Imr 7383

[Denver]

Howdy Guys,

Been playing with the 7383 powder I recently bought, so I thought I'd post the results here. I'm shooting a 1952 vintage Marlin 336RC in 35 Rem with conventional rifling. Boolit is a RCBS 200FP sized to .360 from a "beageled"
mold. ACWW w/Hor GC. Powder charge is 31.5 grs IMR7383 milsurp. The 1st load is with Win Lg Rifle primer. Load #2 is with the Win Lg Rifle Mag primer. Range is 75 yds. Chrono is 10' from muzzle.

Load #1
1 = 1503 AV =1482
2 = 1501 ES = 38
3 = 1465 SD = 18
4 = 1479
5 = 1465

Group size= 2.4" H x 4.4" V

Load #2 (Magnum primer)

1 = 1536 AV = 1522
2 = 1510 ES = 26
3 = 1529 SD = 10
4 = 1520
5 = 1515

Group size= 2.3" H x 2.0" V

I'm going to bump the charge up another grain with the Mag primers trying for 1600 fps+/- and to see what it will do for group size. Still plenty of unburned powder in bore even with mag primer.
I also tried this boolit in this rifle using the AA2520 milsurp powder I bought.
The Accurate handbook gives a starting load of 34.2 grs with a 200gr lead boolit. I got an average of over 1800fps with that load, but 8"+ group at 75 yds.

Ron

[felix]

Denver Ron, treat 7383 like 4064 in your 35 rem. I'd try 36 grains for starters and occillate about that load to tweak the ES/SD, assuming the accuracy and recoil are both satisfactory. ... felix

[Denver]

Denver Ron, treat 7383 like 4064 in your 35 rem. I'd try 36 grains for starters and occillate about that load to tweak the ES/SD, assuming the accuracy and recoil are both satisfactory. ... felix

Felix;

Thanks for the info. I may work up to that eventually, but if I can get 16-1700 fps and good 100 yd accuracy with less, I'll be happy with that.

Ron

[Jeffreytooker]

<<<<Denver Ron, treat 7383 like 4064 in your 35 rem. I'd try 36 grains for starters and occillate about that load to tweak the ES/SD, assuming the accuracy and recoil are both satisfactory. ... felix>>>>

Felix:
Are you saying to treat 7383 as 4064 in all cases or only in Rons 35 Rem? The reason that I ask is that others on this list have said to treat 7383 as 4350. There is a lot of distance between them. On my burn rate chart it is the diffrence between 184 and 212. Just in IMR, 4320 sits between the two of them.

Considering the people on this list who are lamenting not having bought surplus powder when they could, I figure if I will make a buy of 7383 and keep it. It should come in handy for a number of loads.

Keep Well.

Jeffrey

[felix]

When in doubt, assume the powder will burn faster than expected, like 4064. After confidence is gained, then increase the charge as if loading 4350. The reason for this logic is that this particular powder can peak rather unexpectedly after "its" pressure is met. Remember, this powder was specifically made for a large bore size (50 cal) and a case full at that using a 650 grainer bullet. That being the CASE, you can think using the same powder at 40 grains in a 35 won't be too much. ... felix

[Jeffreytooker]

When in doubt, assume the powder will burn faster than expected, like 4064. After confidence is gained, then increase the charge as if loading 4350. The reason for this logic is that this particular powder can peak rather unexpectedly after "its" pressure is met. Remember, this powder was specifically made for a large bore size (50 cal) and a case full at that using a 650 grainer bullet. That being the CASE, you can think using the same powder at 40 grains in a 35 won't be too much. ... felix

Felix:

Go to this link and search for 7383. http://www.ar15.com/content/manuals/TM43-0001-27.pdf 7383 should be found on page 146 and others. There is enough info there that I should be able to figure out the rario of the case volume to the projectile base surface area. This should give me an equivalent cartridge. It also states projectile velocity, and weight. It also states Pmax. Pmax is 38k which is intresting because it is rather low. It also states charge weight of 7383. With this I should be able to figure out charge weight of the equivalent cartridge. I can then go int Quickload and find which powder meets these parameters. If all works well it should come out to the emperical determination of 4064 to 4350. Let me work on this for a while and I will get back to this thread.

Jeffrey

[Buckshot]

............Denver, 7383 is too slow to do much in the 35 Rem. However if it's just for plinking then it would be useable. As an aside, if you want a powder for your 35 Rem that would be WC846. A casefull with a 200gr cast slug will give you about 2200 fps. Accuracy in my bolt gun is match grade.

For 7383 to be usefull it needs some pressure. The closer you get to a straight case, the worse it does for our applications. If you go the other direction like the 7x57 or 6.5x55 you're improving things. About the only thing you can do in cases with low expansion ratios like the 35 Rem is to do as you did, and switch to a mag primer and/or seat a heavier slug or both

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

[Maven]

For what it's worth, IMR 7383 (with standard LR primers) seems to be quite close to IMR 4350 in burning rate in the .243Win. and .30-06 when using jacketed bullets. Here's some chrono. data I recorded for IMR 7383:

.243Win. wi. 85gr. Sierra SP & 87gr. Hornady BTHP; Fed. 210 primers; Ruger #1, 26" bbl.:

38gr. 2,638fps +-42

41gr. 2,911fps +-37

42gr. 3,066fps +-26 MAX!!


.30-06 wi. 125gr. Sierra SP; Fed. 210 primers; Mod. 70 Win., 22" bbl.

55gr. IMR 4350 2,545fps +-23; ES = 64

55gr. IMR 7383 2,697fps +-22; ES = 77


.30-06 wi. 30HBC (~195gr.), same rifle, but Win.LR primers. CB sized to .311" and seated to 3.32" OAL; LC Match brass

49gr. IMR 7383 2,350 +-15; ES = 44


The only load that was inaccurate was the one with the .30HBC and that's due to the CB design rather than the powder type or amount used. The others were m.o.a. or smaller. Let me emphasize what I written before about 7383. First, it's not particluarly CB-friendly and small increases in powder weight may result in large increases in pressure: bareful with this one! As Felix suggested, treat IMR 7383 as IMR 4064 or H 380, i.e., as faster powders, and chronograph your loads. Obviously, you must, for safety sake, use a chrono. If you don't own one, stay away from 7383.

Max. loads of 7383: I use it only for target loads and don't like or need to push my loads to the max.: How much speed do you need to punch paper? Ergo, consider 42gr. in the .243Win. and 55gr. in the .30-06 as essentially MAXIUMUM loads, especially in warm weather.

Powder Fouling & 7383: Not a problem in my experience. I've had no unburned powder in cases or bore and your favorite solvent will remove whatever carbon fouling you get. I find it to be no worse than what IMR 4064 or IMR 4350 leave behind.

[Denver]

I worked up to 35grs of 7383 with the RCBS 200gr FN in my Marlin. 35 grs fills the case part way up the neck and results in a compressed load with this boolit seated and crimped in the crimp groove. I didn't chrono this load as my machine took a $hit after a gas check perforated the display screen, but accuracy was improved somewhat over the lighter loads I tried earlier.

[Buckshot]

I worked up to 35grs of 7383 with the RCBS 200gr FN in my Marlin. 35 grs fills the case part way up the neck and results in a compressed load with this boolit seated and crimped in the crimp groove. I didn't chrono this load as my machine took a $hit after a gas check perforated the display screen, but accuracy was improved somewhat over the lighter loads I tried earlier.

..............There ya go. Onliest other thing you can do it'll fit in the chamber is to stick in a 225 to 250 gr slug. A bit more load to start ergo a bit more pressure generated. Now if you were to neck that 35 Rem case down to 30 cal ...............

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

[rbstern]

Let me pipe in one more thumbs up for 7383.

I just tested it in a batch of 7.5x55: Lee 309-180R (ww, water quenched), 36 grains of IMR 7383. Grouped 8 rounds into 1 inch at 25 yards (shooting indoors). Average velocity was 1908 with an SD of 28.

All told, shot 20 rounds, each with 36 grains of 7383, some with a 150 grain pill. The 150 grainers were more velocity erratic, but neither it nor the 180 produced any fliers; all twenty rounds grouped tight.

I'll be interested to see what these do at 100 yards.

By the way, these were out of a short-barreled (17") K31 "tanker" model...a self-directed bubba project made of AIM Surplus u-fix 'em specials.

A $59, amatuer, hacksawed, dremeled rifle, shooting 5 cent reloads into itty bitty little groups.

[AFRecruiter]

Would you happen to have a pic of you "tanker"? Is it scoped or did you fabricate a new front site? I personally like to keep my milsurps original, but like you, I have a "parts" gun that would be a great candidate for a little bubbification

[rbstern]

You can see it here:

K31 tanker conversion

[Buckshot]

................A very nicely done alteration. I can understand some people getting upset about altering an original milsurp. I think some of it is just mimicing what they've heard other say. Now a truly super fine example that actually IS a true collector specimen would not be my choice to fiddle with.

Having been around the net on various sites I've seen the issue brought up over altering such as Turks. I'm reminded that Swedes were brought in by the shipload after the change in gunlaws in 1986 and they were a glut. Available to FFL holders for $59/M96 and M38's were $79 with the Ag42B's going for $169. Kimber did wholesale slaughter on them to create useable (if not real fancy) plastic stocked sporters with high 'see thru' rings.

One time a charachter was going on about a 'Bubba' job on a rifle. I happened to have one and thought I might make a post poking fun at the whole issue. I was going to hold my specimen as a hostage unless someone bought it from me, otherwise I was gonna sporterize it!

So I agree. Unless it is a really nice or pristine example of the breed it's fair game to be fooled with.

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

[IMR]

Howdy, y'all.
I've been burning 7383 for several years and have really come to enjoy the financial savings of using it. $4/lb. ain't bad. I've burned it in bottleneck calibers as small as .223 and as large as '06 and in straightwall calibers as large as .45-70. I even use it in a .45 Colt Vaquero under a Lee 255 gr. SWC. Gotta compress it, though, to get all the powder to burn. It definitely likes pressure. Seems to prefer a magnum primer, also.

[Ricochet]

I've had good luck with it in full capacity charges under jacketed bullets in .30-06 and .22-250. Doesn't like magnum primers in the .22-250. In .45-70 with 340 grain bullets, it won't burn much. Locked up my Marlin 1895 with unburned powder.

Buckshot, I hate to see an old veteran get cut up, too. Or worse. A year and a half or so ago I bought a Romanian contract Vz24 off of Ric, when we were talking about the relative strengths of Mausers and Mosins and he was planning to "test till failure." I like that old Czech. I'm really glad he sold it to me, I missed out on the wave of cheap ones from the importers. I'm a Turkaholic right now. Love those old long Mausers and Mosins!

[carpetman]

Riccochet---Turkaholic. Take two asprins and go to bed and mail me the check before you go to bed.

[Frank46]

rbstern, for someone with no lathe or other machine tools that "tanker" K31 came out real nice. Likda like the persian camel carbines. Way to go, Frank

[BeeMan]

Like Maven, I found 7383 is great for a target load in 243. I settled on 41.5 gr behind a moly coated Sierra 70 gr HPBT, for 3100 FPS in a 22 inch barrel. Groups are consistently under an inch in a scoped Win 670, at 100 yards. Bore cleans up nice even though this barrel fouls badly with uncoated jacketed fodder.

The 30-06 is a little tougher since I'm trying real boolits. Best load to date is 35 gr 7383 with a dacron tuft and the RCBS 180 FP with Felix lube. This runs about 1.5 inches at 100, in a scoped bolt gun. I know this gun is capable of a bit better, turning in about .75 inch with 165 Sierras and IMR 4350.

Velocity is maybe 1750 FPS. Lighter charges string vertically and have wide ES. The 36 gr load stays in a round round group but opens up. No leading with ACWW in a 20 shot string. Before dacron, powdered bran filler was tried but with less success. Several gentlemen here commented that there was too much space left to safely use the powdered bran as filler.

This surplus 7383 is inexpensive enough to be worth the load development and is fun to boot in my opinion.

BeeMan

[rbstern]

rbstern, for someone with no lathe or other machine tools that "tanker" K31 came out real nice. Likda like the persian camel carbines. Way to go, Frank

Thank you, Frank.

Working on that project has kindled my desire for more gunsmitthing knowledge. I need to get myself down to the local technical college for some basics in metalworking. When I miss by a 1/16" on a wood project, no big deal. Metalworking...1/16" might as well be a mile. Different worlds.