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Thread: Certain Ammunition is Dangerous to Use in its Rifles CMP Warns

  1. #1
    Boolit Master trapper9260's Avatar
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    Certain Ammunition is Dangerous to Use in its Rifles CMP Warns

    https://www.alloutdoor.com/2021/04/2...dangerous-cmp/

    I just seen that Gtec posted on this , this is the link to it
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  2. #2
    Boolit Grand Master



    M-Tecs's Avatar
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    That's what has been recommend for the past 85 years. What's changed? Nothing that I can see. It's just a refresher on 85 year old knowledge.

    50,000 CUP is the SAAMI standard for the 30-06 in CUP. 60,000 PSI is the SAAMI standard in the 30-06 in PSI. https://saami.org/wp-content/uploads...sting-Copy.pdf

    I have personally seen Garand's converted to 35 Whelen, 300 Win Mag and 458 Win Mag. The only ones I have done have been to 308 Win.

    https://www.thefirearmblog.com/blog/...in-mag-garand/

    I do highly recommend heeding the advice about port pressure. That being said in 30 plus years of working on the for Service rifles for competition I have never seen a bent OP rod.

    I made the mistake of agreeing to built two tankers for a buddy. I will never do that again. Saying bending the OP without heat was a challenge is an understatement.

    https://www.handloadermagazine.com/m1-garand-handloads

    Various sources claim the M1 bullet weighed 172, 173 and 174 grains, a mystery explained by a list of .30-06 service loads in Hatcher’s Notebook, the reference work by General Julian Hatcher. The maximum bullet weight of M1 ammunition was a maximum of 174.5 grains but could be as much as 3 grains lighter. Similarly, the maximum weight of the “150-grain” bullet was 152 grains but could be as light as 149 grains.

    Some good info on op rods here https://www.fulton-armory.com/faqs/M1G-FAQs/OpRod.htm
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    Boolit Grand Master 303Guy's Avatar
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    I have just received that warning email from AllOutdoor.com. I can see how an unsuspecting newbe could get caught out. Good on them for warning folks. As a non-Garand owner, this detail is not high on my mind but having owned a mini-14, I am aware of gas port pressures. I had to fit a smaller gas port nipple to it to tame the ejection.
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    Boolit Buddy 2A-Jay's Avatar
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    I load my 30-06 to M2Ball specs My '03 Springfield seems to like it just fine. My Savage 30-06 liked it as well.

  5. #5
    Boolit Master

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    2A-Jay here is something may interest you pm me if interested its at the lone oak rifle and pistol club


    Garand Matches

    Saturday June 19, 2021

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    Sunday November 7, 2021

    Veterans shoot for free on Nov 7th.

    Registration at 8:30

    Match starts at 9:00

  6. #6
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    Larry Gibson's Avatar
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    What I posted over on the CMP forum;

    While I disagree with the CMP warning [because it is too simplistic, somewhat erroneous and can be misleading] it should have been more of a caution than a do not use warning especially with regard to the M1903 and the M1903A3 rifles. Also the article referred to above [https://thegca.org/wp-content/upload...s-vs-Myth.pdf] has several glaring omissions, generalizations along with several of the quoted velocities and pressures are suspect.

    Let me explain. I have been pressure testing upwards of 14 years and have conducted over 3,000 test series of 38 different rifle and handgun cartridges. I primarily use the Oehler M43 PBL and am also working with a Pressure Trace System. I use SAAMI methods and standards in testing. The use of "reference" ammunition as per SAAMI guidelines is used to validate ("calibrate") each barrel initially and periodically and to obtain a correction factor as per SAAMI if necessary. Both use a strain gauge attached over the chamber to measure the "pressure". It is well proven the use of a strain gauge properly affixed in the same location as the transducer will give similar psi measurements. I affix the strain gauge over the chamber in the same location as SAAMI designates for the transducer.

    Since the warning and general discussions revolve around milsurp and commercial ammunition 30-06 ammunition we should understand the difference between C.U.P. MAP (Maximum Average Pressure) and the PSI MAPs. SAAMI lists a MAP both for CUP measurement and Transducer measurement (PSI). For the 30-06 the SAMMI CUP MAP is 50,000 and for transducer PSI it is 60,000 PSI. Thus for this one cartridge we can safely assume that a CUP of 50,000 is the same pressure as the PSI measurement of 60,000.

    Another point not often known is ammunition, both milsurp and commercial, are not loaded to the MAP pressure. They are loaded to velocity specification +/- (fps) while staying under the MAP for the cartridge. Thus, we may easily have a specific type of ammunition that is loaded with different lot or even a different type of powder that has more/less powder giving a slightly higher or lower psi at a given velocity level. This occurs with both milsurp and commercial ammunition.

    Over the 14+ years I have I have been testing I have conducted numerous tests [velocity, pressure and other internal measurements] of numerous different lots (by headstamp and lot number) of military 30-06 ammunition and commercial 30-06 ammunition. What I have found:

    Researching we find there were 6 different levels (types if you will) of U.S "M2 Ball" ammunition. There were 3 different levels of velocity that M2 Ball was loaded for the NG. Those have muzzle velocities close to 2700 fps (original M2), 2650 fps (2nd loading as requested by NG) and 2550 fps (3rd and last variant requested by the NG). The 2nd and 3rd variants were requested so the bullets would stay within the safety fans of numerous NG ranges. The 4th type of M2 Ball was the final version which was to have a muzzle velocity of 2800 - 2825 fps +/-. The 5th also is an "M2 Ball Alternative" which I believe is the precursor to the 4th version. There also is "M2 Ball AP" which is loaded to 2630 fps +/- using a 165 gr AP bullet.

    I haven't been able to find anything to indicate which arsenals loaded what type of M2 Ball by year or lot number. However, I'm sure somewhere there is a record of it. Also note that such M2 Ball of all varieties were loaded with both extruded and ball powders.

    The 30-06 test rifle is a bolt action with a 24" barrel with the chamber cut with a match reamer to minimum headspace.

    A few test results of M2 Ball covering a broad range of years and arsenals;

    Velocity is at muzzle and pressure is psi.

    LC68 in M1 clips; 2655 fps, 44,400 psi

    LC57; 2556 fps, 40,600 psi

    SL52; 2801 fps, 50,000

    SL53 (different lot than above); 2774 fps, 46,600 psi

    TW42; 2565 fps, 43,300 psi

    FA42; 2799 fps, 48,800 psi

    DM42; 2821 fps, 51,000 psi

    SL42 M2 Ball Alternate; 2879 fps, 53,000 psi
    SL42 M2 Ball Alternate (different lot); 2895 fps, 54,000 psi

    I was able to locate for testing some original M1 Ball;
    FA28 M1 Ball; 2638 fps, 51,900 psi

    I also had some LC M72 Match "White Box" and M72 loaded in M1 Clips.

    LC 67 White Box; 2619 fps, 54,700 psi
    LC68 in M1 Clips; 2556 fps, 50,400 psi

    Testing 15 different commercial loadings (110 to 180 gr) manufactured over the last 40 - 50 + years produce pressures from 53,000 psi to 59,900 psi. The velocities were predictably higher with bullet weights equal to or close to the milsurp counterpart. One can see from these limited test results a trend. That being the higher end psi's of the milsurp ammunition just matched the low end of the commercial loads. All, both milsurp and commercial were still under the SAAMI MAP for the 30-06 cartridge. The psi difference, to me at least, is of little concern for use in the bolt action M1903, M1903A1, M1903A3 and the M1917s. My own M72 Match duplication load using the Sierra 175 MK over IMR4895 duplicates LC67 M72 velocity and pressure. I have found it quite safe and very accurate for use in my M1903A1 match rifle and several M1 Rifles.

    However, for use in the M1 rifle I would not use any commercial ammunition not specifically made to US M2/M72 velocity/psi specifications. The author(s) may not have seen any bent M1 oprods but I have over the years. I would especially not use any "SuperPerformance", "Extended range" or "High Velocity" commercial 30-06 ammunition in M1 Rifles. Those types of ammunition all have less than 50,000 CUP or 60,000 psi which puts them under the SAAMI MAP and apparently is "ok" in the warning(?). However, the pressure traces clearly show a much higher muzzle exit pressure, ergo the potential for damage to the M1 oprod.

    In my opinion the weight of the bullet is immaterial, especially if reloading. There are many proven match level loads using 175 - 180 gr bullets that are entirely safe for use in not only the bolt guns but also the M1 Rifle. Specifically to exclude the use of 175/178 match bullets for use in the M1 does the rifle and shooter a disservice, especially if shooting 500 - 1000 yards matches.

    I don't know why CMP came out with the latest "warning" against using bullets over 174 gr and won't speculate. I just disagree, based on my own actual pressure measurements is all. Everyone is free to head the warning should they desire. Thus I am not recommending to anyone what to use or to disregard the "warning".


    The problem with considering only the CUP measurement is it only give a static maximum pressure the load achieved. Any CUP measurement does not give a time/pressure trace nor will it give a pressure at the gas port. We can easily have 2 different loads [same bullet but different powders] giving the same CUP measurement. However, one powder may have a much higher gas port pressure because it is slower burning. It also may have enough residual chamber pressure that the cases have not contracted yet and are still gripping the chamber wall. That is really what "bends" oprods. The case is still gripping the chamber walls as the oprod is attempting to cam the bolt open. That was self evident by the peening of the camming surface in the very few [again, very few] oprods I've ever seen.

    The problem is exacerbated as commercial loads with heavier bullets tend to use slower burning powders. Thus the time/pressure curves are not suited to the M1 Rifle.

    As an example I have pressure tested 2 different Federal 165 SP 3.0W loads. Both were purchased at the same time in the newer grey boxes. One box was listed as loaded with the Sierra 165 gr GK bullet. The other did not list the make of bullet. The box of rounds with the generic 165 gr SPBT had 42.0 gr of a ball powder in them. That load ran 2702 fps out of the 24" test barrel at 53,100 psi. The box of rounds having the Sierra 165 SPBT GK bullets had 47.3 gr of ball powder in them and they ran 2778 fps at 60,000 psi. Two seemingly similar factory loads except for the bullet and load used. The first would be safe in M1As and M1s converted to 7.62. The second would probably be safe in the M1A but probably not safe in the M1 converted to 7.62. Both would be quite safe in rebarreled (to 7.62/308W) DHT M1903s, M1903sA1s or M1903A3s and M1917s.

    BTW; the SAAMI MAP is not the "maximum" psi allowed for cartridges. The MAP is just the Maximum Average Pressure manufacturers should try to keep the production ammunition under. SAAMI uses two other measurements; The MPLM [Maximum Probable Lot Mean] and the MPSM {Maximum Probable Sample Mean]. Just as we find if we chronograph the same load on different days or if the same load is from a different loading time the average velocities will vary thus it is with pressure measurements. They do vary. The MPSM is the maximum allowable pressure of any of the tests of the same lot of ammunition.

    Also, again let me reiterate. With some exceptions, most commercial and milsurp ammunition is loaded to a certain velocity level (performance parameters) while maintaining the psi less than the established MAP for the cartridge. Most all commercial 30-06 ammunition is not loaded to the MAP [50,000 CUP or 60,000 psi]. Also the military arsenals [and commercial arsenals that load for the military] do not adhere to SAAMI specifications but have their own specifications.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  7. #7
    Boolit Master Gtrubicon's Avatar
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    Larry, I cant say thank you enough for the content of your posts. Your knowledge on most anything reloading is inspiring. So I’m gonna say thank you!

  8. #8
    Boolit Master 35 Whelen's Avatar
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    Thanks Larry. That's some really good stuff.

    35W
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    There are people who, for all the evidence presented to them, do not have the ability to understand.

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  9. #9
    Boolit Master

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    Quote Originally Posted by Larry Gibson View Post
    The 30-06 test rifle is a bolt action with a 24" barrel with the chamber cut with a match reamer to minimum headspace.
    ]
    Larry. as a point of interest: if that barrel ever comes up for replacement, would you consider pressure testing any given load, then recut chamber with a normal reamer/chamber and re-test to compare pressure difference between the two chambers?
    Spell check doesn't work in Chrome, so if something is spelled wrong, it's just a typo that I missed.

  10. #10
    Boolit Grand Master


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    Quote Originally Posted by ulav8r View Post
    Larry. as a point of interest: if that barrel ever comes up for replacement, would you consider pressure testing any given load, then recut chamber with a normal reamer/chamber and re-test to compare pressure difference between the two chambers?
    Suppose I could.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  11. #11
    Boolit Master



    TNsailorman's Avatar
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    Great article Larry. I have found in my shooting over the years that leaning strictly on velocity can have its down side and not just in the M1 Garand. I had a Remington 700(1962 year serial # in the 3000 range with a 20" barrel) in 30-06 that for some reason would not shoot loads listed in the reloading manuals using certain powders. I do not have the powder and load information now as the rifle is long gone and the load data not not kept. But anything over a 90% listed load would lock the bolt up tight. I was using mostly military WW II cases that I had been given by people trying to help me as I was fresh out of service and money was really tight about that time. I was not a very experienced loader back then but I did weigh each and every powder charge on a Lyman M5 scale(and still do). I am going to print your articcle for reference. Thank you, james

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BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check