Have you tried any of the .308 caliber TMK bullets loaded in the 300 ham'r? Looks like they have several different options between 125gr and 195gr.
Is the 125 BT the most internally damaging 300 ham'r you've tried?
I've tried the 125 TMK. It's far too long in the ogive to work.
The Ham'r is designed with a really tight throat so short, less aerodynamic bullets work best. Even in a 350 legend mag, you can't load the TMKs long enough to not have the ogive in the case mouth, giving a huge jump into the lands. If you clip the tip off, you can load them to 2.355" but they still have a lot of travel before they clear the leade into the rifling. Accuracy with the clipped tips was ok, but the 125BTs & 130 Hot Cor was much more accurate.
125 TMK vs 130 Hot Cor......
De-tipped TMK vs unadulterated loaded at 2.355.....
Clipped TMK (2.260) vs 125 BT (2.355) vs 130 Hot Core (2.260)
If you compare all there ogive shapes, you can see how much closer to the lands the BT & HC are going to sit, at the same OAL.
In my gun, the Hot Core beats the other 2, accuracy wise, by enough of a margin that that's what I'll be shooting this year. The BTs generally shot under 2.5" for 10 rounds at 100yds, which is fine for a <300yd gun. The clipped TMKs were a hair worse, but still acceptable to me. The 130s routinely knock an inch off that & print between 1.25 & 1.75" for 10 shots.
Like I say, not a huge difference in reality & probably not enough to guarantee any first-round-hit probability difference, but enough to boost my own confidence.
I'm sure the TMKs & BTs show better terminal performance, but the Hot Cor works well enough, by all accounts (from the mouth of Bill Wilson)