ive been reading a little about the 17 mach iv & 17 ackley hornet. the terminal ballistics sound really interesting and im thinking about getting one. does anybody here shoot one of these calibers? what are the pros & cons, whats the best action to build on? thanks guys!

Kcfx... I own 1 17, it is a 17 hornet. I am not sure by what you mean by "worth it" but for me it is a fun rifle/cartridge. The killing power is nothing serious and I have never taken a shot over 200 yards. I shoot mostly birds/GSqrls, and coyotes, 1 bobcat. The 22 mag will out penetrate it.
Mine is a custom Anschutz, though I would SERIOUSLY look at the cooper arms models, they are a great buy.

I've owned several 17's. They're simply "fun guns." The 17 Hornet is about the right case capacity for the bore size. There is a little more to a Mach 4 than just resizing Fireball brass. You need to start with good quality .223 brass. Either that or buy the formed stuff from Todd Kindler. If you just want a gun that's fun and simple to shoot stay with a 17 Rem. Sure, the case is too big for the bore. But with moly bullets mine all seem to shoot good. By good, I mean under a half inch. I have a Sako that shoots generally under a quarter inch with the moly and H414 powder. I like the small Sako actions. But a Rem. XP-100 is fine also. Had a Mach 4 once that we built on a Hart benchrest action with a Shilen barrel. Wasn't worth all the bother. One of the nicest things about the 17's is tht you can put them in a LIGHT rifle and they'll still shoot.

I shoot a 17 CCM and it is the most fun of all my guns....great for crows foxes and other small varms......I have just put in a order for a 14 Walker barrel for the contender.....go SMALL and you will never go back.....Hal

smallfry...what i meant by "worth it", was by investing in dies and cleaning equip., cleaning the barrel more than the 22s to keep good accuracy. does yours need that? i would mostly use it like you said,sparrows,starlings,p-dogs and maybe coyotes once in awhile. i was thinking about the 17hmr too (less reloading) whats the scoop on this round?, or would the 22mag be a better choice for my intentions?thanks

Well, I'm in the load development stage with my 17M4. It's built on a Sako 461, and a Remington 17 barrel. The rifle is set up as a switch barrel, and the other barrel is chambered for the 221 Fireball.

At this point in time, I'm achieving roughly 1 moa (plus or minus a bit), although it appears that a couple of loads might be heading down towards .7 moa. In contrast the 221 FB barrel gives .7 moa with virtually everything I've tried. I basically stopped load development as soon as I started, as it gave good enough velocity and accuracy on the first try.

Noise level of the 17 is appreciably worse than the 221. Recoil is basically none existent with both.

17 is achieving 3800 fps with 20 grain Vmax. 221 is 3400 fps with 40 gr Vmax.

The 17 appears to be finicky, whilst the 221 is easy.

I'm going to keep playing with the 17 because I already have it. But, as far as I'm concerned the 221 is a far nicer round.

Kcfx... I do not clean my 17 anymore then I clean many other rifles. Depending on how much I care. Accuracy starts falling off about 25-30 rounds. This is not much of a concern as it will still shoot decent groups.
I like owning a 17 but dont see one "greater" than my 17 hornet in the future. The reason is These super speedsters will always only add 100 yards on my 200 yard limit.
For birds the 17s rule. I dont know how you feel about the 17HRM but its a cartridge I am going to stay away from for awhile... at least until they add to the 1 plastic bullet load that is offered. I see little advantage in this cartridge in general, though any cartridge that gets people interested in shooting I guess is a good thing.
If you were going to add coyotes the 17 hornet or 22 mag would work just fine. I probably have taken more coyotes with 22mags then all other of my rifles. Out of the box marlin 22 mags have decent accuracy, otherwise expect 1 1/2"-2" groups. Winchesters old 40grain power point is THE most agreable ammo I found for any 22 mag. If you are concerned about accuracy... I have had good success with volqrn aftermarket drop in match barrels.

The 17 is a fun gun as long as the wind's not howling. when they first came out, I sold several,they'd group great, but a 15 mph wind kills them. Of course a lot of people fell out of love with them when they got home and their cleaning rod wouldn't go down the barrel, etc. A bunch of handloaders also found out .5 grains of powder is the difference between a good load and a blown primer in a 17 rem. I wouldn't waste the time- too windy in Missouri and the 220 Swift is way better on coyotes.

After owning a half-dozen or more .17s, I have converted to .20 cal. It is very difficult to get the gilt-edged accuracy from a .17 that you can get from larger calibers. I got tired of fumbling with the tiny bullets. On the other hand, the .17 Hornet is a very worthwhile cartridge, as is the Mach IV....

My .02 worth.

Jordan