Unique charge for 45 colt 300 grain bullet?

[jski]

I went to the Alliant website for Unique and couldn’t find a charge weight data for a 300 gr. semi wadcutter so anybody have any suggestions?

[bmortell]

lyman #4 book says 4.8-6.1gr 300gr swc 45 colt

[bigboredad]

It depends on what gun you are loading for. A colt or clone or a Ruger blackhawk?

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[jski]

Doesn’t it seem a bit strange that Alliant recommends 9.5 gr. for a 250 gr. semi-wadcutter and Lyman recommends 4.8gr - 6.1gr for a 300 gr semi-wadcutter ?

Oh yeah, this is for a S&W Mountain Gun with a
4 1/2” barrel.

[DougGuy]

Unique is probably too fast burning for a boolit that heavy. When you don't see it listed on the powder maker's data, it's usually because it isn't safe or isn't recommended or both.

Mountain gun is probably safe with tier two loads, to 23,000psi but not the 30,000psi Ruger Only loads. I don't know if you will find a 300gr listed in the tier 2 stuff either.

[jski]

This is what I’ve been using for Berry’s 250 gr. plated bullets:

Unique *Of course, what 45 Colt load data would be without this powder?*
10.0gr (which I do not recommend and do not personally load in any 45 Colt applications, just showing it here for reference) 20,304psi 1065fps
9.5gr (which I recommend as max even for the medium framed NM Vaquero) 18,396psi 1026fps
9.0gr 16,593psi 986fps 100%
8.5gr 14,893psi 944fps 100%
8.0gr 13,294psi 901fps 100%

Usually, I load 9 gr.

BTW, This is from castboolits

[DougGuy]

There is a LOT of difference between 250gr and 300gr in this caliber using faster powders. Unique runs out of headroom really quick when you get 270 and above in weight, you don't get to push it much and your pressures are maxed out. The 300gr boolit at least the RNFP needs a good amount of spin to stabilize. Hard to get this in a revolver with slow powders unless you are into the Ruger Only loads, much harder if not impossible to do with faster burning powder like Unique.

To be honest, Unique and 300gr don't even belong in the same sentence if you are talking about 45 Colt.