|Photo courtesy of LuckyGunner Labs|
What is Bullet Setback?
Setback is recognized when a bullet (the projectile) has been pushed deeper into its brass case than where it should normally seat. Many things can cause this; from repeated chambering of the same round (like in a carry gun) to hitting it with a hammer (as in Andrew's case). I have even seen a round or two featuring setback from the factory. Bullet setback is not exclusive to pistol ammunition.
Andrew used a Glock 22 Gen 4 for his testing hoping the combination of the high pressure .40S&W and Glock "hand grenade" would spectacularly demonstrate a point.... but I won't ruin the ending for you.
In a much more unscientific test I performed a couple years ago I found the Glock refused to explode even after 1,000 rounds of ammunition. Weird, I know...
I took a Glock 23 Gen 3 and fired 1,000 rounds of Winchester Ranger .40S&W through it as fast as we could manage. You can find that post with videos in the link below: