Questions about 4 F Powder

[Oyeboten]

When dealing with modern solid-head cases that do not have enough room for the original charge, I will go to the next finer grain size to achieve original performance. For instance, you couldn't get 40 grains 2FG into a modern 44-40 case without a jackhammer, but 38 grains of lightly-compressed 3FG does the same job. And, it's cleaner burning. I'd say the same might be done for, say, 32-20 or 25-20: you likely can't get the original full 3FG charge in a modern case like Oyeboten's situation, so going to 4FG could make sense. But no way would I stuff a full load of 4FG into a large cartridge like 45-70 or even 38-55.

Indeed, my new 'STARLINE' .32 20 Cases seem to hold 18.5 Grains of 3f with medium ish ( not heavy by any means ) compresion for the 120 Grain Bullet to seat to normal depth...and I have a thin .020 or so Beeswax Lube Wafer under the Bullet, so I am of course using up a little space with that.

If I compressed the powder in stages, and compress it pretty hard, I might be able to get .20 Grains of 3f in there, and then be able to seat the 120 Grain Bullet to normal depth...but I have not felt confident this would be wise, since I really do not know if 'hard compression' will raise the output of pressure realized, of the Powder Charge, and I would feel bad if I blew out a chamber on the old m1899 S&W Revolver.

I would LOVE to know what 20 Grains of 4f would do in the .32 20! But I am not going to try it to find out...at least not any time soon...and not with this particular Revolver.

[Hogpost]

Yup, me too; but the point is that if you can't stuff 20 grns 3f in there, you also can't get 20 grns 4f in. But 18.5 grains of 4F would about roughly the performance of the original charge of 20 grains 3F.

[Oyeboten]

Yup, me too; but the point is that if you can't stuff 20 grns 3f in there, you also can't get 20 grns 4f in. But 18.5 grains of 4F would about roughly the performance of the original charge of 20 grains 3F.

Ohhh. okay, I see what you mean.

That is an iteresting thought.

I will try and see just as a mock up ( not to fire it ) , if I can compress 20 Grains of 3f into one of the 'STARLINE' .32 20 Cases, by doing it in stages, and do so to where the Bullet would seat to normal depth ( of course one can hold out the Bullet a little ways in practice, or to just where it will still allow the Cylinder to rotate ).

I do not have any 4f on Hand to see what 20 Grains in weight, would be like in the .32 20 case though...but it ought to take up a little less room I would think...and 18.5 Grains of 4f, might just fit fine with very light compression.

I will have to send off for a Can of 4f so I can see for myself about this aspect.

The old 'Lyman BP Handbook' figures in Post # 10...relay "17 percent increase in velocity, 32 percent increase in pressure" using same weight of 4f instead of 3f in a .36 Cal (which I take to likely have been a Cap & Ball Colt 'Navy' or maybe Remington 'Navy' ).

So...Okay...that seems workable and down to earth...or a good basis for extrapolation then.

32 percent increase in pressure though maybe is kind of flirting with the ragged outskirts of "Proof Load" Territory though...not that most any Revolver would not take it alright, but...some ( ones which have been strained in times passed by prior owners 'Hot' Loads, ) might not...


If one compress a 3f Charge heavily, I have to suppose one is in effect incidentally converting some of the 3f in to more or less 4f.

The harder the compression, the more I think this would be expected to occur.

Now, I am sure guys compressed the living heck out of plenty of 2f, and 3f and even used straight 4f at times, or combined 3f and 4f, in both their Cap & Ball Revolvers, and in any of the early BP Metallic Cartridge Revolvers for which they were Hand Loading, once Hand Loading was being practiced, anyway.

We just have no way of asking them if they found any misadventures with that...but one does occasionallhy see the odd Colt .44 Cap & Ball, or early Colt SAA in .44 40 or .45 Colt, or Merwin Hulbert .44 40 or other old Revolver with one 'blown out' Cylinder Chamber. I know I have seen such at the Antique Arms Show and in images on the internet...and these were old looking blow outs, too...sometimes Forge welded back up sometimes open and filed down so the Cylinder would still rotate for the other chambers to be used...sometimes just ragged and 'as is'.

Who knows of course when or how that happened...but, using straight '4f', or doing it often, might maybe, could have done it!

[Oyeboten]

For .38 Special...

The original Loading was 21.5 Grains of 3f Black Powder, with a 158 Grain Round Nose Lead Bullet.

FPS claimed for this was 950 FPS ( if memory serve ), but with no statement of Barrel Length. I assume they had used a 6 inch Barrel.

I just now weighed out 21.5 Grains of 3f Black Powder of the 'Old Eynsford' Brand, and put it in to a older Semi Baloon Head .38 Special Cartridge case.

I did not use a drop tube, but I did tap the Case bottom on to the Work Bench with the Powder in it, about fifty times, to settle it all I could.

Settled Powder was right on to about 1/16th of an inch below the Case Mouth.

On to this I seated an ordinary .357, 158 Grain Lead RNL Bullet, and in seating the Bullet, I compressed the Powder 7/32nds of an inch...this was a little shy of full seating depth, and I would have to go 3/32 more to meet my Crimp location area.

I will do some to this depth of seating, then do some to the fully seated depth ( then chronograph the difference ), which will then be 10/32nds instead of the seven to seat the Bullet to proper full depth for the Crimp to be ar the right location...giving then 5/16ths of an inch compression on the Powder Charge to fully seat the Bullet to the correct depth and to meet the Crip position for it.

The 7/32nds compression seemed to me to be a 'medium hard' compression...not a "hard" compression to my mind, but definitely a meaningful one.

10/32nds I expect will be getting on to hard compression, which the originals then must have used.

No idea what the pressure would be for this Cartridge.

'SAAMI' for .38 Special is 17,000 PSI max for standard Loadings, and 18,500 max for "+P" Loadings.

I wish I had some way to find out what pressure this Cartridge makes...maybe it is less than today's "standard" Loading? Or...maybe a little more?

Beats me..!

But, hypothetically...if this Cartridge when loaded as originally, in 3f with the somewhat hard compression it would have to seat the Bullet to the right depth...if it were to produce say, 16,000 PSI...

Then, in 4f, we can expect it would be producing a 32 percent increase in pressure...to then be putting out 21,120 ish PSI, which I expect is into the "+P+" charm school at that point, if still some ways below 'Proof Loads', but I do not know what pressure the .38 Special 'Proof Loads' operate at.

I can clock this ( or these ) Cartridge's FPS out of my m1899 S & W 6~1/2 inch Barrel .38 Special and see what it does...and, I will do that soon.

This then ( in 3f when seated to full depth with then necessarily hard compression ) is my re creation ( or as near as I can get to it anyway ) of the original .38 Special Loading.

At which point, the 3f must to some degree, be crushed into having within it, some fair amount of finer particles, putting however much of the Powder, on toward being 4f more or less.

We'll see what the Chronograph says!

[w30wcf]

Oyeboten,
I have had the opportunity to work with some original U.M.C. .38 S&W Special b.p. cartridges several years ago.

The original primers were dead so I had to dissected the cartridges, then replaced the primers and reassembled after replacing the dried up lube on the bullets.

I found that the compression on the original charge of 21.5 grs was .15" when I settled the powder back into the cases. Bullet seating depth was .38".

Velocity in my .357 6" = 938 f.p.s. average / Marlin Cowboy 24" = 1,218 f.p.s.

I think you will find that 21.5 Olde E will produce a bit higher velocity than that since Swiss 3F went 968 / 1255 and in the .44-40 Olde E. is pretty much = to Swiss in ballistic strength and even a bit more so.

Different powders can have slightly different densities, meaning that the same amount of powder by weight can occupy slightly different volumes.
21.5 grains of Swiss 3F = .13" compression
21.5 grains of Olde E = .18" compression ( just checked)

Regarding settling the powder ....
If one dumps the powder slowly through a funnel, holding the powder pan 4-5 " above the funnel, the powder settles well .... about the same as dropping it through a drop tube.

Also- tapping the side of the case gently with the base of the bullet several times before seating it will also settle the powder.

w30wcf

[Oyeboten]

Thanks w30wcf!


I am loading a handfull of 21.5 Grains of Old Eynsford in period Semi Ballooon Head Cases, but where I am holding the Bullet out a little ways.

And a batch where I am seating the Bullet to a normal seating depth to crimp it where it is supposed to be crimped.

Image below shows one of each of two different seating depths, and the one sectioned Case with a full view, which shows something of how far the compression is going, with the Bullet seated to standard depth...being as the settled Powder charge rests evenly at 1/16th of an inch below the Case Mouth when not compressed.

Hosted on Fotki

Hosted on Fotki

Seating to normal depth, is a pretty decent amount of compression!

I will clock these ( ie: ones where I have held the Bullet out a little ways, and, ones where the Bullet is seated to normal depth ) and see if they have a consistent enough and meaningful difference in FPS.

If so, I will do some tests where I try 1/16th of an inch increments of compression to see if I can plot the graph of ratio between how much compression, and FPS realized.

I will also empty one of the 'seated to full depth' ones out, to see if the 3f appears to have discernable 'fines' ( or 4f esque looking grains ) in it from having been compressed...and try and guess roughly what proportion the fines may be to the whole.

Apparantly they were compressing the heck out of the Powder back when, which I had no idea of till now.

I somehow imagined one compressed like to about 1/8th of an inch maybe for .38 Special or .45 Colt or whatever Cartridge of that sort of length...so...it is interesting to see otherwise now with this!

[KCSO]

The Fines they talk about are the small stuff that gets worn off the cans of powder as they are packed moved ect. Back in the old days when we were doing bench rifles we sifted or screened our powder to get real FFF or FFg with out the fines. I have actually tried 4f in both rifle and pistol to see what would happen. At least with Dupont and Go Ex accuracy was poor and the gun fouled out quickly as compared to FFg. I don't use 4F much for anything any more as I found that I could use 3F in my trade gun for both the pan and the charge and saved having two horns.

[w30wcf]

Oyeboten,
Being the curious type, I did a study of factory compression used by the factories on the .25-20 .38 Special, .44-40, .45 Colt. I obtained cartridges for my study from cartridge dealers. The .44-40, depending on the brand and bullet weight (200 or 217 gr) had .20"-.24" of compression. The .45 Colt, .15" - .20".

Oh, the bullets in the .38 Special b.p. were hollow based and held about .8 grs. of b.p.

Here's a pic of the cartridge box that I had purchased at an auction. Note the struck primers on the left. I am glad that the person who tried to fire them did not get disgusted enough to throw them away.



w30wcf

[Hogpost]

Interesting, and I'll be fascinated to see the results of various compression levels. In my utterly ignorant mind, I would think that heavy compression, that turns the powder in a fairly solid slug, would effectively decrease combustion rate: rather than thinking of it as crushing the powder into smaller grains, I think of it as approaching a single huge grain! I would guess the airspace between grains has a lot to do with burn rate, and heavy compression reduces that airspace regardless of grain size. I'm going to sit back and watch you show us what REALLY happens.

[Oyeboten]

Oyeboten,
Being the curious type, I did a study of factory compression used by the factories on the .25-20 .38 Special, .44-40, .45 Colt. I obtained cartridges for my study from cartridge dealers. The .44-40, depending on the brand and bullet weight (200 or 217 gr) had .20"-.24" of compression. The .45 Colt, .15" - .20".

Well, as you can see, I am indeed compressing a great deal more than those figures! And I have to, if I wish to have the Bullet seated to normal crimp depth on the required 21.5 Grain charge.

Now, if I empty out one of my 'seated fully' ones of 21.5 Grains, scrape and dig the Powder out, mash it up a little so it is a powder again with no lumps...I can put it back in to the Case and 'settle' it via tapping, and see where the level is then. If it is lower, then, I can assume I have made some fair amount of 'fines'.

I will do this, sometime soon, and see.

Oh, the bullets in the .38 Special b.p. were hollow based and held about .8 grs. of b.p.

On no!

Lol...

Well, I guess that would make a difference then!

Are you sure about that?

Where can I find some 158 Grain RNL 'Hollow Base'?

Any ideas?

This changes everything!

Here's a pic of the cartridge box that I had purchased at an auction. Note the struck primers on the left. I am glad that the person who tried to fire them did not get disgusted enough to throw them away.



w30wcf

Lovely old Box!

Lovely old Cartridges!


Did the Primers of that era tend not detonate reliably once aging to the Century mark or so?

[Oyeboten]

Interesting, and I'll be fascinated to see the results of various compression levels. In my utterly ignorant mind, I would think that heavy compression, that turns the powder in a fairly solid slug, would effectively decrease combustion rate: rather than thinking of it as crushing the powder into smaller grains, I think of it as approaching a single huge grain!

I do not know.

Other than I have taken for granted that 'good' compression is how a Black Powder Metallic Cartridge ought to be.

Now, just how much compression that is, I have no idea.

I used to load modern .38 Special Brass using 18.5 Grains of 3f BP, and it makes a very nice Cartridge, and it is no slouch.

I was compressing about 1/8th of an inch, maybe 3/16ths, for this...but no more than that...I usually held the Bullets out a ways too, so...no 'hard' compression with those.

That is where I left off about five years ago or so...just doing 'conservative' BP Loadings for fun for .38 Special and .45 Colt, and without any critical insight or curiosity.

Just now getting back to Loading, and starting off into these new directions, from where I left off.

My original notion was merely to recreate the original Loading for the model 1899 S & W "M & P" Revolver, and to clock them and see what they do.

Now I find that the original .38 Loading may well have used a Hollow Base Bullet, and thus a lot less compresion than I am doing with my flat base Bullets.

If I require Hollow Base RNL Bullets to do the recreation ( or as close to one as I can get anyway ), it will have to wait then till I can find a Mold, or find some Bullets of that type.


So...I think I will let the old S & W 'off the Hook' far as 'testing' out things beyond recreating the original Loading...assuming I can find some Hollow Base Bullets to do so with.

And for 'testing' I will continue on with things using my S & W .41 Magnum...even though a .357 Magnum would use a lot less Powder, but, I do not have a .357 Magnum to use, so...oh well.

I would guess the airspace between grains has a lot to do with burn rate, and heavy compression reduces that airspace regardless of grain size. I'm going to sit back and watch you show us what REALLY happens.

As far as I gather, BP does not require any Atmospheric Oxygen beyind what it has available in it's tiny spaces between the granules....but, the small irregular spaces between slightly irregular surface Granules ( how ever small both those may be ) and the size of Granules themselves, may well be factors for conflagration rate...where, in my imagination anyway, and may be in the general consensus also, the smaller the Granules, and the smaller porportion of Air Spaces ( over which propagating conflagration must 'jump' or cross ) between irregular parts of them, the faster the conflagration.

But, I think BP also gets "faster" the higher the pressure in confinement is while it is conflagrating, so, it seems like those two work together. Thus BP's ability to Detonate under some conditions, and detonation of a Charge in a Revolver Chamber or Rifle Breech, I am sure, would be a bad thing.

But then here's something also, I have read numerous times about how one must never have any 'Air Space' between Black Powder the Ball/Bullet/Boolit, since that can cause an over pressure event and burst the Barrel with long Arms. This is not likely to be the same with Revolvers, since there is only so much space ( and not much space ) to begin with, in their Cartridges or Cap & Ball Chambers.

So, how do we understand that then? Does lots of available Atmospheric Oxygen, 'Air Space' between Powder and Projectile, somehow accelerate the conflagration? Does it somehow encorage detonation? Or..? What is going on with that for it go into catastrophic overpressure?

I do not know.

[w30wcf]

Well, as you can see, I am indeed compressing a great deal more than those figures! And I have to, if I wish to have the Bullet seated to normal crimp depth on the required 21.5 Grain charge.

Now, if I empty out one of my 'seated fully' ones of 21.5 Grains, scrape and dig the Powder out, mash it up a little so it is a powder again with no lumps...I can put it back in to the Case and 'settle' it via tapping, and see where the level is then. If it is lower, then, I can assume I have made some fair amount of 'fines'.

I will do this, sometime soon, and see.



On no!

Lol...

Well, I guess that would make a difference then!

Are you sure about that?

Where can I find some 158 Grain RNL 'Hollow Base'?

Any ideas?

This changes everything!





Lovely old Box!

Lovely old Cartridges!


Did the Primers of that era tend not detonate reliably once aging to the Century mark or so?

Oveboten,

Compression -
If your seating depth is .38" and you are using a settled charge of Olde Enysford 3F then your compression should be around .18-.20" based on my testing using flat based bullets.

Primers -
Since the cartridges were pre 1911 (U.M.C. became REM-UMC after that.) the primers were the mercuric type which, as I have read, typically lasted only 30 or so years before dying.

Bullets -
All of the vintage .38 Specials I dissected b.p. and smokeless, had hollow based bullets. Even some later smokeless ones. Other than the U.M.C.'s I tested with the pulled hollow based bullets, I reload all my b.p. cartridges with plain based bullets so I would not worry about that.

Also, if one uses hollow based bullets, a compression die would be necessary if the powder was going to be compressed much. Try not to loose any sleep over that.

Powder -
Breaking it up finer will not do anything but increase the burning rate. The volume will be pretty much unchanged.

w30wcf

[Oyeboten]

Oveboten,

Compression -
If your seating depth is .38" and you are using a settled charge of Olde Enysford 3F then your compression should be around .18-.20" based on my testing using flat based bullets.

I decided last night while falling asleep, that I can simply hold the Bullet out to somewhat less than usual full seating depth, and still have my Cylinder still rotate alright, and compress then a lot less than I would be, if seating the Bullet to normal depth...this over 21.5 Grains, and I can also have my little thin Bees Wax Wafer in there too then, so things stay tidy and no fouling.

Let's say I compress the Powder itself about 3/16ths of an inch then...I expect that would be fine and no worries in my poor head about compressing too much.

This will not be a faithful recreation then of the original Loading as for all the details being right, in so far as I am of course using a flat base Bullet, and holding it out a little, but, it ought to do what the original loading did, to a Tee, even with these small differences.

I can do some with ordinary Small Pistol Primers, and some with Magnum Primers, and see what difference I get...too.

So, "close enough" for my own curiousity and fun, and, it saves me being hung up or bogged down with details I have no ready means of duplicating.

Primers -
Since the cartridges were pre 1911 (U.M.C. became REM-UMC after that.) the primers were the mercuric type which, as I have read, typically lasted only 30 or so years before dying.

Do we know if those early or earlier Mercuric Primers were more like the Magnum Primers of today? than they would like the regular Primers of today? Or, do we have any thing to go on for guessing how spunky they were?

Bullets -
All of the vintage .38 Specials I dissected b.p. and smokeless, had hollow based bullets. Even some later smokeless ones. Other than the U.M.C.'s I tested with the pulled hollow based bullets, I reload all my b.p. cartridges with plain based bullets so I would not worry about that.

This 'Hollow Base' news sure took me by surprise.

I just had no idea the original and early .38 Special Cartridges were using Hollow Base Bullets.

Huh!!

I can not imagine any reason or advantage for that.

S & W had the Cartridge as their own development or invention, and brought out the Revolver to go with it...they controlled very closely their Cylinder and Barrel Bores. It is not like the Cartridge came out with the prospect of having to be used in pre existing multi make or foreign and already old Revolvers with Cylinder Bores and Barrel Bores that would be 'all over the board'.

How odd of them to have elected a Hollow Base Bullet..!

Also, if one uses hollow based bullets, a compression die would be necessary if the powder was going to be compressed much. Try not to loose any sleep over that.

...a shaped Compression die at that I would imagine! so the compressed powder would be ready for the Hollow Base to sit down on to it without further resistences or displacements.

Of course with my flat Base Bullets, I just let the Bullet do the compressing as I Seat it to whatever depth ( and thus, to whatever compression ).

Powder -
Breaking it up finer will not do anything but increase the burning rate. The volume will be pretty much unchanged.

w30wcf

Yes...indeed, the 21.5 Grains stay the same.

But, whatever ( small ) percentage of the 3f, as gets converted toward being more like 4f, in the process of compressing...I would have to imagine, will promote a little faster conflagration and raise pressure a little bit.

I expect I will be just fine with a modertae compression and just holding the flat base Bullets out a little bit. I should be close to where the original Loads were for pressure and resulting FPS, assuming my 'Old Eynsford' is on par with whatever Black Powder they were using at the time.

[w30wcf]

Oeyboten.
Just a quick reply before going to sleep

Airspace - not dangerous in cartridge guns. I will find the reference but back in the late 1800's testing was done in a 45-70 by seating the bullet further and further from the charge. The velocities regressed as did the pressure.

Hollow based bullets have been used in a number of handgun chamberings that originated as b.p. cartridges. Today if you pulled lead bullets from .38 Special, .44 Special and 45 colt ammo (not Cowboy ammo) you would find that the bullets have at least a cupped base if not a hollow base.

b.p. primers back in the daywere very mild and would not reliably ignite smokeless powder.

[Oyeboten]

Oeyboten.
Just a quick reply before going to sleep

Airspace - not dangerous in cartridge guns. I will find the reference but back in the late 1800's testing was done in a 45-70 by seating the bullet further and further from the charge. The velocities regressed as did the pressure.

Huh!

I always heard though it was dangerous in Muzzle Loaders anyway...

I assumed no danger in Revolvers though, since air space would mean less powder and either way, there is no room for much anyway.

Hollow based bullets have been used in a number of handgun chamberings that originated as b.p. cartridges. Today if you pulled lead bullets from .38 Special, .44 Special and 45 colt ammo (not Cowboy ammo) you would find that the bullets have at least a cupped base if not a hollow base.

I had no idea...I had assumed everyone went on to flat base soon as possible, or once a given Cartridge was no longer expected to adapt to really bad Barrel Bore Cylinder Bore relations.

b.p. primers back in the daywere very mild and would not reliably ignite smokeless powder.

Wow...I had imagined the old Fulminating Mercury kind, or their close kin, would have been more like today's hotter Primers. .

I do like how the earlier Primers looked though, rounded and often having some initial or symbol on them...often bronze color.

Flatish 'silver' color Primers just do not look as visually appealing as the early ones did.

Thanks for this info!

[w30wcf]

Oyeboten,
A bit of correction on the Mercuric primers - the ones used in b.p. cartridges were very mild and would not reliably ignite smokeless.
Then there was another version developed for smokeless rifle cartridges.

Found the reference regarding airspace. With airspace, there is more fouling.......

The Shooting and Fishing Magazine July 31, 1890 issue reported on tests that were undertaken to determine if there was any truth to the time honored theory that a space between the powder charge and the bullet would cause a bulge or a burst.

The test firearm was the regulation Springfieldbreech loading rifle. Here were the results:
Powder Charge: 70 grs.
Bullet: 500 grs. Slightly reduced in diameter so that it could be loaded fromthe muzzle.

1.)Service cartridge, bullet crimped in place – 27,000 p.s.i. / 1,377 f.p.s.
2.)Base of the bullet even with the case mouth – 17,000 p.s.i. / 1,324 f.p.s.
3.)Base of the bullet 5” forward of the case mouth – 7,750 p.s.i. / 1,170f.p.s.
4.)Base of the bullet 10” forward of the case mouth – 5,375 p.s.i.
5.)Base of the bullet 15” forward of the case mouth – 4,050 p.s.i.

“It will be seen from the above that the results obtained here were such as to upset the idea that there is any danger in a space between the powder and the bullet.”

That is in cartridge guns only! No muzzleloaders are a different matter!

Some time ago a fellow wanted to find out what it would take to blow up his muzzleloader. He finally worked up to a rediculous amount of500 grs. of b.p. and the rifle was still aok .....UNTIL ......... he seated the bullet seated 1/2 way down the barrelwhich did cause the barrel to burst. But that is morelike a small bomb.!!

w30wcf

[Jeff Houck]

This might help with your current project.

MiHec makes hollow base molds. Here is a current buy for a hollow base wad cutter. The same thing could be done for a semiwadcutter too.

http://castboolits.gunloads.com/show...50-HBWC-38-357

[w30wcf]

Old West has a 150 gr hollow base .358 dia mold.
The profile, though, is not the same as the .38 Special HB bullet which follows the same contour as the current .38 Special lead round nose bullet.

http://oldwestbulletmoulds.com/produ...e-358-diameter

[Oyeboten]

Oyeboten,
A bit of correction on the Mercuric primers - the ones used in b.p. cartridges were very mild and would not reliably ignite smokeless.
Then there was another version developed for smokeless rifle cartridges.

Found the reference regarding airspace. With airspace, there is more fouling.......

The Shooting and Fishing Magazine July 31, 1890 issue reported on tests that were undertaken to determine if there was any truth to the time honored theory that a space between the powder charge and the bullet would cause a bulge or a burst.

The test firearm was the regulation Springfieldbreech loading rifle. Here were the results:
Powder Charge: 70 grs.
Bullet: 500 grs. Slightly reduced in diameter so that it could be loaded fromthe muzzle.

1.)Service cartridge, bullet crimped in place – 27,000 p.s.i. / 1,377 f.p.s.
2.)Base of the bullet even with the case mouth – 17,000 p.s.i. / 1,324 f.p.s.
3.)Base of the bullet 5” forward of the case mouth – 7,750 p.s.i. / 1,170f.p.s.
4.)Base of the bullet 10” forward of the case mouth – 5,375 p.s.i.
5.)Base of the bullet 15” forward of the case mouth – 4,050 p.s.i.

“It will be seen from the above that the results obtained here were such as to upset the idea that there is any danger in a space between the powder and the bullet.”

That is in cartridge guns only! No muzzleloaders are a different matter!

Some time ago a fellow wanted to find out what it would take to blow up his muzzleloader. He finally worked up to a rediculous amount of500 grs. of b.p. and the rifle was still aok .....UNTIL ......... he seated the bullet seated 1/2 way down the barrelwhich did cause the barrel to burst. But that is morelike a small bomb.!!

w30wcf

That is some very interesting info..!

If memory serve the Springfield .45 70 Trapdoor Rifles were still a Wrought Iron Barrel.

I wonder then how or why 'Air Space' in a Metallic Cartridge Rifle with Black Powder, would end up lowering pressure realized, while with a Muzzle Loader, the Air Space can raise pressure to catastrophic levels?

Is it just me, or, is this indeed puzzling??

Fun to read too, the attribution of 25,000 PSI for the Springfield Trapdoor, when using a 500 Grain Buller 'crimped' in to the Cartridge.

As ever, thanks very much for your great info on these things!

[Oyeboten]

This might help with your current project.

MiHec makes hollow base molds. Here is a current buy for a hollow base wad cutter. The same thing could be done for a semiwadcutter too.

http://castboolits.gunloads.com/show...50-HBWC-38-357

That Thread was good for me to read and look into.

I had not put two and two together till reading there, to appreciate that a Hollow Base Bullet would give better obturation with low charges, as for light Target Loads and Paper Target.

This still leaves me perplexed though about why the original and early Loadings of .38 Special, would have used a hollow base RNL Bullet though.

I think for my purposes with wishing to recreate the original Loadings for .38 Special, or at least to emulate them even if I do not actually use the correct Bullet...I will just use my flat base RNL Bullets, and hold them out a little bit.

I do have a 148 Grain Hollow Base 'Button' front Wadcutter Mold in progress in a trade...so, that will be a nice one for me for Paper Target stuff at 50 Yards or closer.

I am thinking to go round up my 6 or 7 inch .357 Magnum ( I do not even remember what make it is...I have not seen it in many years, but, it is a SAA replica, either Uberti or maybe ASM or something, but it did shoot well anyway! ) which is in another State, in order to try out my experiments with 4f...and with progressions of compression down to the 'hardest' I can consistently do.