Thread: .17 Mach IV Barrel

Originally Posted by Wingman

Sorry I have written that info around the wrong way... it is the .17 Mach IV that is longer than the .17 fireball not the other way around. The bolt on a Remington fireball will not close in a mach IV cartridge.

While you might "get away with" firing .17 fireball in your .17 Mach IV it is not good practice. The cartridge body is 6 thou shorter than you chamber so add 2 thou for the std head space clearance and you have a total of 8 thou of head space.. your brass will migrate forward or backward to match the mach IV chamber but at the cost of side wall thinning just forward of the base cup with the risk of case head separation especially if you reload your brass.
Im keen to see pics of your .17 fox if you have any?

I'll take some pics for you. The 17fb ammo is a firm close in my mach iv. I had a heap of cases when I got the rifle (over 200)but the necks have been splitting or were already split they were formed from 221Fb.

Well I sat down to load 100 rounds and at about 20 rounds I was well over it. Im just not set up to load for this tiny mouth cartridge.
First of all the cartridge over all lengths were all over the show but I have no cutter to cut the .17 brass. I decided to improvise and set up my mill to cut them all to the same length.



Surprisingly it was a fast, easy and accurate exercise. After deburring them the were ready to prime.

The second annoyance was charging them. None of my powder funnels or scale measures fitted the .17 neck.

So I whipped one up out of some 6061 T6 alloy in the lathe









Worked great and I loaded 100 20gr vmax to take out on the next hare shoot.

Ha, gave up on funnels years ago,
Now load all sub cals, (.17, .20) with a Harrells bench rest powder thrower, and a 4"(100mm), small drop tube, way quicker, very accurate, and way less frustration than funnel.
just loaded 100 rounds of .17 hornet, 50 round tray of hornet brass, filled powder in less than five minutes, wish it was that quick to prime, and load the 20g v-max.
Anyone doing lots of small game shooting/ sub caliber, should look hard, at a quality powder thrower,

Accuracy is looking pretty good, guessing that last group is around 1/2" no bunny will be safe inside 300m,

@southernman
at 550 nzd they better be flash harry accurate 😂

Ouch, didn't think they (Harrells)were that much, I bought mine, when the Canada dollar was at par, $220, still many pay, as much for a digital, powder thrower, that's much slower, and likely not as accurate. the layman, with three adjustable slides, work pretty good, for much less, just takes a bit longer to set up, the beauty of the Harrell's, is you can record your setting, and dial in what you want, for instance on mine setting 2.00 clicks, works out at 12.5 gr black out, for .17 hornet.
1.90 is 12 grains black out , 8.60 is 48.5gr of IMR4350, for my 7x57. or 49.5gr R19 for 7x57 with 145gr.


Any how back to the Mack IV or .17 fireball, fantastic we small game round, I have had a lot of fun, with mine, squirrels, rats, rabbits, hares, wallabies, a few goats and one deer, plus a few magpies, geese, and plovers. spot your shots, explosive puffs, esp on birds,

Ive actually got a reamer if anyone needs a chamber job. 17Fireball.

Originally Posted by muzr257

Ive actually got a reamer if anyone needs a chamber job. 17Fireball.

Oh now you tell me!

They are fiddly. Simplex press and dies make seating projectiles easy. They just don't look precise.

Sent from my SM-A520F using Tapatalk

Finally tested it on a soft target tonight.
A hare at about 85m with the 20gr V-Max

Yep that's about it for results, from the mighty furball, did you notice the "whomp" sound off the hit, very noticeable, with that cal, I can tell a sold hit, from a miss with out seeing results, out as far as 300m,

Originally Posted by southernman

Yep that's about it for results, from the mighty furball, did you notice the "whomp" sound off the hit, very noticeable, with that cal, I can tell a sold hit, from a miss with out seeing results, out as far as 300m,

Yip quite the pop.. it was a shoulder shot which evacuated the chest cavity of organs and then somehow vacuumed out the contents below the diaphragm too!? Thats some serious hydrostatic shock from a tiny 20gr bullet!

One thing that was obviously clear was that it is far too long for its intended purpose. It didnt even sit well when slung on my shoulder and its very front heavy once suppressed... the biggest issue was the glare on the rear of my suppressor from the spot light washing out my scope picture. I might have to make a smaller diameter custom can for it if shortening doesnt solve that issue. It will get the snip today. Just trying to decide on whether to dock it to 18"or 20".
I' also be shifting to the 25gr bullets once all these 20gr are used up.

Unfortunately the night was cut short early as our personal carrier sustained a mobility deflation issue..
Will head out again in a few days.

Decided to cut it back to 20" and picked up a .17 suppressor baffle kit from DPT today for it. Feels a lot more balanced and only lost 85fps from cutting 4.5" off.

Yep 25 gr is were it's at for the fireball, my rifle is too long as well, 24" plus suspressor, one day it will get a trim, it's ok with out the suspressor, and worked great on gophers in Canada, but they tolerate noise, way more than a rabbit or hare.
That's not bad for velocity loss, might cut mine back the same, it still be ok with a 25 gr at 3700 fps.

Hi, I have a 17 Mach iv reamer and go and no go gauges,
I purchased a Shilan Barrel second hand with DPT suppressor, brass, projectiles, loading gear, rcbs case forming dies ect,
Re chambered and crowned the barrel to fit a Howa mini action that was a .223, fitted it to a carbon stock, and fitted a Vortex 6-24 x 50 Diamondback with the EBR-2c moa reticale.
Haven't done any load development yet only shot the loaded ammo it came with,
I have heard 17 Fireball load data would be a starting point for the 17 Mach iv,

Had the .17 out running hot last night on the rabbits and hares.. total carnage. It hits so hard even at extended ranges.