I was digging around in my reloading room bright and early this morning and found two WW 300-grain JHP rounds on a shelf along with five rounds that I had loaded on for my "G"; my TLC460-350-RF bullet on top of 52.5-grains of Benchmark. I looked at the pressure data of the reloaded ammo and it was semi-conservative so I walked up the hill to the range with the Rossi pumpkin chunker.
I shot the two Winchester rounds at 50-yards, centered but low so made an adjustment but moved the target out to 100-yards before I shot the "Ranch Dog" ammo.
There you go. Pretty good shooting for the first seven shots out the barrel. There is some pre-frontal winds here gusting across the range, that might account for the horizontal deviation but even that is not bad. I do think the bullet needs to be a .459" so I special ordered a kit from Lee while I was sitting at the range. In the meantime, I will adjust the elevation a bit and kill a deer in the next couple of days with it. QuickLoad estimates the velocity/pressure to be 1849 FPS at 31.0K PSI. I suspect that is very close as it ran 1780 at 31.0K PSI in my Guide Gun measure with the pressure trace gear. I might bump the pressure up in the coming weeks as after taking some measurements, I think I will let this rifle idle along at 35.0K PSI. I operate my 1895s at 40.0K PSI. As an example, that would be 54.6-grain of Benchmark at 1895 FPS. H335 and H4895 would give me about another 60 FPS but I will work with all the Hodgdon rifle powders and see what it likes best.
When pressure testing the Guide Gun, about 60 rounds of ammo and I was ready to call it quits. I think this rifle will settle in around 30 or 35 and it will be time to stop. Of course, hunting it is just one recoil cycle. What else... Oh, the trigger is perfect. The rate of twist is 1:20.