Just noticed this:

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Click on it if you need to see it larger--I do.

I noticed there is a little pin through east/west and on the "objective" side there's a little tit sticking out. Nothing moves. Maybe hasn't in a century. Tell me about it? Does it just swivel the aperture down and give you a bigger one? Seems it would become a "ghost ring." Will it reveal threads to screw in another aperture?

You are right on. It is a smaller aperture that swivels down out if the way of the larger aperture. Start soaking it in penetrating oil to loosen the dried oil binding it. Don't force it immediately. Let it soak a few days and try it. Once it moves at all then the penetrating oil will really go to work. Good luck with it.

By golly. I upended it and dunked it into my usual 50/50 ATF/acetone red sauce and set it on the bench. Came back about 30 minutes later and it moved. Applied more sauce with a q-tip and gave it a while longer. It's now moving it's full range, but a little stiffly. More sauce, more wait, then oil, I expect.

Looking through the large aperture I can see why the little option is the one that's available in stuck mode. Like looking through a canning jar ring.

That big aperture is real fast on game though.  Would seem imprecise but it's not. Have used one for years on my Marlin 39A, accounted for a lot of squirrels. Been shooting that rifle lately in NRA Lever Silhouette with the smaller arp, first time I used the small one.

Boats

As BP said it's a 1/1A.  
Depending on the patent date.  If it is Jan. 28, 1879 only it is a first generation.  If it is JAN. 28, ’79 and MAY 6, ’84 it is the second generation of the 1.  If it is July 25, 1905, it is the 1A, which was made all the way until 1955.  The A means it has a locking lever on the left side of the upright pivot.

Eric

Quote:
Kermit - good stuff isn't it to break down and release dried gummy residue just by soaking it for a spell and not having to apply any torque force? 

As tested, the acetone:ATF mix needs the least amount of torque of any tested solvent to 'break free' rusted bolts ... 53 lbs v 238 lbs using WD-40

Since I read the mechanics test on a forum back in 2009 and started spreading the word ... it has been the cat's meow for me and I'm at the bottom of a quart using it for many applications.  Examples:
* I had a decapping pin that had frozen threads with BP residue - dipped it in the mix - took a couple of breaths - twisted the threads with my fingers and it broke loose 
* Bought a Fecker scope with frozen gummy threads. Q-Tip applications and slow light continuous twisting and the threads broke loose and now turn freely
* Broke all the plain steel rusted bolts on my duck boat for replacement with stainless steel
* Latest - removed all the aged hard dried grease on the new original diopter sight from the threads and moving parts 

I gave a quart to my marine engine service guys that work on motors used only in salt water ... they swear by it

For those that haven't seen the comparative test ...
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Other good method for releasing stuck tight parts/bolts is to warm them if the base material will allow it and touch with a piece of bee's wax on the affected area (especially good for heat set bolts on air cooled motor cycle engines and those barrels you swear are welded on), warm it up so wax will melt (I use heat gun) and apply touch of bees wax to joint, wait half hour and try if it still won't come loose repeat above wait a few minutes try again, over night helps on the heats set bolts, standing the actions & barrels vertical works best.
Company I worked for in the early 60's used auto tranny fluid and chlorinated paraffin (think STP with out the auto engine additives) for a tapping compound both came in 55 gallon drums and for  penetrating oil xylene or toluene as they do not evaporate as fast as acetone and auto tranny fluid mixed 50/50 as needed!

The old wish I had, hung on to a quart or so of the auto tranny fluid used then it was from the 50's and told it was made with whale oil, didn't mean anything to me at the time!

Mike

I was wondering about MMO too. Whatever it actually is its pretty good stuff for a lot of applications.  We used it a lot on air tools, (Rivet guns used in building an airplane) usually just a drop or two in the connector before snapping the air line on.  Worked well in cold weather in unheated shop long after other lubes thickened up too much and kept the guns form working.