Anyone have any problems running Blazer Brass 9mm in their blowback PCC ? Read on another forum it had blown up more than one EVO and that it had a weak crimp causeing set back as it chambered. I'm seeing no other mention of issues or details so may be internet run amuck. Any thoughts ?

Blazer brass is my 9mm round of choice (damn you PSA).  I don't have a straight blowback PCC, but I do have a CMMG RDB AR and multiple handguns.  I have personally witnessed exactly one set back bullet.  It was a round I had chambered and ejected several times in a carry gun.  Can't say for certain if that caused it, or I dropped it, or it came like that.  I'm not concerned about it.

I will say that it was a real struggle to pull the bullet back out of the case with pliers.  So I'd say the crimp was plenty tight.

Don’t use Blazer Brass often, but when I do, there haven’t been any issues, in my blowback PCC’s or anywhere else.

Never had an issue myself. And I shoot a lot of PC.  But I almost exclusively shoot speer law man for 9mm anymore.

I've ran two cases of CCI Blazer 1K bulk boxes through my Scorpion. Zero issues!

No issues in my ar9

The range I work at has had Scorpions in the rental program for the past two years. Our range ammo has been Blazer Brass 5200 and 5201 for the past four years. No issues what so ever.

Your probably thinking of aluminum cased ammo.  Aluminum cased ammo is a BIG NO NO in blowback operated firearms. Anything brass cased is good. Steel EH. But you will have all kinds of issues.  Stay away from ALL Aluminum cased ammo IF running a system that is Straight blowback.

I’ve shot over 3000 rounds of aluminum ammo through my Scorpion and haven’t experienced an abnormal amount of malfunctions.

You’re going to need to provide some sort of proof for your claim because there’s plenty of posts on this site alone talking about people shooting aluminum cased ammo in blowback 9mm guns without experiencing the kind of problems you say are prevalent. I’m sure some guns hate aluminum ammo just like some guns hate lacquered ammo and I’m sure older guns are less reliable when firing it but a blanket statement about 9mm blowback guns is unfounded.

With the prevalence of AR pistols in 9mm and the increased popularity of aluminum cased ammo there is a massive amount of the two being combined, if issues were noteworthy in the least there would be plenty of proof to support it.