Garand Extractor Fell Off

Discussion in 'Firearms' started by Silversnake, Jul 7, 2012.

  1. Silversnake

    Silversnake Silverback

    Was shooting a Garand with family and the extractor, extractor spring, ejector and ejector spring all appear to have popped off the bolt face while shooting factory load Serbian 150 FMJs.

    This GI factory rifle was shooting well (1 inch groups at 50 yards) and then failed to extract a fired case. We were shooting it single shot since we all neglected to bring the en bloc clips even after I asked everyone to help me ensure we had everything...three times.

    I suspect loading single shot may have had something to do with it. I have not taken it further apart yet and we may have lost the extractor, but I am sure we have the springs and the ejector.

    Any ideas from the group? Thanks.
  2. ghrit

    ghrit Bad company Administrator Founding Member

    Do you have the TM for it?
  3. Witch Doctor 01

    Witch Doctor 01 Mojo Maker

    I am assuming that this weapon is not a Franken M! (mixed parts gun).....How did the case look? I've heard of similar things occuring due to possibly a bad load and over pressure on the gas system.... some of the european ammon may be loaded a little hot.. (Greek for sure...) or a bad extractor... check the top of the chamber where the extractor is and see if there is a ridge or mark there...

  4. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    "Serbian 150 FMJs."

    You did not state if this was US mil spec 30-06 ammo. Could be it was a hotter commercial load used in Serbia.

    Any damage to the bolt face or the extractor?

    Use only US Mil Spec M1 Garand ammo, any other and you may find the bolt in your teeth.
  5. Silversnake

    Silversnake Silverback

  6. TwoCrows

    TwoCrows Monkey++

    I have seen a high seated primer cause a slam fire in an M1A and blow out the extractor.
    The bolt was not fully closed and locked when it fired, so the extractor blew out.

    If the bolt was locked then the only way for it to come out is metal fatigue caused failure.
  7. Silversnake

    Silversnake Silverback

    That makes sense. One of the younger adults was firing it and had been riding the bolt forward so it may not have been in battery. Thanks.
  8. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    The firing pin is free floating.

    The M1 Garand round requires a Mil Grade Hard primer. Before you fire any M1 Garand check to see that the firing pin is free and that you have rounds with hard primers. Reloaders can purchase Mil Grade primers. YMMV and it is up to the user to make a decision on what is safe.

    You can purchase custome loaded ammo here for the M1 Garand

    Here is the specifications for M1 and others in the 30-06 Ball Ammo thru AP and your purchase. For a ref: I have shot in M1 Garand/Military Rifles matches. The caveat in using the M1 Garand is to stay in the M2 Ball loadings. The system is a balanced gas reaction to the fired round. I would suggest that you have the gun checked by a M1 Gunsmith. The Operating Rod can be bent by excessive gas pressure if an out of spec round is used. "Note that the Oprod is naturally bent a little bit anyway."

    .30 Caliber M2 Ball Ballistic Characteristics

    From Hatcher's Notebook, pages 29-30:
    Comparison of the Various Types
    Type Bullet
    grains Muzzle
    f.p.s. Measured
    @ 53 feet Measured
    @ 78 feet Muzzle
    Ft. lbs.
    Cal. .30-'06 150 2700 2655 2640 2429
    Cal. .30 M1 174.5 2647 2620 2600 2675
    Cal. .30 M2 152 2805 2755 2740 2656
    Cal. .30 A.P. M2 168.5 2775 2730 2715

    Here is the Ammo you purchased.

    Product Information
    [​IMG] Since 1928, Prvi Partizan has been producing custom ammunition in Serbia for competition, indoor ranges and big game hunting. Soft point bullets feature a soft lead exposed nose that create controlled expansion and a uniform mushroom. This ammunition is new product, non-corrosive, in boxer primed, reloadable brass cases.

    Technical Information
    • Caliber: 30-06 Springfield
    • Bullet Weight: 150 Grains
    • Bullet Style: Soft Point
    • Case Type: Brass

      Ballistics Information:
    • Muzzle Velocity: 2903 fps
    • Muzzle Energy: 2802 ft. lbs.
    Good luck, you have a great rifle and one that should last a long time.

    Silversnake likes this.
  9. TwoCrows

    TwoCrows Monkey++

    This is why I prefer not to use an M1 or M1A/M14 for SHTF, it is too dangerous to use off the shelf commercial ammo in them.

    They are great match rifles, and have historical value, just not versatile enough IMO.
  10. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    I don't think I would blame the gun design for an operator's mistake.
  11. TwoCrows

    TwoCrows Monkey++

    That it needs hard military primers to be safe is gun design.
    If at some point all you can get are softer commercial primed loads and it blows out your extractor leaving you with an awkward club instead of a rifle, that is a failure point.
    I have seen that before with an M1A, but all it did then was put the shooter out of the match with a small gash on his forehead.
  12. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Then you can put the SKS and a number of other guns as "design" problems, be it dirt or a wrong round that cause a slam fire.

    As well as many commercial guns that can be loaded with the wrong "shelf " Ammo.

    I will say that loading the M1 Garand, in singles without a clip is a pretty bad thing to do. Many guns can be damaged by this mistake, even the 1935 High Power design could be damaged by loading single rounds, as the extractor would break because it did not engage the rim when feedng single rounds without using the magazine. FN changed the design due to this operator error.

    If you are worried abou over pressure then you can purchase this.

    None the less it is the shooter that decides.


    The purpose of this article is to discuss the M1 Garand gas cycle and the effects of using commercial ammunition in the rifle. The gas cycle pressure was measured using several different brands of ammunition. It is commonly stated that shooting commercial ammunition in the M1 Garand will cause damage to the operating rod. With the supply of M2 Ball ammunition dwindling, it seemed an appropriate time to investigate this topic and look for solutions.
    Several manufacturers sell a venting type of gas screw that addresses the potential of high pressure in the gas cylinder. John Garand patented such a device for the M1 in 1945 (Patent #2369669). The venting gas screw works by bleeding gas out of the gas cylinder. I am going to present a different solution to the potential high-pressure problem, one that I believe is more elegant and simple in design and use.
    At we have designed a new ported gas screw for use in the M1 Garand. Unlike a venting gas screw, our product works by changing the initial conditions in the gas cylinder. The ported gas screw increases the starting volume in the gas cylinder, which results in lower peak pressures. No adjustments are required and no gas will vent from the device. The ported gas screw will produce lower peak pressures in all brands of ammunition that meet the SAAMI specifications for the 30-06 cartridge, regardless of bullet weight.
    To evaluate the design of the ported gas screw, several sets of pressure data was acquired. The first data set measures the gas cycle when using standard M2 ball ammunition. This initial data set will define the accepted "safe" operating range for the M1 Garand gas cycle. The second data set surveys several brands of commercial ammunition. This data set was then compared against the M2 ball pressure set. Finally, the ported gas screw design was tested and its ability to lower peak pressures was verified.
    Testing Hardware
    The most useful data for this investigation is obtained by measuring the actual gas pressure in the gas cylinder, rather then at the barrel gas port. The gas cylinder pressure is easier to obtain then measuring the barrel port pressure. Measuring the pressure in the gas cylinder also saves us the effort of trying to model the gas transfer into the gas cylinder. I will discuss why the modeling of the gas transfer is challenging later in the article.
    The pressure pulse in the gas cylinder is very short, approximately four milliseconds. A high-speed pressure transducer was required for the test along with all the associated amplifiers, computers, and data acquisition systems. The transducer also needed to be able to survive in a high temperature environment. A suitable pressure sensor was chosen and purchased for the test. Two custom gas screws where machined that would house the pressure transducer. The first gas screw would act like a standard GI gas screw; the second emulated the port in the ported gas screw.
    The rifle used for the test was a 2.5M range Springfield Armory Garand purchased from the CMP. The rifle had a new criterion barrel installed. All of the gas cylinder and operating rod components where inspected, measured and verified to be in spec. The barrel gas port was inspected and verified to also be in spec. A new USGI spec operating rod spring was installed and the rifle was properly lubricated. Figure 1 shows the sensor installed in the rifle.
    (Figure 1)
    The M1 Garand Gas Cycle
    To interpret the data provided, we will need to define the gas cycle. The gas cycle on the M1 Garand can be broken up into several distinct stages. Each stage affects how the pressure in the gas cylinder is changing. The Gas cylinder and operating rod assembly on the M1 are lossy. That is to say, gas is always flowing past the gas piston when the pressure in the gas cylinder is greater then the pressure outside of the gas cylinder. The following stages will deal with gas flowing into the gas cylinder. A graph of a typical gas cycle when using M2 ball (HXP) is shown in Figure 2.
    Stage 0: The first stage consists of the bullet traveling up the barrel, compressing the air in front of it. The bullet moves up the barrel faster then the gas can escape from it. This causes the pressure to rises in the barrel. This stage ends when the bullet has moved up the barrel and is blocking the gas port. The compressive force of the bullet traveling up the barrel combined with gas blow-by will pressurize the gas cylinder to approximately 10psi. This initial pressure transient is what we use to start the data acquisition process.
    Stage 1: This stage is defined as the bullet having moved forward of the gas port, but is still in the barrel. This stage is responsible for the highest rate of change of pressure over time (dp/dt). However, it is also the shortest of the stages, lasting approximately 46 microseconds.
    Stage 2: The bulk of the gas transfer will occur during this stage. The bullet has left the barrel and the barrel is now rapidly depressurizing. However, the pressure in the barrel is still greater then that in the gas cylinder; therefore, gas continues to flow from the barrel into the gas cylinder.
    Stage 3: Pressure equalization has occurred in this stage. It marks the point of peak pressure in the gas cylinder. From this point forward, gas will be flowing from the gas cylinder back into the barrel. Gas is also flowing past the piston and exiting the gas cylinder as previously mentioned.
    Stage 4: The gas cylinder is depressurizing. This stage normally lasts approximately three milliseconds.
    Stage 5: The M1 Gas cycle is now complete. The gas cylinder has depressurized. The operating rod has reached its peak momentum. At this point the operating rod has moved rearward approximately 3/8 of an inch. The operating rod will coast rearward using the kinetic energy it gained to perform functions such as: unlocking the bolt, extracting the empty cartridge case, cocking the hammer, and compressing the operating rod spring.

    (Figure 2)
    The Effect of Port Pressure and Bullet Velocity on Peak Pressures
    As mentioned in the introduction, the modeling of gas flowing from the barrel into the gas cylinder is very difficult. This is because the modeling of the flow of gas through the gas port has several variables that are not easily determined. The flow of gas from the barrel to the gas cylinder is choked through the barrel port and is not linear. For this reason, we cannot use barrel pressure alone as an indication of the peak pressure seen in the gas cylinder.
    Bullet velocity plays an important role in determining the final peak pressure seen in the gas cylinder. As bullet velocity increases, the time to transfer gas into the gas cylinder decreases. This factor is often overlooked and under appreciated. The time spent in Stage 1 decreases as bullet velocity increases. This effect moderates the possible peak pressures. For example, if two bullets are fired and each reach the gas port with the same barrel pressure but different velocities, the slower bullet will produce higher peak pressures in the gas cylinder.
    M2 Ball -- Our Benchmark for Gas Cylinder Pressures
    We chose M2 Ball to be our benchmark for what a safe gas cycle should look like. This is reasonable since the M1 Garand in its current configuration is designed to use M2 ball ammunition. The ported gas screw will prevent pressures from exceeding this base line when shooting other types of ammunition.
    Our initial pressure testing showed that the pressure curve varied significantly between different years of production and manufacturers. To be safe, we choose the lowest peak pressure measured as the value that the ported gas screw should never exceed when using commercial ammunition. Figure 3 below shows one pressure curve and the peak pressures measured from several different years of M2 ball ammunition. For historic reasons we also tested M1 ball ammunition and included the results in the graph. The Army technical manual [TM 43-0001-27] describes M2 ball ammunition as being loaded with 50gr of IMR4895. For reference, this load is also included in the figure.

    (Figure 3)
    How the Ported Gas Screw Works
    When a cartridge is fired, it has a limited amount of gas that can be transferred to the gas cylinder before the pressure decays. If we increase the volume of the gas cylinder – by means of the port, the resulting peak pressure must decrease. Peak pressure is the component that can cause damage to the operating rod. Total impulse is the component that determines if the rifle cycles correctly. In simple terms, total impulse is the area under the pressure curve times a constant.
    A venting gas screw drops peak pressure and it drops total impulse. The ported design drops peak pressure and preserves most of the total impulse potential. The result of this design is that the ported gas screw can correctly cycle the rifle at lower peak pressures when compared against a venting style of gas screw.
    Reducing the peak pressure lowers the acceleration of the operating rod, and helps reduces the wear and tear on sliding parts and bearing surfaces.
    Commercial Ammunition Data
    Several of the most common brands of ammunition were purchased for testing. Each of the following graphs will list the brand tested, and show two pressure curves. The first curve is the pressure generated when the ammunition was fired using a standard GI gas cylinder screw. The second graph will show the pressure curve when the GarandGear ported gas screw was installed. Two M2 ball reference lines are included for comparison purposes in each graph. The velocities listed in the graphs are actual velocities measured using a chronograph.
    It is important to mention that the commercial ammunition tested is for a specific lot number. The manufacturers can change the load at any time, and without warning. Some of the loads tested do not produce excessive peak pressures. This can change without notice if the manufacture reformulates their ammunition.
    You can click on any of the graphs below to see the full sized image.

    Hornady Match M1 Garand 168gr A-Max Lot #3110993​

    American Eagle M1 Garand 150gr Lot #V41T496​

    Remington Express Core-Lokt 150gr Lot #K06 JDI​


    Remington Express Core-Lokt 180gr Lot #L08 TBI​


    Remington UMC 150gr Lot #H24 ZBI​

    Federal Power Shok 150gr Lot #V41 K440​

    Winchester Power Point 150gr Lot #690 C72​

    Prvi Partizan 150gr

    RWS ID Classic 150gr Lot #66PB​

    Sellier & Bellot SPCE 150gr Lot # 840/109​

    Fiocchi Extrema 150gr Lot #0728000C09​

    Golden Bear 168gr Lot #M44 2010-11​
    Data Summary
    The following chart summarizes the peak pressures measured during this experiment. It also shows how effective the ported gas plug is at reducing peak pressures.​

    Click to Enlarge Image
    Final Thoughts
    Three factors can result in damage occurring to the operating rod. The first is high pressure in the gas cylinder. The second is binding of the operating rod. The third is caused by poor lubrication. If any two of the three conditions are present, then damage is possible. If the operating rod is binding, the operating rod will flex and bend when cycling until the bind is overcome. It is also possible to damage the operating rod if the rifle is incorrectly field stripped. You should never force the operating rod out of the rifle when field stripping it.
    Using a venting or ported gas screw is a safe way to utilize commercial ammunition in your M1 Garand. From the graphs and data above, it was verified that the ported gas plug limited peak pressures in all cases to levels below that of M2 Ball. The ported gas plug has the added benefit of requiring no adjustments when switching ammunition. In the future, additional commercial cartridges will be tested. If you have a brand of ammunition that we did not test, please feel free to contact us.
  13. Silversnake

    Silversnake Silverback

    I appreciate the insight as I was unaware of the hard primers being an issue. Normally we use a modest load of Benchmark or Varget to get velocity just under 2800. As it was, all my 30-06 loads were 180grain hunting handloads for a bolt action so we bought some 150 grain stuff.

    Since this is an issue with the M1 and M1A, is it also an issue with the FAL? I am purchasing 7.62 battle rifle soon, but hadn't decided on a platform yet. I was considering M1A versus FAL. If the M1A is going to be temperamental towards commercial loads with softer primers, I will likely go with a FAL variant.
  14. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    FAL is a more recent design and the gas is adjustable I would only use hard primers in any arm that had a free floating firing pin.

    One of the reasons I have helped others add a spring loaded firing pin to the SKS. Not to mention that half the SKS that I changed the firing pin on had near locked firing pins. This caused by Mil cosmoline that was never removed from the SKS when purchased.

    One other was found with the SKS firing pin reversed, a sure disaster of going full auto.
  15. Silversnake

    Silversnake Silverback

    Roger. Thanks much.
  16. TwoCrows

    TwoCrows Monkey++

    Another rifle to consider is the .308AR such as the DPMS or Armalite AR10
    The same ergonomics and controls as the AR15 (muscle memory the same)
    In the case of the DPMS, drop free magazines with the option of using Magpul PMags.
    No reported trouble with commercial primers.
    No difficulty with a wide range of load pressures.
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