Since
@Hunter-Habib invited me to this thread, at least he must want to read my thoughts on rimless cartridges in a double rifle…
The classic double rifle is a short-range powerful weapon providing the capability for a very fast second shot at dangerous game. I read long ago how the ivory hunters disliked ejectors because the “ping” of the ejectors firing would let startled elephants know exactly where they were. Those hunters preferred double rifles with extractors allowing the rifles to be tipped upside down and the empty rimmed cartridges would gently fall to the ground. A rimless cartridge will however be held in the extractor even if upside down. If I ever become a market hunter for ivory, I will be sure to use a large caliber double rifle with ejectors. More on this later.
The point about high pressure rimmed cartridges not being suitable for a double rifle is always mentioned. That’s fair enough. If rimmed cartridges generate around 40,000 psi when fired, and rimless generate around 60,000 psi, the higher-pressure cartridges will certainly cause a break action rifle to loosen up faster than the SAME rifle chambered for lower pressure rimmed cartridges. A loose break action shotgun or rifle is considered “off face”. If I were looking for a double rifle built prior to WWII, I would not buy one chambered for rimless cartridges. The quality of the steel used back then is not as strong as that in use today! Modern double rifles, let’s say made after 1960, use stronger materials than those made 100 or more years ago.
Extraction of cartridges is a major concern among many when discussing high pressure rimless cartridges in a double rifle. Days in sub-Saharan Africa in October can made the metal of a rifle so hot it can be very uncomfortable to touch. Cartridges in those conditions will also be really hot! If using Cordite, IMR 3031, or other temperature unstable gun powders, those cartridges will generate higher pressure than when tested in more enjoyable climates. That’s why any competent reloader of today selects temperature stable powders. Additionally, one should not try for the last 50 fps with maximum loads. Leave a little wiggle room for even temperature stable powers.
If pressure in firing cartridges exceeds a certain level, the brass cartridge case will exceed the point when its elastic qualities allow it to expand to seal the chamber from the expanding gas to seep out toward the shooter. That’s Young’s Modulus (
https://en.wikipedia.org/wiki/Young's_modulus) which states “Everything is a spring.” When the pressure limit is reached, the case will reach the point of plastic deformation and NOT contract. Then the action of a of a rifle be it a double or bolt action will not open easily. That’s certainly not a good situation if one owes money to the buffalo they just tried unsuccessfully to kill!
Extraction on cartridge case from the chambers of a rimless double rifle is accomplished using spring-loaded pawls. Pawls are the little detents or fingers that allow a rimless cartridge to slip past and spring out to catch the rim to extract from the rifle. My trusty aforementioned Heym 88B has two pawls in each extractor. One has to love German over-engineering!
A few years ago, I had a Chapais C-10 over-under double chambered in 375 H&H. I couldn’t get any loads to regulate in her. Eventually I exceeded what the gun liked and had a cartridge case stuck in a chamber. I gave the rifle a bump with my knee to open her up and she did. The pawl ripped through a section of the rim on the case! The concept of pawls work! Would an extractor have ripped off a larger section of the cartridge rim? Maybe, or maybe the rifle would not have opened. Needless to say, I reduced the loads for that rifle.
I have faith in well-made double rifles chambered in rimless cartridges. But then, at my age I will never hunt dangerous game as many times as
@Hunter-Habib or many of our members. I have however spent my life operating, repairing, designing, and managing at the enterprise level complex equipment. Add to that I have shot competitively since I was 11 years old to include a summer on the U.S. Marine Corps Rifle Team. I wasn't National Champion but I shot with many. Every once in a while, one of them would congratulate me for outshooting them!
I grew up on a farm when an adolescent kid could buy a box or brick (10 boxes) of .22 Long Rifle ammo at the local sporting goods or agriculture store. And that I did! What does this have to do with double rifles? I like to shoot, a lot! I shot a lot of woodchucks at long range then and now.
To this day my favorite game is the woodchuck. That's ground hog for my southern USA friends.
https://en.wikipedia.org/wiki/Groundhog
How much wood would a woodchuck chuck if a woodchuck could chuck wood?
None, if I see him first!
As
@ActionBob stated above, availability of ammunition and components for loading ammo is a good thing!
My trusty Heym .458 Win made in 1986 and owned by a well to do surgeon hunted all over sub-Saharan Africa. His son provided that his father’s double had taken several lion, elephant, rhino, and buffalo. No telling how many rounds she had down her tubes before I became her caretaker three years ago. Me, I recorded 500 rounds shot in practice with her, plus those shot hunting. So, maybe she’s had 1000 rounds or more shot through her barrels. That’s probably two or more lifetimes for most rimmed cartridge doubles. Guess what, my trusty Heym still locks up like a bank vault! So much for high pressure rimmed cartridges wearing a rifle out! As least not a quality double rifle.
In conclusion, I think that I would not trust my life to an entry-level double chambered in a high pressure rimless cartridge. I would however trust my Heym.
Wildebeest shot at dusk with my .458 Win Heym at 150 meters.
Not my Heym but a Blaser S2 in .375 H&H, a Merkel 140 AE in ,375 H&H, and a Krieghoff Classic in 500/416. Notice the Lab Radar to measure the velocity and the log book to record each and every shot!
But I have shot a blaser S2 .375 H&H and a Heym in .458WM and both were magazine rifle accurate.
I would buy either of those two examples in a heartbeat.
I can attest to that! A .375 H&H double can be as accurate as a bolt action. That is allowing that each barrel can be as accurate as MOA for at least two shots, but the POI from each barrel may be a couple inches from each other at 100 yards. Considering that double rifles are designed as short range rifles, but with the proper cartridge, they can be at least 200 yard guns.