What is bullet setback?

[K.C.]

Posting this for those who never heard of bullet setback before.

[ar15jules]

Good PSA for those unaware.
Jules

[knight0334]

Good post for the newbs for sure.

Setback is easy to deal with.. ...once the gun is loaded - leave it loaded.

[K.C.]

Bumping for the newer members who may be unaware of bullet set back.

[jthrelf]

Good to be aware of this.

It's really easy to make a little pattern in your ammo box that you can keep track and cycle through each round being chambered 2-3 times before burning them at the range. If you don't unload very frequently, this will extend your defensive ammo for quite some time. Ex: 50 round box - 30 in two mags = 20 to cycle through. That's at least 40-60 safe chamberings.

[MikeB0]

And yes it really can cause issues. I was having an issue with an AR pistol one time and was purposely setting aside a couple rounds that failed to chamber and experienced set back do to what I discovered was a piece of broken brass in the chamber. I then accidently(brain fart) reinserted one of the set back rounds into the magazine.

There was then a perfect storm of issues, older Original Carbon 15 AR pistol, set back bullet and a suppressor leading to overspressure. The gun basically came apart in my hands when I fired the round and sent the buffer tube, buffer and bolt straight back into my chin. I was seeing stars. Be careful with rounds that show any signs off bullet set back.

[markshere2]

Aaaaaaaaaaand the exact opposite is an issue, too, in revolvers.
Big Recoil can push the case away from lightly crimped bullets.
Result is too-long rounds that can lock up a revolver.

[MikeB0]

Aaaaaaaaaaand the exact opposite is an issue, too, in revolvers.
Big Recoil can push the case away from lightly crimped bullets.
Result is too-long rounds that can lock up a revolver.

Yes this too. Was a known issue with the real lightweight scandium revolvers and 125 .357 rounds. Probably with others too.

[Delkal]

Good informative video! I am going to have to think about it for a while and see if / how much it happens in my firearms.

This really puts a unknown in seating to any OAL while reloading! Rifles especially are usually more accurate if you seat close (or even touching) the lands, and you have to be very consistent. He seems to be implying your actual bullet length of a chambered round will be shorter and variable no matter how carefully you seat the bullet.

Just what I need..........another variable for reloading! Now its neck tension and bullet crimp.

[Yellowfin]

Bullet setback is when my orders from Xtreme or Graf's get delayed or backordered.