"30cal"I think the barrels a choked and don't work well with slugs. I have not heard of anyone trying slugs in them though. I was told slugs won't work in the .25. I went round and round trying to deside between the .25 and .30 for my HM1000x and finally desided on the .25 for its higher velocity and flatter trajectory.It performes better out to beyond 100 yards, then the .30 will eventually pass it in retained velocity. There actually is a pretty big difference in size between the .25 and .30 pellets. The .30 is almost twice as heavy as the .25. I bought a tin of each when trying to deside just so I could compare. The .30 is huge compared to the .25.
I looked at the Royal 500 as well but the RAW has more power. You might check out the new American Air Arms rifles. They should be out by the end of the year. Very interesting guns! Though not proven yet. But come in small and large caliber and each size has the same 950 fps velocity. Even the large ones. Very cool!