The 357 Sig bullet 'can' creep or slip into the case, even with brand new factory ammo, based on my experience. While this condition can occur with most all calibers, the 357 Sig only has approximately 1/8" of neck to hold the bullet, although that is sufficient if the round is loaded correctly. Another issue which is discussed in item 13 below, is that the 357 Sig shoulder may not always be positioned correctly, which can cause strange light primer strikes and ignition problems.

There is a simple work-around for agencies and those who carry the 357 Sig on a regular basis. This is especially critical for those that constantly unload and reload the same duty ammo into their gun over and over again, possibly for months.

Obviously, if you carry your pistol on duty or in concealed carry, you must occasionally practice with your pistol to make sure everything is working well. In order to do that, you take out the expensive 357 Sig ammo and replace it with practice ammo. After the practice session and after cleaning the pistol, the expensive 357 Sig Duty Ammo is loaded back in the gun. The agencies that I'm familiar with don't generally have the luxury of shooting out the expensive duty ammo and getting a fresh supply during each practice session!

Oh, you don't believe there is an issue? Try this experiment. Measure the Over-All-Length (OAL) of your factory and/or reloaded 357 Sig cartridge, and then put that round into your magazine and rack the round into the pistol chamber, using the full force of the slide spring. Then, carefully extract the cartridge and measure the OAL again. Do this procedure 5 - 10 times in a row. I rest my case. For what it's worth, the bullet holds in place best with new brass.

Various ammo companies such as Speer have indeed replaced 357 Sig ammo on request. Hopefully, in time this concern will become a moot point for this new round, although it's a team effort; the Ammo Company has to manufacture good ammo and the consumer has to follow some common sense solutions as described below. But for now, it's a malfunction waiting to happen. Follow the simple solutions below so you're not caught off guard. 

Next, rotate the order of your duty ammo each time you reload your factory ammo into a magazine. The cartridge that 'was' in the chamber most recently, becomes the bottom round in the magazine next time you reload your gun. Also, before reloading the factory ammo into your magazine(s), use calipers if you are not sure about eyeballing the OAL (cartridge over-all-length). If the original length is say 1.135", then when it gets down to say 1.130", replace it.

I can't necessarily recommend this to others, but I go ahead and shoot the 'slightly' shortened cartridge, as long as it doesn't get too short! This call is best made by you and/or your range officer, and should be based on the type of powder used, etc. You 'should' request a minimum safe OAL from the ammo manufacturer; if nothing else, this would alert the ammo company that you are concerned and are indeed aware of a quality safety issue.

Ernest, an Ammo Manufacturing Engineer, stated the following:

"There are a TON of folks out there who constantly load and unload the top round in their magazine, and then complain that the overall length is changing. In fact, battery of the case neck can weaken it so much, that the shrinking tendency will rebound, and all of a sudden, the bullet is gone! Where? Down the bore! The darn things pop out of the case upon chambering and fly down the bore to create an obstruction for the next round. (This happens when there is excessive free-bore between the chamber mouth and beginning of the rifling) Then, the shooter complains I sent him a cartridge with no bullet. Never mind the fact the powder arrived in a case, without a bullet, and found its way into the chamber without spilling somewhere along the way."

Just because it's factory ammo, regardless of caliber, do not blindly believe it is therefore OK and will always be OK. Go ahead and monitor the OAL and do the thumb pressure test as described in the next section. Take these few simple precautions seriously.

Reloaders should have less of an issue since they normally just load the ammo once into their gun and shoot it. They just have to follow the necessary reloading precautions to make sure their reloads are adequate.

1. Use good brass and check it each time before reuse.

2. Count your brass usage, so everything in a given group has the same age, wear, brand, etc.

3. Check the trim length, especially if you are loading full power rounds. If you use groups of brass as mentioned in item 2, you may be able to just spot check some brass to get a good idea if the trim length is staying within specs. If you don't use groups of brass, then you should check every brass. I've never had to trim my Starline brass.

4. Lightly spray lube the cases before resizing. There is an engineering necessity why bottlenecked cases need to be lubed. Even if you believe you're successfully getting away without lubing the small 357 Sig case, you are asking for trouble. Refer to a good reloading manual for the details.

I have never directly lubed the inside of the case neck, in conjunction with using a Dillon carbide resizer, and have had
no ill effects to date. Although, an indirect lube does occur inside the neck, from my fingers constantly holding the top of
the neck and manipulating the bullet to be seated.

5. Do a full case resizing to form the brass as close as possible to its original shape. I highly recommend the Dillon carbide resizer, which does an excellent job. It's expensive and costs around $75, but well worth it. The carbide resizer still requires lubed cases, but does not produce as much friction as all-steel resizers, and makes operating the press a little bit easier as a result.

6. Do not expand the case opening so you can visibly see the belling effect! Instead, just lightly expand the mouth opening so the bullet will just barely squeeze into the case. This will cause the bullet to hold much more firmly in place --- very important! A bullet with a slightly beveled base, or even a tapered base, is best (examples: Rainier 124 gr. flat point and the Hornady 147 gr. XTP).

For a rough example using Rainier plated 124 grain flat point bullets: I do a full resize and the mouth measures aprox. .374. In the belling stage, I expand the neck to roughly .378 - it does not look belled at all. I then seat the bullet which then measures aprox. .3795. I then crimp which brings the measurement to aprox. .379.

If the bullet does not have a beveled base, you `might' have to expand the neck just a tiny hair more --- but keep it as tight as possible so the bullet just barely fits --- I cannot over-stress this fact. Another possibility is to lightly chamfer the case mouth so the bullet can be seated without crushing the case (I haven't personally used chamfering for my reloads).

7. Use a 9mm bullet that has a .355" bearing surface at the point where you will be crimping, otherwise, the bullet will have a tendency to slip, and/or you will be forced to crimp far tighter than the recommended SAAMI specs.

Many 9mm bullets are unsatisfactory because they have a long tapered bearing surface. Some are deceiving since they measure around .352 at the crimp point, so be careful.

Speer actually makes 357 Sig labeled Gold Dot and TMJ 125/147 grain bullets, These heavier bullets are quieter than the faster 125 grain loads, and are still more potent than when loaded in 9mm Luger or 38 Super --- not bad for being shot out of the same size pistol as a 9mm Luger.

Speer, Hornady, and Rainier bullets can be found in various gun supply stores and mail order stores like Blue Press, Midway, etc. I just found another excellent 124 grain flat point bullet that is full metal jacketed (ideal for maximum velocities) and available for aprox. $55/1000 from D & J Bullets (www.djbullets.com).

8. The SAAMI taper specification is .381. I taper crimp to around .379, which is a firm taper. I have taper crimped as tight as .378 to .379, with no ill effect. It might even cause a slight taper ring around a soft bullet, such as the Rainier 124 grain flat points. Too much crimp can cause accuracy problems, deformation of the bullet, seating problems in the chamber, and can actually cause the bullet to loosen up.

If you are taper crimping down to .376 or so, then the bullet you're using does not have a .355 bearing surface at the crimp point, or you are deforming the bullet.

9. Wipe the lube off by using a vibrator tumbler for 10 minutes, or, use whatever technique you feel comfortable with.

10. I prefer to use the higher end of the maximum Over-All-Length for the 357 Sig cartridge. Maximum is 1.140. So I generally keep my rounds between 1.135 and 1.140. This is a good safety factor for lessening an over-pressure occurrence, just in case the unexpected bullet slippage should occur.

11. I prefer to use a powder that fills the case like Blue Dot or AA#9. These powders can actually help hold the bullet in place and still maintain acceptable pressures, based on studies done by AA and Mermelstein. Another excellent propellant for the 357 Sig and .40S&W is Power Pistol, which is a medium-slow burning powder. The 50th edition Sierra Reloading Manual and the 13th edition of the Speer Reloading manual give examples of several powders used for the 357 Sig. The newest editions of Reloading Manuals that will be coming out in the near future will no doubt be supporting this new round as well.

12. Spot check some cartridges by performing the thumb pressure test. Once again, it's best to be using a group of brass with the same brand, age, etc so characteristics will be similar. Put the bullet end of the cartridge on a hard surface, and gently apply fairly strong thumb pressure on the primer end. Measure the OAL before and after this test to make sure the bullet is holding.

You can do the thumb pressure test on a weighing scale; it should be able to at least handle 45 pounds of pressure. If you keep performing this test over and over again, you will eventually be able to push the bullet all the way into the case.

The cartridge should be able to handle the thumb pressure test in order to simulate having the cartridge forcefully fed into the chamber. In fact, instead of the thumb pressure test, you can use a magazine to simply load a round into the chamber using the full force of the slide spring. Then carefully extract it and measure the OAL to make sure it is passing the test.

13. And Finally, Headspace (To be on the case mouth, or, To be on the shoulder, That is the question):

The very first 357 Sig article I read was in the second half of 1995, written by Ed Sanow. He got his facts from Federal and Sig Saur, with a touch of his own thoughts as well. At that time, he wrote that the 357 Sig headspaces on the case mouth, making it easier to measure the OAL (over-all-length).

Well, it's getting close to 2000, and the 357 Sig has been maturing. Now I've been told from a couple reliable sources, that the 357 Sig headspaces on the case mouth and the shoulder. More, recently, I read that the shoulder has precedence in determining headspace. I have not officially seen something in writing from Sig Arms or an ammo company to absolutely clarify this point.

Based on all of this interesting headspace info, I currently believe that if you are experiencing light primer strikes and inconsistent ignition, then very likely, cases have been sized with an improperly positioned shoulder. All the other measurements like trim length, OAL, etc, are important too of course.

I base this information on my own personal experience, and the archive article listed below, as well as observing weak primer strikes from a fellow shooter at a recent IPSC match.

The base of the shoulder is 0.6490", measured from the bottom of the case. The top of the shoulder measures 0.7150".  I was taught that a bottlenecked cartridge headspaces midway on the shoulder. In the case of the 357 Sig, that means it headspaces at right around 0.6820. With a set of calipers, it is easy enough to measure from the bottom of the case to the mid shoulder position to see if you're in the ball park.

Interestingly enough, with my Dillon 550, Dillon dies and a Lee crimper, I have never had a problem loading the 357 Sig. My agony was to initially find 9mm bullets that were compatible with this new cartridge.

I just reloaded the same 357 Sig brass for the tenth time, and all measurements are still fine. The shoulder is positioned fine, and the bullet is still holding snug. Until recently, I never even measured the shoulder headspacing as a standard check. But I'm very glad to be aware of it now.

I have been lucky with my particular 357 Sig setup. There are many different dies, presses, guns, people, etc. So some people have had problems and others haven't. Hopefully, as we all learn more about the 357 Sig, and "CORRECT" reloading data is published, it will be easy for even a "New Reloader" to come up to speed fast. After all, the 357 Sig ain't a century old like the venerable 9mm and .45 --- nothing like being a pioneer!

Here's some sites that have some good 357 Sig info:

http://www.Gunnery.Net/sig/allnew357.html
http://www.realguns.com/archives/001.htm (357 Sig headspace article)
http://odaiko.ss.uci.edu/sig/sig.html
http://www.rec.guns