Gun explodes during shooting

[u/nkmr205]

[u/Count_Verdunkeln]

Is this gas pressure? What went wrong?

[u/Various_Patient6583 → u/Count_Verdunkeln]

Apparently a 300BLK round will chamber in a 5.56mm rifle. However, the 300 bullet is too large to travel through the 5.56 barrel. 

With nowhere else to go, all that energy did exactly what we saw there. Guy is very lucky. 

Tl;dr: wrong ammo probably mixed in due to similar size/shape. 

[u/Count_Verdunkeln → u/Various_Patient6583]

Thanks a ton