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Which is more durable??
      #10922 - 05/03/04 10:42 AM

Which is more durable and/or stronger, the Jones underlever design or the Purdey double underbite design?

Here is a picture of the Jones underlever bite:



Here is a picture of the Purdey double underbite:



Thanks for your thoughts and/or comments.

Scott


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NONE
.300 member


Reged: 15/12/03
Posts: 110
Re: Which is more durable?? [Re: ScottS]
      #11037 - 06/03/04 03:00 PM

ScottS,

Though I am by all means a amateur in this regard if I may lend a opinion based on my limited knowledge.

I have no idea as to the actual breaking point of either design, I am of the opinion that both are of adequate strength and neither executed in a proper build will cause a problem. The under lever is known for its strength and IMO would be the best or the stronger of the two but the question could be not which is stronger but is either weak and I would say no on this point.

Its quite like is this better then that when both are overkill in the fist place.

Just my opinion,

James F. Nixon III


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RobertD
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Reged: 16/11/03
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Re: Which is more durable?? [Re: ScottS]
      #11312 - 10/03/04 01:19 PM

I believe the question can't be answered for these reasons:

1. We don't know what steel either of these are made from.

2. We don't know the manufacturing process. Example: is it cold forged, machined, welded on, pinned, etc.

3. We don't know the temper and the method of temper.

4. The Purdey has the advantage of more leverage keeping it closed, but it also appears that the hinge pin is the smaller than the Jones. The hinge pin is the weakest link in a double.

5. Neither of these have an upper cross bolt, which I personally prefer to see.

RobertD

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DUGABOY1
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Re: Which is more durable?? [Re: ScottS]
      #11418 - 12/03/04 02:53 AM

As someone above said, it depends on many things, like the steel used, and the hardening process! However, it depends more on the method of attachment of the lump on the barrels, than any of the other things mentioned.

The hinge pin is not necessarily smaller on a Jones lever, but in many cases the camming lump is of the shoe lump veriety (soldered on the barrels), and this isn't exactly the strongest system. If the Jones is fitted to a chopper lump barrel set,or a true Mono-Block, and is fitted properly, it is stronger than the Purdey sliding barr!

Addtionally, the jones has far more camming than the sliding barr, working exactly the same way a two lug bolt rifle does, by camming into a recess for to longtudinal mateing bosses. This caming is done with a very long lever, and pulls the barrels down on the watertable very tightly. The draw back to this type is, they are very slow to load, and require more use of both hands to accomplish!

The advantages are: #1 the action is closed tighter. #2 the "rotating open" is nonexistant with the Jones lever, and the forward thrust is stopped by the hinge pin, if the conventional hinge pin where the lump is in dirrect contact with the hinge pin!

I have a Jones lever cape gun, where the fore end iron, is one piece, and stays with the action when the barrels are removed. The lump on the bottom of the barrels, hooks into the rotateing fore end block. The hinge pin is perminently pressed through the barr of the action, and the fore end iron. This is a very strong system!

The Purdey barr has, by design, to be fitted loose enough so the barr will slide into the bites,on closing, by spring pressure alone. The camming pressure is handeled by a very much smaller, and shorter lever,and is only used to open the action, so doesn't have the leverage of the Jones lever. Additionally, the Jones pulls the barrel set down tightly against the Barr of the action, where the Purdey only holds it when the barrels try to rise, but doesn't pull the barrels down at all! The Purdey is more expensive, because it is more labor intensive, to fit properly,and is more convenient, not because it is stronger!

The third fasteners, for the most part, are simply a safety "BACK-UP". In some cases they also cam the barrels down. This is accomplished by a cam on the end of the top lever, which camms into an angeled bite in the end if the
rib extention, usually a "Doll's Head" type! The doll's head also serves to resist forward thrust of the barrel set to go off face on fireing. If the doll's head has the camm, or "SCREW BITE" as well, it also pulls the doll's head down slightly.

The Greener cross bolt has no camming effect at all, but is simply fitted very closely, to avoid movement in any dirrection. A "SAFETY" more than anything else!


I would say, if all are either real MONO-BLOCK,or CHOPPER LUMP, both made of the same steel,surfaces hardened the same, the Jones lever is not stronger, but closes tighter then the Purdey barr system. If you add a doll's head, then either will be stronger yet. One thing about the Jones Lever is, they are usually only on sidelock hammer rifles,and usually back action, this lets the action barr be left with much more steel intact, because no long slott needs to be cut longetudinally for the slideing barr, or cocking levers. The only cut being one shallow slott for the cam lump, and one hole through the bottom of the barr for the lever cam to go through. This leaves a lot of steel in a one piece action barr!

Many people mistake the snapp action for a Jones lever, and they are not the same at all. The snapp action is simply a Purdey slide, that is opperated by a bottom lever, rather than the top lever. The one thing that can be done with a snapp action is, it can be made where the lever can force the slide into the bites. This give the snapp lever a camming effect, in addition to the spring pressure of the top lever,

As someone said, all the types are addequate for what they were made to do!

--------------------
..........Mac >>>===(x)===>
DUGABOY1, and MacD37 founding member of DRSS www.doublerifleshooterssociety.com
"If I die today, I have had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"


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470Rigby
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Reged: 23/02/04
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Re: Which is more durable?? [Re: ScottS]
      #12109 - 21/03/04 05:04 PM

ScottS - the Jones underlever - all other things being equal is the the stronger. Firstly - the action bar is is nearly completely solid and hasn't been "milled" out for the sliding bolt of the Purdey bolting system. The clamping force generated by the Jones system basically locks the barrel flats to the action bar - guaranteeing virtually zero movement during recoil. You may deduce what the inventors of the Purdey system thought of underbolts by the fact that they used a modified semi-snap action rotary system on their early nitro doubles. Also, the English used the Jones system for most of the heavy nitro doubles (577/600) that they made. That underbolted hammerless designs were later adopted for those heavy rifles is probably more a reflection of the better steels available just before, and after WW1.

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fsrmg1
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Reged: 25/07/03
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Re: Which is more durable?? [Re: 470Rigby]
      #25132 - 25/01/05 02:30 PM

I agree with 470Rigby on this.

The fact that almost all the early Nitro 577s and 600s where built upon the Jones action, when many other action types were availible indicates to me that gun builders during that period felt that the Jones was the safest for the biggest of the Nitro calibers.

--------------------
Cheers,

Rich


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4seventy
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Re: Which is more durable?? [Re: 470Rigby]
      #25147 - 25/01/05 05:46 PM

If the action bar is stronger in one design then that will most likely be the strongest system regardless of whether the barrels are held shut by Jones or Purdey.

Much has been said here about the Jones being able to clamp the barrels tight to the watertable but this is really not the right idea IMO.
It is far more important to try and keep the barrel face tight against the action face and on many sxs doubles, rather than having the barrels hard down on the bar, there is actually a gap or clearence between them.

It has also been said that the Purdey bolt is only capable of holding the barrels down where the Jones can cam or force the barrels downward.
IMO this is not totally correct either, as it is not a difficult matter to set the Purdey bolt to apply downward force and guns set this way will usually have the top lever sitting to the right of center when the gun is fully closed.
The important issue is to utilise the camming pressure of the bolting system to force and/or hold the barrel face against the action face when the gun is fired rather than to hold the barrels tight down onto the action bar.

Regarding how much metal remains or has been removed from the bar of the two systems, IMO a top lever hammer gun with Purdey underbolting, will have almost the same amount of action bar strength as a Jones under lever hammer gun because in reality they both require similar amounts of metal to be removed.



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