Pressures for reloading the 308 Garand

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    SKIP

    SKIP

    Ultimate Member
    Mar 5, 2009
    3,248
    Glenwood/Glenelg
    I have been reading about dangerous port pressures in the 30-06.
    Is there a concern when reloading for 308 Garand?
    I have been using the traditional 3895 and 4064 but with limited availability of powers I want to use others.
    I haven't been able to find any reloading data.
     
    B

    Busa

    Member
    Jul 22, 2012
    90
    So. MD
    Yes you should be concerned with pressures. Follow the reloading guides for the M1A rifle in 7.62. I assume your 3895 is 4895 and that is what I use in the M1A and 308 Garand reloads.
     
    T

    temccoy

    Active Member
    Nov 13, 2020
    103
    The issue that is specific to the Garand is the burning rate of the powder. You want the powder granules to have burned before they reach the gas port at the end of the barrel. If a powder granule goes into the gas port while it is still burning the pressure from the expanding gases can bend the operating rod. We call that a bad thing. Also true of the M1A for the same reason. Pressure levels for 30-06 and 308 loads are the same for the Garand and M1A as for other rifles, (although you can push the loads harder in a bolt gun). You just need to not use a slow burning powder like 4350. As other people have stated, stick with the recommended powders for loads in a Garand, 4895 and 4064 are the classic powders for it.

    Hope this helps
     
    B

    Busa

    Member
    Jul 22, 2012
    90
    So. MD
    SKIP said:
    I'm looking for that load but for the 308 Garand.
    Most manuals are listed for any 308 rifle.

    Example:
    For the 45/70 there are 2 specific loads, one for trapdoor and another for modern day rifles.
    Click to expand...

    The link has a 308 service rifle load that is for Garand and M1A so it will be safe for your 308 Garand. I have also used the BLC2 powder data on that page for general blasting loads with 150 grain bullets.
     
    P

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,327
    Varget is fine in the 3006 garand and the 308. Also fine in the m14. With a 175 match bullet id be around 41-42.5 grains in a 308.

    Op, they make adjustable gas plugs. That may be a cheaper route then buying powder right now.
     
    SKIP

    SKIP

    Ultimate Member
    Mar 5, 2009
    3,248
    Glenwood/Glenelg
    I loaded up 10 with a 150 FMJ using a Lee dipper and Varget. Good results and no ill functions on feeding/ejection.
    The same good results using H-322.

    Thanks to all for the great info.
    Now to load up more for the next trip.
     
    Pinecone

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    temccoy said:
    The issue that is specific to the Garand is the burning rate of the powder. You want the powder granules to have burned before they reach the gas port at the end of the barrel. If a powder granule goes into the gas port while it is still burning the pressure from the expanding gases can bend the operating rod. We call that a bad thing. Also true of the M1A for the same reason. Pressure levels for 30-06 and 308 loads are the same for the Garand and M1A as for other rifles, (although you can push the loads harder in a bolt gun). You just need to not use a slow burning powder like 4350. As other people have stated, stick with the recommended powders for loads in a Garand, 4895 and 4064 are the classic powders for it.

    Hope this helps
    Click to expand...

    Uuh, not exactly.

    It is not about powder granules in the gas port.

    It is about the slower powders having still high pressures when the bullet passes the gas port and the high pressure GASES enter the port.
     
    Pinecone

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    Busa said:
    Use the loads in the lower range, try to keep it around 40,000 psi you will be fine. Happy New Year!
    Click to expand...

    Chamber pressure is not the issue.

    It the pressure when the bullet passes the gas port.

    With a slow burning powder, you could have a low chamber pressure but still too high of a pressure at the gas port.
     
    Doco Overboard

    Doco Overboard

    Ultimate Member
    Jul 22, 2016
    7,863
    The heart of the Delmarva Penninsula
    I think a 3006gas port ID is somewhere around a #47 Db. .078
    A GCA armorer says he opens them up to around #41 or .096 and then makes sure op rod spring length is to spec. rifle lubed correctly etc.

    If you can get your hands on some numbered drill bits it would be relatively easy to make a determination of the gas port size on your rifle just by knocking the gas cylinder off/ measuring piston o.d. roundness inspecting other components etc for working up a load.

    Something else I have learned to do when inspecting rifles testing etc is to have a look at the area just behind the op rod hooks. There is a ledge just in front of it that has a corresponding surface on the front of the reciever. I've seen contact between the two parts when rifles were run with ammo on the warm side and op rod spring was worn or oos in combination with worn bolt lugs opening closing cams in the op rod actuating ramps.

    Worn, slightly peened or rounded, bright-tend area at the receiver face/op rod rear is one of those things that can be seen when the rifle is torn down in between shooting sessions and as one familiarizes themselves with what they are working with and how its going.

    Im not sure how a jump to an adjustable gas plug or the intended range at which they work at, especially with differing ammo combinations remedies a potential problem occurring elsewhere that may have gone unnoticed.

    Basically,when other parts may be out of spec in combination or, specifically if they can mask other problems that may be evident when placing one into use I'm trying to say.

    I dont use the aftermarket gas plugs but can understand why people opt for them I just dont think they are necessary for any rifles Im running. I noticed that a couple clicks of elevation were necessary for ammo I loaded myself that was/is conservatively loaded but that could just be me and shooter error which I do happen to be good at.
     
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