Maximum powder charge...

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  • boisepaw

    boisepaw
    Jan 5, 2015
    380
    Eastern shore, MD
    Loading for a 308...using both 168 & 175 grain SMK bullets. I understand published loads will be conservative for the sake of safety and liability. I understand that you work up slowly...watching for pressure signs.

    Just curious...how many grains above published maximums have you gone before getting into trouble?
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,731
    Socialist State of Maryland
    You shouldn't shoot above published maximums. To do so without a pressure test fixture is like being a blind test pilot. You might not think too much about hurting yourself but how about the guy at the bench next to you?
     

    Oswaldo87

    Active Member
    Feb 1, 2020
    151
    Frederick County
    This kind of question is why so many guys recommend multiple books. Reference as many sources as possible. Doesn’t answer your question but it has given me a few loads that I didn’t realize were possible with only one manual.
     

    DENWA

    Active Member
    May 5, 2008
    272
    Have to understand the motivation of why push the limit.

    You a Competition shooter looking to gain that edge? Or trying to flatten the 308 until it keep up with your buddy's 300WM?


    ***EDIT--I'm skipping over the actual work it takes to get to the point of the story***

    The reason I say all this is because in a short season I have burned through 5x reloads of that brass, and that 8# of powder was gone. and Starting over with all new components.

    Years ago down at Quantico I told Ed Shell what I was doing to make it work.

    He shook his head and said WHY?

    He was right. It wasn't necessary, it was a lot of work to keep up and quite frankly, wasn't very enjoyable.
     

    boisepaw

    boisepaw
    Jan 5, 2015
    380
    Eastern shore, MD
    When Berger’s reloading manual calls for a max load of 41.3 grains of H4895 for a 168 grain bullet in a 308 rifle but Sierra’s manual has a max load of 43.4 for the same weight bullet and powder, I am inclined to wonder why.

    I am Looking for accuracy...plain and simple. I am using Scott Satterlee’s load development method which uses a range of Powder weights to try to find an accuracy node. A faster load will maintain its accuracy for a longer distance. Hence the question...
     

    BigRick

    Hooligan #15
    Aug 7, 2012
    1,140
    Southern Maryland
    When Berger’s reloading manual calls for a max load of 41.3 grains of H4895 for a 168 grain bullet in a 308 rifle but Sierra’s manual has a max load of 43.4 for the same weight bullet and powder, I am inclined to wonder why.

    I am Looking for accuracy...plain and simple. I am using Scott Satterlee’s load development method which uses a range of Powder weights to try to find an accuracy node. A faster load will maintain its accuracy for a longer distance. Hence the question...

    The reason why you have different max loads for different powder manufacturers is because they use different firearms to test with. No 2 guns are the same. I can tell you from experience that max loads are not as conservative as people think. My son a I both bought 2 new savage rifles and I loaded up a ladder test for both guns, His gun showed pressures signs at nowhere near max published loads mine went well over with no signs. To be safe start low and work your way up. It's not fun when primers start blowing out and bolts start sticking or bass gets stuck in your chamber from over pressure. Also Chronographs are a great tool also.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    The OCW method actually has you load above max, but each increment is very small, and you check for pressure signs after EACH round fired.

    The concept being that if one increment has no pressure signs, the next increment will not be dangerous. It any increment shows pressure signs, you DO NOT FIRE THAT INCREMENT AGAIN.

    Max in the book is a guide. It is NOT the safe maximum for YOUR rifle. Your chamber may be such that the max for that rifle is lower than the book. Or you may be able to go higher.

    Also, ANY change in components can change that maximum. A change in case brand or primer can make the difference. Even if you change lots of power, if you running at or near max, you should drop back and work back up.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,665
    Not Far Enough from the City
    The reason why you have different max loads for different powder manufacturers is because they use different firearms to test with. No 2 guns are the same. I can tell you from experience that max loads are not as conservative as people think. My son a I both bought 2 new savage rifles and I loaded up a ladder test for both guns, His gun showed pressures signs at nowhere near max published loads mine went well over with no signs. To be safe start low and work your way up. It's not fun when primers start blowing out and bolts start sticking or bass gets stuck in your chamber from over pressure. Also Chronographs are a great tool also.

    Yep! In addition, bullets of the same weight, but of differing configurations, will have amongst other things, different bearing surfaces. They can thus have different pressure specs and performance characteristics.

    Lots of entirely valid points in this thread. From not being a "blind test pilot" as John so aptly states, to the utility of multiple manuals, to the possible effects of changes in components, to changes in temperature and differences in rifles, to not trying to make a 300 Win. Mag. out of a .308 Win., to proper OCW incremental charge methodology.......ALL valid points by their respective writers!

    PLEASE folks, take the "all about the lawyers" crap with a huge dose of salt. With such simplistic drivel, the tendency becomes a mindset amongst some to want to completely dismiss the data as being complete garbage. Garbage to be ignored. Drives me nuts when some jamoke decides they know more than Sierra and Hodgdon and any and all of the other industry accepted publishers combined. Joe's Bar and Grill isn't a ballistics test lab.

    Is the published data absolute in every instance, and all of the time for every gun and load combination? No. But it most assuredly isn't garbage to be ignored.
     

    Seabee

    Old Timer
    Oct 9, 2011
    517
    Left marylandistan to NC
    All good comments. Too many variables not to work up loads. Different lots of powder, Data manuals not updated recently, varying case capacities, and rifling twist rate all play into it in addition to those mentioned above. I've never been one to use a hornady manual for Sierra bullets but I have compared Sierra data with the powder manufacturer data when using Sierra bullets. Safety, safety, safety
     

    kalister1

    R.I.P.
    May 16, 2008
    4,814
    Pasadena Maryland
    I have manuals from back in 1980 and newer. I have noticed as new manuals come out the MAX load goes down. Is this Difference in powder, Difference in testing methods or Lawyers?
     

    Swaim13

    Active Member
    Jun 11, 2017
    327
    OP, if you are working for a max accuracy node, do the OCW charge method. The big thing to remember is that you can change powders and associated burn rates to help you get the load you want. I believe that it is roughly 85% case capacity is what you aim for.

    223 loves varget. I am sure that 308 has something similar that a lot of ppl have found. I would start w that powder.

    If you are trying to do long range accuracy, figure out if your twist rate can handle the 175s. If so, I would stick w those due to the higher bc. If not, figure out what you are trying to accomplish. Remember that TMKs and SMKs will stabilize differently.

    I would work through the ocw method and find your powder nodes before just trying to ramp up the charge weights. I have found in my 223 that going slightly slower was better for accuracy and consistency. I get velocities that exceed book values at well below the max charge weight.
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    OP, what is your definition of trouble? Flat primers? Swipes? Blown primers? Short brass life? Have to beat the bolt handle open?

    I've had some of those, try to stay away from others.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    OP, if you are working for a max accuracy node, do the OCW charge method. The big thing to remember is that you can change powders and associated burn rates to help you get the load you want. I believe that it is roughly 85% case capacity is what you aim for.

    223 loves varget. I am sure that 308 has something similar that a lot of ppl have found. I would start w that powder.

    Yeah, it is called............

    VARGET :)

    Actually, no reason to do OCW, find some people who have done the OCW, and pick the common load.

    I did the OCW, even got Dan Newberry's input.

    And guess what, I got the same load as over 100 other people got.

    Lapua brass, Sierra 175 SMK, Federal Match primer, 43.5 grains of Varget.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    Running up to higher nodes is mainly for people shooting at very long ranges.
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    , I put lots and lots of varget in my palma gun. But the rules we play by you have to shoot a 308 with a 155 out to 1000 yards. You have to push it 3000 fps to stay above the speed of sound. Rather than go full stupid on the pressure, we use 30" barrels
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    , I put lots and lots of varget in my palma gun. But the rules we play by you have to shoot a 308 with a 155 out to 1000 yards. You have to push it 3000 fps to stay above the speed of sound. Rather than go full stupid on the pressure, we use 30" barrels

    Why do you need to stay supersonic?

    AFAIK, the only match bullet that has transonic transition issues is the Sierra Match King .30 168 grain.

    I know the 175 is fine going subsonic.
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    Plenty of bullets suffer from trans sonic issues. The 168 being the worst, or most well known. That is due to its boattail. But long skinny bullets will do screwing things too. The 175 isnt really that slippery. It's not a tug boat, but it's not a vld.

    Need to go fast to minimize wind effects too. The wind will kick your butt at 1000. So because we are restricted to a 155 grain, you dont want to leave wind drift performance on the table. So we use the most slippery 155's we can, long and pointy, but dont play nice starting at mach 1.2.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    Plenty of bullets suffer from trans sonic issues. The 168 being the worst, or most well known. That is due to its boattail. But long skinny bullets will do screwing things too. The 175 isnt really that slippery. It's not a tug boat, but it's not a vld.

    Need to go fast to minimize wind effects too. The wind will kick your butt at 1000. So because we are restricted to a 155 grain, you dont want to leave wind drift performance on the table. So we use the most slippery 155's we can, long and pointy, but dont play nice starting at mach 1.2.

    Not talking about BC.

    Just addressed in transonic instability. What other bullets? As I stated, the only one that I have read about is the 168 SMK

    Yes, to minimize wind drift you want max velocity, but a different subject. :)
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    Your experience may be different than mine, but have shot at the national at camp Perry many many years, no one shoots a 223 out of AR at 1000 yards. Sone try and figure out real quick why it's a bad idea. Long skinny bullets dont do well in transonic region, which happens at Mach 1. 2 to Mach .8. For example, the 80 grain SMK is a great bullet but not in transonic region.
     

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