I measured a set of 2 7/8" chamber factory original Titanic Steel barrels and they are .120 at the 2 7/8" mark and .130 at the 3 1/2" mark (gets thicker in the forcing cone area). Apparently, your chamber front end was carved out about .030 to get down to your measurement of .100. Hopefully, they get thicker again when the forcing cone taper takes over. Measuring the outside diameter as I suggested in the last post is impossible because of the water table. Too bad. However, I'm shooting the heck out of my Lefever-Parker with the .100 wall thickness and I've never heard of a Lefever sleeve job blowing up. My gun was probably sleeved nearly fifty years ago and has been used regularly ever since. I'm sure this is more than you ever wanted to know.
