Hello ,trying to find out some info on highwalls .How Thick are the walls on a ''thick'' sided side wall ? how thin is a ''thin '' sided high wall ?i dont have pics of bothto compare, as iam only new to them, apart from owning a Browning 1885 some years ago .what calibres can both[thick and thin] be safely rebarreled to ?are some years better than others for rebarreling ? any good websites or further reading Thankyou for any information

You should have kept the 1885 Browning ! There are lots of variables - original Winchester, various copies and for each the dimensions, type steel and heat treatment ??.

You can get a good overview and opinion from Frank de Haas' books, especially his Single Shot Rifles and Actions. The thickness of the walls is not a significant factor in the strength of the high wall action; the size of the barrel's thread tenon is the biggest limiting factor and the gas-handling provisions (or their lack) are also significant.

In my experience the large-shank (0.935") high wall is adequately strong for the belted magnum cartridges if PROPERLY fitted with a modern high-tensile-strength barrel and not overloaded. This action's strength isn't dependent upon the heat-treatment, the receiver will still hold the pressure quite safely even if it's dead soft. AAMOF I personally would prefer an action that's too soft over one that's too hard but that's JMO.

You will find an overabundance of opinions about these splendid actions, their strength, their problems and their suitability for various purposes. IMO most of it is old info from other writers, rewritten and rehashed for new readers. My own opinion is based on almost 40 years' hands-on experience with the action and is worth exactly what it cost you (VBG).
Regards, Joe

Had to add 2 caveats:

'Properly' rebarreled means done by a competent single shot specialist who will also ensure the safety and proper adjustment of the rest of the action. These folks (competent SS smiths) are not nearly as abundant as you would expect from their advertisements for themselves....

'not overloaded' means that I personally would never rebarrel a client's high wall for a belted magnum since I can't ensure good reloading practice on anyone else's part. These actions in my experience will easily withstand 50K magnum-case loads all day, but a significant overload WILL be more likely to bulge the barrel thread tenon than it would on, say, a Ruger No 1 with its larger-dia tenon.
Regards, Joe

I have been looking at an 1885 in 7mm RUM years back, finally gave it up because of the small barrel shank diameter. But Winchester recently made 1885's in the WSM cartridges which are even bigger. Anyone know if they changed any dimensions for these models? If not those walls are really thin!

I haven't examined any of the new ones but I'd be astounded if they DIDN'T have a larger shank. The small shank is one of the very few areas where the original design can be significantly improved and the Japanese probably changed it. I'm sure that someone more knowledgable than I will chime in soon.
Regards, Joe

So a smaller diameter case in a largeshank Highwall is pretty solid then?

Where will the gas go if a case fail?

That depends. On originals, the gas will go A)out of the relief hole in the top of the block, B)down through the bottom of the block's firing pin hole into the action and, in extreme instances of well over 100K psi, C)out of the rear of the block through the firing pin hole following the firing pin which has just blown back the hammer and ejected from the rifle. There's an excellent albeit all-too-short account of John Buhmiller's attempts to blow up a high wall in the old book Custom-Built Rifles, it will give you some indication of exactly what happens (not much).

The so-called Mann-Neidner conversion is thought by many to remedy the high wall's supposed gas-handling problems. IF (?!) properly done it will do that to a great degree, but it's sometimes difficult to find a smith who can do the conversion properly. I've been shooting original high walls since 1970 with high-pressure modern cartridges including many wildcats without ever having had any need or even desire for a Mann-Neidner conversion although I've (temporarily) owned a few and made a few more for others.

The newer Japanese and Italian high walls are different from the originals and from each other and I'm not extremely familiar with all their variations.
Regards, Joe