I did a lot of bump firing my SAR-1 yesterday, heating it up and seeing if I could set the handguards on fire. They got way too hot to touch, turned black at the contact points, and smoked a lot, but no flames.
Had some problems though... about 3-6 times per mag, the hammer would ride the bolt forward amd result in a chambered live round and no bang. Had to pull the bolt back half-way to recock it and continue. It never happened while firing normally, just bump-firing. It also felt like it may have been doubling on occasion while bump-firing.