357Sig KB w/KKM BBL Underwood Ammo

[my_old_glock]

And here I thought they made 357 SIG to hit .357 mag velocities.

The .357 Sig was never intended, nor did it achieve, .357M power levels (in comparative commercial loadings).  It was marketing.  .357 Sig just sounds better than .355 Sig, or 9mm Sig.

I though the 357 Sig with a 125 grain bullet through a 4" barrel was suppose to mimic the performance of a 125 grain bullet through a 4" revolver.



.

[sqlbullet]

Ballistics by the Inch shows the Corbon 125 grain JHP factory loads at 1496 for 357 mag and 1468 for 357 sig from a 4" barrel

The Federal 125 grain JHP factory loads are 1511 for 357 mag and 1426 for 357 sig, again from a 4" barrel.

This does not take into account the real world differences in gun types as the BBTI crowd uses a contender barrel they cut down.  No cylinder or cylinder gap in play here.

They do test in real world guns as well.  In a S&W 686 357 Mag the Corbon load made 1477 fps and the Federal load made 1426 fps.  In a Steyr M357 in 357 Sig the Corbon load made 1410 and the Federal load made 1367.

It seems the 357 Sig trails 50-100 fps behind the 357 magnum in most factory loads.  However, guns in 357 sig of comparable barrel length will be physically smaller and generally lighter than their 357 Mag counterparts, not to mention carrying significantly more rounds.

[my_old_glock]

Ballistics by the Inch shows the Corbon 125 grain JHP factory loads at 1496 for 357 mag and 1468 for 357 sig from a 4" barrel

The Federal 125 grain JHP factory loads are 1511 for 357 mag and 1426 for 357 sig, again from a 4" barrel.

This does not take into account the real world differences in gun types as the BBTI crowd uses a contender barrel they cut down.  No cylinder or cylinder gap in play here.

They do test in real world guns as well.  In a S&W 686 357 Mag the Corbon load made 1477 fps and the Federal load made 1426 fps.  In a Steyr M357 in 357 Sig the Corbon load made 1410 and the Federal load made 1367.

It seems the 357 Sig trails 50-100 fps behind the 357 magnum in most factory loads.  However, guns in 357 sig of comparable barrel length will be physically smaller and generally lighter than their 357 Mag counterparts, not to mention carrying significantly more rounds.

(just a note/comparison)

A revolver's barrel length is measured from the forcing cone to the muzzle. The cylinder length (chamber) is not counted.

I semi-auto pistol's barrel length is measured from the breach-face to the muzzle. The chamber length is counted.

A 4" 357 Magnum revolver barrel is roughly comparable to a 5.5" semi-auto barrel. The cylinder gap may interpolate to a shorter semi-auto barrel.

In overall gun size, my G20 with 6" barrel and a long slide is roughly equal to my 357 Magnum revolver with a 4" barrel. The revolver is wider. Width and length is within 1/4".

From the Ballistics by the inch website, the Corbon 357 SIG w/125gr JHP reaches 1550 fps from a 6" barrel, and the Corbon 357 Magnum w/125gr JHP reaches only 1477 from a S&W 686 with 4" barrel. For the same size gun, the 357 SIG shows ~75fps more velocity. A Glock 20 with a 15 round magazine and 1 in the chamber has twice the capacity of an 8 shot 357 Magnum revolver, and unless your name is Jerry Miculek magazine changes will be faster in the G20.

http://www.ballisticsbytheinch.com/357sig.html

http://www.ballisticsbytheinch.com/357mag.html

.


.

[sqlbullet]

my_old_glock, we are on the same page. 

You came right out and said what I was alluding to.  In a gun of comparable size, the 357 sig will have more velocity and more rounds.

[ppro]

Just thought to mention....re Underwood ammo...I have shot a LOT of Underwoods  357 SIG loads.  I have hoarded quite a bit of it with the Speer 125 gold Dot but note:  I have had a number of S&W M&P's full size and compact, in 357 Sig.  I did have one in particular (full size) that could not shoot the Underwood loads.  The 357 Sig barrel in that gun, was extremely accurate, more so than most but, it would not handle the Underwood ammo...to hot in that barrel.  No problem in any of the other guns.  I suspect dimensions of that were on the tight side, (possibly the chamber too though I don't actually know) but using that particular barrel, it would drop the primers out of the fired case.  I could switch that same barrel into the other guns, and get the same result...primers falling out.  Nothing of the sort with the other guns and other barrels.

So it just goes show that each combination can be somewhat of a rule unto it's self.  Which is why when reloading, the same applies... A number of guns may take a top loading combination...and the next one won't.  Don't assume, test.