Success with Semi-Hot 125 HAP

Blazer 4X-fired range brass/Lee U-Die, CCI 500 SPP, 4.7 gr CFE Pistol, 125 HAP (.356), 1.120 COL, LFCD light crimp.  The charge is 0.1 gr less than maximum from Hodgdon data using a 1.069 COL.  This load gave me my best results to date from my 986 at 50 yards.   9 of 10 rounds 1 3/4", 10/10 2 1/4" from a manual benchrest.  This 986 is proving to be especially finicky with any component change, including brass brand.  Next test will be 5 consecutive 5-round groups with chronograph data.

That load is a pretty close match to my 38 Super load. I am surprised the .356 is working for you in the 9mm. I have some good/accurate loads for the 9 with .355 124gr bullets. But the best load for me is 6.4gr PP behind the 115gr HAP/Zero/XTP .355 bullet. Your revolver has a forcing cone that probably makes all the difference.

Len

It also has a 1-10 twist.  I had the barrel slugged when I had it accurized. I guess I've got to break down and get a pound of PP as nearly everyone who does precision with 9mm swears by it.  More testing to do...rats!  More fun!

LenV.    I am surprised the .356 is working for you in the 9mm. wrote:
Len

Why?

Why? I have not had good luck with a jacketed bullet that is larger then the bore. My 2 9mm match pistols have .355 barrels. I tried as an experiment using the .356 HAP bullet since I had so many of them to see how they grouped. My answer was that they didn't. I have had some success with a couple of .356 lead loads and even one .357 load but nothing in jacketed.

Len

Interesting. I've had good results from the 125 HAP in nearly every barrel I've used it in, 9mm and 38 Super. It tends to be one of the most consistently accurate bullets I've used, even in small bores like a .355 barrel.

This report had very good results with .356 HAPs in a 0.3548" barrel: 
 https://www.shootingtimes.com/editorial/super-accurate-38-super-loads/326242   He even shows good results with 0.357" bullets. 

I get some results I can't make heads or tails of. Sierra 9mm JHP bullets shoot wonderfully in my 38 Super barrel but not so good in my 9mm barrel. Both are Kart 5" barrels. I recently had good results with the Sierra 9mm JHP bullets in a Ruger Blackhawk with a 9mm cylinder, putting 24 rounds in 1.40" at 25 yards. Bullets/guns can be picky with no obvious reason why.

Well, my .355" groove barrels all really like 0.357" bullets.
You have to test to find what works and you have to remember that each gun is a rulebook unto itself.
So far, Power Pistol is still the powder to beat for 9mm. My .38 Supers prefer Silhouette and AA7.