[michiganfan]

I have noticed that the round that I chamber on a daily basis eventually gets shorter in length than a new round. By that I mean the bullet seems to recede into the casing from hitting the feed ramp I am guessing. I have been tossing that round away every few days. Is this a normal occurence? And is the round unsafe to use when it reaches this condition. Thanks

[Zak Smith]

You are witnessing bullet "setback". Some loads are more likely to have this happen. Once I had some Hornady 9x18 Makarov ammo which would set-back considerably in just once "chamber" cycle. On the other hand, the "Proload" ammo I use in my CCW (BHP9) can go through 20 cycles without shortening measurably (ie, less than .001").

Yes, it is likely unsafe! The pressure will increase as the initial combustion volume is decreased. If the round is shorter than the rest, throw it away!

-z

[Poohgyrr]

Yep, bullet setback. It is said to creat high pressure problems that can be dangerous, so don't use the round.

An alternative use for this round, if you reload, is to pull the bullet, dispose of the powder, and reload the round for training. Following all established procedures etc..... I had a box of 135 gr .40's that had this problem.

[WhoKnowsWho]

I try to not unload and rechamber rounds because of that problem. I don't want to toss out rounds that could have been fired until the setback became an issue.

[SelfProclaimedExpert]

This is a good argument for Berettas or other guns with extractors that are supposed to pop over the case rim. You can manually chamber the round and lower the slide into battery without banging up the ammo.

Don't do that with a tilt barrel gun, you'll eventually chip the extractor.

[mete]

When you load the gun let the slide down slowly to minimize the problem. A bullet that has set back into the case will raise pressure !!! Tests with the 40 show set back of .1" will DOUBLE the pressure.

[P95Carry]

With my P series (9mm or .45acp) .... always load chamber round by hand and not off mag ..... close slide on that .... insert full mag .... decock in safe direction.

No harm to round!:)

But yeah ... bullet set-back does = higher pressures.

[SelfProclaimedExpert]

P95 carry. See my post. Doing that continually is damaging your extractor. It may break some day when you need it.

[dfariswheel]

Pressure will go up, but a more immediate danger is "Second round stoppage".

When large numbers of police went to the auto pistol, they started having a problem with officers involved in shootings firing one shot, then having the gun jam on the second round. The second round would fail to feed.

They found out that the routine was to inspect the guns by removing the mag and racking the slide to eject the round. After inspection the mag was inserted, slide closed to load the chamber, and the loose round was re-inserted into the mag.

What this meant was, the same two rounds were being constantly chambered day-after-day. This eventually drove even tightly crimped bullets back into the case, shortening them.

Result was, failures to feed the too short round causing a second round stoppage.

[Edward429451]

I've always been told to chamber through the mag so no stress the extractor also. I actually take turns with the first two in the mag being chambered. After unloading it to clean or whatever, just insert mag and cycle/safety then pop the mag out & top it off with the previously chambered round.

Check em once in awhile with a caliper. I've pulled down and reloaded a few Hydra-Shoks. Silvertips too. No biggie for a reloader.:cool:

[P95Carry]

P95 carry. See my post. Doing that continually is damaging your extractor. It may break some day when you need it. SPE . thx for pointing that out ..... I had not properly seen that previous post of yours.

However ... if you would ... explain what actually happens?? I always close slide carefully .. no ''slam'' ..... how does this prejudice the extractor?

Not tryin to be awkward .. quite literally .... had not seen a risk!:)

[SelfProclaimedExpert]

On your gun, or any tilt lock pistol, the rounds are fed in such a way that the case rim is slid up and under the extractor as the case head slides up the breechface. As the slide closes the barrel tilts up and completely pulls the rim up.

This process is basically controlled round feeding. Some rifles also use a similar method and have a totally rigid extractor - it's part of the bolt.

Pistol extractors of this type have some flexibility, but not much. Under normal use they flex very little. They also have rather blunt noses. This combination means that the extractor experiences alot of impact and flexing stress as it pops over the case rim. Very hard extractors, like the Glock's, will chip. Pivotless extractors, like the 1911, may loose tension and go out of adjustment.

Either way, it's a big deal since recoil guns rely on their extractors to pull the spent shell out. The extractor has the ability to pop over the rim, by design, but that ability is there in case of jams. As an everyday procedure on a carry piece you are risking making your gun single shot.

Hope that helps.

[P95Carry]

Thx SPE ... that does clarify considerably .... appreciate it. :)

[Poohgyrr]

If we were to get into a long discussion about how to chamber rounds so there is no setback and so on, I'd just suggest a good revolver ;). Like a blued 4" Smith M24 .44 Special...... Now that's da bomb No setback at all ;)

[P95Carry]

Aha .. but Pooh ..... don't forget the lightweight revos where set forward and increase in OAL can happen with hot loads ... also not good news!! Potential hazards to everything.:)

[JohnKSa]

If you're shooting a .40 S&W with a heavier than 165grain bullet then you should NEVER chamber a round more than once, and should quit using any ammo that shows noticeable setback after a single chambering.

The 180 gr, .40 S&W pressure skyrockets with relatively small amounts of setback.

The type of ammo you're using has a lot to do with setback. The aluminum cased Blazer rounds tend to be more susceptible to setback than any other type of ammo I've used.

[SelfProclaimedExpert]

John,

Given such a warning about .40, do you think that is a round that should be recommended to private citizens?

[Dr.Rob]

The worst set-back cartridges are the 357 sig (less brass to grip the bullet) the heavyweight 40's and the big hollwpoint 45's.

I noticed iw as getting set-back on my 45/230gr hyrashocks, but that was mostly because I needed to polish the feed ramp.

Watch for this in your re-loads too, ESPECIALLY in 9mm.

9mm cases have a HUGE variance in case capacity, and what may not be a high pressure load in your Federal brass MAY be one in CCi/Remington/IMI etc. When you load 9mm you should always test the SAME brand of cases whenever possible, load light if you are unsure.

[SelfProclaimedExpert]

Dr.

Despite the 9mm variances you mention, have you heard of them leading to a detonation?

It just seems like 9 and .45 are much more tolerant of deformities.

[Logistar]

May I ask why you are chambering the same round daily? The round in the chamber of my carry gun has been there for a month now. I will inspect/clean it soon. The chambered round will be inspected and placed in my "shoot me next at the range box".

I have seen setback but WHAT would keep this from happening when you originally chambered a round. There would be no way for you to know this happened and would fire the round anyway. :what:

Hmmmmmmmmm.
Logistar

[michiganfan]

I have been chambering the gun daily because I always unload the gun when I get home. I have young children and I don't like the idea of a round bring in the chamber even with a lock on the gun. In my neighborhood I don't as a practical matter need a round in the chamber for self defense..

[WonderNine]

I haven't gone shooting lately, so my Browning HP has been sitting cocked and locked with one in the chamber for the past month. I see no reason to unchamber and rechamber rounds all the time.

michiganfan, if I were you, I'd probably just carry the gun unchambered, depending on what you have.

[Poohgyrr]

P95,
Only crazy people load magnums in those new Ti lightweight revolvers. My hand hurts just thinking about it :banghead:

Now a good K, L, or N steel frame, is a different story, with a happy ending. :D

[SelfProclaimedExpert]

MIfan's problem isn't a unique one. Many cops that do much courthouse work are also forced to clear and rechamber several times a day. That alone would make me seriously consider a straight feeding gun just to avoid the hassle.

[Sean Smith]

Some brands are much more resistant to setback than others, as was noted above. Try a couple brands of ammo and see if one lets you get away with more cycles. If a round has excessive setback, toss it... it can be unsafe depending on the cartridge.

[JohnKSa]

Given such a warning about .40, do you think that is a round that should be recommended to private citizens?
The failure mode isn't generally life threatening, but it can ruin a gun. It's also much more of a problem with some types of ammo and some types of guns than others.

I guess what I'm saying is that there are a lot of .40 pistols out there and not many are blowing up. Still, IMO, taking simple precautions is worthwhile even if it only slightly reduced the chances of a mishap.

Also, I'm not trying to say that the .40 S&W is an accident waiting to happen and that all other cartridges are perfectly safe. Many gun/cartridge combinations have little quirks that an owner is well-advised to be aware of. Glock/lead bullets, CZ-52/dryfiring, etc.

FWIW, my P89DC manual specifically states that single loading by putting a round in the chamber and dropping the slide is an approved method of loading the pistol for training purposes, or when a magazine isn't available. In fact, there's over half a page devoted to explaining the technique. "Lock the slide back, drop a round in, drop the slide using the slide catch." In general, it's a good idea to avoid it unless the manual gives you the go ahead.

[Logistar]

I understand where you are coming from, Michiganfan. Personally, set-back (and the possibility of a slamfire when chambering daily) would make me feel uneasy but I guess if you are careful it should be OK.

As mentioned earlier.... suggestions...

Wheelgun
Always leaving it unchambered 24/7 (not sure I like that one)
Having gun that is not prone to setback.
Change nothing - just keep an eye on it.

(My Taurus WILL eventually cause setback. My "smooth-feeding" Beretta has never caused a set-back for me using the same ammo and under the same conditions.) I think some guns (as well as some ammo) are worse than others.

FWIW
Logistar