It sounds like an extension of the heavy high BC bullet in an undersized case trend that's going around right now.
I just had a 25GT chambered and have shot about 100rds through it at this point. I'm a long time Dasher and BR shooter. I've seen people post on here how the recoil increase of the 25 cal 135 is negligible over the 6mm 105, citing a minimal 3 grain increase in powder charge. I can tell you that is not my experience. That 135gr at 2665 recoils significantly more than 105 at 2900. It gets .1mrad better wind at 1000 than a Dasher.
Yesterday I was shooting 1" dots on paper at 300yds as an extended zero confirm. We normally have heavy mirage and 80* temps in the afternoon but a storm was rolling in over the mountains so it was perfect shooting conditions. Overcast, no wind, still. I could see trace into the target in the prone. I also shot 5rds off a makeshift barricade to ensure I was maintaining my zero in multiple positions. However the makeshift barricade was a massive, immovable concrete shooting bench so shooting kneeling off a bag is as optimum barricade as you can get. I could also watch my trace going into the bottom right edge of the dot kneeling as well but I was putting a lot of body into the gun. Sounds like the claims are correct, right? I think the issue is going to be when you're shooting 2 min or 90sec 12rd stages with two targets and 6 pos changes on shitty barricades. You won't have time or the infrastructure to drive the gun that optimumly on those types of stages. This is where the Dasher normally shines. I guess I'll find out tomorrow at the club match. Max distance is 800 yds so no noticable wind advantage to the heavier 135gr.
I would imagine a 190gr bullet is going to be the above, on steroids. And knowing Sherman cartridges, subtract 50 - 100fps from initial velocity claims for realistic speeds.
