Over the years, I've been lucky to acquire, for very reasonable prices indeed, nine IXMOOs. I shoot them in my M3, and also in my M6--my London second-hand Leica dealer had a black chrome base plate to fit the tulip takeup spool in the M6 that also had the plate/key for opening and closing the cassettes (which the M6 normally lacks). He benevolently let me negotiate it to a very affordable price for me. I even have five of the black plastic canisters the IXMOOs came housed in originally, and four of the aluminum, Leica-stamped canisters which I think were actually made for the FILCA, but work just fine--and are very classy--with my IXMOOs. Nine is a nice number, as it's just about precisely half a 100-foot roll of film.
I use a Watson loader. I find that if I turn the crank for 39 clicks (I just count them, I don't bother resetting the counter each time) and a little extra, I can get 35 exposures on a roll--the right length for a 7x5 Clearfile negative page. I do lose an exposure at the end of the roll because I load the end of the film into the IXMOO in daylight, to make sure it goes in properly centered, rather than fumbling around with that in the dark. So the very end of the film is exposed. I always just try not to shoot anything super important on what should be the last frame of a roll.
When you trim the end of the film to insert it into the IXMOO, the correct distance is three sprocket holes. If you start cutting from just beyond the third hole and angle toward the approximate center of the strip of film, you'll get it right. If you're using an M2 or M3, you don't have to trim the leader of the film to the modern shape, as if you cut it straight across (I generally round the corners a bit, which makes it easier to load it on the reel for developing), it will slide into the flange on the takeup spool just fine. If you are going to shoot it in a camera with the quick-loading tulip takeup spool (M4 and later), you will find it a lot easier to load the film if you trim it to approximate commercial rolls of film. I think the actual distance on factory-trimmed rolls is like seven sprocket holes, but 5 or 6 will work just fine and saves a tiny bit of film.
After loading your film, make sure you turn the knob on the loader in the correct direction to close the cassette. Remember, it turns counterclockwise. Some of the cassettes can be a little stubborn to close (you're pitting the pretty precisely-fitting metal of the cassette against the plastic of the loader) so listen carefully for a click telling you it's closed...and locked. I've found that even if it doesn't fully lock, *normally* it will close far enough that the cassette's film gate is shut completely; just make sure when you take it out of the loader to turn it the small extra bit of the way so it actually locks until you put it in the camera and unlock it by locking the baseplate.
When you finish the roll of film and are opening the cassette for processing, gently--I said *gently*--pull back the locking tab in order to rotate the inner part of the cassette. You don't need to pull on it much at all. I've seen a few IXMOOs in camera store drawers and on eBay where the locking tab had been bent back forcefully enough that it could no longer properly lock the cassette closed.
Here's an important thing to remember: when you are unloading the film for processing, do *not* try to pull the end of the film out of the spindle. It's far, far better if you push the remaining bit of film *through* the spindle instead of pulling it out. So as you're loading it on to the processing reel in the darkroom/changing bag, just cut it straight across when you reach the end of the roll. Later, when you're cleaning up, if you take your scissors and lop off one side of the little tag end of remaining film from the end of the roll, you can easily push the rest through and remove it that way. The spindle is designed *not* to allow you to pull the film out (at least at all easily), so that when you reach the end of a roll while shooting, you don't accidentally pull the end of the roll out of the cassette when advancing the film if you're caught up in the excitement of the moment, let's say. That's a very nice thing about the IXMOO, you don't have to tape your film at all, a properly functioning spindle will hold it very securely indeed.
The IXMOOs are great! Made out of solid brass, no felt light trap for debris particles to get trapped in--which may leave a scratch along the length of your film. Some of mine are showing their brass mostly, some are still black--you could, if you acquire one that's lost its blacking, use gun blackener to restore it. I haven't bothered on mine, and haven't noticed any problems.
As I sort of mentioned above, you can get about 18 rolls (plus a little extra, usually) of roughly 36 exposures from a 100-foot roll. Nowadays, given the prices of a 100-foot reel, loading your own is not nearly as much of a saving as it used to be. And if you factor in the cost of the IXMOOs--which tend to be quite pricey nowadays--the loader, the occasional bit of wasted film, and your time/effort to do the loading, rolling your own for Leica may actually not be ultimately the most economical or convenient way to go. I just like doing things the old-fashioned (but high-quality and customizable) way, and I've tended to get lucky in finding recently-expired rolls of film at significant discounts. And loading up the film and using the superb old cassettes is just *fun*; if you're not having fun while actually using your Leica, why the hell go to the expense of having one?
Hope that's helpful; if I've left anything out or anyone has a question for someone who uses IXMOOs and loaders regularly, please ask--if I can answer it, I'll definitely be happy to assist.
Leica IIIc with VIDOM and FILCA
