Re: IOR 6-24x 35mm
Mach V, I owe you an appology. I shouldn't put so much faith in my memory and make so many assumptions. I mistook you for somebody else. Sorry.
So it has happened more than once. By "close to turrets" do you mean placing the ring as shown on the last scope in your pic above? I've always thought putting a ring that close to the erector assembly was a bad idea just on principle. I know it used to spell death for Leupolds many years back before they revised the design (which had nothing to do with tube walls). I'll bet the locking up issue is simply a matter of having the ring so close to an already tight fitting lense that needs to move that with a bit of squeeze on the tube the lense is just too tight. But that's no more than speculation--even if it's not the case I'd still move those rings though.
As for tube hardness, 6061-T6 is 6061-T6 and if properly heat treated to meet the Mil Spec (as all needs to be to be legally sold under that designation) the raw material all these various scope makers use for their tubes (nearly all use that material) should all be so close in hardness that we'd never notice a difference. If one tube dents more easily than another it likely has thinner walls.
Since that rifle is at the 'Smith for a new tube, I took off a ring (Badger, not lapped) from the scope above. Yes, there were marks. The same rings mounted the same way didn't mark a Leupold at all. However, there's no indication they are anything but marks in the finish. The finish on the IOR does seem to be a bit thicker and more easily marked than the Leupold (both Matte). Of course if one torques the snot out of the rings all bets are off--I've done this in the past before I used a torque wrench and have seen many where the tube is actually crimped a little (mostly Leupolds--Leupold slut family growing up [img]/ubbthreads/images/graemlins/wink.gif[/img] ). But like you said, with decent fitting rings mounted properly, I don't think it's a problem for IOR (or pretty much any other scope for that matter).
The BDC. I modified my Ballistics spreadsheet (linked in the sticky in Bullets, Barrels & Ballistics) to spit those out. I'd be happy to send it to you, but it'll only work for an IOR with 13 MOA per rev. You'd need to modify it for another model (and it seems they make every single model different!). That's the hard part. It took much effort-hair pulling, etc, to get the spacing exactly right. That's with the scope in my hands, there's no way I could get a different number of clicks right without the scope to lay the thing on and make adjusments. But if you want to try, I'd be happy to help.
I'm really liking the concept so far (I've always just used drop charts in the past). Most of the "bad" things people say about BDC's is with the assumption that they're some $100 laser-engraved aluminum things that you're stuck with even when your load changes, you location changes, the weather changes, etc, and so they'll be off. But now that it's made, I can change this just as easily as a drop chart. Well, I'd say it takes me 15 minutes or so to rip one off, make a new one and install it on the scope so it's a bit harder, but nothing like ordering a new custom $100 BDC from someplace.
But after looking up values in dropcharts, interpolating click values (charts only every 50 yds so they aren't friggen huge), clicking that value into the scope, etc for so long, the instant and visual way of skipping all those steps is making me a fan. Keep in mind though, I don't plan on trying to kill anything at 1000+ any time soon--I think at extreme ranges the usefullness would give out, when you really need real-time weather data and new calculations simple MOA clicks would more practical. But like I said, they're somewhat a PITA to make but if you'd like to give it a try I'll be happy to help.