Accurate 11FS range report.

Spent a lengthy amount of time developing loads for my 475 Linebaugh using Accurate 11 FS powder.

Love the accuracy potential of the powder but it?s one of the dirtiest powders I?ve ever used.

Cases come out filthy. After first 5 rounds in my clean BFR, I had trouble getting next 5 to load without pushing them into the chamber.

11 FS was a military powder that was chemically designed to reduce muzzle flash by 90 percent.

Maybe it has better application in rifle cartridges but definitely not pistol or revolver.

Never used that powder but I am curious about the bullets you did use with it? Flash suppressant is like adding sawdust to a powder,,, too much will always end up in bad results. ( like unburned powder) OR the flash suppressant burning much dirtier.

I also question the crimp. I have seen blowback with the brass ending up real dirty, because the powder was not burned up before the bullet leaves the chamber. A good crimp is needed always.
I am not questioning or denying the facts that some powders seem to be more dirty than others. Heck Unique advertised, that it was cleaner burning with the newer formula.

Using 375 and 400 grain hard cast with gas check from Montana Bullet Works. Heavy roll crimp with Lee carbide dies.

Makes me think about how that sometimes powders have sweet spots as to when they burn all the powder. Thinking of 4227, in particular. You have to start getting near the max load in some cases, for all the powder to burn and cases can sometimes clear up somewhat.
I did think about a jacketed bullet, ( just to try for grins and giggles ), but alas no data for them on the Alliance website.
You didn't state load data but maybe you can possibly step it up and burn more of the powder and reduce the residue.

oh and what primer you using? I have never agreed with the idea of Winchester LP primer that can be used as a regular of mag primer. I would try a mag primer to try to burn everything.

Using Winchester large pistol. I could take a few cases and uniform the primer pockets to large rifle primers with a start load and see what happens.

I would suggest trying some magnum primers and reducing the powder charge a little, working back up.

Rifle primers are longer than Pistol primers and the primers are going to protrude past the case head. These should not work in your pistol, and should hit the recoil shield.
Stick one in the case without powder or bullets and try if you want. RIFLE PRIMER IS NOT THE DIRECTION TO TAKE.

In my experience powders burn cleaner up near the top end loadings.
I have never shot 11FS but shooting Unique, 231, Blue Dot, Red Dot, and a host of others at lower charge weights results in massively dirty cases and guns. As you bump the charge weight up, the powder gets cleaner and cleaner until you just have some light gray dusting at the muzzle and around the cylinder gap.

In the end I have found that it is better to pick a powder that is providing the velocity you want up near 80-100% of the max charge weight. If you need to download then pick a faster powder.

When he uniforms the primer pockets it will take them to the proper depth for the rifle primers...