Posted: 12/27/2019 9:11:02 PM EDT
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. 
Five shot at ten yards offhand. 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 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. https://generalcartridge.wordpress.com |
| Sorry guys. CorBon is garbage. I bought some of the older DPX rounds from a third party vendor. These rounds did NOT have the Barnes bullet, but some sort of proprietary all copper bullet. The first rounds I fired seemed to work okay, it hit the target and everything. Picking up the brass, I noticed that some of the 20 I fired had primers missing. I thought that this might be enough of a problem so I called their company. Several months before, I had ordered rounds from them and NOTHING had showed up. I called the company and their excuses ran from: It was shipped to, we just moved the company and are going to have to find out where it was sent. Letting them know I had bought more of their ammo and that the ammo in question was WAY too hot (pressure wise), they advised me to ship the ammo back to them and that they would REPLACE THE AMMO WITH NEW STOCK. By this time I had it with their company. I said "Seeing as how I ordered ammo from you in the past and it hasn't shown up, Why don't you ship me the replacement ammo to me FIRST and then I'll ship the old stuff back to you. Believing in the philosophy: Fool me once, shame on you. Fool me twice, shame on me. The guy went on and on about the company "moving" and said they'll be getting back to me later.......................I haven't heard from them since................... I now use Barnes for their copper bullets......... |
|
Originally Posted By T-TAC:
Corbon recently sold the company. I'm hearing quality isn't up to snuff. I shot some of their 115 gr. 38 super this week. Worked ok, but charges felt alittle light. |
|
Disappointing. Thanks OP for risking life and limb to bring us data.
The last time I shot some Cor Bon, it was some of my old 90's stash of 9mm 115 +P and many of the cases had splits. Maybe the 25+ years sitting around has not been kind, although the ammo fired, ejected etc perfectly. That brass in the OP is Starline, which is/was considered excellent brass. What could they have done to it to make it prone to such failure? Bad lot of brass sold cheap or wrong powder used? That extreme spread is horrific!! |
|
Thats a bummer, Corbon used to be a great, pioneering company.
The failures are odd, as this is not at all 'too hot' for .357 SIG. Underwood has been loading theres to 1500fps from a G19 for years, and .357 sig is rated for 44kpsi by CIP: https://www.youtube.com/watch?v=ughIFOrIP_w Likewise, my buddy who is huge into .357 sig has fired 5000+ equivalent .357 sig loads, with no issues; his load is a 125gr @ 1600fps from a g35, and thats using 1x fired brass. Either Corbon had a bad batch of brass, or is using an unsuitable powder for their loads. |
|
Originally Posted By 5pins:
Well, the gauges came in and the pistol checks out fine. So it's not a headspace issue. This is very uncool to see pistol rounds rupturing, especially in a relatively common round (albeit high pressure). Appreciate your testing as always. |
|
Originally Posted By bigern314:
When I bought my first pistol I thought Cor-Bon 115gr +p was the shit since it was so high velocity. But I haven't bought any of their ammo in a long time. Sad to see. |