Right around 2850 with a 17 inch barrel. Yes you could but my throat isn't close to long enough. Being a single shot with a custom throat anything is possible, no mag restrictions. It is chambered in .223 wylde. When I had the barrel made I had the opportunity to have it throated for a dummy bullet but the hbc wasn't out yet and there was little terminal performance data on monos with .223 so I wasn't willing to make the jump. As is it shoots the 75 eldm very well and to a similar POI so even though I lose some case capacity I am pleased with it as is. My goal was 400 yards above 2000 fps and I got there.
I have shot or loaded for others who have shot a pile of animals with the hammer hunters. This year was our first season using tipped hammers. If you are familiar with the hammers you know that there can be significant differences from one hammer hunter to the other on mode of kill. Some like the later 124 6.5 HH were more violent and shed a lot of weight. Others like the 121 HH were more controlled expansion. This season we took 3 deer with 6mm 104 tipped hammer hunters, 1 with 6mm 75 grain tipped HH, 1 with the 69.5 HBC and 1 with the 120 HBC. The performance was all good and every deer was a bang flop. But the HBC line was much more violent with massive entrance side wound channels and acceptable but smaller exits. Whereas the tipped hammers were more controlled but still excellent. I will confidently use the 69.5 going forward and the results make me want a slightly faster .22 cartridge for those 76 hbcs. But the 69.5 seems to have realized every goal I was after when I got the wild hair to make that little carbine.