7.5x53.5 M1890 for Schmidt Rubin 1889

[Stoats]

I see one of these rifles in my future, and want to load a bullet as original as possible, with the knowledge of now. The idea is that the bullet would run heeled PP with the M1889 Schmidt Rubins, and gas checked on the heel shank for a fat 303 with a worn throat.

Here's the post on Swede Nelson's group buy forum:



Hello.

I'm working on designing a bullet to replicate as far as possible the old heeled & paper patched 7.5 GP90, and would like to gauge interest. What I have come up with so far.

Basically, this is the original cartridge and bullet:

http://oi50.tinypic.com/25p0e39.jpg

There's an iron cap to the bullet which we can forget about. For the rest, apparently the bare bullet measures as follows (will confirm once I've got hold of one myself:

Body: .315"
Heel: .302"
Length of heel: .233"
Length of bullet: 1.167"

Small hollow base in the heel. Consider that a "(very) nice to have" rather than a necessity.

2 wraps of paper to add .006".

Yes, the bores run about .308" groove and under .300" lands. No, they are not .304" (that figure comes from people measuring a groove to the opposite land - they're 3-groove). The bullet is vastly oversized and is swaged by a long tapered throat. I'll measure one, but I'd be surprised if the hardness of the originals was over 11 or 12 BHN. As for the size, that's just how they were in the original.

Right. So I was thinking: make the bearing section Loverin-style, with lots of grooves.

But, how many people want to load heeled PP for an obscure cartridge? Not that many.

But how many people have a fat .303 with a long throat? Plenty. It just so happens that the heel is basically the same diameter as a .32/8mm gas check shank (.3015", or correct me if I am wrong). So, here we have a bullet with a long parallel section, to nicely fill a cordite-wrecked Enfield, with a gas check. The long shank will act as another (shallow) lube groove.

Am I crazy? Perhaps.

Or I may have solved 2 problems with 1 bullet.

Thoughts?


Any thoughts? Any interest?

[enfield]

My 1889 blows out the neck extra large as it is ( I know of others that do this as well ). how would a heeled boolit be an advantage ? would it have to be paper patched to make it work ? I've been sizing the necks down as little as possible to hold the boolit but maybe theres a better way.

[Stoats]

The heel is there in the original., and that is what I am trying to recreate as far as possible, avoiding the finning that is likely from a smooth sided boolit.

[Stoats]

Otherwise all diameters could be increased .006 to give a hollow based heeled bullet with the original overall measurements, but as a conventional grease groove design.

But if you could safely chamber a normal .321" with gc, that might have the same effect, or even better.

[45 2.1]

You might try the 323471. Size the base to fit into the fired case neck and taper the bands to fit that long funnel like throat/leade.

[jonk]

Unless 'just because' there is no reason to re-invent the wheel here. Slug your bore (mine is spot on at .308), pick a suitable mold (I like a 200 gr Lee), size properly, and go to town. The 1889 is plenty strong for any cast load you're going to shoot.

[Wdog01]

Mr. Stoats: I use LEE 8mm MAX 235 grs. bullets sized to .321 with gas-check. Plus 28 grs. of ACC5744. Works perfectly and gives about 1900fps. Similar like original ammo GP1890.

[Newtire]

Mr. Stoats: I use LEE 8mm MAX 235 grs. bullets sized to .321 with gas-check. Plus 28 grs. of ACC5744. Works perfectly and gives about 1900fps. Similar like original ammo GP1890..323 seems like a halubba-big boolit for a .307" bore. I know that the throats are large like this. I have used a .310" boolit (Lyman 311290) before I found out about the large diameter throat situation. Will have to give this one some further investigation.

[Wdog01]

Hello,
... I size to .321
... bore is .310
... you are right, bullet is rather bigger.
On the other hand, original GP1890 Swiss military lead bullet was .315 without paper patch and .321 together with paper patch.
So we can say:
... you can put min. .321 to the throat.
... the lead bullet .315 (without paper-patch) is OK
... the size between .315 and .321 is a subject for test. In my opinion is clever and economic to use LEE 8mm Max or Karabiner Bullets.
Bye Ales.

[Newtire]

Like I say, I'll have to give this one some thought and a chamber cast.

[zuke]

I just PP an as cast boolit. Come's out around 314 pushed with 5gr of 700X

[Ricochet]

Can any of you tell me what the I.D. of your fired case necks is? My 1889 hasn't gotten here yet, and of course I'll test it myself, but this would help me with my thinking about what to try. I'm looking at posted chamber casts and seeing an outside neck diameter of .355", and suspecting it will come out close to .323" I.D. My thought is that paper patching (or perhaps using an 8mm boolit) to fit the fired case with little or no sizing would extend the life of the brass.

Another question: Have any of you tried loading for the 1889 with large boolit and case neck diameters with Lee dies? Does the larger diameter cause hangups in the bullet seating die?

[Maven]

Can't answer your questions, Ricochet, but glad to see you posting again. You've been missed!

[Ricochet]

Thank you, Maven!

I just got my 1889 from Simpson Ltd, and it is beautiful! Simpson is great to do business with, too, BTW. I haven't done anything besides pull it out of the box and snap a few pics, because I'm busy making a batch of soap today!

[Duckiller]

Welcome back Ricochet! I don't understand this thread! I have a Bubba'd 1911 Schmidt-Rubin 7.5x55 and everything I have ever read says it is a slightly undersized 30 caliber. Jacketed .308 bullets work as do cast boolits sized with my smallest 30 cal sizing die. Must admit I do not shoot it that much. I hate to throw away the pretty Swiss brass but depriming Berdan primers is a pain. I do have some 284 Win brass but with our condor protection laws I don't hunt with it and ranges are packed on weekends. Are people saying that these rifles have had too many cleaning rods run through them and have large barrels?

[Ricochet]

Not at all. They were designed and made with very large diameter chambers in the neck area, long tapering throats, and originally loaded with swaged lead bullets with a steel jacket cap on the nose only that didn't contact the bore. The bullet was heeled like a .22 LR bullet, with a hollow recess in the base to tuck the paper patch into. The diameter of the main bearing surface was about .315" on the naked bullet, and the heel was about .308", according to "Guisan" on theswissriflesdotnet forum who took some apart and measured them. The bullet was paper patched and lubed on the outside with Vaseline, the final diameter being .321" on the main body and .314" on the heel that went into the case. This is way oversized for the bore, but there is a long tapered throat to swage it down. That's the way the Swiss did it from 1890-1923, when the GP90-03 round with the 213 grain paper patched, steel capped lead bullet was replaced with the GP90-23 round with a round nosed 190 grain jacketed bullet of .306" diameter, which is a proper groove diameter fit in these rifles but is loose in the throat area. The 1889 rifles were long obsolete in military service then, but that ammo was primarily made for target shooting and apparently worked well enough to suit them. However, the Swiss didn't reload their ammo. If we size our necks down to hold a .308" bullet, then fire then in a chamber that lets them blow out to a diameter to accommodate a .321" one, then size it down again, they won't last very long. And it may well be that using a bullet that fills that long throat and can't tip or get eccentric will give better accuracy. I've been reading lots of posts about experiences with various loads, and results and opinions are quite mixed. But we do now how the Swiss did it for 33 years.

[Ricochet]

It didn't let me edit the couple of little typos I see in my post. Anyway, as a reminder, the 1889 rifles are different from the 1896/11, 1911 and 1931 rifles and carbines. The 1889s can't safely shoot the GP11 cartridges or modern commercial 7.5x55 cartridges as the action with the rear locking lugs can't handle the pressure. It was marginal with the lower pressure 1890 cartridges. The case length was 2mm shorter, and I've already mentioned the much larger diameter bullet, chamber neck and throat diameters. With the 1911 you don't have these concerns, and the 1896/11s are 1889/96 models with the stronger upgraded action with the lugs moved toward the front, and were rebarreled to use the GP11 round with the .306" jacketed spritzer boattail bullet. They all look similar, but the pre-11 models are different critters!

As for cleaning rod wear, the Swiss didn't use cleaning rods for this reason. They used pull through brushes and swabs with a line on each end. The approved method was for two men to use it with the rifle horizontal, pulling the pull through all the way through one way then back the other, something like using a cross cut saw. That prevented belling either the muzzle or throat rifling.

[Ricochet]

Spritzer bullet. I think I've been autocorrected. :mrgreen:

[zuke]

I use LEE Collet dies, no problem's yet. I also use the same type collet dies for my 308 96/11 schmidt rubin

[Ricochet]

Great! That's what I use, too. I'm prepping some "Fat 30" boolits from a group buy several years back that I intended for the Mosins. They're something like 210 grains and cast at something like .317" if I remember right, with a nose reminiscent of the Lee boolits for the SKS and AK, with conventional lube grooves and a gas check. I sized these to .314" when I checked them. I just measured the nose, it has a fairly long .308" section ahead of the top band. Those will certainly do for fire forming my brass and are just liable to shoot well as they are. My intention is to cast some more of those for paper patching. I've never done any if that. I've been reading about it with interest since I was a kid.

[abunaitoo]

Fallowing this thread, I tried some .321 boolets.
They chambered fine. Shoot great.
Problem I'm having is blowback. Neck all black with soot.
Yes, I've annealed the necks.
I've tried 2400, and IMR4198. 30/40 Krag loads. 200gr GC

[Ricochet]

Yesterday I loaded some NuJudge boolits, a fattened version of the Lyman #314299 casting at something like .316" on the body. My caliper says the "bore riding" section of these is .308", and I'd gas checked these while running them through a .314" sizer. They're scrap lead water dropped, medium hardness and malleable. Tumbled them in liquid Alox, then dipped them in my homemade "Brown Thunder" lube. Following a suggestion here and elsewhere, I used new untrimmed 7.5X55 brass from Prvi Partisan for the first firing. With the .314" boolits they required an extra firm bump with the heel of the hand to finish locking the action, and the case mouths tapered enough after firing that I can't push a .314" boolit in by hand. Not restrictive enough to run pressures way up with a cast boolit, though. I'd used a very mild load of 7383 that averaged in the high 1600s I'd say. Haven't averaged the Chrony readings yet. My caliper indicates the case mouth opening is about .312", and though it's hard to measure on a taper, the O.D. right at the mouth seems to be about .336". Below the taper the neck O.D. is .346". My chamber is tighter than some. Next I'll trim the necks back until the taper is gone, which looks like it might take me all the way back to 53.5 mm, and see what the I.D. is there. An unsized Fat Thirty may turn out to be a good fit in the case neck, and I may have to go back to regular .30s if I still want to try paper patching. I'll see when I get the cases trimmed to length. As for shooting, I was trying to hit 100 yard targets. The closest sight setting is 300 meters, calibrated for a 1968 FPS boolit. So I found I had to aim at a point way under the target board near the ground. Hard to shoot tight groups that way with no aiming point. The windage is off. There's a scribed line on the sight and base that's staggered, and I bet if I get it realigned it'll be right on. I'm going to have to go climb up the bank to the 300 yard targets, looks like.

[Ricochet]

I found that to get rid of the chamber pinch taper on the necks, I had to trim all the way back to 53.5 mm. I chamfered the necks inside and out with the Lee tool, followed with the Lyman VLD chamfer tool on the inside. The inside diameter of these unsized fired necks is precisely .321". Fat .30 boolits will drop into them, but it would take some thin paper to wrap a .316" boolit to .321". I'm looking at the moulds I have that cast in the .309-.312" diameter range, with patching in mind.

[45 2.1]

The inside diameter of these unsized fired necks is precisely .321". Fat .30 boolits will drop into them, but it would take some thin paper to wrap a .316" boolit to .321". I'm looking at the moulds I have that cast in the .309-.312" diameter range, with patching in mind.

The Lyman 323471 is an excellent boolit to size down for these rifles. You can size the bands down and taper in front of them in a properly fit Lee push thru die. They fit and shoot well that way.

[Ricochet]

Thanks for the tip!

[abunaitoo]

So it seems that IMR4198 is not working out.
I used to use Bluedot.
I changed to see if I could get rid of the blowback issue.
.321 cast chambers fine and shoots well at 50yds. 100yds not so good.
What is 7383 powder????
I'm collet sizing the necks to .319. Boolet is gas checked.
Necks have been annealed...again.
Not sure wht I'm getting so much blowback.
Any ideas?????

[Ricochet]

IMR 7383 is a milsurp powder. Made for the short .50 caliber cartridge for the spotter rifle mounted on the old 106mm recoilless rifles. Much smaller and less powerful than the .50 BMG. That cartridge was supposed to match the trajectory of the 106. You'd aim at the target and fire a .50 to check. It had a tracer and exploded with a flash and puff of smoke. If it hit the target, the 106 was immediately fired. 7383 is an odd powder. A jug that holds 8 lbs of most powders holds 7 lbs of 7383. The grains are black through and through, unlike most powders that have a dark graphite surface coat and are translucent yellowish or greenish inside. It is almost flashless but makes lots of smoke and soot. In the original spotter cartridge 120 grains of 4831 was used. In later updates 110 grains of 7383 gave the same ballistics, which will give you an idea of its burning rate. Maximum average chamber pressure was 38,000 PSI. I have hypotheses as to how this powder is different from other IMR powders, aimed at minimizing flash and optimizing burning for that modest pressure, but I have no authoritative data on its composition and characteristics. My lot of 7383 seems in my limited testing to act something like 4350, but the bulk limits the amount the case will hold. In most medium size cartridges with standard weight bullets it won't quite reach the velocities that most powders will. You can't load enough in most cases to reach maximum pressures and velocities. I've tried compressing it hard and recommend strongly against it. Pressures do appear to rise very rapidly when it's compressed. I find it very useful in cast bullet loadings for old military rifles in the .30 caliber-8mm range. It is sooty, you'll have to scrub hard carbon out of the throat after shooting it a lot especially with jacketed bullets, and in most of my loads it doesn't reach a pressure level that will completely burn it so it leaves a lot of partially burned grains. My Chrony collects lots of those partially burned grains. It also makes a strong ammonia smell that I've never smelled from any other powder. It seems to come from the surface layer that burns off first, because in most loads the ammonia smell is all in the exhaust cloud that blows out the muzzle and what remains in the bore and cartridge case smells like regular IMR powder smoke. I've had fellow shooters exclaim "Couldn't you find any smellier powder?!" One of my hypotheses is that the ammonia smell is a clue to nitroguanidine being used to reduce the flash, as it commonly is in artillery powders. It's an eccentric, quirky powder, but it was very inexpensive when I bought it and it serves my purposes well. YMMV.

[Wdog01]

Hello,
some maybe useful info: for M1889 rifle I use RCBS 7,5x55 NECK die, for FMJ .308 bullets (aka GP90/23 cartridge) I use expander ball .306, and for cast G-C .321 bullets (GP90) I use expander ball .319, made from cal.8mm expander.
I found, then best accuracy and less speed standard deviation (8fps) is about the speed as original Swiss GP90 cartridges had, so about 1900fps for my 235grs bullet. For example, same cartridges with lower load and 1700fps have higher speed standard deviation (20fps). I think the same load as original had could offer the best expansion and sealing of the case in the chamber throat. It could be the solution for Mr. abunaitoo blowbacks - to use higher load.
I can recommend ACC5744 powder, and the load 28 grs.
Bye Ales

[Ricochet]

Thanks, Ales. I've read lots of your posts while searching the Web for info pertinent to loading the 1889.

[Ricochet]

I have my first batch of "real" 7.5X53.5 loaded. I had to go all the way down to that length to eliminate all case neck pinching in my chamber. The I.D. of the fired case necks after trimming off the pinch is .321", best I can measure with my calipers, and .323" sized 8mm boolits can't be pushed in by hand. They accept .316" boolits patched up to .323" easily in the press and hold them snugly. Even though I chamfered the cases, I had to flare them a little to start the boolits. Smartly shoving the rifle's operating handle forward would chamber them and remove the flare, but I held them upside down in the top of an 8mm Mauser Lee Factory Crimp Die to remove the flare after trying that. Now they chamber smoothly. As this light load of 7383 gave a bit more erratic velocities than I like with the initial firing of the .314" gas checked lubed boolits, I used polyester fiberfill in these. I spent too much time getting it all figured out and done to try shooting them this weekend. That will likely have to wait till the next one.

[Ricochet]

OK, I have some data now. With my original load of unsized, untrimmed Prvi cases (that pinched down in the end of the chamber to a .312" opening after firing), NuJudge 200 grain boolits (similar to #314299 but fatter), sized to .314" and checked, CCI 200 primers and 2.8cc (about 33 grains) of my IMR 7383 powder, no filler, I got an average of 1670 FPS. I don't have QuickLoad, but the online Powley Computer's rough estimate for that is 18200 CUP. With the necks expanded and unsized, unchecked NuJudge boolits paper patched with a triple wrap of office exam table paper to .321" and lubed (as were the naked ones) with my homemade "Brown Thunder" waxy lube, CCI 34 primers, the same 2.8cc or ~33 grains of IMR 7383 and a snug tuft (around 1 1/2 grains) of polyester fiberfill, the average velocity was right on 1800 FPS, which the Powley Computer estimates at 21,200 CUP or 22000 PSI. I should be able to easily step it up to match the velocity of the original GP90 or even the GP90/23 while staying well below the pressure rating of the 1889. These numbers may not match your rifle if you have an 1889, its chamber and bore dimensions may differ from mine, and if you have IMR 7383 from a different lot, it may burn at a different rate. Start low and use a chronograph to check while observing pressure signs. Mine appears to be quite low. I can't say too much about accuracy. I'm just learning the hold-under to get the boolits on paper at 100 yards with the 300 meter sight setting, and I'm aiming at a pointless area at the bottom edge of the target frame under the target, also estimating windage compensation. Speaking of which, we had 20-25 MPH winds at the range today. So, while I got a few lucky tight clusters like a 5 shot 2 3/4" X 1 3/4", my groups weren't always printing in the same area and some were pretty strung out. I feel the rifle's capable of shooting a lot better than I can now. Time to patch some more boolits and load up the next step! :D

[Stoats]

By the way, my 1889 has an extremely tight bore - .2965 minor, .3035 major, and .300 across the slug. Am rather worried about finning, but when I get the chance I'll chuck some 314299's down it to see what happens.

Why 314299? Well, it's what I have on hand, and is big enough to meet the cavern of a throat that these things have without making a transatlantic flight.

[Ricochet]

I don't have any recovered boolits. I expect they look funny, with the whole length of the nose and shank engraved with the rifling through the patch and the shoulder obliterated, with the grooves very much narrowed down. The gas check shank should help prevent finning back to the base of the boolit.

[dominicfortune00]

Where is the NOE Group Buy for the boolit mentioned on the first page>

I looked in Active Group Buys and couldn't find it.

Thanks!

[Stoats]

here you go:http://noebulletmolds.com/smf/index.php/topic,78.0.html

[Old Iron Sights]

I was lucky in that my 89 has a throat just a tad larger than my 1911's & K31. I need to sort out some brass just for it but haven't worked with it that much yet.
I did do some initial load testing and came up with this. BTW, I order almost all my Swiss's from Simpsons.

[abunaitoo]

A few gunshow ago, I picked up a factory box of those rounds. I made a post on them.
They have rifles that shoot almost the same round. It's called a 50cal BAT.
If it's like IMR4350, it must be a slow powder.
I try to use med to fast for my cast loads.



IMR 7383 is a milsurp powder. Made for the short .50 caliber cartridge for the spotter rifle mounted on the old 106mm recoilless rifles. Much smaller and less powerful than the .50 BMG. That cartridge was supposed to match the trajectory of the 106. You'd aim at the target and fire a .50 to check. It had a tracer and exploded with a flash and puff of smoke. If it hit the target, the 106 was immediately fired. 7383 is an odd powder. A jug that holds 8 lbs of most powders holds 7 lbs of 7383. The grains are black through and through, unlike most powders that have a dark graphite surface coat and are translucent yellowish or greenish inside. It is almost flashless but makes lots of smoke and soot. In the original spotter cartridge 120 grains of 4831 was used. In later updates 110 grains of 7383 gave the same ballistics, which will give you an idea of its burning rate. Maximum average chamber pressure was 38,000 PSI. I have hypotheses as to how this powder is different from other IMR powders, aimed at minimizing flash and optimizing burning for that modest pressure, but I have no authoritative data on its composition and characteristics. My lot of 7383 seems in my limited testing to act something like 4350, but the bulk limits the amount the case will hold. In most medium size cartridges with standard weight bullets it won't quite reach the velocities that most powders will. You can't load enough in most cases to reach maximum pressures and velocities. I've tried compressing it hard and recommend strongly against it. Pressures do appear to rise very rapidly when it's compressed. I find it very useful in cast bullet loadings for old military rifles in the .30 caliber-8mm range. It is sooty, you'll have to scrub hard carbon out of the throat after shooting it a lot especially with jacketed bullets, and in most of my loads it doesn't reach a pressure level that will completely burn it so it leaves a lot of partially burned grains. My Chrony collects lots of those partially burned grains. It also makes a strong ammonia smell that I've never smelled from any other powder. It seems to come from the surface layer that burns off first, because in most loads the ammonia smell is all in the exhaust cloud that blows out the muzzle and what remains in the bore and cartridge case smells like regular IMR powder smoke. I've had fellow shooters exclaim "Couldn't you find any smellier powder?!" One of my hypotheses is that the ammonia smell is a clue to nitroguanidine being used to reduce the flash, as it commonly is in artillery powders. It's an eccentric, quirky powder, but it was very inexpensive when I bought it and it serves my purposes well. YMMV.

[abunaitoo]

Just happen to have some AA5744. I tried it in a few different calibers and couldn't get a good load out of it.
look to be a little faster than IMR4198.
Closest boolet I have would be 321/250gr.
I'll start with 24.0 and work up.


Hello,
some maybe useful info: for M1889 rifle I use RCBS 7,5x55 NECK die, for FMJ .308 bullets (aka GP90/23 cartridge) I use expander ball .306, and for cast G-C .321 bullets (GP90) I use expander ball .319, made from cal.8mm expander.
I found, then best accuracy and less speed standard deviation (8fps) is about the speed as original Swiss GP90 cartridges had, so about 1900fps for my 235grs bullet. For example, same cartridges with lower load and 1700fps have higher speed standard deviation (20fps). I think the same load as original had could offer the best expansion and sealing of the case in the chamber throat. It could be the solution for Mr. abunaitoo blowbacks - to use higher load.
I can recommend ACC5744 powder, and the load 28 grs.
Bye Ales

[Wdog01]

Hello abunaitoo,
yes, try it and please report your results here. Load 24 grs of ACC5744 is good start, I call it my target load, and my maximum, military load, is that 28 grs. No other filling to the case! I use ACC5744 and this load 28 grs for more older (cca. 1870-1890) rifles, all with cast bullets, and for my earlier big surprising this load is universal and perfect in these old rifles and several different calibers from 8mm to .50. Yes, seems little faster like IMR4198, I think this ACC5744 is the fastest rifle powder from Accurate.
Bye Ales

[Wdog01]

And , as independent promoter of ACC5744 ... :-) ... I can place original producer´s powder description from some older Accurate manual:

XMP-5744
Our XMP-5744 has proven to be an extraordinary powder! XMP-5744 is a short cut, extruded, double
base rifle propellant. Its burn rate is between our No. 9 and 1680. XMP-5744 is not intended to set new
velocity records. What it will do, however, is allow you to shoot reduced loads, without fillers, in just about
any cartridge, especially the older, low pressure, rifle cartridges. IHMSA shooters take note, it is also useful
in large capacity handgun cartridges.
XMP-5744 has some very specific design criteria. First, it is double base with a high percentage of
Nitroglycerin. This gives the propellant a high energy content. It also promotes consistent ignition even
with low volume powder charges in the large capacity ‘‘old timers’’ such as the 50 Sharps. In fact, the 50
Sharps was used in some of the development work for this propellant. Nitroglycerin contributes to excellent
shelf life and reduces the effects of humidity and temperature.
Second, XMP-5744’s short length provides uniform metering so you can spend more time shooting
and less weighing charges.
Third, XMP-5744 has a relatively low bulk density. This contributes to its ease of ignition. In fact,
ease of ignition and consistent velocity, regardless of powder position in the case, are the two main criteria
we set in manufacturing new XMP-5744.

Bye Ales

[abunaitoo]

Shot it this weekend with 5744.
Loaded up with 24.0gr, 25.0gr, 26.0gr and 26.0gr.
I tried it with dacron filler.
24.0gr-- 50yds 1/2" to 1", 100yds 2" to 3". Blowback gone.
25.0gr-- 50yds 1" to 2", 100yds 2" to 3". Primers flat.
Didn't try the 26.0gr and 27.0gr loads.
I'm going to try without the filler next.

[45 2.1]

IMR 7383 is a milsurp powder. You can't load enough in most cases to reach maximum pressures and velocities. I've tried compressing it hard and recommend strongly against it. Pressures do appear to rise very rapidly when it's compressed. I find it very useful in cast bullet loadings for old military rifles in the .30 caliber-8mm range.

What you've said is basically correct.... and compressing it is a poor idea. There are some additional things that you should probably know about this powder. It is possible to max out the pressure in a cartridge with it. I have done so in the 7.5 Swiss (K31). If you drop tube powder into the case slowly to full case capacity with a jacketed bullet, of the same weight or there abouts, as the military load, you get full duplication and accuracy as the military loads. Not all cases will give this as there are at least 9 different makers of these cases with various case weights. Merely loading it normally will not get there. The drop tubed charge weighs more also and gives full duplication pressure from what I've seen. If you try this with cast, let us know.

[madsenshooter]

7383 is coated with nitroguanidine, and it's hard to light. The powder was meant to be lit by a 50BMG primer and even a Federal Magnum won't light it right. The nitroguanidine is fragile, when you start compressing the powder, it fractures. Then you have some easier to light nitrocellulose that the primer flash can get too. But that's not the way it's supposed to work. What makes it flashless is the gases evolved from the first lit nitroguanidine keep the nitrocellulose from burning with a flame. I have had some success with a small kicker of double base powder, 3.5gr in the 30-40 Krag, which gets the temp and pressure up where the nitroguanidine burns first. No compression on the load above the kicker, base of the bullet touches just enough to hold the large flaked kicker in place at the rear. The unburned powder goes away and the smoke out the end of the barrel is white, not black. Flashless powder is also supposed to produce less smoke. I have some 190gr 316365 spitzers loaded in 30-06 this way that are going to get shot out of my Garand soon. 3.5gr 10B101, 43gr 7383. Yes, I have an adjustable gas plug, but it probably won't be necessary.

[Ricochet]

I've worked up my 7383 load to where I'm going to stop. 40 grains of it is a 3.4 cc Lee dipper pushed down into the powder for a gravity fill and the top scraped off with a card. With the 200 grain NuJudge boolits patched up to .323" that gave me an average velocity of 2077 FPS with good consistency. I'm using CCI #34 primers and have no problems with ignition, nor have I with standard large rifle primers in other cartridges. The reason for the unburned powder grains everyone comments on isn't poor ignition, it's loads that don't generate enough pressure for long enough to burn it efficiently. This load burns cleanly. The old Powley computer estimates the pressure at 28,800 CUP or 30,000 PSI. I'm aware of the large margin of error in its estimates. It's said to usually overestimate pressures in the 30,000 range, and I'm confident that I'm not pushing the limits with my 1889 in any case. I'm exceeding the original GP90's MV by 100 FPS, but the boolit is 200 grains vs. the original's 213 grains. The GP90/23 used a round nosed 190 grain FMJ bullet at 2050. I expect the trajectory will be close enough for the sight elevation to work reasonably well. I need to get out to the range when I have it to myself and hike out to the 300 yard position and put up some targets. At 100 or 200 it shoots so high that it's an exercise in Kentucky windage holding on imaginary spots below the target board to get it on paper, so I can't say much about how it groups. I had a problem yesterday with patches not separating from the boolits. I believe my "Brown Thunder" waxy lube penetrated the patches and glued them to the boolits. It is sticky. As a side note of interest, I found that when standing behind and just to one side of another shooter firing it, with a low angled bright ray of sun in front of the bench and shadow over the field, the white patched boolits were very clearly visible at over 2000 FPS whizzing from the muzzle downrange like tracer bullets! I could even see that some of them had the patches partially torn away and flared out, making the white blob noticeably bigger in diameter than .30 caliber! I have to fix that to get any decent accuracy. I'm about to patch up another batch, and just lube the patches with Vaseline as the Swiss did originally. That won't glue them on. Oh yeah, I'm not using any filler with these now, the case is nearly full.

[Ricochet]

I'm paper patching these boolits for the following reasons: 1) This is the way the Swiss did it from 1890-1923. It's a quirky way with both the "core" bullet and especially its patched diameter being much larger than the bore dimensions, but it worked for them. 2) I've never done paper patching before and wanted to try it. 3) It has turned out that once I'd selected suitable paper and determined the patch dimensions I can mass produce them on a paper cutter on my kitchen counter, then patch them right there on the counter top. 4) It takes little if any more time and effort to patch the boolits than to gas check, size and lube boolits. 5) Most importantly, once I've fireformed the cases by shooting them with gas checked boolits, the necks are grossly oversized for regular or fat .30 caliber boolits. Sizing them back down works the brass a lot, and either I'll have to frequently anneal them (which is a lot of work) or start losing cases to neck cracking early on. After all the work I did trimming these back with my hand-turned RCBS case trimmer, I want them to last as long as I can! I barely kiss the mouths with a Lee Universal Expanding Die, and the Lee 7.5X55mm bullet seater works fine. I don't try to remove the barely visible flare of the case mouth, they still chamber fine. I'm shooting low pressure loads, and the cases should last through a lot of firings this way.

[Stoats]

Shot it yesterday with the following loads:

Steps of 11-13gn Unique-equivalent behind a Lee 312-155-2R sized 312 (gave 1320 to 1520 fps)
Steps of 34-36gn N140-equivalent behind a Lyman 314299 (200gn) sized 312 (gave 1755 to 1860 fps)

Carnauba Red lube and a gascheck.

No blowback in either case. Interestingly, 35.5gn N140 equivalent behind a 175gn j-word does give a little blowback, whereas all of these sealed rather nicely. Accuracy was excellent at 25m (although I shot standing offhand due to using the chrony).

Apparently no ill effects from squeezing .312 lead down a .3035" hole :)

[Eddie1971]

My load I have used is with a Lyman 314299 powder coated, gas checked and sized to .314. This sits over 32 grains of IMR 4895. No bloeback and pretty accurate.

[ukrifleman]

I use the Lyman 200g 314299 bullet, gas checked to .312 and tumble lubed with liquid Alox.

I F/L size 7.5x55 PPU brass with a Hornady custom die, then trim back to 53.8mm with a LEE 7.5x54 MAS trim gauge.

I then neck size to .311 with a Lyman M die.

My powder and charge of choice is 28.5gn of Reloader 7, which gives an average M/v of 1862 fps and no blow-back.

DISCLAIMER
This load works in my rifle and is not intended as a recommendation for others to try, but is for information only.

Use this load data entirely at your own risk.

ukrifleman

[Eddie1971]

Tried a new load load out using my new NOE mold, 312299. Powder coated, sized to .312 and gas checked I loaded over 35-36 grains of IMR 4350 and I had great luck, better than IMR 4895. My gun a is a little bit of a beater, but it has a great bore and all matching. Shows no pressure signs or blow back. Like others mention use at your own risk.