Ray Atkinson recently posted the following:

"Also all the nitrogen goes out of any scope after about a year, even in todays best high dollar scopes or so the big boys have told me..the secret is in the seal. Just passing that on for what its worth, I suppose they should know.

But, if one takes one of these scopes apart then do it in a clean enviorment and keep the scope standing on its front lens at all time and don't let it tip..Nitrogen is heavier than air and will not come up and out or the scope unless you tip it..carefully slide on the ring, then the rubber collar, then ocular lens and presto you still have the nitrogen in it, at least for awhile and if it had any in it to start with, which isn't likely in the first place on an old Lyman...Anyway thats the process used back yonder by the best of gunsmiths."

I claim NO EXPERTISE in the area of optics, but I would be surprised/disappointed if the nitrogen leaked out of my Leupolds. Likewise, I wouldn't be the least bit surprised that the nitrogen, if there ever was any nitrogen, in my old steel-tube Weavers and Lyman Alaskans has leaked out over the years.

Jeff