How much to reduce this 9mm load?

[Jal5]

I am shooting a S&W MP shield 9mm.
I have the Lee 358125 RF which I size to .357 based on the slugged barrel measurement. I also measured the longest OAL that will properly fit using the barrel as the Gauge and that is 1.10

I have a lot of Unique and would like to try this powder but the OAL in most sources is 1.150 which is too long for my gun. I used the 358125RF withUnique at an OAL of 1.10 which fits my chamber as measured by me. Not being able to find much data on Unique at this OAL, I saw in the Lee Manual for a OAL of 1.150 using lead bullets, the min/max powder as 5.3-5.5

To allow for the smaller OAL, I reduced it by 10% and came up with a 4.7-4.9 trial, 5 rounds each. No fail to feed and the rounds felt just a little less powerful than factory rounds for a 115 bullet. None were terribly accurate though 4.9 was best. I may try bumping it to 5.0 and see how that goes. But the boolit does work fine in the gun at this OAL with taper crimp of .377 at the mouth. I used Win brass, cci500 primers, and BAC lube.

My question is about my extrapolation of the load from the Lee manual- does 10% reduction seem right or should I figure it a different way? I never tried to extrapolate a load like this before. Thanks for the help.

[NuJudge]

In my Beretta 92 I use that bullet and the lightest load of 231 that functions the pistol, and get great accuracy. Can I suggest you try going down too?

[runfiverun]

i'd have started more like 4 grs.
nothing wrong with your 10% reduction.
i'm just very leery of the little tiny high pressure 9m case,
and would have looked at how much more case capacity i had used up too.

[Jal5]

I don't really want to go higher up the ladder either, that Unique fills up the case quickly.
I will try some lower and report back with the results. Thanks.
Merry Christmas!
Joe

[GREENCOUNTYPETE]

you would be absolutly amazed how little powder it takes to get a 9mm boolit down the pipe

i wasn't working in Unique , but rather power pistol , i got down to under 2 gr of powder , I forget where i stopped when I had the bullet bounce of the board i shot it at , yes i just wanted to see how low i could go basically , the test was shoot a 2x4 to see how light of a load still penetrated the 2x4

you could probably start at 3-4 gr and work up for function as soon as it functions the slide every time put it on paper .

[Shiloh]

I am shooting a S&W MP shield 9mm.
I have the Lee 358125 RF which I size to .357 based on the slugged barrel measurement. I also measured the longest OAL that will properly fit using the barrel as the Gauge and that is 1.10

I have a lot of Unique and would like to try this powder but the OAL in most sources is 1.150 which is too long for my gun. I used the 358125RF withUnique at an OAL of 1.10 which fits my chamber as measured by me. Not being able to find much data on Unique at this OAL, I saw in the Lee Manual for a OAL of 1.150 using lead bullets, the min/max powder as 5.3-5.5

To allow for the smaller OAL, I reduced it by 10% and came up with a 4.7-4.9 trial, 5 rounds each. No fail to feed and the rounds felt just a little less powerful than factory rounds for a 115 bullet. None were terribly accurate though 4.9 was best. I may try bumping it to 5.0 and see how that goes. But the boolit does work fine in the gun at this OAL with taper crimp of .377 at the mouth. I used Win brass, cci500 primers, and BAC lube.

My question is about my extrapolation of the load from the Lee manual- does 10% reduction seem right or should I figure it a different way? I never tried to extrapolate a load like this before. Thanks for the help.

I have run that boolit with 3.7 grains of Unique and taken them as high as 4.5 gr. Cycles fine, accuracy is good seated at 1.04

Shiloh