This is why I use 12 exposure rolls of expired film to test new cameras versus a $10 roll of T-Max. My new Pentax ME (see earlier post) got used this week. I loaded a roll of Fujifilm 100 and took it out. Seemed to work A-OK, but at shot 13, 14, 15+ it was like oops, something is wrong.
I stopped my shooting a re-rolled the film and by feel immediately new that the film leader had not been properly been attached to the takeup reel. After about 2 turns of the rewind handle the film went slack. I opened the back and it was fully re-rolled.
The takeup real operates in a "backwards" manner (it doesn't move the direction of the advance handle) and I "thought" I loaded it correctly, but guess I didn't. Oh well, it was a test roll anyway. I'll reload it tonight and put a bit of extra care in my film loading. If it still doesn't work then I break out the gaffer's tape. No mere camera is going to defeat me!!!