I once owned a Chapuis C10 over under double rifle in .375 H&H. It did NOT have a Kersten Lock cross bolt and the action would open when I fired the top barrel. That was not very comforting! It would open with factory Federal ammo and my handloads.
It was a very nice rifle that I sent to JJ Perodeau (
https://jjperodeau.com ) for a tune up and he assisted me in passing it on to the next caretaker. I kind of wish I still owned that Chapuis but I learned my lesson.
I wanted to refresh my memory on Kersten Locks, Greener Crossbolts, and Rising Bites and I thought I'd share what I found with everyone on AH...
Example (not mine) of
Double Kersten Locks - Two such locks; one on either side of the barrel set. A system of lockup usually found on German over & under shotguns such as Merkel and Simson.
From:
https://hallowellco.com/double_kersten_locks.htm View attachment 608636
This link is for a very good article from Rifle Magazine:
https://www.riflemagazine.com/double-gun-bolting-systems
Note: This is from the same company that provides for an annual subscription LoadData dot com.
A LoadData subscription is worth every penny!!!
Double Gun Bolting Systems
Spindles, Bites and Underlugs
Feature By: Terry Wieland
Here is an excerpt from it in case one doesn't have a strong Internet connection:
"As Donald Dallas described it in
The British Sporting Gun and Rifle (2008), the Purdey bolt and underlugs are “simple, convenient, hard wearing, and very strong.” Ironically, its strength was not fully appreciated at first and many gunmakers, including Purdey, looked for a “third bite” to supplement it. This was partly due to the influence of J.H. Walsh (“Stonehenge”), editor of
The Field, who was a great believer in maximum strength – understandable, since one hand had been severely damaged in a gun accident early in life, ending his career as a physician.
Many different approaches to a “third bite” were tried but the most common was an extension of the barrel rib that locked into the standing breech. Some were simple “doll’s head” extensions – knobs that fit into a corresponding opening in the standing breech. Others were flat blades that fit into a slot. In theory, a doll’s head helped alleviate the tendency of the barrels to push forward, while a simple blade only prevented lateral movement.
In Birmingham, W.W. Greener used a blade but added a sliding bolt that passed through it from side to side. This was operated by the top lever. The “
Greener crossbolt” became a fixture, mainly on lower priced guns in England (aside from Greener’s own) and on the continent, particularly Germany. For reasons no one has ever explained, several Greener inventions became standard in the German trade, including his sliding safety on the left side of the frame."
View attachment 608643
Purdey’s own “third bite” was a smaller rib extension that fit into the standing breech but was not visible when the action was closed. Being small and unobtrusive, it did not get in the way of fast loading."
Rising Bite from Rifle Magazine article
View attachment 608642
"Undoubtedly the best and strongest (and most difficult to make) of all rib-extension fasteners is the famous Rigby
rising bite. John Rigby & Co., now back in London, is reintroducing the rising bite after an absence of more than half a century."
From the above article written by one more versed in this subject than I, a well made double doesn't need a third bite. JJ Perodeau recommends Chapuis double rifles and they do NOT have a Greener Crossbolt. George Chaplin (
https://www.champlinarms.com ) states that his company provides a lifetime guarantee on any Chapuis purchased from them.
Even with the above wisdom from JJ, George, and Terry Wieland, for any rimless, "high pressure" cartridges like the 375 H&H and 458 Winchester chambered in a double, I want a Greener cross bolt or Kersten lock!
-- PS: I do own a Blaser S2 in 375 H&H that doesn't have a Greener Crossbolt. It does however have strong lockup:
From a post by
@Opposite Pole https://www.africahunting.com/threads/blaser-s2.44067/
"I don't own S2 but do own a couple of K95s which also use the Jaeger locking system, only difference being it is for single barrel. The pin is used to release the locking block. After removing the barrel you press in the pin which allows the key to open further which releases and allows for the removal of the locking block.
Interesting system this Jaeger block. You can take the barrel (or barrels in S2) out of the receiver and slide the lock into the barrels to provide a solid, bolt action strength lock up. You could literally fire a round of by banging the firing pin with a hammer and the lock up is strong enough for it, no receiver needed. It is quite popular in break action rifles in Europe and is used by Blaser, Merkel, Haenel and probably a number of other makers. Bolt action strength in a break action rifle."
