The M1 Garand, Commercial Ammunition, and Oprod Velocity

What happens when you shoot commercial ammunition through an M1 rifle? No, what really happens? Take a look at InRange TV’s video on the subject, embedded below. Ian and Karl go one step further than the average “let’s find out” video, and shoot the M1 against a measure with their high speed camera, so take a look:

The pair also tests the M1 with the 220 grain ammunition and a vented gas plug, designed to release gas from the cylinder earlier than the standard M1 would. This reduces pressure and operating rod velocity, and allows the M1 to cycle those hefty loads just fine, without risking damage to the rifle (the action of the M1 itself is plenty strong for these loads, and is in fact one of the strongest service rifle actions in existence). In a previous article on the M1, I showed you where to buy a good M1 Garand gas plug wrench, and how to disassemble the rifle for maintenance and modification. If you want to install a new gas plug in your rifle, check the link here.

The M1 is a rifle steeped in history, but it’s also an extremely idiosyncratic weapon with a lot of unique and strange qualities, even among its peers of the day. Anyone who is a student of small arms theory and history should absolutely study the M1 closely.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • Blake

    super cool, thanks.

  • tts

    Karl’s intro was the best on this video.

    “Uh you’re kinda scaring me.” Indeeeeeed.

  • ostiariusalpha

    Karl channeling his inner Rick Morranis. Good stuff.

    And looking pretty svelte too:

    • Tassiebush

      Yeah Karl mentioned in one of the videos he’d recognised fitness was an opportunity to improve on his 2gun performance. He’s definitely pretty motivated by the look of things.

      • tts

        That and health too. If you can keep your BMI below 30 you’ll not only likely live longer but also have better quality of life when you do get older.

        The maintenance of quality of life is the bigger factor IMO. To me there isn’t much point living past 100 if you’re bed bound and can’t even make it to the bathroom.

        • Tassiebush

          Well I can’t argue with that.

        • Tassiebush

          I found some good advice on the topic

          • ostiariusalpha

            Dr. Rudi needs his teeth punched out.

          • Tassiebush

            Yeah he totally does! I think I missed my mark with that attempt at sharing humour. He’s an abrasive unhelpful advice giver from a show called Life Support. It just occured to me that without being couched in the show as I have it would just look offensive without being all that funny so I’ve removed it.

          • Missed the “Comedy Channel” logo in the corner, did you? 😉

          • ostiariusalpha

            I totally did, but Dr. Rudi still needs to eat more knuckle sandwiches. For his health.

          • Tassiebush

            I have to share this. It’s a compulsion. sensitivity and taste be damned! This is Peak Dr Rudi.
            edit: oh and trigger warning

          • RMP52

            Umm- that was from Comedy Central –it was a skit, I thought it was rather funny. And actually a lot of truth to it.

          • ostiariusalpha

            Cool story, bro. Did you know that telling people with eating disorders to “just eat less” is about as useful as telling alcoholics to “just drink less” or “just stop” to smokers? A lot of unhealthy eaters are stress eaters, maybe they should “just quit stressing out so much,” yes? You’re a genius to have found such wisdom at such a tender age. Bravo.

          • RMP52

            You need to chill dude it was a joke. As a former smoker I can tell you that if you want stop smoking you should just … wait for it… stop smoking. Saying someone is a “stress” smoker, eater, etc is just an excuse. We all stress about something at sometime, does that mean we should all be obese, smoking alcoholics? With your brilliant mind you should be writing speeches for Hillary. Congratulations.

          • ostiariusalpha

            Ah, of course, I should definitely chill out on mocking your inane comments because “it was a joke.” And your victory over Demon Tobacco certainly gives you carte blanche to judge overweight women, because reasons. With your brilliant mind, you should stick to restroom stalls.

  • Gorilla Biscuit


  • Red79cj5

    Anyone have experience with the “ported” gas plug that garand gear sells? It’s a hollowed out gas plug that does not vent but is said to reduce pressure with the increase in gas system volume. No adjustments necessary for different loadings. They have a lot of science on their site but I haven’t heard from anyone who’s used one.

    • Matthew Black

      I bought one because I’d heard they worked. I’ve installed it in my rifle but honestly haven’t made it to the range since then. I wish I could give you more info but I’ve heard good things about them at least.

    • The_Champ

      I’d like more info on this product as well. If it works as claimed it appears to be a very easy, solve all, solution.

      They do go to great lengths on their website to try and prove that it works as advertised.

    • Ian McCollum

      We just bought one to try out, and will publish an update video once we are able to do so.

      • Ericc

        Great video guys. One thing to consider with the ported gas plug is it’s designed to reduce the forces acting on the operating rod, rather then focusing on slowing the bolt. It applies a lower force for a longer time period. A good analogy is the difference between a hammer and a dead blow hammer.

        Lowering bolt velocity was secondary to getting those high peak forces down. We achieve some reduction in bolt velocity due to the longer gas cycle which allows more gas to leak past the gas piston. For the same bolt speed the ported gas plug configuration will have much lower peak pressures; less bending potential on the op-rod.

        If you want the lowest possible bolt velocities then venting is the solution to achieve that. If you want the lowest forces acting on the op-rod then changing the starting volume of the gas cylinder will get you there.

        You can see the same design philosophy in the BM59 gas plug.

        You might also look at various years of M2 ball. We found significant variations between the years. I think HXP-65 was the most mild and HXP-69 was the hottest.


    • Andrew Foss

      I have one. No complaints here. YMMV, though.

  • LG

    The original gas trap M1’s were tested with the M1, 173 grain FMJ SPBT, round. When the M1 was first shown and demonstration shot for the first time before WW2 in the National Matches at Camp Perry, all the shooting was done with 173 grain match M1 rounds. The M1 was not originally predicated upon M2, 150 grain FMJ, rounds. I believe that if one reviews the records, in combat zones, more armor piercing rounds were issued than M2 ball, even for the M1 rifle. If memory serves the armor piercing round was 173-175 grains and loaded about equal to the M1.

    • M2 AP was about 165 gr at 2,7000 ft/s.

      • Tassiebush

        Phenomenal velocity!!! 😉

        • nicholsda

          Really flying there. 😀

          • Tassiebush

            It’d be hard to zero before the barrel wears out. I guess it’d be matched with a 1 in 120″ twist. :p

  • The_Champ

    I think similar caution needs to be shown around many old military self loaders. I’ve read a lot about softer modern primers and slower burning powders being blamed for many slam fires and out of battery detonations in rifles like the FN-49, AG-42, SKS, etc.

    Although the adjustable gas on my FN49 gives me some comfort, there seem to be some problems around the firing pin being over length or shaped incorrectly in some guns, especially ones made of mix and match parts. The one piece vs two piece firing pin issue aside, I have several different pins for my rifle, and they vary in size and shape. I did experience a couple slam fires, but I believe I remedied it with a different pin.
    I’ve had no problems in practice with my AG-42 and commercial ammo. Functions great, and the used brass doesn’t really show signs of being over stressed. That said, the force with which it kicks out brass and sends it flying a great distance is a little worrying. I do wish the Swedes put an adjustable regulator on their rifle the way the Egyptians did on their Hakim.

    The SKS is easy because so much military ammo is still floating around. And I’m careful to maintain the firing pin and channel.

    Haven’t heard of any similar problems with the SVT-40 although you’d think it would be prone to similar problems….. again adjustable gas is quite useful for modern ammo. Mine runs like a charm on modern ammo.

    As for my M1, I really do appreciate that Federal produces “M1 Safe” American Eagle ammo.

  • Vitor Roma

    Given how big the case of the .30-06 is (63mm), I’ve always found kinda stupid and wasteful to use a 150gr bullet. Yeah, I know the whole shorter shooting ranges deal, but something around 190gr would be a sweet spot.

    • Remember that the .30 Government series is an extremely early family of cartridges of its type, and was originally designed to get maximum velocity with 220gr pills.

      It was only with the M1906 that they went to 150gr projectiles, in response to the German S Patrone.

    • ostiariusalpha

      I feel the same. I’ve never even bothered with loading any bullets under 180gr for .30-06. It’s a decent sized case and I want it to push on decent sized bullets, that’s the whole point for me.

  • StraightshooterJeff

    Without a doubt one of the BEST instructional firearms videos I have ever seen. Extremely well done guys.

  • mazkact

    I run Schuster valves on mine and have no complaints.

  • Tassiebush

    Haha that’s good. It reminds me of the Monty Python’s how to cure the world of all known diseases
    For peak Rudi Google Dr Rudi domestic violence.

  • 277Volt

    Sweet Laibach shirt!

  • leewardboy

    M1 – needs powder close to 4895 in burning rate. Slower powders – such as 4350 or 4831 will result in excess gas port pressure and cause higher op-rod speed. In high-power competition we routinely used 168 and 173 grain bullets – even 180 Match Kings. Used either of the 4895s or 4064. Better results at 600 yards.

    Many decades ago – we loaded slow powders and shot our M1s. These loads were actually not hot at all but the Garand opened violently and the clips hit the range roof – about eight or nine feet over the firing line. IIRC correctly – the M2 ball was developed for machine guns to enable, supposedly, searching fire to hit the reverse slopes of hills and such. Some archaic tactical idea similar to long-range volley fire.


  • ciscokid3750

    I have read where the M1 was issued a special water resistant grease made by Lubra-Plate (still in business today) because the op-rod would gall the receiver when fired in the rain without any lube on it. Also the op-rod tended to break which was a problem the designers never corrected because of the way the gas system was designed. All this was changed and corrected in the much superior M14 which came after WWII.

    • Lubriplate 130A, the lubricant that’s on my M1 as I type this, because I am an authenticity nerd.

      As for the M14 being “much superior”, well, Hitch didn’t think so, and neither do I. The M14 replaced the camming lug with a roller, which caused its own problems and only sort of solved the galling issue. It took until 1959 for the damned things to be issued, too, so the US ended up with a rifle that was bordering on obsolete the day it came out.

      Not Ordnance’s finest hour, for sure.

  • FalconMoose

    Thanks. I just got a Garand, and am looking at the ported gas screw from to be able to shoot my commercial hot loads.

  • ElderAmbassador

    As to the majority use of M2 ball AP ball ammo (the one with a steel core penetrator to defeat “soft” armor like truck sides), that is the Only ammunition we used in the 1963 Pacific Division Match (USMC) on the Puuloa range on Oahu. Using Match Conditioned M-1 rifles, that ammunition was Very accurate with Most cleaning the 600 yard target. NO one experienced any problem with their rifle after spending about 2 weeks firing at least 60 rounds, not counting practice (sighting in your rifle) per day in practice.

  • Richard Lutz

    The 8 round M1 Rifle is an overrated gun. Way too long and heavy for most combat use. The M1 Carbine (15 or 30 round magazines) is much better for most combat use, the vast majority of which occurs within 100 yards. X the tip of the .30 Carbine FMJ bullet with a knife and it has fantastic stopping power, outperforming the .30-06 FMJ bullet which drills through without doing f##k all.