.357 SIG Bullets

[giggitygiggity]

When reloading .357 SIG, what bullets are appropriate? It looks like it can take all .355 and .356 bullets that a 9mm Luger can fire, but I remember reading that the .357 SIG has bullets specifically designed for it (something about hollow points of the regular 9mm Luger design not expanding). I just need to know whether I can and whether I should use the same .356 plated or FMJ bullets that I use for my 9mm loads in a .357 SIG. Thanks.

 

[fxvr5]

357 SIG bullets are somewhat special. they have a short nose compared to typical 9mm luger bullets. they're short because the SIG round has very little bullet protruding from the brass. if a 'normal' 9mm luger bullet is used, the bullet shoulder might be below the SIG's case mouth, greatly reducing the neck contact on the bullet. This greatly increases the chance of bullet setback during feeding, which can cause pressure increase and misfeeds.

Some 9mm bullets work fine in the SIG. Sierra's JHP bullets normally have a short nose so they will be fine. Other 9mm bullets should be avoided.

Compare the nose length of Speer's 124 grain 9mm bullet and their 125 grain SIG bullet. note the shorter nose on the 125 SIG bullet.

Look closely at the nose length, and select those which have a short nose.

 

[Walkalong]

They need a longer bearing surface than some common 9MM bullets have. We have plenty of .357 Sig shooters here and they can give you a great selection to choose from.

RMR shows three they say are suitable for .357 Sig.

https://www.rmrbullets.com/product-category/bullets/pistol/357-sig-355/

Here are the RMR 124 Gr TrFPs and MPR JHP bullets. A nice long bearing surface so when they are seated in .357 cases the full diameter part fills the short neck.

Other vendors/makers have suitable bullets as well of course.

 

[vaalpens]

There are a lot of bullets that will work in 357sig, but with every bullet you need to first ensure it will pass the plunk test, it will cycle in your gun and that you don't experience any setback. You can load plated or jacketed bullets, but with plated you need to make sure it can handle the velocity. The thicker plated bullets are the preferred plated bullet to use. I will get a list of the bullets I have loaded successfully in 357sig, but following are the current bullets I load:

RMR 9mm 124gr TCFP matchwinner
https://www.rmrbullets.com/shop/rmr-in-house/9mm-124-gr-rmr-truncated-cone-flat-point-matchwinner/

RMR 9mm 124gr JHP MPR
https://www.rmrbullets.com/shop/rmr...hollow-point-multi-purpose-round-bullets-new/

Sierra #9925 125gr V-Crown JHP
https://www.sierrabullets.com/store/product.cfm/sn/9925/355-dia-9mm-125-gr-JHP

The TCFP bullet I load with a COL of 1.140", the MPR with a COL of 1.125" and the V-Crown with a COL of 1.125".

The above bullets are very accurate and works well in my P229.

 

[JimKirk]

Add the Sierra 125 grain(8125)...
Hornady XTP 124&147 grain...
Nosler 115 & 124 grain ...
Montana Gold 125 grain..

 

[vaalpens]

JimKirk listed some good ones. The MG JHP is a favorite for a lot of 357sig reloaders.

Another good and accurate bullet is the Zero 125gr FPFMJ which was designed for the 357sig.
http://www.rozedist.com/mm5/merchan...RZD&Product_Code=R158-A&Category_Code=ZBJ-9MM

 

[Chuck R.]

Berry's also has a specific 357S Bullet:

https://www.berrysmfg.com/item/bp-9mm-356-124gr-hbfp-tp

and I've loaded these from Xtreme Bullets:

https://www.xtremebullets.com/9mm-124-FP-p/xc9mm-124fp-b0500.htm

As the other guys said, short nose, long bearing surface .355 diameter combined with a slow case filling powder.

 

[giggitygiggity]

Thanks! You guys are awesome! That makes sense about needing a longer bearing surface in order to eliminate bullet setback.

 

[JimKirk]

Thanks! You guys are awesome! That makes sense about needing a longer bearing surface in order to eliminate bullet setback.

The longer bearing surface really has nothing to do bullet setback ...the 357 SIG has such a short neck 0.15" . ... The reason that the long bearing surface works is because the parallel part is far enough forward on these bullets that the neck rests on the parallel ... some .355 bullets have a big Ogive that the neck falls on to the curve ... and does not have neck tension and fall into the case ....

This is also the reason that powders that nearly fill the case works so well with the SIG .... a case full of powder supports the base of the bullet and helps prevent setback...

 

[vaalpens]

The longer bearing surface really has nothing to do bullet setback ...the 357 SIG has such a short neck 0.15" . ... The reason that the long bearing surface works is because the parallel part is far enough forward on these bullets that the neck rests on the parallel ... some .355 bullets have a big Ogive that the neck falls on to the curve ... and does not have neck tension and fall into the case ....

This is also the reason that powders that nearly fill the case works so well with the SIG .... a case full of powder supports the base of the bullet and helps prevent setback...

Excellent write-up explaining why the 357sig needs the longer bearing surface.

SAAMI standards for 357sig is a max COL of 1.140", but is mostly loaded to 1.135". You can load with a longer COL if it will work in your gun. With a bigger/longer ogive it gets difficult to keep the ogive out of the neck and still stay under a COL of 1.140". The ogive must be outside the neck, the round must fit in the magazine, the round must pass the plunk test, setback should be kept to a minimum, round must cycle through the gun reliably.