Originally posted by u/N3oxity at 2025-06-30T17:39:45Z

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Hello, I just wanted to start this post glazing u/Pfunk117 for introducing the wackmack, one of only functioning super safe mac11 builds I have found in the sea. I have tossed hundreds of dollars into other super safe mac11 DB9 derivatives all for them not to work and destroy my barrel.

My upper is a VMAC 11".

Now for my main issue, I was using my wackmack as normal on the range and dumped 120 rounds through it for 3 days. Keep in mind, the only range ammo I used when running this gun was Remington and Blazer FMJ’s. I let one of my friends try out my weapon on the range and he loaded some Winchester Full Metal Jacket Flat Nose target rounds through my gun and it exploded leaving this.

Bullet Remanent

Bullet Powder ruminants

The bullet was stuck in the barrel and the rim of the brass shell was also stuck in the chamber. I asked the RSO for a push rod to clear my barrel and they pointed something concerning to my attention after clearing the barrel. The RSO pointed out that some metal chipping in my barrel that looked like my barrel liner chipped out and flaked but I’m not certain.

Chamber View

From of gun top down view

I was going to see if I could simply remove the material sticking up, but I think I may need to swap the barrel.

chambered sim rounds with burrs

Things that I hypothesize causing this issue:

1. My friend chambered this round wrong and babied the charging handle causing an OOB.
2. The Round was chambered correctly but the issue was Winchester QC.
3. VMAC QC failed me.

I would love assistance and feedback for my next steps on what I should do from here. I would also want to know how this issue happened and what I can do to prevent this from happening (like not letting other people shoot my guns).

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Source: https://a.thumbs.redditmedia.com/FWnu8op7xWKo7g4E-2YK7actM-1ID0Dbj7Gh-goCNp4.jpg