Cordite equivalent load data

[cpileri]

Is there a powder (any kind: smokeless, black, substitute) that is equivalentto cordite?

Reason I ask, is i was going through my double rifle book by Graeme Wright again, and noticed that in the Nitro-for-Black section, he lists some 577 x3" loads that are cordite lobbing a 650gr bullet at ~1000fps and are within (but high-end) pressure limits of a 20ga shotgun.

Iam thinking a 1&3/8oz slug out fo a 20ga ought to add some real thump and the better sectional density of the 20ga vs 12ga might aid penetration- a nice 'poor man's paradox' or 'poor man's double gun' load.

But the data is not extensive enough to draw comparisons to the cordite loads, and all smokeless loads listed in the book are too high pressure for a SAAMI 20ga.

I know that there are smokeless-to-black equivalents, like the 30% 4198 to blackpowder rule, so i figure someone might know of a similar equivalency to cordite.

Thanks!
C-

[Chicken Thief]

You cant just say:
Well i'll use another boolit, another caliber and another powder but still use the same reloading data!

There are several powder manufactors that post reloading data online and there is umpteen good books on shotshell reloading with good data.

Cordite is highly corrosive on the bore and a very agressive propellant. They used it because it was what they had, not what they wanted.

A very brief Goolge search gave this:

http://forums.nitroexpress.com/showflat.php?Cat=0&Board=doubles&Number=163010&Searchpage=1&Main=128041&Words=+Ron_Vella&topic=&Search=true

Please bear in mind that the old Nitro Express rounds loaded with cordite had/has a BIG void (Lots of room and little powder) and that will lower pressures. In a shotshell that is not possible. I know because i have tried!

Think of a 38SPL
Little amount of fast powder and lots of room. Low pressure and low speed.
Now seat the boolit way down onto the powder and watch the revolver selfdestruct.
Pressure will spike big time.

[longbow]

You should read up on what Ed Hubel is doing, and loads he posts. He has developed quite a number of very high velocity loads using large amounts of slow powders running within shotgun allowable pressures:

http://castboolits.gunloads.com/showthread.php?7916-12GA-FH-Slug-Tester

There is a lot of reading there!

Specifically for 20 ga.:

http://castboolits.gunloads.com/showthread.php?7916-12GA-FH-Slug-Tester/page16&p=641197#post641197

Post #302 talks about RE7 for 20 ga.

I know I have seen more of Ed's loads but there is a lot of info to wade through. Dig and you will find loads that have been developed using pressure testing equipment.

Longbow

[cpileri]

Thanks. Ed's thread is alot to wade through. i've been following it of course (who hasn't?).
I was just noting the similarities between the 577 3-inch and a 20ga 3-inch shells. Thinking there might be some possibility there.

The 20ga 3" has an approximate internal capacity of the 577 (2.75 length x (1/2 diameter=.623 internally all thw way along) x (1/2 diameter) 577, maybe a bit more even since the 577NE starts at the base .662 (external) and tapers to .585 internally at the mouth, but is longer at an actual 3 inches.

Anyway, Im just brainstorming.

C-

[cpileri]

Hey check this out, from the link you provided:

1.10x IMR 3031 = cordite
1.19x RL15 = cordite
1.31x IMR 4831 = cordite
40-44% IMR 4198 = black powder

Apparently IMR-3031 is not preferred as blow ups have occurred. And RL-15 seems to be the current prom queen.

C-