Comments on: SHOT Show: New Reloder 33 and Power Pro 1000 from Alliant

By: Rex

Rex — Sun, 22 Jun 2014 08:11:55 +0000

Now if they would only make a powder implementing the same technology in the 4831 burn rate or slightly slower we would be set

By: Dan

Dan — Wed, 30 May 2012 19:11:54 +0000

Any published dates yet? it should be out by now right? VV is a litle pricey for the 338 and I would really enjoy working some loads up for this..

By: Tommy estes

Tommy estes — Sat, 26 May 2012 21:02:56 +0000

Looking forward to trying this powder in 338/378 weatherby mag. 28″ barrel. Any comments?

By: Neil Gibson

Neil Gibson — Wed, 25 Jan 2012 14:16:48 +0000

Thank you for your kind comments with regards to my reply.

I guess it’s down to years of testing the larger gun models (cannons, artillery and tankguns), reading rather too many ballistics papers/presentations and working for a certain defence publisher.

By the way, I’m taking it that the progressiveness of the propellant is purely due to the deterrent impregnation. As I’ve not seen the propellant kernels of either RL17 or RL33, I can’t say yay or nay to if they are multi-perforated or not? Multi-perforated grains would also give a progressive burning powder, though they work by increasing the surface area (hence gas production area) as they burn and not only on the deterrent layer. The initial geometry of the grain is the largest factor varying the burn rate of most propellants.

By: Neil Gibson

Neil Gibson — Tue, 24 Jan 2012 14:09:29 +0000

So this is a extrusion impregnated (EI) deterred progressive-burning powder made by Rheinmetall Nitrochemie and imported by Alliant (ATK). The deterrent processes used allows the deterrent to penetrate deeply into the propellant grain, both deterring the burn and reducing the nitroglycerin (NG) loss over time. The effect of the deterrent during a propellant burn is to increase the burning rate later in ballistic cycle (further down the barrel), making the powder a progressive type. This will increase the average pressure in the barrel, widening the pressure vs time curve and increasing the area under the curve, not necessarily lowering the peak pressure. The area being the amount of energy (work) available to push the projectile out of the barrel.

If like EI-Niesen 145, marketed in the US as Reloader 17, this deterrent may be plasticiser like dibutylphthalate (DBP). Unfortunately the MSDS does not list the components of the propellant other than NG and nitrocellulose (NC).

Strangely, the only listed powder made by Nitrochemie for the .338 Lapua Magnum is WLP 250, which isn’t an EI propellant. I suppose it could be EI-Niesen 150 EA (listed for the .300 Win Mag) or a newly developed type just for the .338 Lapua.

EDITOR: Neil, your summary of how RL17 and RL33 work is the best I’ve seen so far. Thank you! As you correctly point out, the Peak pressure is not necessarily lower, but pressure doesn’t spike as quickly and there is more overall energy “under the curve” to push the bullet.