duplex loads

[rupe01]

If you guys REALLY want to explore smokeless duplex loads, do a search on the Cast Boolit site. Lots of info there.

 

[GBExpat]

... By the way, if you have to ask how to do it, you shouldn't be doing it.

 

[spitballer]

Interesting concept and worth reading about, but I would never try it myself. Might be worth investigating for artillery or naval guns tho

 

[Malamute]

I believe the long flash tube idea was used in some artillery shells at one time.

 

[Comrade Mike]

I believe the long flash tube idea was used in some artillery shells at one time.

That's true, they used flash tubes so that the powder charge would burn from the top down. I don't remember exactly why this is beneficial but it does have some performance benefits.

 

[MErl]

At a minimum it doesn't push unburned powder down the barrel, less mass to accelerate at the start.

 

[Malamute]

I believe it has to do with changing the burn characteristics of the powder. It allowed slightly higher velocity without more pressure.

 

[redbullitt]

It's a good way to burn off that surplus 50 BMG class powder. Fairly common in cartridges like the 4570 with cast bullets. Nice tight powder column with enough compression to keep the kicker powder from shifting about. You want to keep it right by the primer.

Cast boolits site has plenty of info on it if you are still curious.

 

[rupe01]

Its a very safe and useful procedure in most rifles as long as you know how to do it and follow the rules. Definitely not safe for beginning reloaders though.

 

[Venado]

Advantages of a stratified (triplex) load in a .45acp: .460 Rowland ballistics in an unsupported barrel, using regular acp cases, low muzzle flash, and with no bullet set back. No risk of a double charge, since a person is using a compressed load. People are spending lots of money on conversion kits, when they are unnecessary. My pressure testing equipment shows a consistent pressure curve most of the way down the barrel. The fast powder next to the magnum primer, gets the powder charge moving away from the base of the case, which keeps the base from taking the brunt of the pressure. The fast powder on top of the charge helps burn up powder and gasses, that would otherwise be muzzle flash. Case life and primer pocket life is increased. Also is a good survival method. I have used IMR 4895 in the .45 acp, and got good results. There is no one powder made that can do all of this. Sorry to disappoint you, but have never blown up a gun.