When finding the max OAL with the 124gr HP berry's bullets I ended up with this.
9mm Springfield XDM: 1.049" touching lands
9mm Hi Point Carbine: 1.163" touching lands
I've only ran test loads so far through the Hi point using Blue Dot Powder and HS-6 powders.
I worked backwards from the max OAL for the Blue Dot: 1.148, 1.138, 1.128
Blue Dot working up: 5.1gr, 5.4gr, 5.6gr, 6.0gr
The HS-6 loads where intended for the XDM, but being new to this I found out the CAOL was different from bullet to bullet. I accidentally seated the bullet to long making it hard for the action to shut. So i tested them in the Hi Point.
I worked backwards from max OAL: 1.095, 1.085, 1.075
HS-6 working up: 5.1gr, 5.4gr, 5.6gr
I had no problems getting them in the magazine. If my memory serves me right I did have a few long ones having a hard time chambering. All cases seemed to look fine to me.
I need to look at the targets again but I think the shorter COAL with the higher grains of HS-6 were doing the best, but not great for a 50yd target. I feel like a longer barrel shooting with a scope should do better than a 4"-6"+ group.
One thing I really didn't like about the Hi Point was the long trigger pull.