around with it a bit in the shop. The bore slugs .267 and like the 7x57 I referenced in an earlier post, this rifle shoots really well with both cast (150 grain round nose at .269) and jacketed (156 grain .264) and 7383 and beginning data for 4064. As could be expected, accuracy went south with the cast boolits as speed increased (the Carcano-Arisaka is 1:9 twist), but groups were hovering around 1.25 inches.
As with my earlier posts on 7383 and the 7x57, the jacketed loads showed far more complete burning of the powder charge (not as many “crumbs” in the bore after each shot), but ignition was still not 100% - which has been widely mentioned as a sign you’re getting into pressure issues. I feel very confident that 7383 - when used intelligently and with heavy-for-caliber bullets and boolits, can provide a safe and accurate loads for those of us who choose to use it. I’m sure it’s not the right powder for “big” cases or tight bottlenecks, but it does offer some real value in the right applications. Just to restate, the lot I’m been using is marked 48000.

I hope this helps some folks, but remember, my guns and my reloading bench aren’t the ones you’re using. Don’t take ANY of this data as the Gospel, take it as a place to work to, not necessarily from.

Cree