Obsolete cartridge: Have to just trust QuickLOAD/GRT?

[smdub]

Say you're wanting to load an obsolete cartridge for which there is no known data for (unless you happen to have some cordite.) I own QuickLOAD so I plugged some numbers in and got some data out. As long as you are well below max pressure (it is only a simulation after all) is there any reason NOT to trust it as a starting point? I'll download GRT and double check with that.

And is there a way to know which powders CAN'T be safely loaded light? For example: I use H110 for 357Mag and recall the load data saying don't go below published minimums. But I don't find that data on the bottle or Hogdon's website. Obsolete cartridges have no published minimum. What to do? Too low and you can get a squib - I can detect that and fix. But there is the rare kaboom where a light load of slow burning powder creates an air gap and too much surface of the powder simultaneously get the flame front and burns too rapidly. That's the one I'd like to avoid I've read in some places that filling >80% of case capacity doesn't exhibit this problem (and some suggest thats where the minimum load comes from.) It does make sense that if there are no large air pockets the flame front can never reach a larger surface area than roughly the case diameter.

 

[BradMacc82]

What’s the cartridge?

Wouldn’t be surprised if someone here may have some info, wouldn’t put it past this group.

 

[Todd S]

I have recently gotten some very old reloading manuals. Post the round and I'll see if I have it.

 

[smdub]

What’s the cartridge?

Wouldn’t be surprised if someone here may have some info, wouldn’t put it past this group.

$100 bucks says you're wrong

But people here DO have a huge wealth of experience which is why I'm asking here. I would bet some folks have been in a similar situation bringing something back from the grave so I'm leaving the question more hypothetical for now. I'm really curious to the answers. What do you do when you have nothing to start from?

I'll go public when I get further along making the brass. Its a cool project. Some folks know what I'm working on and might out me.

 

[Melnic]

Is it possible to use a PC or coated lead bullet and go pistol powder (Unique is my favorite) with your gun?
I loaded up a Vetterli load last year but was too chicken to shoot it yet. Used quickload and GRT.
PC cast and Unique.

I have had good luck with Unique and Blue Dot on some powder puff rifle loads already (7.62x54r, Carcano 6.5, 45-70)

There is also Trail Boss.

David

 

[Doco Overboard]

Say you're wanting to load an obsolete cartridge for which there is no known data for (unless you happen to have some cordite.) I own QuickLOAD so I plugged some numbers in and got some data out. As long as you are well below max pressure (it is only a simulation after all) is there any reason NOT to trust it as a starting point? I'll download GRT and double check with that.

And is there a way to know which powders CAN'T be safely loaded light? For example: I use H110 for 357Mag and recall the load data saying don't go below published minimums. But I don't find that data on the bottle or Hogdon's website. Obsolete cartridges have no published minimum. What to do? Too low and you can get a squib - I can detect that and fix. But there is the rare kaboom where a light load of slow burning powder creates an air gap and too much surface of the powder simultaneously get the flame front and burns too rapidly. That's the one I'd like to avoid I've read in some places that filling >80% of case capacity doesn't exhibit this problem (and some suggest thats where the minimum load comes from.) It does make sense that if there are no large air pockets the flame front can never reach a larger surface area than roughly the case diameter.

You should identify the cartridge.
It’s important to know some of what control characteristics are may be shape of the powder, size of the powder and the shape of the vessel it’s burned in. Other things could be selection composition, how much heat is transferred to water once a chemical cha ge takes place.
Filling a bottleneck cartridge case up to the shoulder with stick powder and seating a bullet to not below it could be a benchmark for you,being you don’t want to say.
Monomial method comes to mind too but that sort of equations for powder characteristics mY only be found in a book.
Once you discover that sort of thing one could discover that all powder is the same it’s how and what you apply it too that matters with some small caveats of course.

 

[BradMacc82]

Respecting the secrecy/anonymity of your project - if you have to make your own brass, then yeah that’s highly likely a round I wouldn’t have any info on.

 

[4g64loser]

$100 bucks says you're wrong

But people here DO have a huge wealth of experience which is why I'm asking here. I would bet some folks have been in a similar situation bringing something back from the grave so I'm leaving the question more hypothetical for now. I'm really curious to the answers. What do you do when you have nothing to start from?

I'll go public when I get further along making the brass. Its a cool project. Some folks know what I'm working on and might out me.

I could use the $100, haha. PM me if you don't want to post it. I may have data. Let's just say that some of my old metallic case forming and loading manuals are ancient.

 

[lazarus]

Respecting the secrecy/anonymity of your project - if you have to make your own brass, then yeah that’s highly likely a round I wouldn’t have any info on.

Cordite makes me think .577/450 Martini. Of which there is plenty of reloading data out there. You form it from 24ga brass.

But I'd think OP would be less super secret about it.

As for the original question, there are three reasons you might want not want to go too light depending on the powder.

Powders that are highly position sensitive if loaded light, might result in a squib.

Powders that are highly position sensitive, might still go off with the bullet exiting the barrel, but your extreme spread might be really, really big, depending on how the gun is being held when shot. You might see 100-200FPS difference between aiming down a few degrees and aiming up a few degrees.

Rifle or magnum powders that are loaded too light can have very inefficient combustion to the point they don't develop sufficient pressure to eject the bullet from the barrel. Squib time. If you are CAREFUL, the worst that happens is you are stuck with using a brass rod to punch the bullet out of the barrel (do not use a steel rod because you screw the rifling if it contacts the sides of the barrel pushing out a bullet). If you are not careful, you send a round right into the squib.

There are rumors a detonation can occur. As near as I can find, it is internet lore. The occasional person who claims they have had it happen to them. I have never heard of anyone actually being able to re-produce this. Either individuals attempting to do so, or ammunition makers/powder companies. Compared to the number of stories of someone OVERloading a cartridge and blowing up a gun, or a squib and then shooting a bullet right into the squib and bulging the barrel or blowing up the gun, it is hundreds of those anecdotes to everyone who had a friend blow up a gun because it was loaded too light (and I'd bet anything, it was actually overloaded).

Before you have issues with squibs and stuff, usually you are going to see inefficient combustion show up as lots of fouling and very high standard deviation and ES numbers shooting over a chronograph. As an example in 357, a full house 158gr load is somewhere in the range of 16.5gr of H110. I've heard tell of people loading it as light as 12 something grains and it worked okay, but filthy. Load it in to the ideal range there of ~16gr and it burns real clean and you get great velocities. Load it down around 12gr or so, and you might as well load a light charge of bullseye. You'll get as good or better velocity and much cleaner burn, and less recoil for the same bullet muzzle energy (less unburned/partially burned powder getting thrown down range, generating recoil). It is a reason smokeless powder and things like BH209 generate a lot less recoil for the same muzzle energy as true black powder. That blackpowder isn't nearly as efficient, so you are throwing a lot more solid and semisolids down range that isn't being converted in to gas pressure pushing the bullet, but lots of it is still going to go out the barrel with the bullet, not just deposit in the bore and breech.

For example, in my muzzleloader about a 120gr charge of black powder with a 240gr .430 XTP with about a 5gr sabot on top heads down range at something around 1600fps. Off the top of my head, that is volumetrically about 80grs of BH209, or something like 50-60gr by weight, to produce about 1600fps of muzzle velocity out of my 24" CVA wolf (I run a 105gr volumetric charge of BH209 normally). Overall, you are throwing about 17% less mass down range. Now, its likely not quite that bad, because the BP is leaving several grains of residue in the barrel that the BH209 won't, but you still have in the range of 10-15% less recoil for the same ME as a result. An even hotter charge of BP versus BH209 or smokeless would be an even unfriendlier comparison.

 

[BFMIN]

Just "fill em to the brim" with "Holy Black"& compress it when seating the pill. If they're cordite proofed, no matter how "secret squirrel" they are it probably can't be overloaded with B/P!

 

[E.Shell]

Homer Powley?
http://www.kwk.us/powley.html

I used the original Powley Ballistic Computer to establish starting charges for several wildcat cartridges and it was almost dead-on.

 

[Brickman301]

Just "fill em to the brim" with "Holy Black"& compress it when seating the pill. If they're cordite proofed, no matter how "secret squirrel" they are it probably can't be overloaded with B/P!

This is the way!

 

[Cochise]

I have Ideal manuals back to the 30's....

 

[boule]

I'm really curious to the answers. What do you do when you have nothing to start from?

That entirely depends on the cartridge in question. There are three possible ideas:

- you are using an obsolete and rare black powder cartridge. Any load density of 85% up should be fine. And yes, you do not need to fill BP up all to the top that was done for other reasons (demixing of simple meal powder, breaking of grains when transported on animals or when you are accellerating a huge column of powder over an inch or more - proof can be found in different swiss "Stutzen"), but there is no reason to be skimpy so just fill them up.

- you are using an obsolete cartridge using stuff other than BP or smokeless. Now, you are either using .303 or 450-577 and try to find a replacement for cordite..... so please refer to your load manual

- you have a rather obscure military cartridge for which the propellant is either foamed, multi-core extruded or some other prototype. Good luck with that!


Just as a point of reference. If there is no further data, I would go with a closed bomb pressure model. That should give you a rough estimate on which powder to use. If you have the burn rate coefficient and then refine it by adjusting the volume for the burn products generated throught the acceleration of the projectile. You should at least end up within half an order of magnitude of reality.

 

[Bertfish]

@The Saint might be able to comment. He's an obsolete cartridge guy

 

[BFMIN]

That entirely depends on the cartridge in question. There are three possible ideas:

- you are using an obsolete and rare black powder cartridge. Any load density of 85% up should be fine. And yes, you do not need to fill BP up all to the top that was done for other reasons (demixing of simple meal powder, breaking of grains when transported on animals or when you are accellerating a huge column of powder over an inch or more - proof can be found in different swiss "Stutzen"), but there is no reason to be skimpy so just fill them up.

- you are using an obsolete cartridge using stuff other than BP or smokeless. Now, you are either using .303 or 450-577 and try to find a replacement for cordite..... so please refer to your load manual

- you have a rather obscure military cartridge for which the propellant is either foamed, multi-core extruded or some other prototype. Good luck with that!


Just as a point of reference. If there is no further data, I would go with a closed bomb pressure model. That should give you a rough estimate on which powder to use. If you have the burn rate coefficient and then refine it by adjusting the volume for the burn products generated throught the acceleration of the projectile. You should at least end up within half an order of magnitude of reality.

I was filling them 100% because it was .303 British, I had no other way to get close to the compressed pellet loads that were in the originals.

 

[Rockzilla]

Got an ole Herters Manual with some odd cartridges

-Rock