So, I was playing around with some riveting the other day (trigger guard) and it occured to me that forming the rivet might be made easier by heating the rivets red hot first, I figured when it cooled it would shrink up nice and tight. I know this was how big rivets used to be done (and might still).
At first I worried it would unduly harden them, but as long as you cooled it slowly.
I am going to drag some scrap metal and a torch home from work and try some hot ones versus cold ones and then destructively test them against each other, but this will take me a while to get around to as