What bullet are you using shadow9?
I have mostly been focused on 44spl as it will be by sons hunting load. Got out to do testing for the first time with 44mags last month. I suspect 2 possible issues that were causing my low velocities. Bad powder, It was older W296 from a friend already open. I have new H110 I am testing next outing. Or the Win large pistol primers (for standard or magnum) are not really good for magnum loads. I did get some CCI large pistol magnum, but wanted to try the powder first, then the primers.
I have been testing with the 240g Hornady XTP, they feed really well.
I also cast my own and just got the lee mold for 240g gas checked SWC that I am sizing to .430. They are getting gas checks and powder coated. I am testing some air cooled ones that should be around 13bhn, and some water cooled ones, that I have no idea of the BHN on. repurposed brazos 9mm bullets. I have some loaded up and am hoping to test them out Wednesday. Here is my current mold lineup, the 44 SWC are all the way to the right.
Last outing 3-10-2022
Starline 44mag brass
Winchester Large pistol primers (marked standard or mag)
W296
Hornady XTP 240g
seated and firmly crimped in the middle of the cannelure.
Henry big boy, 20in barrel
10rnds, 21.5g, Avg 1462, SD 27.71, ES 73
10rnds, 22.0g, Avg 1470, SD 12.71, ES 37
10rnds, 22.5g, Avg 1498, SD 15.56, ES 49
10rnds, 23.0g, Avg 1553, SD 21.99, ES 69
Next outing.
Starline 44mag brass
Winchester Large pistol primers (marked standard or mag)
Fresh H110
seated and firmly crimped in the middle of the cannelure.
Henry big boy, 20in barrel
Hornady XTP 240g H110
5rnds 23.0g
5rnds 23.5g
5rnds 24.0g
5rnds 24.5g
Lee 240g SWC H110, gas checked, Powder Coated, Air cooled
5rnds 22.0g
Lee 240g SWC H110, gas checked, Powder Coated, Water Quenched
5rnds 22.0g
Lee 240g SWC AA#7, CCI standard large pistol, gas checked, Powder Coated, Water Quenched
5rnds 15.0g
5rnds 15.5g
5rnds 16.0g
I would really like to do 10rnd tests, but Im down to 300 mag rated primes. gotta make em last....
And I will be testing some 223 with 75g Hornady match bullets and 3 different powders.... Add in pistol practice, its gonna be a full day at the range
Sorry, I know its a LOT of data.... Been doing a lot of testing.