Per 
Item #: SCP-XXXX
Object Class: Safe
Special Containment Procedures: Keep SCP-XXXX in a 4 meter by 50 centimeter crate facing due North/South at all times not devoted to testing procedures. Keep locked with standard F-Series lock, and the key located in [REDACTED] office.
Description: SCP-XXXX appears different in almost all iterations and times of testing. This is because of the object's nature- every time it is submerged in blackness darker than 0.42 Candela, the object changes its contents and form to match the ammunition type and standard magazine of the nearest firearm in proximity, replicating the polymers and metal parts perfectly. The firearm type has been tested multiple times and of multiple different calibers. from .22LR to 20mm, various weapons of each type have been tested and confirmed to work. So far, it appears that no weapon has, to date, stumped or been mismatched.
The Organization was called in to collect this item from ████████ Police Department in █████, Iowa after officials reported that the magazine taken from a murder weapon had gone missing. It was seemingly replaced by a standard, loaded police sidearm magazine, only to have the original re-appear when this magazine was left in an evidence locker next to the murder weapon.
Coincidentally, it was this murder [Titled Case# ███████ in the precinct for reference] that prompted our research into the item. It appeared that the murderer's weapon misfired after loading SCP-XXXX into the weapon. This would normally not be interesting, aside from the weapon being reportedly in top condition and the magazine suffering zero damage despite the explosive misfire which nearly destroyed the weapon. Trying to replicate this scene, the D-Class operating the weapon containing SCP-XXXX nearly lost her hand in the resulting backfire, despite the weapon being tested thoroughly by ██████████████ in engineering first.
A second test was done with similar results, despite using a completely different type of weapon.
Thus, we have concluded that this magazine seemed to either possess an intent of its own, or some moral drive opposed to murder.
Further research has been done, leading to the publication of this form which has indicated even more.
Nothing done directly to the object could get it to misfire or act out in aggression. Throwing it, burning, electrocution, even digging it directly into exposed flesh has not caused any reaction. Only attempting to fire it at an innocent or otherwise unwilling target* has proven to have any negative result. Delving into what history we found, we can assume to have had this weapon appear as early as World War 1, in the hands of British Army Officer ██████████████████. A few famous hands are believed to have held this item, including John Dillinger and Li Feng, however this information comes mostly from third sources and personal entries, so concrete information on exactly who has owned XXXX is difficult to corroborate.
*Unwilling varies in effectiveness.
