Q: I’ve heard rumours that Winchester was to introduce a new .17 calibre rimfire cartridge, but have been unable to discover any information about it. What can you tell me about it? I can’t see howit could be much better than the Hornady .17 HMR if it is a rimfirecartridge. But a question that’s been bugging me is: will I be ableto have my CZ Classic rifle in .17 HMR rechambered for the new .17Winchester Magnum?
A: My own information is rather limited at this time. All I know isthat the .17 Winchester Super Magnum shoots a 20gn .17 calibre bullet at an impressive 3000fps, eclipsing the ten-year old .17 HMR’s 2550fps by a considerable margin, but falling short of the Hornady .17 Hornet’s 3650fps. Three years in the development, the .17WSM is said to be a .270 case necked down to .17 and that thetechnology Winchester has used over the years making builder’s nailgun loads that are fired into wood, concrete and other constructionmaterials helped in the design of this new cartridge. It’s loadedwith three different bullets – the 20gn Varmint HV Plastic Tip and20gn Super-X JHP at 3000fps and a 25gn Varmint HE (High Energy)Plastic Tip at 2600 fps. Winchester claims the new .17 WSM is thefastest rimfire calibre in the world – offering a flattertrajectory, less wind drift and 2-1/2 times the energy of both thethe .17 HMR and the .22 WMR. My calculations indicate that the 20gnloads could be zeroed at 175 metres, then the bullets would be17mm high at 50m, 45mm high at 100m, 28mm high at 150m, drop 43mm at200m and 180mm at 250m. That’s flat shooting enough to hit a rabbitat 250 using a bit of holdover. The 25gn Varmint H.E starting out400fps slower could be sighted in 37mm high at 100m for a 150m zero,but has a more curved trajectory, dropping 101mm at 200 and 285mm at250m. A retained energy of 186 ft/lb at 200m compared with 174 ft/lbfor the 20-grainer combined with more penetration should make it an effective load for small game out to 200m. Savage will be the firstto offer a totally new bolt-action platform for the .17 WSM, but nodoubt other riflemakers will be jumping on the band wagon beforeyear’s end. I don’t think you’ll be able to have your .17 HMRrechambered for the .17 WSM as it looks to be too longto fit into the magazine of your CZ.