Caution: Watch How You Are Loading Those Semi-Automatic Rifles

Round In Chamber Of Gun AR15 Ammo Bolt Ejection Port
Caution: Watch How You Are Loading Those Semi-Automatic Rifles
Virginia Citizens Defense League
Virginia Citizens Defense League

Virginia –  If you have a semi-automatic rifle that has a free-floating firing pin, such as an AR-15 or an AKM-47, do NOT drop a round in the breach and let the bolt slam forward!

The only safe way to load the round is to load it from a magazine.

The reason is the rifle’s design counts on the bolt slowing down as it strips the round out of the magazine.

Without a magazine, the bolt won’t slow down and hits full force, possibly allowing the free-floating firing pin to strike the round’s primer hard enough to set it off unexpectedly.

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Virginia Citizens Defense League, Inc. (VCDL). VCDL is an all-volunteer, non-partisan grassroots organization dedicated to defending the human rights of all Virginians. The Right to Keep and Bear Arms is a fundamental human right.

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  • 20 thoughts on “Caution: Watch How You Are Loading Those Semi-Automatic Rifles

    1. Most .223/5.56 and .308/7.62×51 AKs (Saiga/Vepr) have spring loaded firing pins because commercial ammo (soft primers) is often used in these rifles. AKs chambered for the Russian ammo 5.45×39/7.62×39 (having military “tough” primers) have free float firing pins, and don’t experience a slam fire.
      Solution: use Military grade ammo in your semi-auto.

      I have experienced slam fires at the range. I got some funny looks from the folks next to me.

    2. Sig just recalled their MCX due to a possible slam fire condition, was only noticed in .300Blk they claim they found it but betting SOCCOM pointed it out. They said it was very difficult to duplicate but the fact they redesigned their BCG and adding a spring on the firing pin, tells me someone with lots of $$$$ noticed it and wanted it fixed vice a consumer. It’s not like a .300BLK MCX is easy to find.
      HK 416/MR 556A1 also has a firing pin lock setup to prevent slam fires.

    3. In my 34 years of AR shooting, including my time in the US Army, I have never seen or heard of this happening. Not buying this story…

    4. It is mostly an issue with softer primers. If you use 5.56 mil spec ammo you are fine. .223 sometimes has softer primers. If you reload CCI no 41 is one of the are harder types. Personally I just load one in the mag but holding the charging handle all the way and then using the forward assist works too.

      1. Fired HP for over 15 years, though a few years ago, but don’t remember a single slam fire in an AR.
        Used Fed 205M primers in a Colt HBAR with TI firing pin never had a misfire.
        The TI pin being lighter developed less enertia than a steel one reducing possibility of slam even further.
        Bent a few TI pins over the years.

        Most problems were old M1 with vintage junk ammo.

    5. Has anyone ever seen this really happen?
      If you’re really worried about it just put a ton of FrogLube in the pin chamber…. I’ll junk up and slow EVERYTHING down.

      1. Yes, happened to me once while taking a class for NRA High Power matches with an AR15. Shooting the standing 200 yard portion, placed round on top of magazine using the single load adapter, let the bolt go and BLAM. Rifle was of course pointed down range and slightly below the targets, probably impacted about 50 yards down range.
        I looked back at instructor wondering what to do but never said anything. He looked at me and said “Aim higher”.
        That was using CCI primers. I’ve since switched to Winchester.

    6. Thanks for the Warning. Quite new to ARs (though I understand the design quite well), but I have not thought of this as a potential issue. I have a “sticky” free float pin on an old .22 LR bolt action that I need to work on. It has a tendency to get stuck after firing one round; then when you go to load another round you must physically push the pin back so that when you go to slam it home it doesn’t fire the round by slamming the bolt closed.

      Question to anyone out there:
      Would using a Lighter firing pin, perhaps made of Ti, be safer in the sense of reducing the Pin’s mass/inertia thus preventing the possibility of a “Slam Fire” happening?


      1. Titanium firing pins are used on some 1911s, that do not have physical firing pin block safeties, to avoid the interference of a mechanical safety linkage with a smooth trigger release. The low inertia of the light firing pin reduces the chance of it striking the primer with sufficient force to set it off if the pistol were dropped. However, a sticking firing pin, as you have described, can set off a primer regardless of the firing pin weight.

        You might try using a penetrating fluid, like Kroil, to loosen the firing pin in the bolt of your .22 bolt action rifle. After removing the bolt, squirt some penetrant into the firing pin cavity of the bolt from each end of the firing pin cavity to loosen any residue. That should make it easier to remove the firing pin, so you can thoroughly clean the pin and the pin bore cavity in the bolt before reassembling the bolt. Some non-free floating firing pins are used in firearms with a light spring on the primer striking end of the firing pin to hold the pin in a retracted position, until struck by the striker/hammer with enough force to overcome the force of the spring. This requires the strike to the firing pin to be sufficient to overcome the spring force to set the primer off. This reduces the possibility of a dropped firearm causing the firing pin to gain enough momentum to strike the priming of the cartridge hard enough to fire it.

        Do not use any liquid lubricant or grease for the firing pin because it tends to trap solids, like unburned propellant, in the firing pin bore, which is where you are now with your .22. This is especially true for .22 rimfires, as the propellant often doesn’t burn cleanly. If you want to use some lubrication, before reassembly try some graphite spray lube that leaves only a thin, dry film after the carrier fluid evaporates. After reassembly, carefully check the action of the firing pin in the bolt before loading a live round. Control the direction of the muzzle of your firearm when chambering a round (and always).

    7. ARs are a pain to load one round at a time. M1 Garand and M1-A are easy; just “cram” the round into the clip/magazine area and release the bolt. Slam firing is a very real deal, the round may detonate due to the floating firing pin hitting the primer (especially softer commercial primers) before the bolt can rotate and lock the round into place and the round will detonate like a small grenade which can hurt the rifle and may well harm or even blind the shooter.

      1. The firing pin can not even get close to the primer until the bolt retracts into the bolt carrier while locking. With that said, a slam fire can occur even when loading from the magazine with some commercial ammo. That is why no matter what kind of firearm, always point in a safe direction when loading.

      2. Not so easy for your average bear to load 1 round at a time into a Garand’s en bloc clip. G.I.’s were trained specifically in this art should they need to top load during a fire-fight with less than eight loose rounds near at hand.

    8. We loaded a single round at a time when on the range shooting a slow fire string for USMC qualification in the 1980’s. I have never heard of a round going off unexpectedly.

    9. After inserting a round into the chamber, pull the charging handle to the rear and, while continuing to hold it, release the magazine catch and ease the bolt forward. Then tap the forward assist to ensure that the bolt is fully seated. This will reduce the risk of an AD. In the Army, we were required to insert a magazine, whether firing 1 round or 30. Good article!

      1. All the bob sled is is basically a nylon trough or tray just that centers the round when placed in through the ejection port. The bolt is then released, but the bolt wouldn’t be slowed as in “stripping” it from the tray like a magazine, it would just be pushing the round into the chamber. Would that slow the bolt enough to not accidentally fire ?

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