Removing the rear sight on a mosin... *Use Kroil!!*
So I've spent the best part of this afternoon *attempting* to remove the rear sight on my 43' Izhevsk 91/30 as per 7.62x54r.net's instructions (drift the two pins out on the side) and can not for the love of me get them out. I was wanting to take it off and put some dovetail scope rings on the "rail" for a cheap scope. Already slid the front sight out and got the rear left spring out without any trouble; however I did have to soak the trigger screw in WD-40 for half an hour to get the screw off. I looked on the rear sight and didn't see any noticeable solder, but I sat it down vertically with the muzzle down and heated it up to about ~210*F surface temp with map gas but didn't see any solder come out. Also soaked it in WD-40 for ~15 min, after that I wasn't even able to budge the pins. Also got the straight pin that held the rear slide in and tried to press one of the pins out with my vice and just bent up the pin from the rear sight slide...
So I'm currently soaking it in more WD-40 over night but am more than welcome to any suggestions?
As a side note the rear sight section of the gun is virtually cosmoline free now

Kano Kroil. WD40 is not a penetrant. Kroil will creep to the millionth of an inch.
Look for IraqVeteran8888 on Youtube.
He's got a series of videos about sporterizing a Mosin Nagant,
one of with deals with taking the rear sight off.
It's a man's job.
[youtube]http://www.youtube.com/watch?v=Z-y8lNlnLMM&feature=results_video&playnext=1&list=PL1B52C67D10E62782[/youtube]
Thanks, I'll go pick up some Kroil tomorrow and soak it in that tomorrow night and see if it helps. I watched that video and all they had to do was drift the pins out >.< Although I guess it is harder to change the temper in the barrel than I thought it was? They had that thing red hot to melt the solder...
If the kroil doesn't work do you guys have any more suggestions?
Well most likely they pins are rusted fast. Penetrating oil like Kano Kroil or PB blaster is probably going to be your best bet, just soak the pins a few times and try beating the pins out again. The penetrating oil should break down part of the rust as well as lubricate the pins making them easier to remove. If that don't work you would always heat the pins and try beating them out while they are still glowing orange but that could mess with the tempering on the barrel and damage the rear sight, also make sure to oil the gun as soon as it is reasonably cooled or you risk some serious rusting. Lastly there is always the option of just drilling out the pins, but with out a drill press and a reasonable amount of experience you risk doing some serious damage to the barrel as well as the rear sight.
I was going through the same thing as you not too long ago. But I ended up getting the damn thing off and I put an NcStar scope on the dovetail!
The penetrating oils did noting for me.
I ended up getting a larger punch which had a nail type head (not the chinese crap) it was treated steel, and I put the nagant in a vise and i noticed it would move down the vise everytime i would hit it.
So I ended up putting two steel pipes under the nagant to support it. After i did this the nagant wouldn't move when I would hit it, so all my energy would transfer into the pins. When you hit it you should be forming a crater in the center of the pins, this will be good because it will allow you to hit it harder without worrying if the punch will veer of of the pin.
The thing you want to make sure you do is transfer all the force directly into the pins. They will eventually come out, you just need to hit it extremely hard.
BTW, i heated my nagant before I took the pins out and no solder came out, but once i got the pins out i realized it was soldered. So I just had to heat it up again and the rear sight just fell off.
Haha, well I will get it off, eventually. I picked up some kroil today and letting it soak tonight, hopefully that'll work. If not I'll definitely be buying a better punch and a sledge hammer.
Edit: Well the kroil worked! Man that stuff is the ticket, and luckily there wasn't a trace of solder either. Thanks, definitely gona keep some kroil around from now on.