re-chamberng the top round multple times

[Mobuck]

How many times do you or would you consider re-chambering the top round in an AR magazine? When we're moving between calling stands by vehicle of course we unload so often 5 or 6 load/unload cycles per day.
As some may already know, the firing pin on an AR "taps" the primer each time a round is chambered. For this reason, I seldom load a round into the chamber and drop the bolt(that makes a bigger dimple than loading from the magazine).
In the past(when I was shooting more than now), I'd just drop that "X-times chambered" round in a cartridge box labelled "sighters" and top off the magazine. The alternative is just shoot that top round at the 300 meter plate as I've been doing lately.
Anyhoo, just let those opinions fly.

 

[Enigma]

I will typically chamber the same round a maximum of three times, handgun or rifle. If you check, you can frequently see that the bullet is being seated deeper after each trip into the chamber. Some police departments require their officers to rotate the top round in the magazine because of this.

 

[contender]

I'd say about 3 times would be a good place to rotate the round. In my CCW handgun,, (a 1911 a lot,,, when not carrying a DA revolver,) I usually keep it loaded most of the time. Yet,, when I unload it,, I always take the chambered round & set it aside after I drop my magazine. Then,, After a few times of this,, I start checking the round for ANY change in bullet seating depth. Quite often,, I just replace that round with a fresh one,, and put that one aside for range time.

 

[sncup]

Mobuck / Contender you are talking about 2 completely different things, and different ends of a loaded round.
For AR / 223 you can reload with Mil spec small rifle primers that have a thicker primer cup.

CCI PRIMERS, NO. 41, MILITARY STYLE SMALL RIFLE FOR 5.56 MM

If you do not reload then perhaps only chambering a round a limited # of times is a sensible precaution.
PS: You should chamber a round in an AR from the mag. Not letting the bolt drop. Slam fires are rare but have been reported.

Chambering a pistol round from the mag and worrying about bullet setback. A justified worry even with factory ammo. In roloading it is advisable to test the bullet tension by chambering a round multiple times and checking with a Micrometer if the OAL of the cartridge changes.
Not a bad idea for factory ammo also.

 

[contender]

You are correct,, two different firearms,, and different potential issues.

But, I related my experience,, to show a different perspective.

 

[Mobuck]

All of my reloads use the CCi#41 primers and have the bullets crimped but the commercial factory varmint loads don't.
I did some very unscientific tests by using non-#41 primed cases and could not get a slamfire even after 15-20 bolt drops on a chambered, primed case but the dimple did get fairly deep AND the primer did fire when I pulled the trigger at the end of the test. Just because it didn't happen that time doesn't mean it WON'T happen on a different primer/case/rifle.
My carry pistol is only unloaded for cleaning and the top & second round set aside. After cleaning, the top and second rounds are fired for function test of the re-assembled pistol.