gregrn43
Have you ever tried any other powder and if you dont mind what type of sabots do you use out of yours?
I do not have the G series so I can not be sure of what you might need. I have a Model 97 White Ultra Mag with a .504 barrel. The barrels on the U-Mag have a large bore - What the bore diameter of the G series is I am not sure.
In the 97 - I shoot a MMP HPH-.458/50 cal Orange sabor or a MMP HPH-12 .451/.452 - 50 cal black sabot. I have also learned of late the regular MMP .451/.452-50 short black sabot might be the better sabot as it might be a bit tighter.
I shoot basically three different bullets from the gun for hunting and 1 really fun bullet to shoot.
First sabot/bullet combination..
My elk load is a .458 (45-70) 300 grain Nosler partition pushed by 110 grains of T7-2f or if I were using the #11 cap I would swith that to T7-3f. I do substitute the a Hornady .458/300 grain HP for target practice or general shooting. Actually it would also make a real decent hunting bullet. Both of these bullets are real rifle bullets and are very tough. I also shoot a .451/300 grain Nosler partition pistol bullet or a .452/300 grain Speer Gold Dot (less expensive) but a bonded poor man's Nosler. The velocity of these bullets is right at 1750/60 fps
For deer, I switch to a .451/260 grain Nosler Partition with the same powder load or a .452/250 grain Speer Gold Dot. Both of these do an outstanding job on Whitetail and Mule deer. Velocity - 1860
The fun bullet is a 10mm (40 cal)/ 200 grain Hornady XTP with 110 grains of T7....2200 fps. It is a great plinking load and does a devil of a job on peepers - ground squirrels. Plus several people have written that work very well on deer also.
For a conical if I were to shoot conicals from that gun it would be a .5045/460 grain MTNex from Bull Shop. with 90 grains of T7-2f, I also use a Track of the Wolf .125x.510 shot card between the conical and the powder.
Hope some of this information helps...
mike