#11
|
|||
|
|||
17FB is easier to resell as accurate and dies are less than half.
|
#12
|
|||
|
|||
Really there are some pretty reasonable dies through Hornady. With out factory brass the 17 FB is no more resellable than a 17-222 or MACH IV.
__________________
NRA Lifetime Member NBRSA Member |
#13
|
|||
|
|||
Anything but a factory chamber eliminates likely over 90*maybe 99*
of buyers at any price. I agree with Dean on this issue. Kenny
__________________
sicero I pride myself in being able to make decisions with little information. |
#14
|
|||
|
|||
Fireball
It looks like the fireball is being phased out.
|
#15
|
|||
|
|||
Quote:
[IMG][/IMG] Next I measured the Rem 17 FB brass and found them to be 1.405" out of the bag. The chamber is cut to accept a Maximum Case Length of 1.400" so I trimmed them to 1.390" which is listed as 17 Mach IV Case Trim Length in a number of sources. Not trimming would have been a problem. Then I measured the OAL to the lands with a Hornady 25 V-Max and found it to be 1.923". I then seated a bullet to 1.893" which is 0.030" off the lands with a seating depth of0.170". I measured the loaded round neck diameter at 0.200" which left me with 0.0015" clearance at the neck. I don't have to turn the necks but may clean them up slightly. [IMG][/IMG] While the new 17 FB cases were to Max Saami specs for shoulder lengths the shoulder and 0.200" datum diameter's were .0070" and 0.0039" under Max respectivly. This allowed them to fit in the Mach IV chamber with plenty of clearance after trimming. I them fired a round and found that there was 0.005" Headspace at the shoulder datum when comparing a new brass to the fired round and the length had increased to 1.395". The fired round holds about 0.5 grains more IMR 8208 than the new round. I then FL sized the fired round with a Redding die and found that I could just size it with 0.0005" HS at the shoulder datum. The shoulder diameter was reduced back to the same as the new brass which increased the brass length to 1.400" for a total of 0.010" which is quite a lot and required trimming. Subsequent firing and FL sizing with the redding FL die stretched the case by another 0.003". I found that I could actually "bump" the shoulder by 0.0005" and reduce the shoulder and 0.200' datum diameter by 0.0005" with the redding Neck Sizer die. It may be possible to do a minimum FL sizing, without moving the shoulder, with a 17 FB die which would be great. Perhaps someone could measure a FL sized 17 FB brass to help determine if that is possible. I have loaded some test rounds with IMR 8208 XBR and RS X-Terminator using the Hornady 25 V-Max. Just waiting for the wind to die down and some warmer weather so I can run them over the Chrony. |
#16
|
|||
|
|||
Trying to understand this...
From what I can garner, a .17 Mach IV will fit in a FB chamber, but not vice-versa. Not a good idea to fire the Mach IV in a FB chamber unless it's checked by a gunsmith and it is within spec for the Mach IV cartridge. Can a Mach IV be rechambered for FB without having to set back the barrel? |
#17
|
|||
|
|||
Quote:
|
#18
|
|||
|
|||
True.
As for the Old, Old question from the OP, go with the 17FB, much easier to find dies, etc. and they shoot side by side, really overall. |
#19
|
|||
|
|||
For me it would definitely be the Mach1V.
The 17 Fireball is a factory chamber and freebore in most cases so its a crap shoot. If your thinking factory ammo with the Fireball you might find a box or two but if you need a few hundred for a trip good luck. Plus I'm old enough that's all we had in the old days. |
#20
|
|||
|
|||
Different variations of the Mach IV
I wonder how different the Kimber 84's factory Mach IV chambers are than the Coopers, given that Cooper Rifles was started by ex-Kimber employees.
It seems that the critical dimensions for interchangeability between the .17 FB and the .17 Mach IV are:
If the chamber allows these to fall within tolerances then the FB factory ammo is safe to fire in the Mach IV chamber, right? And this can be ascertained by cerro-casting the chamber and comparing the cast against a particular lot of factory ammo, right? Or, alternatively, could one use a .17 FB go/no-go gauge set to determine this for a particular Mach IV rifle? Last edited by obijohn; 01-07-2023 at 04:15 PM. |
Thread Tools | |
Display Modes | |
|
|