The ones I use are real short. I use a blank pistol, the race starters use. They are cheap and work well. With that pup here is a simple method to get it gun broke. Take it for a run. When it is out in front a fair distance. shot a blank behind your back. put the pistol back into your back pocket. The dog will most likely come running back to you, for comfort and reassurance. VERY IMPORTANT, Do Nothing and Say Nothing. Just keep walking like nothing happened. The pup will take off and after a bit shoot it again. Exactly as before do and say nothing. 3 times in one outing is the limit and keep doing it on each outing until the dog just keeps running and don't even look back. You then have a dog that will not be gun-shy if treated properly.......Bob