how to...

Discussion in 'Ammunition & Reloading' started by matt g, Jun 23, 2009.

  1. matt g

    matt g New Member

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    I need to push a 175 gr. Sierra Match King .308 to between 2600 and 2700 ft/s. I need them to also be as clean as possible and need them to be dead nuts consistent out of a cold, fouled barrel, using fire formed M118 brass.

    Ready, set, go!
     
  2. Dillinger

    Dillinger New Member

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    is this for your M14 project? Because barrel length and the fact that you need to bleed some of that gas to cycle the op rod will come into play as well.

    Bullet Name
    Diameter inches .308 dia
    Weight grains 175gr
    Sectional Density .264

    Ballistic Coefficients.
    .505 @ 2800 fps and above
    .496 between 2800 and 1800 fps
    .485 @ 1800 fps and below
     
    Last edited: Jun 23, 2009

  3. matt g

    matt g New Member

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    It'll be an 18 inch Krieger, medium heavy, chromoly barrel on a match grade M14 with a chamber cut for M118LR.

    Pride Fowler says that the reticle on their RR800-1 is calibrated for the 168 gr. Sierra Match King traveling at 2700 ft/s and the 175 gr. traveling at 2600 ft/s.
     
  4. matt g

    matt g New Member

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    Keep in mind that I've never reloaded a single bullet in my entire life.
     
  5. Dillinger

    Dillinger New Member

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    Damn, I had this big long post - and it probably amounted to nothing - but I lost it when I hit Reply. :mad:

    I'll leave it at this. There are much more qualified people than I to answer this question. :D

    JD
     
  6. matt g

    matt g New Member

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    Where is Robo these days?
     
  7. Dillinger

    Dillinger New Member

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    I don't know - He has been popping in from time to time, but me thinks he is off doing his Superhero thing...

    cpttango is an excellent source, if you can put up with him ( :rolleyes: ) - He should be along shortly and he can help you, I am sure.

    I was just going to point out that 2700 fps from a short barrel ( meaning hotter round as it leaves the brass ) is going to lead to some tuning issues with the pressure being seen by the operating rod and action.

    But, again, I only dabble in this field and am NO EXPERT....

    I look forward to seeing the finished project. Too bad you live in Kalifornia - a threaded flash hider and a screw on can like Shurgart had in Black Hawk Down would be an AWESOME SHTF weapon. :D

    JD
     
  8. matt g

    matt g New Member

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    Indeed. SEI ships all of their rifles to the military with direct connect cans.
     
  9. robocop10mm

    robocop10mm Lifetime Supporting Member

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    Try this reference: 25 loads available in .308 Winchester with bullet weight equal 175

    You are going to need a chronograph to be sure your shorter barrel is wringing out he velocity you need. I would stick to the faster burning powders like H-335, W-748, BLC-2 and maybe Varget.

    Varget may be the ideal answer. It seems to give outstanding accuracy in most guns. You have a daunting task of putting together an accurate, clean, consistant load that leaves the muzzle at a prescribed velocity. Good luck with this project. Prepare to burn some powder.
     
  10. cpttango30

    cpttango30 New Member

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    that is easy put them 175gr SMK over some good VV N550 or 540.

    VV powder are the cleanest I have used. You can also try 42 to 43gr of RL15 that is the go to load of a few F-class shooters I know.

    RL17 is a new powder and supposed to give high velocity with normal pressure.

    Check 6mmbr.com's 308 page for some very good very accurate load data. http://www.6mmbr.com/308Win.html

    VV308.JPG
     
    Last edited: Jun 23, 2009
  11. RL357Mag

    RL357Mag New Member

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    The highest recommended velocity listed for a 175 gr.Sierra MK HPBT is 2600fps using 44.8gr. of BL-C(2), and that won't be the most accurate load. According to Sierra's Data, top accuracy for that bullet is achieved with 42.2gr. of IMR4064 driving it at 2500fps.
    If you drop down to 168gr. Berger Match VLD bullets or Sierra 168gr. MK's you can use 45.5 gr. of Varget with Fed. 210 G.M. Match primers and make sub .5moa groups while achieveing your goal of 2700 + fps.
    This info is from a Dec 2008 article in Rifle's Handloader Ammunition Reloading Journal, Issue #257 - the article is entitled "Developing the most accurate .308 Win. Load", by Gary Sciuchetti. I used the Varget/Berger VLD bullet suggestion for my DPMS LR308B and achieved a .40" 100 yd. group which chrono'd at 2792fps. The LR308B has an 18" barrel. From now on I use nothing but Varget or BL-C(2) powder for the .308. Berger VLD (Very Low Drag) Match bullets will run you almost $40/100. Not for plinking.

    PS. - you would do good to look up that magazine article - M118 brass failed after only 11 reloads and produced an average group of .625". Remington commercial brass failed after 20 reloads and produced groups averaging .5469". Remington "once fired" cases produced average groups of .4375" and M118 Mil "once fired" brass produced groups averaging .6094". According to the article, the most accurate brass was Nosler "once fired" and Federal "plated" "once fired" each producing groups averaging .3281 and .3750 respectively. In all cases, "once fired" brass was more accurate than new brass, and in all cases, M118 brass came in second to last in accuracy.
     
    Last edited: Jun 23, 2009
  12. matt g

    matt g New Member

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    What rifle was used for the tests? I'd bet it was one that wasn't specifically chambered for M118LR.
     
  13. cpttango30

    cpttango30 New Member

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    IMR powders are not known for being clean burning. That is why I stopped using them.

    Varget is ok in the 308. Min e didn't like it one bit. As we all know each rifle is different.

    I would go with VV N550 because I have a VV N135 load for my 223 that is pushing a 50gr V-max at 3600 fps with a midrange powder charge. This load is also one of my most accurate producing groups in the 4's.

    I shot all day with VV powder and didn't even need to clean. Bore looked just as it did when I started.
     
  14. RL357Mag

    RL357Mag New Member

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    Prior to the test the author wanted to select a factory rifle that was capable of .5 moa accuracy out of the box to eliminate discrepancies in accuracy which might be attributed to the rifle. He first selected a Remington 700VLS but was unable to achieve the stated accuracy consistently, so he went with a Sako TRG-22 which is a commercially available "competition/sniper" rifle of sorts, and very expensive. The accuracy I achieved in my AR (LR308B) mirrors what the author was able to achieve in the article with his Sako, which is truly amazing for a semi-auto action. The LR308B which I bought for my son as a present when he arrived back from Iraq, did not shoot M118 ball ammo worth a sh!t. The groups were all over the paper and we had FTE and FTF every 2nd or 3rd shot during the break-in period. Also, the M118 brass is thicker walled than commercial brass and cannot be loaded to max powder loads without compressing the powder charge.
     
    Last edited: Jun 24, 2009
  15. matt g

    matt g New Member

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    I understand that military brass is thicker, but you've got to understand that the dimensions for 118LR are a little different from .308 Win and 7.62 NATO. Because of that, it'll only run properly if fired from a rifle chambered for it. I may very well use Remington brass and fire form it prior to loading for accuracy.

    How many firings does it take to fire form brass?
     
  16. matt g

    matt g New Member

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    VV powders it is. Are they widely available?
     
  17. RL357Mag

    RL357Mag New Member

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    That's why once-fired brass was more accurate. It takes only one firing to form a case to your chambers' dimensions. What you say about M118 is not completely true. Some AR's are chambered for 5.56 instead of .223 and vice versa. They are not interchangeable because of the leade length of the chamber creating pressure differences which can be dangerous. The same relationship does not exist for the .308 vs. 7.62. Any commercially produced .308 rifle can safely fire 7.62 x 51mm military ammo with the exception of M-60 machine gun ammo which is loaded to pressures which could damage a commercial rifle. There are no exterior dimensional differences, only the wall thickness and subsequent mil spec loading is different. Consequently military brass should be loaded 1 to 2 grains under the max load indicated in reloading manuals.
     
  18. cpttango30

    cpttango30 New Member

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    Vihta Vuori powder can be bought online at Midwayusa, Grafs (I think) and Powder Valley. The 500 series of powders act like and work in the same cartridges as the 140 150 and 160 powders. 540 550 560 just produce more energy than the 100 series powders. Bit more expensive than Hodgdon, or allient powders because they are imported from Europe. It was told to me by more than a few guys that VV powder often exceed the book specified velocity unlike other powder that may get close but are under the shown velocity.
     
  19. RL357Mag

    RL357Mag New Member

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    The M118 designation, whether it is "LR" or "NM" is EXACTLY the same dimensionally as any 7.62 x51mm (.308) cartridge. The only difference between the M118, M80 (147gr. FMJ), or any other designation is the bullet weight/type. M118 NATO MATCH ammo, like the M118 Long Range ammo is loaded with 175gr. Sierra BTHP bullet heads. The cases are identical dimensionally to any military or commercial 7.62 case. I handled hundreds of thousands of rounds of every type of 7.62 and .5.56 ammo during my first two years in the Corp. as an ammo chief in the field and at Redstone. After having pulled many bullets from different types of ammo I learned what commercial powders closely resemble what the military arsenals use. H-335, H-322, BL-C(2), and some older Winchester powders are as close as you can get to milspec powders.
     
    Last edited: Jun 25, 2009