Here is the quick run down of how I did things,
I cut up a 5# shoulder and chilled in freezer to make the chunks fairly solid. I ran the meat through a medium plate (northern tools #12 grinder). I chilled the meat again and ran it through the fine plate in the grinder. I then added my spices (a quick mix found on internet). Everything was mixed by hand.
I use hog casings and had soaked them in warm water for approximately 30 minutes prior to stuffing. I also washed the insides out by running water through them. I just bought the casings earlier this day. They were packed in salt.
I use my grinder as a stuffer and began stuffing the sausages. The first one I did looked very nice, but towards the end it split out on me. The second and third ones were not as pretty looking, but I didn't have any blowouts.
I twisted them off into links and put into the fridge overnight.
Next day I poked a few holes in each casing and put in a bath of beer over low heat for 15 minutes or so. I then put them onto a very hot grill (direct heat). I will add that I would cook a store bought brat over the same grill heat and haven't had the problem of the casing breaking.
The casings were fine coming out of the beer bath and I would agree that the high heat from the grill would likely be my problem.
Thanks for the help so far.