I'm wondering this because I think the 5.7 round is an awesome round. There are a couple of companies working on, or maybe they're out, bolt action rifles in this caliber. I know where a Savage Model 24 Combo rifle/shotgun in a 20 gauge with .17 HMR.
The 17 HMR is a great caliber but I really don't want to add a new caliber to the stable. I've been resisting buying one of several Ruger Blackhawk .41 magnums priced very reasonably over the past couple of years, and it seems everywhere I go I see one for sale under $400. I've resisted because I don't think I need the in-between to the .357 and .44. My dad had one, and I wish that I had it. So every time I see a Blackhawk with a 7.5" barrel used for sale, and I've seen lots of them over the years, there's a twinge to get it.
So I don't want or need a gun in .17 HMR, but since they never made and still don't make any combo gun with a 5.7 chambering, I'm wondering if it would be possible to fit the chamber of the 17 HMR barrel to accept the 5.7 x 28mm cartridge.
I know the .17 HMR barrel could be bored and re-rifled by a competent gunsmith, and the donor gun barrel is stout and has plenty of metal in it and is very thick. The velocity of the two rounds is similar with similarly sized projectiles, but the maximum operating pressures are very different.
Chuck Hawk's says that the maximum operating pressure of the .17 HMR is 26,500, and Wiki says the pressure of the 5.7 x 28 round is 50,000, nearly double.
So I guess the question would be is the barrel stout enough to support being bored, likewise the action? I think the action is stout enough, and the barrel looks stout enough as well with plenty of boring room
I also know I'd have to change out the hammer since 17 HMR is a rimfire caliber and the 5.7 round is a centerfire. I don't think this would be a big deal with parts available from other Savage 24's.
UPDATE: I talked to one of my gunsmiths and he was highly skeptical on making this mod on that particular gun. For one thing, after boring the barrel, he would be concerned about the great increase in pressure that the barrel receiver would have to tolerate. He wasn't sure there would be enough barrel left to support that kind of pressure.
Secondly, modifying or replacing the receiver could be easy or tough. The rimfire firing pin would have to me either highly modified with some Savage centerfire parts and some receiver drilling or the receiver replaced entirely.
Good idea, he said. He had apparently wondered the same thing about chambering that gun for the new Hornaday centerfire 17 caliber.