A possibly silly question, but just want to verify. I have a 375 JRS, basically a slightly blown out 375 hh. To my knowledge brass has the same overall length, and of course, it headspaces on the belt. Would it be safe to fire 375 hh ammo? Just as you would with a 375 wby? Thanks!

I would say the answer is "yes"

Think the shoulder is moved slightly forward on the JRS, but I'm not quite sure..

http://www.municion.org/375/375Jrs.htm

M

Some say yes and others say its not..I did on the one I had with excellent results, just a good way to fireform cases..I'm told you need to seat bullets out to touch the lands, but I didn't do that. I just shot my 375 H&Hs thru it and factory ammo to get brass.

Ooops, I had an Ackley IMP. but its pretty close but I wouldn't swear to it.

emron,
Congratulations, again you have scored a cool rifle.
Not a silly question.
I had never thought of it, so had to take a look at the cartridge drawings, and plot the shoulders on graph paper at 100X scale to see it:
The .375 JRS reamer does not completely clean up the .375 H&H chamber.
Easy to check on graph paper with a pencil and a ruler:
The graph paper ruling is 10x10, each tiny square is .001" on a side, and the larger squares are .010" on a side @ 100-scale, 1" on paper = 1/100th inch on cartridge case.
Draw the dots.
Connect the dots with a pencil.
Voila:


There could be some interference in chambering the .375 H&H in your .375 JRS, assuming max spec brass and minimum spec chamber.
However, that is rarely the case.
Brass is purposely made smaller than max spec, and chambers at minimum would be rare perfection.

If you can chamber the .375 H&H cartridge in the .375 JRS, due to the usual tolerances, it would be perfectly safe to fire it,
but you need to try it before depending on it in a pinch.
If it works well with various makes of ammo or brass, then no problem.

Ray seems to have found this to work just fine.
I have never had a .375 JRS.
I am stuck on the .375 Wby.


Jon R. Sundra created this wildcat (that was submitted to SAAMI by A-Square for certification) about 1988.
It is supposedly the 8mm Remington Magnum necked up to .375, or the .416 Remington Magnum necked down.

If there is interference near neck-1, making .375 H&H brass hard to chamber,
just running it into the .375 JRS FL sizing die will take care of that before fire-forming.
Hopefully no dreaded doughnut from that, with such a tiny change,
ditto for necking up 8mm Remington Magnum.
Necking down .416 Remington Magnum might thicken the necks a little.
Hopefully no neck inside-reaming or outside-turning required.
Got any .375 JRS headstamped brass?

As always, RIP, you are a cornucopia of information. I discovered that the JRS is just 1mm longer than the 375 HH. But 375 rounds chambered,thanks to chamber slop, and fired with somewhat anemic velocities. 300 gr accubond at 2400 fps with max 375 loads.
Still, a cool rifle.
Once I get my pictorial posting skills in gear, will post pics. Groups with JRS ammo are great, 2" with federal express factory ammo.

emron,

Ah so. No problemo. The chamber minimums are always bigger than brass maximums, and
actual brass is always smaller than brass maximums, and the .375 H&H works well in .375 JRS.

Hope you get some pics up.
Just join at www.photobucket.com and upload pics from your puter there.
That gets you a URL address for the photo.
Then all you have to do is insert that address between [img] ... and ... [/img] with no spaces and the picture automatically shows up here.
Or use the little tool bar at the top of your reply here,
or use the features at photobucket for copying and pasting shortcuts.
You'll learn, like riding a bicycle.

Photo-posting help topics here:

http://forums.accuratereloadin...0106691/m/1521036511

and

http://forums.accuratereloadin...0106691/m/5571053971