Bullet seating depth increases from chambering

[Anonymous]

I have noticed that the first cartridge in the magazine, which gets chambered multiple times after clearing the pistol for one reason or another, tends to make the bullet seat a little deeper each time. At least this is what I've noticed with my SR40c.

The round I've been carrying lately is the Federal HST 135gr. Where new cartridges measure 1.125" OAL, one which has been chambered about 3-4 measures 1.108". I realize this is a difference of only .017" but is visibly noticeable.

I can only imagine that a deeper seated bullet is going to increase case pressure when fired so I have decided to put these bullets aside and put a fresh round in the mag to replace it. It may not be much of an increase but since the .40 is a rather hot round in the first place I'd rather not take any chances. After all, there has to be a reason we don't see .40+P rounds.

So my question to all of you is this, "do you replace the frequently chambered round that gets shorter and, if so, what do you do with them?"

 

[Anonymous]

.40's are notorious for having bullet setback from multiple chamberings.

Just one of the reason I hate the .40. I would not shoot the round if setback is noticeable. Unfortunately, .40's need to be rotated in the magazine unlike any other cartridge I know of.

 

[Richbaker]

This is normal for most semi's, just don't keep chambering the same round every time. If I have to eject a live round, it goes to the bottom of the mag NEXT time I reload the mag..... or, I'll pop a couple rounds out of the mag and reload that one 1st.

 

[Tam 212]

+1. Rotate your SD ammo.

Also, I ease the slide closed on my SD ammo and then do a press check when chambering/re-chambering my SD/HD ammo.

 

[GKC]

+1. Rotate your SD ammo.

Also, I ease the slide closed on my SD ammo and then do a press check when chambering/re-chambering my SD/HD ammo.

I have read many times that you should not ease the slide closed to chamber a round...it is bad for the extractor. You should ease the slide closed on an empty chamber. I can't say that it is fact, since I've never done it and can't relate any personal experience with damage and/or problems as a result, but that is what many others have said.

I have also read about the setback issue on other caliber rounds, not just the .40 S&W. I once read a good suggestion: after you have chambered a round and then subsequently manually eject it, put it in a range-only ammo box. Some even marked the brass with a magic marker. You can also do a quick compare of your "range-only" ammo with an new, un-chambered round to see if there is any setback. It seems a little too cautious to me, to relegate a round that has been chambered only once to a range-only box, but I would certainly do so with a round that has been chambered several times. I would also visually inspect and compare them to "new" rounds as I was loading my magazines for carry.

 

[Sal1950]

As others have said, setback from repeated chambering happens with all semi-autos, in all calibers. It can vary from gun to gun depending on how hard the bullet nose is slammed into the ramp during chambering, and also vary with different ammo depending on how tight a crimp the manufacturer uses.
Bottom line is that this is a normal occurrence and ammo rotation of some kind is mandatory.
Sal

 

[NixieTube]

It shouldn't happen each time but it can happen. I do worry about setback and it happens to a greater or lesser extent with different ammunition brands. On some ammo. brands it's almost invisible and on others it happens more easily.

My rule of thumb is that if you think you're going to rechamber the same round, rotate that sucker!

I try never to rechamber the same round more than 3 times. It's worked for me with all the ammunition I've run through my SR9.

There is a test that you can easily perform: unload whatever rounds you're currently using, line 'em up on a table and put a straitedge ruler across their tops and look carefully. If you see any setback, don't use those cartridges.

I frequently have to unload my pistol because I live in Massachusetts and because of that I've learned to take account of the possibility of bullet setback. So far it hasn't been a big concern because I rotate the cartridges.

It shouldn't happen "easily" unless the ammo. is really badly made but it can lead to anomalies when it does, if you constantly rechamber a given round. There's no hard and fast rule about this except that if you hold two of the same rounds in your hand and one is visibly shorter after rechambering it several times, it's probably in your best interest not to use it.

I have not heard of anyone suffering an injury from bullet setback on a Ruger SR pistol but it's not unimaginable, so if you want to be safe, be safe and do what I do: measure 'em if you rechamber them.

One of the nice things about semiautomatic pistols in other words is a cause for a bit of concern when done too often. That's a common refrain in life and ammunition is no different.

Usually it's a small concern but if you have any doubts, just go ahead and line up all the ammo. on the table and straightedge it and if you see anything weird, toss that particular round and think about taking it apart and using it in a charm bracelet or something

 

[Sal1950]

OR,
If you want to avoid the issue, drop that first round into the chamber by hand, close the slide. Then insert the magazine. Many guys do it this way to get the +1 capacity.
Sal

 

[Anonymous]

OK... so one responder say to relegate such rounds for range only implying they are still safe to shoot. Another says to toss said rounds. I guess to be on the safe side it would be wiser to toss them.... but where? Should the go into a can of oil or some solvent to render them inert?

 

[NixieTube]

OR,
If you want to avoid the issue, drop that first round into the chamber by hand, close the slide. Then insert the magazine. Many guys do it this way to get the +1 capacity.
Sal

Yup that works too, 100% of the time. I've *never* seen bullet setback on a round fed from the magazine the first time, either.

 

[Anonymous]

OR,
If you want to avoid the issue, drop that first round into the chamber by hand, close the slide. Then insert the magazine. Many guys do it this way to get the +1 capacity.
Sal

This is what I have chosen to do to avoid the setback and to get the +1.

 

[NixieTube]

OK... so one responder say to relegate such rounds for range only implying they are still safe to shoot. Another says to toss said rounds. I guess to be on the safe side it would be wiser to toss them.... but where? Should the go into a can of oil or some solvent to render them inert?

I've only had 2 and I fired them both anyway. I don't recommend it but I did it. There was zero damage, and I had no trouble. These pistols are tough. My chamber is in great shape and I barely noticed the difference. Those rounds are long gone and once I realized why they were set back, I decided to prevent it.

I don't mean to make this sound glib, but it's basically a manual-of-arms kind of deal. If you're concerned about it, rotate the rounds. If you're really concerned about one that you see after not rotating the rounds, you're not shooting enough!

Also, I'm sure there are a lot of people in the ammunition reloading business who can tell you how to safely disassemble a loaded cartridge if you think it's no longer usable. There are also threads available on the internet that describe how to do exactly the same thing if you really want to disassemble them. Otherwise, I would suggest shipping them back to the manufacturer and complaining about how their bullets set back.

http://forums.outdoorsdirectory.com/showthread.php/95129-How-to-Unload-Cartridges

 

[Tam 212]

I have read many times that you should not ease the slide closed to chamber a round...it is bad for the extractor. You should ease the slide closed on an empty chamber. I can't say that it is fact, since I've never done it and can't relate any personal experience with damage and/or problems as a result, but that is what many others have said.

From what I've been told, this applies to dropping a round into the chamber and then closing the slide - especially on 1911s.

I'm easing the slide close to feed a round from the magazine. This is no different than racking the slide on a full magazine.

To "barney bullet" it and top off the magazine, I chamber the first round, remove the mag, top it off and then re-insert it.

 

[Anonymous]

.....
I don't mean to make this sound glib, but it's basically a manual-of-arms kind of deal. If you're concerned about it, rotate the rounds. If you're really concerned about one that you see after not rotating the rounds, you're not shooting enough!

Being concerned about something means one is not shooting enough? No offense but that makes absolutely no sense to me. I shoot plenty of FMJ to practice but none of them spends more than a few seconds in a magazine and never gets chambered more than once. When it comes to SD hollowpoints, one cannot shoot enough of those given their high price.

Before even beginning this post, I chose to simply load one into the chamber, release the slide lock to close it and then insert a full magazine. This should prevent any more setbacks.

 

[NixieTube]

Being concerned about something means one is not shooting enough? No offense but that makes absolutely no sense to me.

Hey no offense to you either, I guess we just don't know each other's posting style that well. I was concerned about this problem myself and in fact if you search the forums you'll see I have a thread on it.

I experienced bullet setback early on with my SR9 with two rounds that I'd repeatedly rechambered and I just stopped doing that after the advice I got in my initial thread. It was inexpensive ammunition (Hungarian MFS on sale, FMJ) I'd bought right after I purchased the gun, and I'd rechambered several rounds several times and saw some setback on a couple of rounds after repeated rechamberings.

It wasn't +P ammo, the setback wasn't very large, and I fired those rounds without incident.

Once you get to know me you'll find I'm a very cautious person as well, I didn't mean for my response to sound dismissive. I should have put a smiley after the "...you're not shooting enough!"

Like: "...you're not shooting enough "