Neck Sizing Bottle Neck Pistol Cartridges?

[Brian Pfleuger]

Why not?

I mean, aside from the apparent fact that no one makes the dies....

Why could you not or would you not neck size cartridges like the 357sig?

Why could a person not use a lathe to drill out a full length die and make it neck size only?

[Christchild]

Unless You're using the bottleneck pistol cartridges in a bolt rifle or a revolver, they should be full length sized, as we all know is the case with bottleneck rifle brass.

That is a pretty good idea, though...

If You've got an extra die and the tooling, It'd be an interesting project.

[Brian Pfleuger]

Unless You're using the bottleneck pistol cartridges in a bolt rifle or a revolver, they should be full length sized,

Why? Will they not extract correctly the second time?

My chambers measure like .426, the max size specified for the case body is .424 and my die sizes them to .421 at the bottom and .419 just before the shoulder. They're rather "sloppy" when chambered. Seems like neck sizing would improve accuracy and brass life....

[oneounceload]

Rifle brass for semis are FL sized to ensure feeding into the chamber - I would think the same principle would apply to a semi pistol. My one pistol that uses a bottle-necked cartridge is a bolt action, I neck size the brass and get 15-20 reloads from each piece

[Brian Pfleuger]

Rifle brass for semis are FL sized to ensure feeding into the chamber - I would think the same principle would apply to a semi pistol.

Isn't that less of a problem if they're always used in the same gun? Or is a close fitting case likely to stop the bolt from closing on a semi?

[Crosshair]

One way I've heard to size .357 sig without lube is to size the body with a carbide 40 S&W die, then size the neck with the .357 sig die. Never tried it so do so at your own risk.

[Brian Pfleuger]

I am currently sizing with a 10mm carbide and a sig die. I'm just wondering why it couldn't be neck size only.

[Tex S]

Reliability issues are your answer Pete. Brass in a semi auto pistol needs to be fl sized to ensure it will feed properly.

Take a fired case and measure the body. Fl resize it, and measure again. It sould be a few thousandths of an inch smaller. This few .001's may seem miniscule, but it is actually very important for proper feeding.

[SL1]

Tex S,

I use the body (only) of a Lee FCD in .40 S&W to size my .357 Sig brass, then run it through my Sig die. That reduces the base of the case less than using a regular 10mm or .40 S&W carbide sizing die, because it is not trying to reduce the base of the case to the same diameter that it needs to reduce the mouth in order to grip a bullet. You might see if that works for you before you start drilling out Sig dies.

I am assuming that you are using the .357 Sig cartridge in an autoloader. For that use, the method above works fine, as you would expect using the .357 Sizing die last. I am not sure that it would still work if the Sig die only neck sized, because the shoulder needs to be bumped back a few thousandths. I load my .357 Sigs to head-space on the shoulder, with the case head being set at 0.002-0.003" below flush with the end of the barrel, but when I measure fired cases, they stick-up above the end of the barrel by a few thousandths. So, unless you bump the shoulder, then cartridges may not let the gun go fully into battery. That can lead to failures to fire or worse.

If you are using these Sig cartridges in a Contender break-open action pistol, there is another reason to not neck size. I will only go into that if you ttell me that is indeed what you are using them in.

If you are using them in a bolt-action, then I think you can treat them like any other bottleneck case in a bolt action gun and neck size them, only.

SL1

[Brian Pfleuger]

I use the body (only) of a Lee FCD in .40 S&W to size my .357 Sig brass, then run it through my Sig die. That reduces the base of the case less than using a regular 10mm or .40 S&W carbide sizing die,

What is the diameter of the finished case? If only there was a way to fit the FCD die with a decapper....

[SL1]

Peetzakilla,

All of my reloaded .357 Sigs have been fired right now. I will process a case and answer your dimension question later.

I DID put a decapping rod in a Lee FCD. I had to buy a hex head bolt that fit the Lee die body and drill/tap it for an RCBS decapping rod. It took a drill press with machinist vice and a couple of tries to get the hole drilled straight enough to make the decapping pin line-up properly with the case flash hole. So, it is not a job you can do with a hand drill and bench vice.

SL1

[Brian Pfleuger]

I wonder if I don't run the case all the way into the 10mm die if I might get better sizes. I have run a few cases through the sig die alone and it doesn't seem THAT hard... but I would probably get one stuck eventually. I bet that I could run it about halfway into the 10mm and then go to the sig die and be OK though. I'll have to try that and see what I get.

[azredhawk44]

Pete, the shoulder also needs bumping back.

.357sig and .400corbon headspace off the shoulder.

Too much headspace and you have the pistol out of battery. If the primer goes off while the pistol is out of battery, you have a bad thing. Much like an unsupported case explosion in an older .40 glock.

You have to full length resize to ensure proper headspace on the shoulder and that the cartridge doesn't hang up due to being slightly oversized around the body.

[Brian Pfleuger]

You have to full length resize to ensure proper headspace on the shoulder

Hm, what I was actually thinking was a die that would do the neck AND shoulder. Now that I think about it more I would imagine that it wouldn't work. You'd most likely crush the case if it wasn't supported when you tried to size the shoulder area.... So, the case would have to be supported and a supported case is going to mean a sized case.....

So, what I really need is a sizing die that actually makes the cases .424 instead of .421 sloping to .419.

[SL1]

Peetzakilla,

I used a range-pick-up .357 Sig case to get your measurements. It was not (yet) fired in my gun, but was in somebody else's and I don't know what make or model.

Dimensions as-found, afte sizing in a Lee .40 S&W FCD die body, and after sizing in a Redding .357 Sig steel sizer are as follows:

                         base                     Shoulder
As found:          0.429-to- 0.430              0.423-to-0.427
After FCD:         0.426                        0.423-to-0.425
After sizer:       0.426                        0.423-to-0.424

Apparently, the shoulder was squashed a little on one side, maybe by ejection. It looks like you would get your 0.424 shoulder with this set of dies. That is not to say that another sizer die wouldn't leave smaller diameters than mine does.

I have never had a failure to feed with this die set-up.

SL1

[Brian Pfleuger]

Hm, that would be perfect. I guess I could decap them manually. Not the most attractive option but I don't know anyone with the machinery to drill a decapper assembly like you mentioned.

[SL1]

Why not just size in the .40 S&W die body first and then decap and size with the regular .357 Sig die?

I made the decapper insert for my .40 S&W FCD because I wanted to load .40 S&W. I size with that first, and then with a regular .40 S&W carbide sizer just far enough down to get a little below where the bullet base will stop when seated.

SL1

[Brian Pfleuger]

Ah yes. I wasn't thinking straight. That would work wouldn't it.
Why would the 40SW FCD size cases larger than a 10mm carbide though? That part doesn't make sense. Plus, the sizes you measured are larger than my sig die makes by itself so I've got to wonder if running the case through the 40 die would even help or if I'd just end up with the same size anyway.

I don't particularly want to buy more dies.... I think I'll try running the cases only half way into the 10mm die and see if the final size is better. If not, is it safe to assume that a 10mm FCD would produce the same results as the 40? At least I might actually have a use for that someday. I don't plan to ever own a 40.

I also just noticed that Lee is making bottle-neck pistol FCD. Their site says that the FCDs are carbide but doesn't specifically address the new bottle-neck versions. If the sig FCD is carbide then that would seem to be the obvious solution.

[SL1]

Peetzakilla,

I THINK you said you are using a regular 10mm sizing die, not the body of a 10mm FCD. If that is true, then you are sizing the case down more than enough to be able to grip a bullet (even after you expand it with the next die). If you did that with a steel die, it would be tapered so that the base is not sized as much as the mouth. But, with a carbide die, the sizing is done by a short ring in the die mouth, so the only taper that can occur is over a distance that is the thickness of the ring (or less). That means that the wall area of the case way down by the web is sized almost enough to hold a bullet when you use a carbide sizer die. I think that is what is happening to you. In contrast, the Lee FCD (for straight cases) has a carbide ring, just like a regular sizer die, but the ring has a larger diameter. It is NOT intended to make the case small enough to grip a bullet, but rather just small enough to ensure that it will chamber.

If I remember correctly, you are using the carbide 10mm die before the STEEL .357 sizer die because you are trying to avoid lubing the steel die. You can do that successfully with the body of a Lee FCD, but without getting the base undersized.

Regarding the Lee FCD for the .357 Sig, I have recently read somewhere (this forum or another) that Lee is making a FCD for the .357 Sig that is like their FCDs for bottleneck rifle cartridges. If so, then that is a completely different design from the FCDs used for straight-walled cartridges. It would not have a carbide ring in the body, bt would use a collet to squeeze the mouth of the case to make the crimp, instead of using a tapered sleeve. So, that might help with a crimp or set-back issue, but not with a sizing issue.

I think I read that Dillon makes a real carbide sizer die for the .357 Sig, (and that you need to be rich or have a government bailout to buy it).

SL1

[Brian Pfleuger]

You remember correctly.

I guess I'll be getting a 10mm FCD die. Thanks for the explanation.