View Full Version : 375jdj

Ursus horribilis
August 31, 2005, 06:56 AM
I´m thinking about transforming my mod 94 Big Bore .375 win to .375JDJ. Now i wonder if any of you could give me advice if this is doable and if so, wher i could find a reamer for this project.
Best Regards

Harry Bonar
September 15, 2005, 07:50 PM
Dear Shooter:
Yes, I suppose it would be O.K. but I'd as leave use the 375 Win!
Why, I don't know; other than rebarreling bolt actions, etc, I don't like conversions or "improved" cartridges", although they can be done. I'm just an old dinosaur, speaking of which -- we are so over-gunned in this country it's pathetric; I'm convinced you could kill any game on earth for the last 300 million years with your 375 Win.
After all it's n overgrown 38-55 and until the magnum craze hit is it was considered great for anything - that is, when men were cool shots.
Harry B.

Ursus horribilis
September 16, 2005, 04:44 AM
Dear Harry,
Yes, you are quite right both from a philosophical and physics point of view. However, Swedish law regarding firearms and hunting is mainly written by people so ignorant on these topics that i don´t even know were to start. Among other absurdities, a cartridge used for big game hunting must produce 2000J of energi at 100m to be legal and thereby disqalifying a lot of large bore/low-medium velocity cartriges. I can get my .375 win upp there but it´s borderline and i don´t like lodading on the edge of high gas pressure. As i inherited this rifle from my late father i want to keep it(otherwise it would be easiest to trade it for a new 94 trapper 45-70) but i also want to be able to use i for big game hunting (Moose). That´s the background to my apparently silly project.
Best regards

Harry Bonar
September 16, 2005, 06:06 PM
Dear Shooter:
I understand now; I'd proceed and find out if it's possible. I hope your conversion is O.K.
Yes, it's shameful that government is so stupid!
Harry b.

September 16, 2005, 08:18 PM
Dear Bear,

I can see why you are interested in the .375JDJ. You would be able to load to your required energy level with considerably less pressure than the .375 Winchester requires to get that result. I looked at the dimensions of the two cartridges, and while the rim of the JDJ case (12,95mm) is only slightly wider than the old Winchester case (12,85mm), it is nearly 15 mm longer. I think this may cause real problems with the magazine and receiver feed mechanism. You can use a wood dowel that just slips inside a .375 Winchester case, but cut it to stick out to 80 mm. Whittle a narrow spot in the dowel just ahead of the case so it is easy to break off if it gets stuck in the gun. Now you can load this dummy round into the magazine and see if it still can be chambered without hanging up?

The only possible solution I could see in the same case length is to make a wildcat by necking a .430JDJ to .375. The .460JDJ case rim (13,06mm) is also a little wider than the other two cartridges, but there is still a chance it may fit your gun. You would have to try a case or else take a bolt face diameter measurement to predict it.

Before you consider either conversion, you want to acquire actual cases or turn them from wood to see if the magazine and feed mechanism will accomodate them?


Ursus horribilis
September 19, 2005, 09:47 AM
Thanks to both Harry and Nick for taking their time to ponder upon these problems. Yes i will most certainly test a mock cartridge to see if it feeds ok. the main reason for starting at this point,was to find out the level of difficulty involvet and a approximation of the cost by locating tools as well as some opinions regarding the project. I might end up optimizing loads to cope with the energi problem but i wanted to investigate alternative solutions. In summary i appriciate any additional input in these matters
Best Regards,