Keep it 17 Mach IV, or chamber to 17 Rem Fireball?

[TheCZKid]

I'm getting a used custom rifle soon, which is coming in 17 Mach IV. It's a Remington XP 100 in a rifle format, Lilja barrel, HS Precision stock, Neil Jones upgraded trigger, with Redding dies and some formed / shot brass, plus fifty new 221 BF brass.



What I'm thinking, is why not have my gunsmith change the chamber to a 17 Rem Fireball, get new dies, sell the Mach IV dies, and start fresh in my loading / shooting with a 17 Fireball.

Then the rifle will take factory ammo and brass, etc. and have a higher resale value, and shoot pretty much exactly the same for me. Only downside, having to pay for the chamber change, and remark the barrel (if it's marked).

 

[snert]

I'd shoot it as is till the barrel wore out, then rebarrel

 

[L.Sherm]

Theres really no iota difference in the 2 id keep it the way it is.

 

[TheCZKid]

I'm leaning that direction, plus I save money and get to shoot it post haste!

For clarity sake, I was talking about having my gunsmith simply ream the same barrel, just change the chamber to 17 Fireball, which should be a very minor cut, as long as the neck dimension stays the same. Maybe a 1/16" cut, then headspace and reinstall.

 

[Mark M.]

If you're going to eventually switch over to the fireball, then my decision would depend on how many formed cases it came with, if it only came with a few, I'd have my smith rechamber, start fresh.

 

[roband]

Have both, real close performance wise not enough difference that i would want one over the other.
I would see it shot (accuracy) then go from there.

 

[swd]

You’ll probably use up your increase in resale with the money spent on the rechamber. The MK4 is a great little cartridge, just shoot it. Mine shoots 20gr VMax’s at 4250.

 

[L.Sherm]

You’ll probably use up your increase in resale with the money spent on the rechamber. The MK4 is a great little cartridge, just shoot it. Mine shoots 20gr VMax’s at 4250.

The one I've been around shot outstanding with AA2230 and 20 gr nightmares

 

[Hotshot]

I've had both years ago. I changed to all 20 cals because I hated loading those little 17 bullets with my arthritis. Seems like I could fire the 17MK4 in the fireball chamber but not the other way around.

 

[TheCZKid]

I got the 17 Mark IV mainly as a fun caliber that fits between my 17 Hornet and 20 Vartarg. I didn't need it, but it sounded like fun! I just thought it might make sense to convert it first, but performance wise, it wouldn't make any difference I'm sure. I don't know yet how many formed cases it has with it.

Loading the 17 Hornet was a new challenge mostly in the need to have my loads be really exact, had to get a better digital scale. They are small too, everything about the 17 Hornet is small.

Do you guys normally use 20 grain or 25 grain bullets in your 17M4 or 17FB? I was thinking of using it with 25's, as my Hornet shoots 20 grainers about 3675 fps, and my 20 Vartarg shoots 32 grain around 3800 fps.

If you don't mind my asking, what's your "pet loads" with the 17 Mach IV or FB? Bullet weight, powder, and speed?

 

[swd]

Coyotes 25gr, squirrels 20 or 25’s. I haven’t shot it a while but it’s H335 for either. 25’s go around 2800. Fun cartridge!

 

[TheCZKid]

I've been looking at possible loads, and the powders I have on hand are RL-7, H335, IMR 4198, 8208 XBR, and N133. I do have some AA1680, but it's never proven a "great" powder so far. And, have some N120 and CFE BLK and LT-32.

 

[Rick in Oregon]

I've found that any powder that works well in the 20VT or 221FB works well in the 17 M4, as they're all based on the same FB case.

A1680 has always seemed just a tad 'fast' for these cartridges to me. YMMV
RL-7, H4198 and H335 have all worked well for me. CFE BLK I have not tried, but from reports here it seems to also be viable. With the stash of RL-7 I've got, it's doubtful I'll try it any time soon.

 

[L.Sherm]

If you got a 10 twist you might be stuck with 20's.
I also agree with Rick the 1680 burnrate powders seem a little fast with the Mach IV

 

[TheCZKid]

If you got a 10 twist you might be stuck with 20's

Hmmm, that's a question I can't answer yet.

 

[Mike Casselton]

My Cooper 17 Mach IV will chamber and safely fire 17 Fireball.
All I can say is I wish I had laid in a big supply of the 17FB brass way back then

 

[TheCZKid]

My Cooper 17 Mach IV will chamber and safely fire 17 Fireball.
All I can say is I wish I had laid in a big supply of the 17FB brass way back then

That's encouraging! I make 20 Vartarg brass from LC, and had someone want me to make him some 17 Fireball brass from new Starline 223 brass. So, through a bunch of testing, I figured out how to do that, but it's a pain! Currently, Nosler must have done a run of 17FB brass, as it's available here and there, like Natchez.

 

[L.Sherm]

I dont see why you couldn't just neck down your 20VT brass to 17 only thing might be whatever chamber your neck is for clearance.
The VT and MachIV are essentially the same from Base to shoulder, the IV is about .004 bigger at the shoulder.

 

[TheCZKid]

I'll try making some 17M4 brass from LC when my dies and rifle are here. I'll have some shot brass, and
the rifle chamber to match my new brass to.

 

[L.Sherm]

If you compare 20VT print to 17 Mach IV the biggest difference is in nk dia.
Would be interesting just to neck down a 20VT case to 17 and see what uou come up with I wouldnt be surprised if you good to go if the MachIV neck chamber is .201