I shoot carbon arrows and have no problem blowing through deer. GPLB may not be the best indicator for proper arrow weight for deer. IMO KE is a better measurement, for example;

I shoot a 458g arrow @74lbs for pull. I'm shooting 6.189 GPLB. Another archer could be shooting a a 255g arrow @ 37 Lbs of pull and they'd be shooting 6.081 gplb. These two setups are very close as far gplb but not even on the same scale if you figured out the KE for both.

GpLB are great guidelines to go by for safe shooting and to reduce wear on your bow but the figures can be misleading when it comes to choosing an arrow for your set up.