GMX vs SST in Hornady Superformance

[CoachHunter]

Other than some slight differences in ballistics and the fact that GMX are about $10 more expensive, can anyone offer any info about the difference between the GMX and SST cartridges by Hornady's Superformance? And why are the GMX more expensive?

I want to use them for my deer rifle (Browning .270).

 

[Texas1911]

Biggest difference is the cost of materials ... the GMX is their Barnes X-bullet variant and is thus, all copper. The SST is an A-Max that probably failed the first round of QC and got cannelured to improve seating for semi-autos.

Honestly, just use the SST. The GMX would be better suited in a .270 for heavier game like an elk or mule deer. A .270 on a hill-country white tail is like a frog being hit like a mac truck.

The SST has shot well in virtually every gun I've tried it in, including alot of .270s. The all copper bullets like the GMX are really finicky because of the change in shank bearing area relative to their grain weight. They act like a much heavier bullet, and require a relatively fast rate of twist.