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M1A Load

Discussion in 'Handloading and Reloading' started by ping, Apr 12, 2009.

  1. ping

    ping Well-Known Member

    I just got my "Loaded" M1A from SpringField last week and now need to get some reload info. I currently reload for my Garand & A3 using sierra HPBT 168 amd IMR 4895. I want to stay with these components. I do have some IMI brass that I will be using. My question is where do i start as to grains of powder & max. Also it appears 2.80" is the OAL and trim is 2.005". Are these good figures. Also if I decide to use win .308 brass how much different will the power be. I believe the IMI is considered milsurp thus a 10% decrease in power use as compared to commercial .308 win brass. Any help would be greatly appreciated. Any additional info would be great related to loading for my new M1A.
  2. 30Cal

    30Cal Well-Known Member

    The standard M1A load for the 168gr Sierra in a .mil case is 41.5gr IMR4895.
  3. Mark whiz

    Mark whiz Well-Known Member

    IMI brass is definitely mil-spec brass....................... and damn fine brass at that! :)

    All your numbers mentioned there are spot on for OAL and brass length and the 41.5 gr of 4895 with mil-spec brass has been the standard charge for high power shooting with the M1A/M14 for eons.

    Here are 2 good word of advice for loading the M1A:
    1. Make sure your primers are installed slightly below the face of the case head.......................high primers can cause a bad day in the form of slamfires.
    2. Since you got a new rifle, there should be a card enclosed that tells you what your chamber headspace is............LIVE by that number. Make sure your sized cases are headspaced at least .003" less than that number - again, this will go along way in preventing slamfires.

    I've gotten very good wear out of my cases with my M1A, but I anneal the brass after 3 loadings and I think that helps case life tremendously.

    As far as using commercial brass, rather than mil-spec brass..................the old NRA formula calls for reducing the charge by 12% when going from a comercial case to a mil-spec case. If you weigh your batches of brass, you can reduce by the percentage difference between the different batches weights............................. but always make safety a 1st priority and work up to a new load.

    Also watch what powders you decide to use if you venture off from 4895........the gas system doesn't play to well if you go with too fast or too slow of powders.................4895, 4064, Win748, Hod BL-(C)2 and those other powders in that same range are safe to use. Varget is questionable - I've heard and read good and bad things, so be careful with it.

    Here is a great link to everything M14/M1A:
  4. 30Cal

    30Cal Well-Known Member

    A lot of guys shoot Varget. I'd put it in the "OK for M14" category.

    The Zediker article is pretty good although he hasn't shot the M14 in over 10 years now.
  5. NuJudge

    NuJudge Well-Known Member

    In terms of burn speed, Varget was designed to be virtually the same burn speed as IMR4064, but with short granules, which flow a lot better.

    I've never had any luck with Varget or IMR4064, but excellent results with IMR4895.

    Try at least these two burn speeds, one one should work for you.
  6. FredT

    FredT Well-Known Member

    ping, as the other guys said, buy all means, use your 168s and your IMR4895.
  7. ping

    ping Well-Known Member

    Headspace question followup

    Mark & Guys;
    Thanks for all the information. Mark you did say one thing about the tag i got with my new rifle indicating headspace. I did see that. You said to make sure i am .003 less than that. I have never really messed with headspace and that concept still is confusing to me. so how do i do this. normally i just worry about coal and trim and the other basic reloading pieces. can you explain what i need to do with this. trying to be real careful with my new rifle and safe. That headspace concept is just hard to grasp. sure appreciate everyones info.
  8. USSR

    USSR Well-Known Member


    An easy way to do this is to get yourself a RCBS Precision Mic and measure a factory loaded round of something like Federal Gold Medal Match ammo. Then, set your resizing die up so that it bumps your shoulder back to read the same. Since your headspace will be on the "minimum" side in your loaded M1A, you will be GTG.

  9. glockman19

    glockman19 Well-Known Member

    Would Winchester NATO stamped brass be commercial or Mil Spec?

    I'm reloading Q3130
  10. TexasRifleman

    TexasRifleman Moderator Emeritus

    Anything with the NATO headstamp is thicker, ie milspec.
  11. Mark whiz

    Mark whiz Well-Known Member

    Ping -
    USSR gave you good advice on setting up your case headspace - I use my RCBS Precision Mic religiously for semi-auto rifle loading.

    A simple definition of headspace as far as the case is concerned: it is the distance from the case head to the datum line on the shoulder, which is basically the mid point of the shoulder - but that is a little different with each different type of round. What happens if your headspace is too long is that the round does not fit all the way into the chamber so when the bolt closes it can be prevented from closing and latching all the way.
    This is a 2 prong problem with the M1A - since it has a floating firing pin, if the cartridge isn't far enough forward in the chamber the movement of the pin can pierce and ignite the primer when you least want or expect it..... i.e. a slamfire. And if the bolt hasn't locked in (i.e. in battery) you have an out of battery ignition which is basically going to destroy the rifle and possibly mess up your manly good looks :what: .

    As long as you maintain the Springfield spec headspace, you should be just fine, but for safety's sake, I set my cases up about .003" less just to make sure I don't have any issues; and I'd bet that if you Mic'd a Fed GMM round, it's probably real close to that .003" over the Springfield spec.

    When sizing a batch of cases, I usually Mic at least 3 or 4 of the cases out of each batch to make sure all is well. I have found that every once in a while I get a case that has to be hit a 2nd time to make sure it gets down to the right spec..................especially when using Mil-spec cases like Lake City or IMI - they are thicker brass and give more resistance to sizing.

    And yes - I am kinda anal when it comes to reloading...............but I love my face and my firearms too much to risk them when there are options to prevent it.
  12. Bart B.

    Bart B. Well-Known Member

    For what it's worth, after the 7.62 NATO round was first allowed in high power matches back in 1963, the most accurate ammo with 168's and 180's in both converted Garands or M14/M1A rifles had IMR4064 in them. Military teams proved this testing their rifles from machine rests with all sorts of ammo.

    Military arsenals also got better accuracy with IMR4064 than IMR4895 in .30-06 Garands, but they had to weigh the powder charges individually. High speed powder measures didn't meter it as uniform in weight as IMR4895; that's why IMR4895 was used in most service and match ammo.
  13. win308

    win308 Well-Known Member

    I don't think a micrometer case gage measure is worth the cost. Simply take your sizer die all the way down to the shell plate and size a fired case. Clean the case of any lube, and insert in your chamber with the op rod removed and the extractor removed. If the bolt closes, with no force on the newly sized case, back you sizer die off the shell holder 1/4 turn and size another fired case...clean and insert into chamber and close the bolt. Repeat by backing off 1/4 turn each time until the bolt just closes on a newly sized case. Now the head space is dead on....but since you are shooting a gas gun and need to have the bolt close with no strain or stress at all, tighten the sizer die back down 1/4 turn and lock it right there. You should have perfect head space plus just enough wiggle for THAT GUN for all your sized cases from that point on.
  14. 30Cal

    30Cal Well-Known Member

    A quarter turn on a resizing die is worth almost 0.020" of headspace.

    Dangerous. A 1/16 turn is the difference between decent case life and premature head separations. Not a good idea in a gasgun.

    Get a gage.

    Even if you adjust the sizing die in tiny increments, the chamber can only tell you if your case is too long.
    Last edited: Apr 16, 2009
  15. Bart B.

    Bart B. Well-Known Member

    30cal posts:
    Gee, isn't it amazing what grade school math can do for us handloaders?

    Let's see, one turn on the die is 360 degrees. A 1:14 thread count makes the threads 0.0714285.... inch apart in a full, 360 degree turn. And turning the die 90 degrees for a quarter turn moves the die 0.017857.... inch; gee, that's almost .020-inch.

    I personally know of two folks who did this "quarter turn then resize" thing increasing relative headspace way too much. Blew the heads off cases damaging their very expensive fancy wood stock from the gas blowing out the escape hole.

    Many years ago I wrote RCBS about making a set of full length sizing die lock rings as follows. The bottom one's scribed on its flat top with radial lines every 5 degrees and had a set screw to lock it in place just like the regular ones. On the set screw locking top ring was a flat section on its side with a witness mark vertical on it. Once the bottom ring was set in place close to the proper location of the die to size the case, the top ring was locked half a turn or so above it aligning its witness mark to a scribed line on the bottom ring.

    After the case was sized and measured with a case headspace gage, if the die needed to be moved 6 thousandths of an inch (up or down), just loosen the bottom ring, move it in the correct direction 6 scribe marks then re-tighten in on the press and lock its ring. Each mark changed the die's setting by .000992.... inch; close enough to .001-inch for this job. Size another case to verify it's sized headspace changed 6 thousandths from before.

    RCBS loved the idea. Never made such a set of rings.

    I made my own. It's easy. Do so yourself and save some time making a necessary job easier.
  16. ping

    ping Well-Known Member

    Thanks Mark and all:

    Guess I need to get a gauge. looked on line tonight and midway has them for $44.99

    Guess when i get it i can figure it out. never used one so it will be interesting. it is time i started looked at this. thanks again everyone for the information.
  17. Mark whiz

    Mark whiz Well-Known Member

    The Mic is real simple to figure out, you drop your case in the long piece, then screw on the top piece, when it hits the case it stops screwing and you just read the hash marks on the side..................... just like reading a set of calipers or a micrometer of any type.
  18. Bart B.

    Bart B. Well-Known Member

    Ping, one other thing about case headspace gages; they ain't all exactly perfect.

    I've got a custom made one built long before any company mass produced them as well as an RCBS Prec. Mic; both for .308 Win. Across 7 different "GO" gages supposed to be exactly 1.630-inch, none zeroed exactly on the index and the spread was almost .002-inch. No problem. Industry normalcies.

    These gages are to be used to see the difference between a fired case right out of the chamber then again after it's full-length sized. This number is all that's important as it's your rifle the sizing task is being done for.
  19. dmazur

    dmazur Well-Known Member

    You can also get a Wilson type cartridge headspace gauge. This has "steps" that usually match GO/NOGO dimensions for chamber headspace gauges.

    You can use calipers to measure the distance from your once-fired brass to the base of the gauge, and then the distance after resizing, ignoring the steps.

    You can also use this gauge for a quick check of case trim length, holding the gauge vertical on a flat surface and checking the brass to see if it sticks up past the other end...
  20. Slamfire

    Slamfire Well-Known Member

    Cartridge headspace gages. So cheap, and yet worth their weight in gold.

    I pull mine out each time I am sizing brass.


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