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

[TOBY458]

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.

 

[Andrew Short]

Following this

 

[Shootist43]

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.

 

[Ruraldoc]

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.

 

[Kevin Peacocke]

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!

 

[Houston Bill]

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.

 

[Ruraldoc]

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.

 

[Ruraldoc]

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.

 

[318AE]

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?

 

[TOBY458]

@rookhawk what say ye?

 

[Kevin Peacocke]

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.