If I was you I would go read the reviews on NSA website and watch the videos on Mr Hollowpoint website. There is a lot of info on there. I use the NSA slugs in my Texan carbine. Very accurate. I’m sure someone with the Hammer will chime in. Good luck.
I have used NSA's .510 388gr HP in both my Umarex Hammer, and my Hatsan Piledriver 50. This ammo shoots well and accurate out of both. Been deer hunting, and it does the job.
OK, magazines have been .511, my sizing die is polished out to .5105 Powder coated rounds are slippery and like to fall out of the mag when loading. Think I may need to polish that die out a bit more!
Nsa 388 grain. That's what I use in my Hammer. Hollow points expand to a nice deer killing size. With the power of the Hammer deer don't stand a chance out to 100 yards. Hope this helps
I have not hunted deer with a big bore airgun but I really want to and have my eyes set on the lehigh defense fracturing copper air gun slugs. The fracturing pedals do a lot of damage and the base of the slug can carry on for a clean pass through. downside is they are not cheap and maybe hard to find.