One word of caution when reloading for the M1 and other semi-auto firearms with floating firing pins. Pay careful attention to details, such as cleaning primer pockets and seating primers .002-.005” below case head. Mil Spec primers are a good idea, as well. Checking resized brass to be sure they fully chamber in your rifle using a good case headspace gauge. Keep rifle chamber clean, etc.
In other words, anything that can cause a “high primer” or the case to stop short of fully chambering can result in a slam fire, which if it occurs before bolt is completely in battery, can ruin your day.
Thankfully, slamfires are a relatively rare occurrence in any gas gun, but they have been documented in M1’s in spite of the safety measures engineered into the rifle by John Garand. See these features @ 4:15-5:00 in this excellent video:
https://youtu.be/GJJeBXZeVZU?t=313
I've fired many thousands of reloaded rounds through gas guns using regular primers and have never had a slamfire in one of my rifles. Having said that, I now use CCI #34 mil spec primers when loading for the M1/M14 as an added precaution.
http://www.cci-ammunition.com/products/primers/primers.aspx?id=30
A slamfire in either the M1 or M14 can have disastrous results if it occurs before the bolt is in battery.
Lack of care in following careful reloading practices or a bit of debris on bolt face, or perhaps a broken firing pin, combined with a soft primer can also cause a slamfire.
I personally witnessed this incident, which occurred with an M1, and illustrates what can happen should an out of battery slamfire occur.
A friend who is a very experienced highpower competitor and reloader wrecked his match grade M1 Garand using the same handloads he had used for years when the rifle slam fired out of battery. Bent his op-rod, blew extractor/ejector out of bolt and rounded the receiver locking lug recess about 1/8" showing the bolt lug (thankfully) had barely entered the recess but was not fully in battery at the time the slamfire occurred. . The bolt parts (extractor, ejector and springs) were not recovered. He received a cut on the forehead by a piece of shrapnel which penetrated his cap sweatband and had an adverse effect on his trigger control for some time thereafter. Fortunately, the rifle, and his shooting ability have since been restored.
Close examination of the remaining lot of ammo, we found that the rounds were slightly oversize resulting in a snug fit in his match chamber. He had loaded this batch of ammo using the same (full length) die setting as always. Remember, all previous lots had measured and functioned just fine. The problem stemmed from the fact that this particular lot of brass had been fired at least 8 times and had work hardened. His dies had been set to give proper headspace with once fired brass and he failed to check headspace on this lot after loading. The harder brass springs back more than softer brass after sizing which resulted in oversized (for his chamber) rounds.
A good friend related another incident which he witnessed several years ago, proving that use of mil-spec primers alone is no guarantee against a slamfire.
“I was on the point just to the right at 600 yards during the State Service Rifle matches. A junior was shooting a DCM arsenal built State NM M14 using Spanish Berdan primed NATO ball.
Apparently there was a sensitive primer on a
singly hand fed* round in the chamber that got impacted by the firing pin before bolt lockup when the kid released the bolt with the bolt release. There was an empty magazine in the rifle that got damaged along with the bolt and op rod.
I don't think the action or barrel was damaged beyond use but the stock was splintered and the shooter got a bruised left arm and minor abrasions and splinters through his 10X tan cloth shooting jacket. I remember hearing this unusual explosion on my left and getting hit by stock hardware and bolt roller parts that ended up on my mat, I looked over and the kid was lying there with a stunned look on his face with his rifle stock bent down at the action and smoke rising out of the left sleeve of his coat.
Luckily he was wearing glasses and the closed back end of the action controlled most of the blowback so he suffered only minor injuries and major questioning from his laundry lady! It is my opinion that it was a classic M1/M14 premature firing pin impact before bolt closure into full battery.”
*Many experienced service rifle competitors recommend loading the gas guns through the magazine or dropping the round in chamber, easing bolt down and hit op-rod w/heel of hand to assure rifle is in battery as opposed to single loading for this reason.
Regards,
hps
