Montana Gold 357SIG/125gr JHP - OAL question

I just ordered a sample pack (100) of the MG 357SIG/125gr JHP bullets to see what the fuss is about. I am planning on testing them out for setback, cycling through the gun and a few exploratory 357sig loads. I am also planning to see if/how they perform in 9mm.

For those out there that load these bullets in 357sig. What is the minimum safe OAL for these bullets assuming you have mixed length brass. Can you load them to 1.135" with the mouth of the case still safely below the bullet ogive, or do you need to go a bit higher? I know the OAL is gun specific, but I just want to get and idea what the MIN OAL is based on the bullet shape.

Thanks in advance for any comments/information.

blarby said:

I'm actually just running this exact combo- SIG and 357 sig- just finished 600 of them last night, as a matter of fact.

Like 'em in front of 9.1grs of HS-6


You can load these to whatever length you need for your gun. They are the ABSOLUTE PERFECT bullet for the 357 sig.

Click to expand...

Thanks blarby. I will pick my longest case and verify what OAL the bullet will accept as a minimum OAL. I normally load 1.135" or 1.140".

blarby said:

Sig mags can be tight.

Try and keep it at 1.135 if you can, but don't worry about 1.140 if they function

I've found that "plunk testing" all my 357 sig loads after loading has saved me a lot if aggravation.

Sizing, as well as bullet, are critical on 357 sig. With mixed brass, I always get a couple that don't chamber right and get pulled. If after resizing, they still won't chamber, they get culled.

I got a lot less culls after I lapped my shell holder and my sizing die to mate perfect. Took about .003 off the shellholder, and just .002 off the die... They mate like a glove now, and my shoulders are much better formed.

Click to expand...

blarby, thanks again for the advice. I load Berry's 124gr HBFPTP at 1.135" and RMR 124gr HMPFN at 1.140". Both cycles without any issues and my P229 magazines have no problems feeding them. I even load my 40cal to 1.142" using the same magazines. Also no feeding issues.

Do you test chambering after resizing, or after round completed?

I have just added a debulging step to my process for 357sig and have not had any feeding issues so far.

For my sizing die I just measured all my shellholders and picked the thinnest one. Not sure if it helps any, but at least it is not causing any issues.

I received my sample pack of golden beauties today and loaded up 3 dummy rounds. The dummy rounds were loaded up as follow:
-Selected .860" Speer cases (yes, I measure my 357sig cases)
-Expanded/belled each case
-Seated with target 1.135" COL
-Taper crimp with Lee FCD to .3785"

The following test was completed for each rounds:
-Lock slide back
-Load round in magazine and seat load magazine
-Release slide
-Measure COL
-This test was done 3 times for each round
-Plunk test
-Do a final bathroom scale test to see if we have any neck tension left (please note that I use a digital bathroom scale so I need to hold the bullet for about 5 seconds before the weight registers. It is a good test)

Following are the starting COL and COL after each cycle and the bathroom scale lbs.

Round 1:
1.1355"
1.1335"
1.1325"
1.1295"
Passed plunk test
18lbs test without bullet being pushed into case

Round 2:
1.1370"
1.1365"
1.1360"
1.1355"
Passed plunk test
21lbs test without bullet being pushed into case

Round 3:
1.1370"
1.1370"
1.1370"
1.1360"
Passed plunk test
19lbs test without bullet being pushed into case

My conclusion is that I will be able to use these bullets in 357sig with my current process. It looks like I will seat it with a 1.1370" COL since it seems I had less setback starting at 1.1370"

misterarman said:

Shoot Glocks and 1.140 works for me.
Shot my new load yesterday. AA#9 with the MG 125gr JHP .357sig bullet.
Have done hornady XTP and MG JHP in 115 and 124gr and all have worked but I like the new combo best.
Cam over on sizing works for me for shoulder set back and sprung for the Dillon carbide sizer.
Love my RCBS stuff but they consider it a rifle cartridge and will only do a 2 die set.
Had a lot of trouble with nickel cases scratching the inside of their sizer die and getting proper shoulder set back.. Ended up with 3 and were returned more than once to get polished and have since been moved along.

Click to expand...

I have not tried any of the AA powders, but will probably try the AA#5 or AA#7 first. I prefer powders that can do double duty in 9mm and 40s&w.

Can you share the results from your AA#9 shooting?

Interesting comments you have regarding the nickel cases. I have a few of those but have not loaded any of them. Probably won't scratch my cheap Lee dies.