Modifying the Mini-14/30 Bolt To Fire Imported Ammunition

Many years ago, I purchased a Mini-14 manufactured by Sturm, Ruger & Co., Inc., in .223 Remington caliber. The manual that came with it stated point-blank that I should not use imported ammunition with this rifle. I soon found out why. After firing only 30 rounds of Russian .223 Remington ammunition, the rifle would no longer fire. Upon examination, I found the firing pin was jammed. I disassembled the bolt and found it filled with small, round, brass disks!

I removed the disks, fired another 30 rounds, and once again, the firing pin jammed because the bolt was filled with those brass disks. I recovered some spent shells and discovered each primer had a neat, round hole in the center of the primer that corresponded to the brass disks I found inside the bolt. This problem was caused by the combination of three factors. First, foreign ammunition manufacturers apparently use softer, thinner metal in their primers.

Second, I carefully examined the bolt face and found a sharp, raised burr around the firingpin hole, which was probably the result of the machining process when the hole was drilled. And third, using a firing-pin-protrusion gauge, I discovered that the firing pin protruded 0.010 inch too far in front of the boltface. The long firing pin created a toodeep indentation in the primer, possibly stretching and cracking the metal.

Then, during recoil, the case head would be pressed against the boltface, where the burr would cut around disk out of the center of the primer. Next, the blowback through the ruptured primer caused the disk to be blown into the bolt body through the firing-pin hole. And once enough disks were blown into the bolt body, they would jam the firing pin. To fix this problem, I removed the extractor and firing pin from the bolt. I used a narrow 400-grit stone to remove the burr around the firing pinhole.

Then I shortened the firing pin by 0.010 inch. I did this by rubbing the end of the firing pin on a smooth Also, check the firing-pin protrusion with a firing-pin-protrusion gauge. stone, being careful to maintain around end. With these simple modifications, I could fire my Mini-14 all day using imported ammunition with no failures or jamming. Conclusions/Recommendations Ruger has since corrected this problem’presumably’and the rewritten manual now warns only against shooting imported ammo with corrosive primers.

However, I recently purchased a Mini-30 and, once again, the bolt had a burr, which I polished smooth for this article to avoid any problems with imported ammunition. On the Mini-30, the firing-pin protrusion measured correctly, so I did not have to make any changes there. So if you see a Mini-14 or -30 with a jammed firing pin, the first thing you want to do is to check the bolt face for a burr, and then measure the firing-pin protrusion. I

AMARAD6 Armorer’s Course, AMG Version, Spread Ad (p/u from 11/08 issue)

AMARAD6 Armorer’s Course, AMG Version, Spread Ad (p/u from 11/08 issue)