doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Can someone answerer a question?

What's the last word on the lower left part of the action after M'spring? And what's it do? Does it give the mainspring more oomph? It's on a Charles Lancaster.

The word is “cramp”. Unfortunately, I have no idea what it does. Nor have I seen a Lancaster in person with this feature. What’s the address on the barrels? 151 New Bond?
Cramping in the gunmaking term would normally mean a device the restricts movement, etc. The mainspring on Lancaster is long and flat. It requires no cramping (squeezing) to remove from the action, when the barrels are removed from the action, the mainspring is at rest.
Im not sure what this feature actually does🤷🏽‍♂️.

Cramp:

http://www.champlinarms.com/Default...amp;mid=409&StyleID=3&GunID=2028

Same gun from 2009 sales site from left side:

I'll take a somewhat wild-assed guess. A mainspring cramp ( not clamp) is a little tool used to properly compress a gun's mainspring for removal or replacement. So I'm guessing this could be a built-in feature to keep the spring in a compressed state to safely permit in field servicing or replacement of a broken striker.

Some people would probably wish to carry a mainspring cramp in a gym bag, along with their white cotton gloves and other myriad accoutrements, to gun shows. This is because we all know most gun show vendors are very receptive to anal tire kickers disassembling their wares and pouring oil into the ribs.

If my reply is not censored, it should show up by Tuesday or Wednesday. By then we should know if I am right or not.

I believe that disables the 'Spring Opening' feature. The 'Wrist Breaker'.
But it's just a guess as I have never worked on one.

Self Opening/Spring Opening are Ok but you have to cock the spring(s) that is going to assist-open the bbls for you at some point. That is generally when you close the bbl's .
Some don't care for that heavy closing feature all the time, so the ability to disable it and have a peasent style SxS while no one looks on can be of use.

In Crudgington and Baker, Volume 3, at page 246 there is reference to the Lancaster second model A (“Wristbreaker”) distinguishable by “the lack of a built in mainspring cramp”.

I cannot find any earlier references in Volumes 2 or 3 to the cramp under either Lancaster or Beesley’s patents.

I understand that the flat mainspring operated as a cocking lever. I would conjecture that the cramp screw operated an internal cam to disengage the mainspring from the lock mechanism before removing the locks.

This would avoid forcing the locks back in against spring tension with the risk of damaging the lock or inletting.

Mike,

I bought a pair of these, Lancaster SLE Self-openers from 1908 with the same M Spring Cramp. Did you ever figure out which position does what?

Thanks,

Joe In Charlotte

The clockwise arrow seems to indicate, logically, that rotating the screw clockwise applies the cramp.

Sadly, whilst gunmakers might be more logical than lawmakers they may only have a narrow lead.

The contraptions that came out of London are known for that.......

Mike Harrell;

I am sending you a PM that includes my email address. Send me an email and I will reply to that email with photos of the inside of a Version 3 Lancaster SLE self-opener like yours that show the spring cramp and you can see how they work.

Back in 2014 LeFusil (Lancaster gun enthusiast) provided an excellent discussion and overview of the earlier version of the Lancaster self opener guns, both the "body" action and the side lock action guns. https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=364009. In addition LeFusil referenced the article by the English gun author David Baker in the Vol. 9, issue 3 of 1998 Double Gun Journal--a must read for the Lancaster SLE self opener version 1 & 2 owners or enthusiasts.

David Baker later authored the 3 volumes of THE BRITISH SHOTGUN with the 3rd volume co-authored by the late Ian Crudginton. In volume 2 and 3 a limited writing about the Lancaster SLE's if recorded and enough information is there to determine that one of the major problems with the Beesley designed self opener for the Lancaster guns was that the barrels did could not open enough to provide proper amount of "gape" to allow cartridges to be ejected with automatic ejectors as the spent cartridges would contact the top of the standing breech of the gun action. H.A.A. Thorn, owner of Lancaster at the time along with his gun makers and outside gunmakers devised modifications to the pivot pointy of the gun's mainspring to allow the gun's to have more gape.

About 1908 or earlier Thorn along with others modified the Beesley self opener mechanism where a V mainspring i.e. Purdey-Beesley style (somewhat) replaced the single leaf mainspring used in all earlier body and side lock self openers. The Lancaster SLE from this design change is known as version 3 and has the spring cramp screw device added to cramp the mainspring closed in order to remove the side locks. Along with the design change of the V mainspring, Thorn and another outside gunmaker designed a ejector tripper slide that is moved forward when the tumbler is fired in order to trip the ejector kicker in the fore-arm when the barrels are opened. This ejector tripper slide is runs the full length (from rear of the action through the knuckle of the action) of the action and is 1/2 inch wide by about .100" thick where the tumbler contacts it to a reduction is size where it protrudes through the knuckle where it is a round bar of only about 1/8 inch diameter. This somewhat complicated ejector tripper slide engages an additional mechanism built in the bottom of the action (located under the action bottom plate) that locks the ejector tripper slide forward until the barrels are closed (released by front barrel lump)after the ejection of the spent cartridges.



Kind regards;
Stephen Howell