My experience with those two conicals is in 54 caliber, so the weight is different but the construction is the same. The T/C's I have are 430 grain and the Hornady are 425 grain. With that in mind, the Maxi tend to end up with a flat front and a bend at the first band. The GPB tends to flatten the front and end up like a wadcutter. I think the HP moves the lead out or down and it shears off. This is on large animals and ballistic "tests" on different materials. A deer sized animal can rarely detain the projectile for recovery. You have a slightly different weight difference in 50 caliber, but since the construction is similar, I would expect the performance to be similar from caliber to caliber. Overall, I have had the GPB penetrate more in a straight line than the Maxi. There are some assumptions to be made: both are made from soft lead (the Hornady is but the Maxi may be from TC or a clone cast from a mold with "harder" lead); the bullet hits hard matter head on (bone); the shot placement and animal presentation is the same; the projectile is stable in flight. In my observation, the GPB will out-penetrate the Maxi under the same exact circumstances. This contradicts thoughts on conventional bullets where a HP is thought to open quickly and vastly and hamper overall penetration compared to a non-expanding type. But, it is what it is. The Maxi does expand some due to the soft lead but I think its the grease grooves that weaken it somewhat and cause it to bend and turn. I personally have not fretted much about using either on big hogs, nilgai, large introduced species and black bears. But, the biggest curve ball you are throwing is the close range. I'm shooting 50-100 yards and the performance is very similar with the Maxi tending to veer off some and bend. By the time these projectiles (in .54 remember) reach the animal they are at or below 1000 fps. You're probably 300-500 fps more at 25-yards and in .50 cal. I think the HP front on the GPB will be gone in an instant and it will continue on as a wadcutter. Not sure what to expect with the Maxi, but if it bends at slower velocity, it has the potential to bend much more severely in your circumstances. Conclusion - I'd hedge my bets on the GPB.