17 Fireball or 17 Mach IV

[tred1956]

I understand there is some difference in these two cases. But I also understand that they are about ballistic clones.
I have seen a couple of Contender barrels listed on Ebite chambered in 17 Mach IV but sold with 17 Fireball dies or it could have been the other way. Memory not as good as it used to be.
I so confused
Question: Will EITHER 17 Fireball or 17 Mach IV dies load for both rounds? Will one of them only load one?
I have a set of Mach IV dies and am considering a Contender Barrel. Just trying to decide which to get. Fireball dies are not that expensive.
MGM has a Fireball in stock and ready to go.

Would also like to hear which you would get Fireball or Mach IV and why?

Also what would be the optimum barrel length for these calibers?

Thanks in advance
Doug

[cam_mackps2]

Just my opinion but i would get a Fireball for factory ammo. Not that i would use the factory ammo but for resale factory ammo opens up more potential buyers than a reload only wildcat.
I went FB for my rebarrel.

[L461]

I am interested in the replies to this thread.As I have just put a deposit on an A1 in 17 Mach 4

[Bodei]

Definitely the Fireball for the reasons already mentioned.

[L579]

Assuming tight gauging on both chambers when they are reamed. The 17 Mach IV will chamber in the 17 Fireball but the 17 Fireball will not chamber in the 17 Mach IV. The fireball is wider at the shoulder by .006". So the Mach IV dies will load both cartridges but will work the Fireball more when FL resizing and the Fireball will not size the Mach IV at the shoulder. With the Fireball you get the 1 in 9 twist factory barrel were most Mach IV were 1 in 10. With the Fireball you get a factory support with ammo and components and a SAAMI spec were the Mach IV is a wild cat so chamber dimensions can vary. Throat length on the Mach IV can be what ever you want to suit the bullet you are using were the Fireball can be long throat-ed so unless you have the barrel reset it can be difficult to Jam the 20gr bullets into the leade. I run a 22 inch barrel on my Mach IV. Which one I would I have. I will not be selling/rechambering my Mach IV any time soon.

[sicero]

In real life they are the same thing. The only place you might get into trouble
is with a tight necked Mach IV. You either need to know enough to check the chamber out or have it done by someone who does know.
You can cite all kinds of differences by looking at reamer prints or saami specs
but that don't amount to a hill of beans. It don't matter if the chamber length
is 1.432" or 1.420" as the 221 FB or 17 FB brass is going to be 1.400" or less.
Yes you might find an oddball piece of brass longer than that but if you are a reloader you should know , all brass is to be trimmed to the same length or at least measured.
Same goes for the shoulder. Most common diameter at the shoulder for a Mach IV chamber is .6340". 17 FB chamber is a little larger in diameter but it don't matter as new brass comes small enough at the shoulder to fit in either chamber.
People in the know used 9 twist barrels for their Mach IV.
10 twist was common when the only bullet was a 25 gr HP.
I chamber for the 17 FB with a Mach IV reamer. It just makes the FB a little less sloppy.
You just need to know your chamber and how to fit brass to it.
I have my fire proof under wear on so have at it. Kenny

[mulepasture]

Last two posts are good ones..the short version: know your chamber, reload carefully and accordingly. I have 3 Fireballs and one MIV...I keep brass separated by caliber and by RIFLE. Performance wise on game, no difference. 9 twist in each one. The differences in my rifles relate to type and use. MIV is a Cooper Mdl 21 single shot. the Fireballs are Mdl 7, TC MGM Encore and my favorite carry rifle of late built by Dasherr on a Sako Riihimaki L46 action. Each has a different best use.
All that said, it is handy to grab a box of store bought and head out the door..
There are a few places you can pick up MIV ammo...but the variations pointed out above come in to play.
If you are an experienced reloader or patient motivated learner I would not shy away from MIV. If you like to shoot more than reload, FB is your ticket...
Just my opinion, an opinions are like........, everybody's got one.

[Chuck Miller]

I dumped my 17FB's and kept my 17MK4's but I was already setup to load them, ie reloading dies and form dies. In my case both of the '4s were customs and the 17fb's were factory rifles. Needless to say there was no comparison in accuracy and so at the end of the day when it came to deciding which rifle I wanted to use the choice was easy. They're pretty close but I would never take ammo loaded for one and shoot it out of the other. Now I would take either case and run it through the FL die that I was planning on shooting it out of, taking into consideration the neck sizes of the finished round. My experience is that I don't get the best accuracy when I do that but it will go bang. When shooting at something 3-400yards away it makes a big difference, where at 100yds you shrug and say that's ok. There is some merit to choosing the 17FB if building a custom if for nothing else than the die cost.

[Coyotejunki]

I have one of each. I reload for both. Factory UMC 17 FB with 25gr Hornady HPs work very well in both.

I did have the Rem 700, 17 FB's barrel setback about .012", not rechambered, just setback. Still closes on a go-gauge now.

[Oleman]

I thought about the for some time the 17 FB brass has dried up so which ever way you go you'll probably have to form brass. So I went with a 17 222. One pass with .222 brass through the 17 222 FL die and you're there. I'm waiting on my reamer 15 more weeks. I squeezed a dozen cases so far and no bad cases yet.