Test Gun: Sig P229.
Barrel length: 3.9 inches.
Ammunition: Cor Bon .357 Sig 125gr JHP
Test media: 10% Clear Ballistics Gel. Distance: 10 feet. Chronograph: Caldwell Ballistic Precision Chronograph G2. Five shot velocity average: 1397fps
Gel Temperature 70 degrees.
It’s been a long time since I used Cor Bon ammo. Back in the late ’80s, it was my load of choice in the 9mm. A lot has changed since then and ammo today is no exception. At the time their 115gr JHP +P was the cats meow so to speak. If my chronograph at the time was to be believed I was getting almost 1300fps out of my Glock 19.
This test was the first time I have shot any Cor Bon in forever but I decided to pick up some in my recent ammo buying spree. It’s also been a while since I tested any .357 Sig, so I got it in that caliber. As we will see, it was unfortunately wrought with problems.
I got a five-shot average velocity of 1397fps with a high of 1493 and a low of 1355fps. That’s a 138fps extreme spread.
When picking up the fired cases I noticed that one of the cases had blown a primer. At that point, I decided to check every case as it came out of the gun.
The first round across the chronograph had a velocity of 1335fps, and when I picked up the case it had a noticeable crack around it about midway up the case. It was also visible on the inside of the case as well.
At this point, a smarter man would have stopped, but I’m not a smarter man and decided to move forward. There were no other blown primers or cracked cases for the rest of the four rounds.
The first round into the bare gel had a velocity of 1410fps and penetrated to 16 inches. The recovered weight was 91 grains and it expanded to .48 inches. Round two. Wait, what happened to round two. The round would not chamber and I discovered the previous round had a case head separation and the front portion was still in the chamber. I tried to find the case from the first shot before loading the second but I couldn’t. I finally found the back portion the the case after looking some more.
At this point I became a smarter man and stopped. After getting the front half of the case out of the chamber I fired 20 rounds of some Sig FMJ and a few Sig V-Crown I had left over. There was no blown primes or cracked cases.