I'm not a gun & ammo expert by any means. I find something that shoots true and works, and I go with it. That being said...

My hunting rifle is a Savage 111 in 25-06

My bullet of choice is Hornady Superformance SST 117 grain. Most deer drop in their tracks with a behind the shoulder shot, and one and only one managed to make it a mere 30ish yards out of the past several years.

While looking to buy a few more boxes, I stumbled across Hornady Full Boar 90 grain, thought to myself I'll buy a couple boxes of this also,,,,then started overthinking the hell out of it.

I obviously dont understand the logic, but why would I want a lighter bullet to head shoot a hog?

((not looking to be ridiculed, looking to be educated. thanks))

Since you said that you don't understand the logic...

1. manufacturers don't know that you already have a 117 gr bullet that you like for shooting deer and are happy with it.
2. lighter Full Boar bullet will have less recoil
3. slightly flatter trajectory at normal hunting distances (out to 300 yards)
4. At 3300+ fps with a GMX monolithhic bullet, it is going to drill holes through most hogs out beyond 200 yards no problem, even large hogs. SST will come apart into a bunch of pieces and also likely have some exit.
5. GMX fragments less than SST overall and while the bullet may have petals break off, GMX is all copper and won't contamination meat like the SST will when it breaks apart into a lot more pieces.
6. some people have rifles that will shoot the 90 gr more accurately.

and last...

7. the logic is that the manufacturer is giving you options on what you can use. Some people like X factors of performance, some like Y, and some like Z. There isn't necessarily a right or wrong answer for hunting per se, but only in getting the performance that you like. Remember, the manufacturer is selling to people other than you.

Use an ammo manufactuers website to compare bullet weight within a caliber to others , Federal ammo has good information for a wide array of weights , the info is specific to velocity and energy.

Then compare bullet construction between Federal and Hornady to get an apples to apples comparison.

In other words just because velocity is going to be much more for the 90 grain vs the 117 grain the Energy of the 117 grain is probably "better" for hogs

good information

thank you both

Those were very thoughtful answers. The SST and the GMX are at opposite ends of the hardness/energy transfer spectrum. To be honest, I'm not sure that I'd recommend either bullet to someone who wasn't specifically looking for the qualities of that particular bullet, as something in the middle, such as a Winchester PowerPoint or a Hornady SpirePoint, provides a better balanced product for all around use.

Don't take this to mean that I don't like either the SST or the GMX. I don't use the SST myself, but would willingly do so should the need occur. I've also had very good experiences on game with the GMX, and count myself a modest fan of the bullet. What you are already doing is working well and you're happy with your current setup, so don't let others talk you out of a good thing.

30 yards to the head? You an use a .22 and it will drop it at that distance.
But for cavity shots at 30 yards either the SST or GMX will do just fine. I "believe" the GMX is what they use in their line of "Full Boar" ammo. I believe the GMX is a copper monolithic bullet similar to Barnes TSX line (feel free to correct me).
Again 30 yards with almost any bullet (minus FMJ) should take care of business.

I cannot believe Hornady's website doesn't have velocity and energy figures for their ammunition offerings....

From Federal's website:

An 85 grain bullet (close enough to 90gr) will have 3550 FPS at the muzzle and 3226 FPS at 100 yards

A 117 grain bullet will have 3030 FPS at the muzzle and 2767 FPS at 100 yards

Energy data:

85 grain at the muzzle - 2378 ft.lbs and 1964 ft.lbs at 100 yards

117 grain at the muzzle - 2385 ft.lbs and 1989 ft.lbs at 100 yards

So what is to gain by changing ammo if the energy is nearly identical... I can tell you which will have a louder crack and burn your barrel/throat out quicker....

This is purely extrapolation, bullet design is different between SST and GMX so the energy data doesn't indicate that you'd have to headshoot anything because it has just as much "kill punch" as the heavier bullet.

My experience with the SST was with my .308 and 30-06 rifles.

They were both very effective at swiftly dropping game, but I found they also made the process of field dressing a bit to messy for my liking.

Since then, I've only used the SST bullets for things I don't intend to put on the dinner table, or take to the taxidermist. Coyotes, etc. I now use BTSP's for deer, but I also have some ELD-X I'm wanting to try out this year.

I do like the SST bullet, it is effective. I just don't like using it on an animal that I'm going to field dress or run thru my meat grinder.

The two bullets will have different external and terminal ballistics, it just depends on what you are looking for in performance. I believe the GMX is supposed to perform more like a soft point on impact. If you're only taking head shots on the hogs, you're not really ruining any meat anyway, so I guess the only advantage might be less recoil?

Im no expert either, this has just been my observation of the terminal ballistics of a few different bullets.