Pyrodex RS v. Pyrodex Select?

[badlander]

LAST EDITED ON Oct-22-07 AT 08:58AM (MST)[p]I have been shooting through a couple of old bottles of granular pyrodex RS (labels say 1999) as I have switched back to granular powder. I have been very happy with how these have been shooting and the trajectories that I have seen (zeroed at 150 yards, ~3" high at 100 yards, ~7" low at 200 yards) out of a TC Pro hunter shooting 250 grain Barnes TMZs.

I just finished up the last old bottle of RS and decided that I should "upgrade" to Pyrodex select. When I took the select out to the range I immediately noticed that my trajectory had dropped off significantly - to get close I had to adjust to about 3.75" high at 100 yards and that put me at 11" low at 200 yards.

For both, this was using 110grains of powder, both loads were able to consistantly shoot MOA groups or better out to 200 yards.

I don't have a Chronograph, but quickly looking the tables that come with the gun/pwder/bullets I think I was seeing around 1900fps previously with the "RS" and probably dropped to high 1700's by swithing to "Select".

I know both are more than capable of killing a deer at either of those velocities etc and accuracy was fine either way. But I thought Select was supposed to be more potent? Do the BP substitutes get more volitile with age? Have they changed the formulations of Pyrodex in recent years that would cause these changes? Or is Select just not as powerful?

I just bought a jug of Triple 7 FFg that I am going to try during my next trip to the range to see if I can re-gain the previous velocities I was getting?

Any other thoughts?

 

[badlander]

Oh - also. I noticed that the Select was much larger grained than the RS. Is that possibly enough to make the difference? I assume larger grain = more loosely packed = less powder in the same 110 grain measure.

 

[Blank]

I use Pyrodex "P" instead now, and get great groups all the way up to 120 grains in my White Whitetails, before the spread starts to open up. I tried both the RS and Select and didn't see much difference between them, but did get more consistency, velocity, and better ignition with the smaller grains of "P".

Whatever you do, don't use 150 grains of loose 777! Too Hot!!!