Some bring a camera and report back.

38 years of shooting cap & ball in SASS and never had a chain fire.  Easily prevented.  In fact, I charge all six chambers and cap five to comply with rules... sixth chamber remains uncapped unless I have a cap malfunction, or need a reload to meet stage requirements.  I use full strength mainsprings, now use SlixShot nipples, .375 balls to shave a slight ring of lead and a lubed wad under the ball.  Reasonable charge of powder to meet the task at hand.  In my .36s it's right around 15 grains by volume to ring steel.  Doesn't need any more to punch holes in paper either!  I haven't had a hammer bounce back, haven't lost a cap off a nipplie in I don't know how long... at least as long as I quit using stock nipples.  I use Remington #10 or RWS 1075 caps, preferably the Remingtons.

But keep using lightened mainsprings, max loads, poor powder control and poor fitting caps & balls and you'll keep having chain fires.  But, please, don't make it about the gun. 

Another bump in the road, I'm having troubles again/still same as friday called Dr and we are upping one of my meds Try that.  Rita has got a whole bunch of Drs confused.   

Very nice.

Slim

I'm a little late jumping in but I've always used Pure Neet's Foot Oil followed by Skidmore's Leather Creme with good results. Works the best when you let everything dry thoroughly between coats.