Reloading .357 Sig/9mm


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Dorryn
January 1, 2008, 02:02 PM
Apologies if this is addressed elsewhere: I did a search and did not find anything exactly answering my question.

Given that many reload to save money (as I do), and given the rising cost of components, one way I would like to save money is by reloading rounds with which I can "double-up". For example, I can reload both .357 Magnum and .38 Special with the same set of Lee Carbide Dies. This saves money because I dont have to buy any new dies.

What I would like to do, eventually, is begin reloading both 9mm and .357 Sig. Currently I do not have firearms for either of those platforms, although I have plenty of brass saved from the range for both. Many have said that the .357 Sig is a 40 S&W necked down to take a 9mm. However, this is of course not entirely correct:

9mm Luger bullets are listed as .356, while .357 Sig are .355. One of the reasons I thought I might be able to save money (albeit probably not much) would be to use the same bullets for both, by buying in bulk. However, then I discovered that the bullets are two different sizes, though only 0.001 apart. Does this really matter? Are the bullets interchangeable or only one-way or neither? Is the difference a practical concern (I dont really load hot rounds) or is it no big deal?

Apologies for my ignorance, I just want to know what can and cannot be done so I can plan what new rounds to expand into reloading.

I already load .40 S&W and .38 SPL... I derived the above information from the Lee Modern Reloading book(2nd Ed.).

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ReloaderFred
January 1, 2008, 02:51 PM
Both the 9x19 and 357 Sig use the same diameter bullet, but in the 357 Sig, you'll have to use a flat point or hollowpoint bullet, due to the short neck of the case. Pointed bullets don't allow enough neck tension in this round and bullet setback can be a serious problem, since it works at a high pressure to start with.

I'd suggest investing in some good loading manuals before you start loading. The Lyman 48th Edition is a good one, and there are others. I own them all and believe you can't have too many manuals.

Hope this helps.

Fred

RidgwayCO
January 1, 2008, 03:13 PM
Fred's right... .355" diameter for both 9mm and .357 Sig. I believe the .356" diameter is for lead bullets.

I've always stayed away from the .357 Sig because I assumed the bottleneck case needed to be lubed prior to sizing, and wanted to avoid the mess.

Then I read somewhere that you could resize the case body with a .40 S&W carbide resizing die, and then resize the neck with a carbide 9mm resizing die. Sure it adds an additional step, but it's still much simpler than having to lube, resize, and then clean the lube off the cartridge cases.

I shot a .357 Sig for the first time last month, and liked it a lot. Might have to look into this cartridge in 2008!

Dorryn
January 1, 2008, 03:26 PM
So all 9mm bullets are .355, not .356 as is listed in the Modern Reloading book? Which would mean my only concern is not diameter, but how deep I seat the round (and how the tip is shaped)?

ReloaderFred
January 1, 2008, 04:11 PM
The 357 Sig lubing is a small item to deal with. You just give them a quick spray with lube and then after sizing and cleaning primer pockets, tumble them for about 20 minutes in untreated corn cob. As for sizing them in two different dies, you could run into a problem with the shoulders, and a lot of 9mm dies are belled at the opening of the die, which means they may not size the neck properly, even if set up for the right depth. Just use the proper die and it's no problem.

As for the diameter of the bullets for 9mm, I've even loaded .357" diameter lead bullets in 9mm and they worked just fine. You just have to work up your loads, just like for any other change of component.

Hope this helps.

Fred

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