Best third fastener on double rifle/shotgun

[steve white]

In addition to the usual double under-lugs which keep a break action tight, there is often a third bite/fastener on guns. I have read that most Greener cross bolts do not actually make contact. I do not in fact see wear marking indicating that mine do. Have also heard that dolls heads are of dubious actual function. Most side clips are demonstrably decorative as they do not make actual fitted contact with the barrel breech.
What in fact are the type fasteners which do help keep guns tight and on face and WHY/HOW do they actually accomplish the task? The only closure I have owned that indisputably passed the test was on a double made in MontMerault, France. The flat Greener type bolt visually rubbed over the top of a "nose" extension of the barrel breech--sort of like a closed Greener, with movement pressing down from the top. I have wondered if it was what is called a "Purdey nose." Don't know, but it worked well! Yes, tight under lugs can keep an action tight by themselves, but why not an actually effective third bite?
What are you favorites based upon engineering and function? Perhaps some accomplish a different goal than others? Be sure to explain WHY, please.
I know that some early American designs like perhaps the Elsie's have a curved ever tightening feature, but I am most wanting to hear about third fasteners in addition to double underbites.

 

[WAB]

On shotguns, I think it’s questionable whether any of the third fastener designs contribute to the strength of the platform other than in a catastrophic failure scenario.

 

[Bigfoot Hunter]

Webley Screw grip because it’s beautiful and most/all third bites are essentially just “insurance”

 

[steve white]

Webley Screw grip because it’s beautiful and most/all third bites are essentially just “insurance”

How does it work? Pictures?

 

[Bigfoot Hunter]

How does it work? Pictures?

The top lever essentially just rotates over the barrel extension. The top lever is usually larger and looks more attractive in my opinion.

 

[JvW]

One more vote for the screw-grip. According to the patent specifications:

“An ordinary Purdey bolt is made to act on the lump as usual and is worked by a top lever spindle with a cam at the bottom of an ordinary form. But outside and round this spindle is another of a larger size, on which is cut a fine square-threaded small screw, which works in a female screw cut in the head of the break-off, close behind the top extension, and impinging on the doll’s head”.

Easy language, I know...

A good friend of mine is very well connected to the English trade. He had lunch with the head gunmaker/shop foreman of one of the very well known remaining makers. Said gentlemen, in spite of the fact that the firm he works for makes some of the nicest boxlocks and sidelocks out there, made no bones about the fact that he preferred the screw-grip over all the rest. "they don't shoot loose", was his words. From having owned two of them and having used them extensively, I agree wholeheartedly. The have long action bars and the third bite is cammed into place. It's a great, though difficult to manufacture, setup.

 

[yamoon]

I don’t know much about double rifles, but I read somewhere about a Kerstin rotating bolt locking system. Was it used on double rifles?
Mike

 

[steve white]

One more vote for the screw-grip. According to the patent specifications:

“An ordinary Purdey bolt is made to act on the lump as usual and is worked by a top lever spindle with a cam at the bottom of an ordinary form. But outside and round this spindle is another of a larger size, on which is cut a fine square-threaded small screw, which works in a female screw cut in the head of the break-off, close behind the top extension, and impinging on the doll’s head”.

Easy language, I know...

A good friend of mine is very well connected to the English trade. He had lunch with the head gunmaker/shop foreman of one of the very well known remaining makers. Said gentlemen, in spite of the fact that the firm he works for makes some of the nicest boxlocks and sidelocks out there, made no bones about the fact that he preferred the screw-grip over all the rest. "they don't shoot loose", was his words. From having owned two of them and having used them extensively, I agree wholeheartedly. The have long action bars and the third bite is cammed into place. It's a great, though difficult to manufacture, setup.

Long action bars in themselves are a plus.

 

[Kevin Peacocke]

Correct, the longer the action bar the greater the leverage of any third bite machanism as it is further away from the pivot.

The Webley screw with a long bar sounds to be ideal, but I also like the Greener cross bolt because it is so absolute a lockup. Why? Because it is at 90 degrees to the opening force in all directions, it just can't fail. As to the cross bolt not making contact it all depends upon the accuracy of the machining. Certainly to get the two underlugs as well as the cross bolt to all interact perfectly at once is a big task, but it can be done with extreme precision machining. I have examined my Heym minutely and I believe it does exactly that. If I close it slowly thou by thou you get to that very last micro movement where the bolt moves across but doesn't go all the way across, and then finally a fraction more and everything clicks into place and the bolt goes fully home.

 

[Dewald]

Webley screw-grip for sure, followed closely by the Webly PHV1

 

[rookhawk]

Agree with everybody's posts above. The generic "Greener Crossbolt" of which most are not truly Greeners is half the equation. For a double rifle, the pressures are so high the bigger question is the integrity, size, and strength of the top rib of the barrels that falls into the crossbolt upon closure.

Heym's design is a very trustworthy implementation of the Greener. Webley screw grip is very good too.

The American A.H. Fox had a top lever design that was ingenious because the more it wore out, the more bearing surface it provided. The opposite of other guns where the older and more worn they get, the less safe.

OP is correct, side clips are a mark of quality, but they are vestigial. You'd like to see them on a double rifle, fowling gun, or live pigeon gun as a show of excellence, but they don't really prevent the barrels from blowing off the action anyway. Especially since all the guns we're talking about are monoblock chopper-lump designed barrels that cannot split apart at the breach anyway. But I like them nonetheless.

 

[Aaron N]

Does anyone have a Tolley Gaint Grip?

 

[VertigoBE]

This is one of the reasons I like this forum so much. The combined knowledge of the group members on sometimes very arcane or detailed topics is a joy to share in and learn from!

 

[Hunter-Habib]

W. W. Greener cross-bolt. But only the ones actually made by W. W. Greener (prior to Webley & Scott buying the company on 12/11/1965).

 

[Nevada Mike]

IMO, third fasteners are largely useless. They do sell guns, but have minimal effect on breech movement when a gun is fired. Purdue double under lugs do a great job of holding an action during firing and, if you look at high quality London guns you will seldom see a third fastener employed, most all are the standard Purdey double under lug design.
Additionally, a third fastener will wear in use and is nearly impossible to rejoin so that both the hook/hinge pin AND the third fastener are properly fit.
Of my SxS guns only one has a third fastener (a Lindner Daly) the rest (Harkom, Atkin, etc.) do not. The third fastener may have a role on double rifles, most commonly built on Scott Screw Grip actions. I do not like them except for the Purdey hidden fastener, which is unobtrusive and does not interfere with loadiing.
YMMV

 

[C.W. Richter]

i've seen a lot of camo duct tape around 'em in country. lol