Dry firing and magazines

[Naxet1959]

The other day while I was getting ready to dry fire my daily carry M&P9c, I realized that when I'm done and I reload, I have to take the bullet that was in the pipe and reload it into the magazine (after racking a fresh round).

What wear would this have on the magazine and/or the bullets (as I tend to rotate the top 2 bullets)? I dry fire generally once a week...

[GTM]

I've started taking the cleared round and storing it separately. I then load a new, fresh round into the magazine. This way it's easier to keep track of the number of times a round has been chambered in order to prevent setback.

[asme]

Every time you chamber a cartridge, its bullet is set a little further back into the casing. If done enough the setback can raise chamber pressure upon firing to dangerous levels.

I tend to toss out rounds I've chambered three times. A round costs a quarter; my safety is worth more.

[QuickStrike]

I sometimes place the chambered round between two fresh ones and put a straight edge over the top. If too much light shows through above the chambered round I ditch it.

A quick and easy way to check.

[TAZ]

Every time you chamber a cartridge, its bullet is set a little further back into the casing. If done enough the setback can raise chamber pressure upon firing to dangerous levels.

I tend to toss out rounds I've chambered three times. A round costs a quarter; my safety is worth more.

Some guns are worse than others about this. In the past I haven't worried about it too much and I dry fire 2-3 times a week. I've measured my rounds and they don't change OAL over numerous chamberings, and I tend to shoot atleast a mags worth of defensive ammo every range outing, worst case once a month.

ASME is correct though, unless you've measured and insured that your not changing OAL your safety isn't worth the $0.50 a defensive round may have run you.

I like the idea of simply taking the top round and replacing it with a new one every time and storing the old round in a different box. After a few weeks or days depending on your cycle you'll have a once chambered round to shoot at your next range session.

[Naxet1959]

Great advice guys... I was mostly concerned with the magazine spring not even considering the setback on the rounds! Live and learn....

[DaveR]

I posted this pic on Glock Talk shortly after I destroyed the round.

I was working on a G17 that came to me for a trigger change, NY1.

I got it with a full magazine and a round in the chamber so I started off cautious. Two rounds of Hornady Critical Defense 9mm. On the left is the round that had been rechambered many times, the owner wasn't sure of the count.

http://i1103.photobucket.com/albums/g466/darock2/9mmSetbackweb42211.jpg

I've always wondered what that round would have felt like with that much set back.

I carry with a round in the chamber and fire that round at every range trip. Small price to pay.

Dave

[Naxet1959]

Just checked on both of the my Speers that were being rotated and shockingly not setback at all. None the less, they are out of the rotation. Thanks again guys!

[thopkins22]

Setback is a legitimate concern, there's some good info by DocGKR in the Terminal Ballistics forum on it.

Don't worry about "set" with springs. Seriously, there will very likely not be a problem for years if at all. And on carry mags I change the mag spring at a set interval anyway.

There's no sense having anxiety over a part that's easy to change and costs less than a movie ticket.

[skyugo]

Just checked on both of the my Speers that were being rotated and shockingly not setback at all. None the less, they are out of the rotation. Thanks again guys!

I use speer gold dots and fed 9bple and i've seen no significant setback... i think the worst i've ever seen was .010. I tend to check my rounds with a dial caliper and rotate to teh bottom of the mag.

I think the more rounded profile of these rounds is less likely to set back then the hornady's triangle profile. ymmv.

[skyugo]

I posted this pic on Glock Talk shortly after I destroyed the round.

I was working on a G17 that came to me for a trigger change, NY1.

I got it with a full magazine and a round in the chamber so I started off cautious. Two rounds of Hornady Critical Defense 9mm. On the left is the round that had been rechambered many times, the owner wasn't sure of the count.

http://i1103.photobucket.com/albums/g466/darock2/9mmSetbackweb42211.jpg

I've always wondered what that round would have felt like with that much set back.

I carry with a round in the chamber and fire that round at every range trip. Small price to pay.

Dave


aren't hornady critical defense factory rounds nickel plated? (the casings)
any chance these are reloads with a light crimp?

[DaveR]

Sorry, skyugo, my error. Took the pic earlier this year.

Those are the factory Hornady XTP which don't have the polymer insert. They are brass.

I've seen some bad reloads like that so I can understand why you would question that.

Dave