Question on Setback

[thirtydaZe]

After reading an article from SFG in another thread, i had a question about setback, and how everyone who carries handles it.

I like to get to the range at least once a week.  I carry a shield .40, and like to shoot it on each outing, however i always switch ammo to the cheap stuff.

Essentially what happens, is i cycle the same 2 rounds of my SD ammo.  When i get to the range, the one in the chamber comes out, then when i leave, i cycle that next magazine round in, and put the one that just came out of the chamber back on top.

Well, i haven't measured either round yet, but seems likely that chambering after chambering would eventually set the bullet back.

What do you do, shoot one each time?  i almost hate to do that, as to keep the good stuff for an if needed situation, but i hate to have an over pressure situation too..

[SemperFiGuy]

thirtydaZe:

You'll think I'm hounding your footsteps........

Actually, I have no friends and no life and nothing to do and my wife and dog ignore me, so I pass my days prowling the Forum and pouncing on Interesting Posts.

Anyhow:

Well, i haven't measured either round yet, but seems likely that chambering after chambering would eventually set the bullet back.

Actually, it depends.

I've tried the recycling-the-rounds exercise many times and many times have gotten pretty much zero setback.   Both with my own reloads and factory ammo.   Using a mike to measure and all that.

And sometimes you do.

It depends.

Try it with your own mike and see wot's wot.

Now....If you ask me how much setback causes how much pressure increase in a given caliber, gotta refer you back to that article.   Which applies only to .40S&W, as I recall.

Happy reloading.

sfg

[landon410]

when i took my ccw class from 88 Jason the teacher said he did it one night on purpose, he showed up the round and after awhile it was a visable differnce

pretty crazy....

[Dan W]

Setback problems are the reason I don't own a 40...way to sensitive to anything that increases the pressure.  9mm and .45ACP don't have nearly the problem with setback related kabooms


I deal with setback by keeping my EDC gun fully loaded 24/7/365, so even with practice and cleaning the chamber round doesn't meet that many feed ramps

[ghknives]

I keep the rounds that have been chambered in a separate container and shoot them during practice sessions. I practice mostly with reloads but want to use my regular carry rounds enough to know reliability, recoil, accuracy  muzzle flash and etc.

[bkoenig]

I remember reading an article somewhere (American Rifleman maybe?) where they experimented with pressures and bullet setback.  They used a press to set back bullets in measureable increments, and they found no significant increase in pressure.  I think this was in 9mm.

[unfy]

I'll skip any bro science and just say what I do:

I happen to carry a pistol in .40 as well.

I cycle the rounds in my magazine when I do end up deholstering and unloading the weapon.  Just to help avoid similar 'setback' concerns.  I *rarely* deholster / unload the weapon, so it's not that much of a concern.

I DO shoot a magazine of SD ammo once a year though.  This way I cycle the stock of SD ammo I have and get a nice reminder of how the weapon will perform while shooting it.

[JTH]

I DO shoot a magazine of SD ammo once a year though.  This way I cycle the stock of SD ammo I have and get a nice reminder of how the weapon will perform while shooting it.

Yep.

I shoot a 9mm, and setback of course can occur with any caliber.  (Whether or not it will be an issue is a different discussion.)  I tend to also practice with my carry gun, and as SD rounds are expensive the SD ammo does get cycled in and out of the gun pretty frequently. 

Mostly---I don't really worry about it.  If I feel I have cycled a round a number of times in 6 months or so, I take a close look at it.  (Haven't seen any issues yet ever.)

About once a year I shoot through my ready magazine of SD ammo, to remind myself that it feeds reliably in my carry gun, and to make certain that my gun still remembers how to shoot it.  Then I reload the magazine and gun with new SD ammo, and move on.

I don't know how much differently I'd act with a .40----but probably not too much. 

(That got me curious, so I just measured the chambered round which has been cycled in and out quite a few times---and its OAL matches the stated factory OAL for the round.  Maybe my Glock 17 is just nice when it chambers?    )

[barmandr]

I cycle my rounds also.  As an additional measure, I ride the slide forward when chambering the first round of carry ammo after cleaning.  Other than cleaning/range visits, I keep it loaded/chambered.  Zero setback when you ride it forward.

[David Hineline]

Can alway buy a second gun exactly the same configuration and never have to unload the defensive pistol.

[Gary]

Measure new rounds from a fresh box, jot the measurement on the box.   Measure cycled rounds to see if they are getting shorter.

If your daily routine has you cycling rounds, maybe it is the routine that needs changing, as much as your ammo? 

I know some people only cycle CC ammo once, then it goes into the range bucket, to shoot for target practice. 

[docwithaglock]

When I unload my weapon I mark the base of the chamber round with a sharpie then put it somewhere in the mag when I reload.  When all the rounds have 2 stripes I shoot them.  This allows me to cycle the rounds and not chamber the same round too many times.