The F.B.I.’s D.S.U. (Division of Criminal Investigation - Domestic Security Unit) has released their scathing report on their field testing of the Heckler & Koch UMP40 Submachine Gun. In the July 18th 2006 dated report, the DSU detailed its extensive testing of 4 guns that were purchased with the intent of possibly choosing them, replacing the now-obsolete H&K MP-5/10mm Submachine Guns currently in inventory. The test guns were brutally abused by Special Agents, in attempts to expose any and all weaknesses of the polymer-framed pistol-caliber weapon. Dunked in mud, sand and water as well as operated dry of any lubricants resulted in acceptable percentages of weapon failure. It wasn’t until a 9mm service round was introduced into the barrel, 4” from the muzzle, and a .40 caliber Service cartridge was discharged resulting in a typical squibbed barrel (where a previously discharged projectile is lodged in the weapon’s barrel due to an inadequate gun powder charge of the round) did the submachine gun suffer from a catastrophic failure. The firing of the .40 caliber cartridge, into the blocked barrel, which exploded the guns chamber and destroyed its polymer receiver permanently, disabled the weapon beyond repair. Even Heckler & Koch admits that such a destroyed weapon receiver is non-repairable even for them. It has been H&K’s hopes that the FBI would pick up the UMP40 as their new Tactical Entry Gun, but thanks to this singular event, those hopes have been officially bashed on the head! -- Ok sounds like it did ok, did they expect it to not blow up when they had the squib? I'de like to see what would of happend to a 10mm mp5 in the same situation.