357 sig issue

[packetloss]

So far I've only loaded about 100 rounds of 357 sig. The first 50 were all using nickel plated Speer cases and I didn't have any issues with them.

The second set however, I used once fired Winchester brass, everything case gauged and plunked in the barrel, however, the gun wouldn't go into battery with them. If I gave it a light tap, it would go into battery and there was no bullet setback or any other marks on the round. I'm guessing I messed something up (neck adjustment? - I did reset the sizing die between when I ran the first batch and the second), but figured I'd solicit some advice before I make any adjustments. If it plunks and spins, shouldn't it go into battery? Sig P320.

My setup is a Dillon 750, Dillon 357 sig dies. Using RMR 124gr MW bullets with a 1.41 OAL, Crimp is .3770. These same bullets with this same OAL worked fine with the Speer cases.

 

[Blue68f100]

Did you load to the same charge as last time. If lower it may not be moving the slide back far enough to feed properly.

 

[packetloss]

Yes, the same loads as first time. It won't go into battery on any round (first or after firing a round) and the rounds eject rather far as would be expected for 357 sig.

 

[WrongHanded]

I wish I had an answer for you. I too use the RMR 124gr MW at around 1.40" OAL, though I use Starling brass.

It could be the brass, or perhaps it's a difference in charge (if there is one), or maybe something unaccounted for such as a different magazine?

 

[fxvr5]

Based on what you described, it sounds like the sizing die is not screwed down far enough and the rounds are headspacing before they are fully chambered.

 

[dcloco]

Unfortunately, this is typical of bottleneck pistola cartridges.

Your chamber might be on the minimum spec of SAAMI.

Without filling with powder or primer, make a dummy round, as your press and dies are set up now.

Use a black sharpie and color the shoulder area, above, on, and below - basically, a black ring around the entire shoulder area.

Color the very top edge of the case mouth and bullet/casemouth junction.

Let the ink dry for fifteen minutes.

Now...TRIPPPPPPPPPPLE check the pistola is unloaded. Install mockup round in the mag, open slide and hold in open position, insert mag into magwell, pull back and release slide, let slide seat with normal recoil spring tension. Did pistola go into battery or still held up slightly? Remove dummy round and check the ink - should tell the story.

 

[loadedround]

If you are using Dillon dies in your 750, you are experiencing the same problem I had when loading .223/5.56 cases in my AR15. Dillon sizing dies need to be slightly ''over torqued'' when first setting them up in your press. By ''over torquing'', I mean screwing your sizing die in until it touches the shell plate, then giving it approximately a 1/2 turn more and then lock it in place. This tip came from Dillon Tech service and it worked for me. I also suggest your buy a case gauge for your 357 Sig case. A case case for that caliber is worth it's weight in gold! I load 357 Sigs also and I speak from experience.

 

[JimKirk]

You said you reset the sizing die ....did you adjust it in or out and how much?

 

[packetloss]

Thanks everyone. I do suspect it's the shoulder. I had adjusted it out slightly from my initial load since I figured I shouldn't push the shoulder back out further than it needs to be. I had plunked that case and it fit fine in the barrel (but so did the reloaded rounds). So at this point I will adjust it further in and load up a few dummy rounds to make sure it goes fully into battery with them.

 

[fxvr5]

I had adjusted it out slightly from my initial load since I figured I shouldn't push the neck back out further than it needs to be. I had plunked that case and it fit fine in the barrel (but so did the reloaded rounds).

Since this is a bottlenecked cartridge, they could easily pass the plunk test and still not headspace. It might not be a neck issue, because a shoulder issue can also prevent it from seating all the way. The 357 SIG officially headspaces on the case mouth, but if the shoulder is too long, it won't chamber all the way. The shoulder has to be pushed back far enough to allow the round to seat. Some folks set up their dies for it to headspace on the shoulder, and that's fine, too.

 

[dcloco]

Thanks everyone. I do suspect it's the shoulder. I had adjusted it out slightly from my initial load since I figured I shouldn't push the shoulder back out further than it needs to be. I had plunked that case and it fit fine in the barrel (but so did the reloaded rounds). So at this point I will adjust it further in and load up a few dummy rounds to make sure it goes fully into battery with them.

Sharpie will be your new best friend............