SmallCaliberCentral

Am about to order the barrel to go on my CZ.

Anyone with a 17 Mach 4 (or who has read up on them) want to recommend a twist rate for 25gn projies. You guys probably have the 17fb in your shops so FB owners can chime in!

I was guessing that small charges of relatively fast powder would easily expend all their energy in a relatively short barrel. Was wanting 22 inches.

Anyone know the recommended barrel length required to get the cartridges best velocity?

trevort: I shoot a custom Sako in 17 Mach IV, and tried many powders before settling on H322. Any other powders in that burn rate area should work also. N-133 is also a good choice for this little baby.

For shooting 25gr bullets, you'll want a 10 twist barrel. All I shoot in mine is Berger 25's, and it shoots them quite well. Getting 4,000 fps using 20gr V-Max's is no problem, but I also shoot a 17 Ackley Hornet, and the 20 grainers seem more suited to the smaller Hornet case, at least to me.

As for barrel length, mine is 24", but you won't give up much at all going with a 22" tube. My 25's are running right at 3,900 fps, so yours at 22" should be well around 3,800 fps or so I'd think.

Here's a 17 Mach IV ready for Skippy in my Sako Vixen L461, loaded with the 25 grain Berger Varmint bullet, WS2 coated:



Some R-P 221 Fireball cases freshly formed, neck turned and annealed to 17 Mach IV:



Redding dies are all I use for these small calibers in order to keep the runout to a minimum, and guarantee the ammunition will be as good as possible without resorting to an arbor press and hand dies.



The little Vixen giving Skippy the fits off the bench:



You'll love the caliber, less recoil than the 204, very effective on small varmints past 400 yards, flat shooting, relatively quiet, see your hits, cheap to load for as it uses only around 16 grains of powder, and extremely accurate. Friends in the US midwest swear by it for fox hunting. I'd imagine the 17 Rem Fireball will be the full equal of the Mach IV if Big Green has done their homework well.

Thanks Rick. Quite a lot of feedback on several forums. It seems that if you want to use the 25 Vmax then 1 in nine is best option. Havent seen one as yet but guessing its long for calibre as users with standard hollowpoint ammo were happy with 1 in 10.

I ordered the 1 in 9 just to be sure and it will be a number 6 Lilja. Probably will stay at the 24, maybe 23. 10 weeks to decide before it gets here!

Off the topic, but Rick, what is the rest you're using in the pics?

And Trev....don't use it on our skippys.

I'm not Rick, but I believe that is a Sinclair.

jb747: WP is right on the money, it is my Sinclair All-Purpose Front Rest. I've tried others, but this is the final outcome of all my testing and searching for what I feel is the best setup available.

For the money, the Caldwell BR Rock is also a nice unit, and less than half the cost of the Sinclair.