fire 17 FB in a cooper 17machIV ??

[nobovine]

Thinking about trying 17 fireball from HSM, in my Cooper 17machIV. Should work? Pretty much the same beast only the 17FB, is one of those hairs smaller! Has any one tried it?? I thought instead of the hassle reworking the 221's to the mach IV. I could just fire form the 17 FB, on rodents! And the reload the fired brass on my 17 mach IV dies. Any ideas or help appreciated!! Thanks Ted ???

 

[vmthtr]

Actually it will probably work. Depending on your chamber.

Mike

 

[savageboy]

Any time there is more headspace in a high pressure round, you stand a chance of explosion- I am not sure if it is safe or not, I think that firing a round of any sort in another caliber- even when "close" could be disasterious- its your face that is next to it. Be careful!

 

[vlcakc]

Ted, I hesitated quite a while before deciding to respond to your post. Since the 17 M4 is a non-standard caliber the chambers can vary a lot. Therefore a positive answer to your question is not possible. Unless you or your gunsmith have the knowledge and precision tools to check your chamber it is a very BAD idea to shoot 17 FB ammo in it. I'd call Cooper and get their recommendations before doing anything. Having said all that, the answer to your question is maybe. I can fire 17 FB ammo in my 17 M4, BUT I checked out the headspace and other chamber dimensions BEFORE shooting. The reason I hesitated to respond was the probability that some dimbulb out there would try this without checking chamber dimensions first and get into serious trouble. Headspace on many, if not most, 17 M4 chambers will be excessive for 17 FB factory ammo, resulting in case separation and a face full of very hot gas or worse. Vic

 

[nobovine]

Thanks guys! I think I'll mik. a couple of fireformed cases I made from 221 fireball, and see what they measure, and go from there, problem is I'll have to buy a box of the 17 FB so I can measurse them, and see what's the difference!

 

[CJ6]

Get some Cerro-Safe and cast the chamber take the measurements and decide/go from there.

 

[vlcakc]

The proper way to check your chamber is with a set of 17 FB headspace gages. Checking headspace is not rocket science, but there are a few things you need to know to do it properly. Also, you will need to check neck diameter of a loaded round to make sure it's not too large for your chamber. My 17 M4 was supposed to have a no turn chamber, but sometimes blew primers with less than max loading manual loads in reformed 221 FB cases. A check revealed the chamber neck was a few thousands small and that some of the lot of 221 FB cases I used had necks a bit thicker than usual. A light case neck turn took care of the problem. Now no more blown primers. Good shooting! Vic

 

[CooperNV]

When the 17 FB came on the market I called Cooper and I was told they where shooting FB in their Mach IV's. Cooper's people stated that the chambers where very close and wouldn't present any problems..
I think either casting the chamber or go-nogo would be a good idea just to be safe.

 

[vmthtr]

I looked for but could not find the thread on Saubier.com about this same thing. Guy did the measurements and was only .001" off on headspace from his Cooper Mach IV to the factory 17 FB ammo.

Mike