Third Bite/Greener Crossbolt On Double Rifles. (Or Lack Thereof)


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Jan 23, 2014
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Madison Georgia, USA
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Was wondering what the concensus is on the need of a third fastener on a double rifle. I've noticed that they are used on many doubles, notably in Heym and Merkel, but not used on others, such as Chapuis and Krieghoff. What makes some manufacturers use it, and some not? Do guns such as Krieghoff and Chapuis have a different barrel lock up on the bottom that negates the need of it? Or is this just a means of cutting corners?
I'm considering a new double in the future, and was just wondering what those in the know have to say on this.
Toby, I find it ironic that both a high-end and an entry level manufacturer include and exclude the "third" fastener as you called it. I too am looking forward to being enlightened.
Greener cross bolts are common on a lot of continental firearms are so equipped.

I have three drillings as well as a Merkel 470 with them. All have been flawless.

I just don't see any down side to the Greener system.

It is taylor made for high pressures of rifles and drillings.
A double breaking double rifle, or shotgun for that matter opens about a single pivot. The line of action of the force upon firing is above that pivot point, so there will be a moment trying to open the action. The further the underlugs trying to hold the barrels down are from the pivot point the easier their job will be to hold the action closed. However, there is a physical limit of how far away the back lug can be, especially so with a shorter water table, action, so to really add insurance a third bite mechanism as far back as possible makes the action lockup immensely strong.
I the case of the Greener cross bolt, the locking force is at 90 degrees to the plane of the turning moment around the pivot, so it is probably the best solution that physics can throw at the problem, genius in fact.
Does it matter? You bet it does! I experienced the problem first hand and apart from the frustration of an opening breach spoiling shooting or a hunt, it is downright dangerous.
In my humble, but professional engineer opinion, the Heym 89b system with a) a long water table, b) a very solid A&D underlug system positioned as far back as that long water table allows, AND c) the very substantial oval section Greener cross bolt, this is the strongest double rifle action there is.
Peace of mind that comes in a beautifully built, accurate and highly reliable package is a pretty high bar to beat. Seriously I rate the Heym above any other double, including the expensive top end because it has the very best features. And you can dress it up if you wish!
The reason for the added fastner like the greener bolt, Rigby's rising bite and dolls head, the 3rd hook on the bottom of he VC action is to hold the action and barrels in alignment for a longer period of time. When you shoot a double there is a lot of pressure causing twisting of the barrels that occurs. Over time the barrels and action get out of adjustment. Theoretically it extends the amount of time, number of shots you can shoot before you will have to have your double serviced. For rifles that don't have this extra fastener you might have to have your rifle serviced after 1500 shots or so. But most people don't shoot their double that much.
I have never owned a Heym,but one of my good friends and neighbors has one. Like my Merkel,it is a 470.

It is without question a fine rifle,but I would most likely not trade with him. My double has more visible sights and so far is better regulated. Also my ejectors are more energetic.

At present,I would rather take mine into a fight.
I have noticed more people find fault with the Merkel double on the internet than in the world of Professional hunters.

I have hunted in RSA with Arno Van Niekerk who used a 470 Merkel and has actually killed more than 30 buffalo with it.

Also Lin Stanton uses a 470 Merkel for elephant and buffalo in Zimbabwe. Lin handled my Merkel when he was at my camp in Alabama and told me that the gun was a perfect dangerous game rifle in his opinion.

PH Dave Freeburn saw my gun and told me the same thing.
Rising bites and greener cross bolts are super cool. A lot of these third bites were introduced when metallurgy was a little less predictable than today. Anyone other than Kevin have first hand experience with a failure? Kevin- can you share more about that?
Rising bites and greener cross bolts are super cool. A lot of these third bites were introduced when metallurgy was a little less predictable than today. Anyone other than Kevin have first hand experience with a failure? Kevin- can you share more about that?
Everyone is probably bored with the story 318, so I will DM you. Suffice it to say I have come across four cases similar to mine so far.
I understand the importance of third fasteners . Got all sorts of variations on double rifles - hidden 3rd fasteners of H&H and Purdey DRs , a Greener cross bolt on a WR sidelock and a rising bite on a 500NE . Al interesting and doing the same thing . But the traditional Greener cross bolt is the ugliest thing on a gun . I do not understand why a “blind” Greener cross bolt isn’t used more often . Probably manufacturing cost - but they are attractive . Here is an example on a William Powell shotgun I bought last week .

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Everyone is probably bored with the story 318, so I will DM you. Suffice it to say I have come across four cases similar to mine so far.
Haven’t heard it - post it up.

Honestly no posts really sell me on doubles - expensive, less versatile single purpose things it seems.
While I would dearly like to have back a Kersten double greener locked double in 9.3x74 in SXS (sold it to finance first safari) and while I have several drillings and BBF with the Greener system...I have never seen wear marks on any underside of a cross bolt indicating actual contact. It is certainly there in case of something catastrophic, but by the time it made contact to hold things together, it would seem things would already be pretty loose? The only secondary closure wherein I have seen contact was on a French sxs that utilized a flat bar moving like a greener, but OVER the top of a nose on the extension. That thing was really tight and it was obvious that contact was made. Greener locks usually mean Greener safeties--not the easiest to manipulate in an emergency! I like the lock up, but wish they could just have a tang safety--and the cross bolt be actually fitted to contact. JMHO

BTW, I have a doll's head that a gunsmith suggested had stretched in the little necked section so it could be tighter--but how to fix that? Non-issue since I have had it put back on face, tightly.

Call me crazy, but I LOVE break action guns! And some of mine are really accurate, too. I also don't understand why combo guns aren't more popular, given how taken many are with a single shot rifle.
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I have put back of face several shotguns , double under lug, dolls head etc.. but never seen one with a greener cross bolt that needed it. Not saying they arnt out their, just like their are plenty without one that doesn't need it. As was stated above, newer steel is better, but it's my opinion that a greener cross bolt will keep the breach closed a lot better then not, from marginal pressure , like under a hot sun. If you have ever had a pierced primer or a hot cartridge open your breach, you will be glad that you have it. Just my two cents.
A third grip is also my preference on DR due to the higher pressures.

Purdey, H&H have the hidden grip (mainly prevents the rotary opening motion). Rigby, WR and Heym an extension of the rib (also reinforcement in the longitudinal direction, not going off-face. But at the same time some "hindrance" when loading new rounds due to the extension). This is to illustrate some of the known names.

More complex ones are technically interesting, but are not necessarily an advantage

The best depends mostly on implementation. No support or bearing is no use. Not only at the level of the third grip itself, but initially already at the hinge. Some types are also a company feature, which is retained.

Indeed, the article describes mostly shotguns, but the principles remain the same.
Rising bites and greener cross bolts are super cool. A lot of these third bites were introduced when metallurgy was a little less predictable than today. Anyone other than Kevin have first hand experience with a failure? Kevin- can you share more about that?
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 ( ) 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.

This link is for a very good article from Rifle Magazine:
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."


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​

"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 ( ) 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

"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."


  • Greener Crossbolt.pdf
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