Interesting video. Tongue-in-cheeck comment follows: So - snugly seating a bullet 50 thousandths too long as he suggests, put it in, close the bolt, measure from the front of barrel to the tip of the bullet, remove the bullet, close bolt, measure the distance from front of the barrel to the bolt face. And voila - you have your jammed bullet seating depth. Then do what you want with that info. Seems like that gets to the same measurment without a lot of extraneous work or calculations. I also suppose if you notice accuracy falling off, you recheck your measurements, powder, etc. Seems intutitively obvious that shooting bullets thru a barrel is not a static process, and one would expect changes over time and compensate for them.