IMR7383 with Federal GM215M primers

[madsenshooter]

I got out today to fire off five rounds of 30-40 ammo loaded with 40gr IMR7383, using a Federal GM215M primer under a NOE 316365 weighing 190gr. It was better than it was with a Federal 210, but there was still some unburned stuff. The grains left in the barrel were partial grains rather than the nigh full sized grains I got with the 210s. Bottom line is, there's not enough heat in a LR primer, of any brand, to get this stuff burning the way it's supposed to. Way it's supposed to? Yea, the nitroguanidine, which is the outer coat of each granule, is supposed to explode first. Gases generated by that explosion keep the nitrocellulose from burning with a flame, sorta like putting out an oilwell fire with nitroglycerin. Maybe I'll try a flash tube like the 50 cal spotter round has, or maybe I'll just keep duplexing it. Group wasn't bad, strung horizontally left to right, but all at the same height, which indicates to me that velocity was pretty consistent. POI was about 3" higher than what I'd been getting with 38.8gr of RL19. Incidentally, I found a .5gr difference in weight between 210s and 215M primers.

[Nobade]

Interesting. As soon as I get a round tuit I am going to try duplexing that powder with a black powder kicker. I am very curious to see how that works. I'll let you know what happens.

-Nobade

[Hamish]

Your PM's are full man!

[Bullshop]

I promised to report on my results in duplexing with BP. I have been busy but seeing this jogged my memory so here goes.
I was very surprised with the results of the one simple test done. The surprising results were probably due to the quite heavy for caliber boolit used and to some degree the caliber.
I tested in the 375 Whelen with 370gn boolits. The control load or maybe I should say the load I would like to duplicate with the cheaper powder is 57gn H-4831 which produces on average 2020 fps and is superbly accurate. Slightly faster powders get more velocity with this boolit but the H-4831 is the accuracy champ and not lacking in killing ability.
Working up to a slightly compressed load of 55gn of 7383 gave me an average of about 1950 fps. This shows that even though 7383 is slightly faster burning at least according to Jeff Bartlett that it is bulkier than the H-4831 because I could not fit an equal weight charge of 7383 in the 375 Whelen case as with H-4831.
Now the strange part. I substituted and equal volume of 7383 for ffg black I think the volume was .5cc. So now total volume was the same and was slightly compressed so couldn't mix. The average velocity yielded was 1850 fps or very nearly a 100 fps drop in velocity.
This is hard to understand and I don't really so wont try to explain. With the straight charge of 7383 there was really very little if any unburned powder. One or two kernels could be seen in the barrel after each shot but they were not solid. Tapped out of the barrel and pressed between fingers they just crushed into dust. The accuracy was very good with the straight 7383 load but not quite up to the velocity of the H-4831 load. However at timber hunting ranges I think the 1950 fps from the 7383 load with a 370gn boolit will get the job done.
Today just to try something different I tried 7383 in a 1/9" twist 223 with the 62gn NOE boolit. I was not weighing charged because I felt there was no danger of an over charge. First load tried I will guess at about 90% density and shot about 2" at 100 yards. Second load went to 100% density and shot a vertical about 6". Third load dropped down to 80/85% and started shooting nice round clusters at near moa.
All the loads left lots of powder in the barrel and a little in the cases as well. The unburned powder was hard not crumbly so really unburned. The accuracy is respectable even though the unburned powder is there. The trick to using for the 223 will be to extract the empty cases with the muzzle pointed up so the powder stays out of the chamber. Next try with the 223 will be with the NOE 73gn boolit to see if like the 375 Whelen the heavy boolit get a better burn from the powder.
BTW no magnum primers were used. Both rifles used standard CCI rifle primers. Maybe a SRM in the 223 with the heavier boolit will do the trick. Even if not I am still pleased to see usable accuracy in the little case from this powder.

[Bullshop]

More interesting results today duplexing with BP. As I mentioned yesterday I was shooting the 223 with an eyeball measured 85% capacity load of 7383 with under the NOE 62 gn boolit. I weighed the charge today and it turned out to be 20.5gn and it produced an average velocity of 1950 fps. Since this is obviously a mild load leaving much unburned powder in the barrel and in the case I decided to try duplexing it with BP since I still had about 15% capacity empty. Not really know why but remembering the Dick Casull triplex 45 Colt loads with a fast kicker powder on top I decided to reverse duplex and put the BP on top of the 7383 then compress with the boolit.
After the 20.5gn 7383 was put in I then put a .3cc scoop on top. .3 cc was jut the right amount to fill the case to the mouth.
Where as in the 375 Whelen the kicker did no good because the powder was being about completely burned already in this case the result was far different. The reversed duplex load produced on average about 2400 fps for an increase of about 350 fps. The black powder is obviously burning at the front of the powder charge and it is eliminating the unburned powder in the barrel and case.
I was still using the standard CCI SR primer for this. The best accuracy still went to the straight 7383 charge of 20.5 gn but I think the alloy was not up to the velocity/pressure gain. The alloy was scrap lead and recovered boolits at about bhn-9 quenched to about bhn-15.
I think this reverse duplex will shoot at this velocity/pressure if I stiffen up the boolits a bit. That 1/9 twist has to be hard on a boolit of this weight/length 62gn at that velocity 2400 fps.
I guess with this type powder and the small charge of BP at the forward end of the powder column the powder is being burned from both ends so seems to be burning completely. This just opened up a new door and I barely have my foot in but intend to enter fully and get well acquainted. Stay tuned!

[Big Boomer]

Here is one more positive report on 7383 ... I had tried a recommended load of this powder in the .243 Win Browning I have and it was very accurate with a 100 gr. Hornady bullet but left things very dirty and had all kinds of unburned powder in the barrel. So I loaded up another five rounds one-half grain heavier and was waiting for a convenient occasion to give them a try. I saw a groundhog about 150 yds. from our basement door and hurriedly got that rifle and shoved one of the test rounds in the chamber. At the shot the groundhog dropped in his tracks. I'll probably have to spend a couple of days getting the black crud out of the barrel but in this one instance the powder delivered. Big Boomer

[9w1911]

anyone use this for 45-70?

[madsenshooter]

I have some 3/32 tubing coming. I'm going to make up some flash tubes to use with first, regular LR primers, then LRM primers. If those don't stoke the 7383 coal enough, (I don't think they will, not even with the tube, a 50BMG primer weighs 3X as much as any LR primer), I'll try sitting the high nitro powder at the top of the flash tube with 7383 above and below it. Goggle patent 2269316. In the book, "Hell I was there", Keith claims he's the one got O'Neil thinking about this.