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Frank46
07-28-2005, 05:07 AM
I've seen this powder mentioned in some of the more recent postings. In what cartridges can it be used and where can it be purchased from?. Any quirks that I should be aware of?. I tried jeff bartlett's site but did not see it available. So any help is appreciated. Thanks, Frank

sundog
07-28-2005, 09:07 AM
Frank, try this:

http://www.iidbs.com

My best performance so far is 168 gr Sierra BTHP in 30-06 over 50.0 IMR7383 (fills case to shoulder and bullet seats on it with no room for powder movement). I shoot this load for High Power in a heavy bbl Mdl 70 and it does more than its share to produce good score at 200 yards (we shoot reduced course as that's all the range we have). Velocity on this load in my rifle is a steady 2395 with SD in single digits and ES in the teens. Two months ago I shot a slow fire prone of 199-11X. Last Saturday it was a 191-4X in alot of mirage (big boil). This rifle/ammo is capable of cleaning a target if the nut behind the butt plate would do his job.

I have not yet experimented with this powder much with cast so I don't have any recommendations. Early on I did try a few cast rounds in 06, and I remember them leaving alot of trash in the bbl. Maybe the heavy deterrent coating on this stuff requires more pressure to get a complete and consistent burn. I do have one observation though. This stuff leaves ALOT of carbon, evident VERY heavy black residue on first several cleaning patches. However, it appears to burn completely and does NOT interfere with accuracy even after firing three stages (66 rounds including sighters) as evidenced with above prone scores.

Maven had a several comments early on about this powder to the effect that it was somewhere in the neighborhood of 4350 then decided more like 4064. When I first loaded some it only took several rounds across the chrono to get the above mentioned load - start low and worked up until the case was full. It just happened to be a very good combination.

One caution. Some of the fellers have expressed a concern about this stuff being 'peaky', that is get to a certain point and add a little and get a big jump in pressure. I've not experienced that, but I've not pushed it either. sundog

Maven
07-28-2005, 09:30 AM
Frank46, Yes, I have tried IMR 7383 in 3 cartridges: .243Win. with jacketed bullets only; 7.5 x 55mm (in a K-31) with CB's only and in my .30-06, again, only with jacketed bullets only. However, I'm about to try it in my 8mm Mau. primarily with cast bullets. What you need to know is that you use 7383 only with standard primers and chronograph your loads religiously until you develop a "database" for your lot of it. Also, I wouldn't try compressing too much, as it doesn't respond well to that sort of thing. (I think Sundog wrote that.) And yes, according to Buckshot, it can be "peaky." As for results, I found my lot of 7383 to be slightly slower than IMR 4350 in both the .243Win. (wi. 85-87gr. Sierra & Hornady SP's, the latter a BT) and the .30-06 with 130gr. SP's, yet accuracy was better than 1 m.o.a. (low extreme spreads & standard deviations). In fact, the ES & SD were better than 4350's in the '06. As for the K-31, a very limited sample (n = 9) gave me excellent accuracy and "numbers" as well. Sundog has found his [lot of] 7383 to be dirty, but I haven't. I.e., it fouls no worse than 4064 or 4350 in the .243Win & .30-06, which get a thorough cleaning and copper removal anyway if I'm to use them with CB's. In sum, if you have a chronograph, use starting loads of IMR 4064 as your guide and work up cautiously. E.g., in my .243Win., I use 42gr. or less of 7383 with 85-87gr. CB's (can't get much more into the case) and still exceed 3,000fps. How much more velocity (and accuracy) do I need to punch paper?

carpetman
07-28-2005, 03:10 PM
Maven---You havent tried the powder with cast in .243? CRS attack here---do you have .243 mold??? If not send me an E and I'll send some cast bullets.

Maven
07-28-2005, 04:19 PM
Ray, I have 3 molds for the .243Win., but I only use 2 on a regular basis. The 2 Loverins are OK, but the 95gr. Lyman SP and the RCBS 100gr. SP didn't shoot at all well in my Ruger #1: 6 m.o.a. on a good day. As for slow milsurp powders in the .243, I tried that once, but got so much unburned powder in the chamber that I had to practically hammer the fired cases out from the muzzle. I wouldn't recommend IMR 5010, WC 860 or WC 872 for a the .243Win. or for that matter, the 6.5 x 55mm, either. Thanks very much for your generous offer though.

Maven
07-28-2005, 04:24 PM
Ray, I forgot to add that 7383 may not be the ideal CB powder either in a cartridge like the .243Win. or the 6.5 Swede. However, with jacketed bullets it has given me stellar performance in both the .243 and .30-06 with case filling loads. The latter occurs quite naturally since 7383 is bulkier than IMR 4350.

Buckshot
07-28-2005, 05:26 PM
...........I had gotten a pound of IMR7383 a few years ago from Jethrow Strait as a thank you I suppose, for hauling some lino over to him and his crew. I tried it in the 35 Rem, 6.5x55 and another which I don't recall offhand.

Typical of ALL powders, the higher the pressure the better they burn. But with these slower ones I think the heavy deterant and maybe even some type of flash suppressant cause additional effects. Don't ask me what particularly that might be, as for me it's just seat of the pants second guessing, or theories that sound good to fit the situation. Heck, even the big grain size may play a part.

In the 35 Rem with it's modest case volumn to bore size (expansion ratio) the powder works, but the accuracy was rather ho-hum. You can't get enough in the case to get in trouble. Since I only had a pound to work with, no testing was real extensive.

I'd loaded up 5 rounds for each, crimped and 5 rounds uncrimped. The loads were 30, 33, 35. and 37 grains. Dumped from the measure, 33grs of this course powder filled the case. Via a 24" drop tube I was able to get the 37gr charges in. Velocities with a 200 gr Saeco ran: 1457, 1683, 1753, 1835.

All were seated to engrave. As you might expect, all those that were crimped produced tighter stats. As for instance the 35.0gr load. Un-crimped- crimped SD's were: 51.0 vs 27. ES was: 119 vs 72. No vel diff at: 1753.2 and 1752.3

The 6.5x55 Swede with it's larger case and much smaller bore dia did very well with this powder. Trying it with jacketed slugs showed untoward velocity/grain increases as the case filled. I graphed them out as the increases were noticeable. The powder wasn't a benign acting as some other surplus numbers I'd used like WC852, WC846 and WC872. These loaded in increaseing charges proved very predictable as to the velocity increase you'd get.

There was a small percentage change with them as the case filled, ie: less empty space added to the energy per grain, but no surprises. IMR7383 on the other hand didn't seem to track as uniformly and at a point the velocity increases per grain doubled and almost tripled in some instances. From what I recall when this powder was first released on the market, info available showed 3 maybe 4 lots out there. I also recall the surplus dealers weren't exactly sure which lot it was they were selling.

It's surely possible that the peaking I saw was limited to the lot I had on hand. Also relevant was the difference in case volumn vs bore diameter and barrel length in the rifles I was using. IE: 35 Rem and the 6.5x55 and a 20" bbl and a 29" bbl respectively.

In any event when using surplus powders, testing should be done with a chronograph and components you're familiar with, such as primer appearance changes and a rifle you know well as to bolt lift, extraction and case appearance.

...............Buckshot

jethrow strait
07-29-2005, 12:12 AM
This has to be the most erudite, analytical and downright calm thread we have had on this surplus powder since we first started wringing our hands over it back on Shooters in '02. There's not a word I would disagree with, excepting perhaps the extremes of peakiness(as I recall that moment in history, the shooter was perhaps more peaked than the powder, driving himself madly to complete an array of experiments in a couple days that would take a mere mortal at least a week). I am too tired to add either heat or light at the moment.
Lately, I have been content to just enjoy the KISS quality of 7383----that is, using it up in medium bore cases of c50-65gr. capacity with condoms. 7383 has never failed me in that role, loaded to full or nearly full cases(but never compressed)at 80-95% of factory velocity. I'm not usually such a dull boy, but aided by the heat of season and my own laziness(in switching from Alox to Orange Magic lube) I've decided to just "keep it simple stupid" with 7383 for now.-----jethrow

Frank46
07-29-2005, 05:04 AM
Gentlemen, thanks for the info regarding 7383. I looked in my military loading manual and 7383 was used in loading 50 caliber spotting rounds. Not the regular 50 cal we know. In my sako 75 I use dupont (yep its that old) 4350 at 55.5grs with the nosler ballistic tip and get 2820fps the last time I chronographed that load. This is with the cci large rifle magnum primer. Velocity is very constant and shoots very well. Only have about two pounds left and will miss it. I had been following the 7383 thread and hoped to use it in my 9.3x57 when I get it with cast bullets. Thanks again. Frank