Newbie questions .308

Discussion in 'Reloading Forum (All Calibers)' started by jeff423, May 16, 2018 at 9:57 AM.

  1. jeff423

    jeff423

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    I'm just getting to reloading for Bench Rest shooting and have some newbie questions. I have been reading the Berger book on reloading and have found the method they describe on pages 100 - 101 about adjusting seating depth very helpful and did find one group was noticeably better. Now using the same bullet, will that depth be the best for my gun and will it be the same when I vary the powder charges? Or do I have to start the process over again for different powder charges, and if so where do you stop? FWIW I'm using Varget.
    I'm using Lapua brass but I have about 100 pieces of Winchester brass. Should I just scrap the Winchester.

    Thanks,

    Jeff
     
  2. riflewoman

    riflewoman

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    Keep the Winchester, but you’ll likely find you have more variance if you weight sort it.

    Most people vary the powder charge or even type to get best accuracy first. Start with a seating of .030 jump first unless you have magazine length issues. Then when you’ve settled on a charge weight and powder type vary seating depth to tune the rifle.
     
  3. retired

    retired

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    if you did not start with powder variation, you are only half way there.
    stick with the lapua brass
    start over with the bullet right at the lands( pressure goes down from there when moving away)
    your choice: do a 10 step .4 gr ladder( 10 single shots in .4 steps) at 200 /300 yds,or
    it you are stuck at 100 consider 3 shot groups. up and down from where you are now.
    you did not list rifle, scope, bench equipment.
    308 win if not a normal br cartridge.
    600 ok, 1000 not
     
  4. jeff423

    jeff423

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    Thanks for the replies. I'm shooting a Savage FTR so magazine length won't be a problem. I'll try the 0.030 jump. I've done the "ladder" for a given powder weight.
    Savage FTR, 1 in 12" twist
    44 gr. Varget
    Sierra 168 gr. HPBT
    Leupold 36x scope
    Randall Machine front
    Protektor rear

    Shooting at 100yds for now.

    Right now this looks like a "chicken or egg" question.
     
    Last edited: May 16, 2018 at 12:28 PM
  5. SteveOak

    SteveOak Silver $$ Contributor

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    Quantity of powder or optimum seating depth first? The answer is;



    Seriously, a few months ago I asked if anyone knew what the mechanism was that caused a change in accuracy as the result of changing seating depth/jump/jam. I don't know and no one answered the question in the thread.

    http://forum.accurateshooter.com/threads/jump-or-jam-how-does-it-affect-the-results.3944106/

    There was a lot of discussion but no theory of how a change in seating depth results in a different group was offered.

    If anyone on this forum knows, either they didn't see the thread or they ain't sayin. :)
     
  6. jeff423

    jeff423

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    That's what I was afraid of.:)
     
  7. jim_k

    jim_k

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    Take whatever advice you wish, but my Savage 12 (.308 Win) shot a 0.60" 10-shot group at 100 yards using Lake City brass. I've shot a 0.68" 20-shot group with Lake City brass in .223 Win. I've weighed water capacity of LC compared with Lapua, and they are equally consistent with regard to water capacity. If Lapua is better, it is for some other reason. You would probably do well to talk to the BR shooters you will be shooting with, about how they work up loads. They do a lot of things different than other shooters. My Savage 12 likes Sierra 168's at 2.88" OAL. I wouldn't change the Varget part of the load, just vary the charge, and work from there. A long-range BR shooter posted his work-up ladder on the internet a couple of months ago, and he picked a certain seating depth, then varied the powder about 0.5 grain. If there was excess windage, he worked on that with minor change of seating depth, after the powder charge was determined. Was that Alex Wheeler or Tom Mousel? Anyway, that'll work.
     
  8. barefooter56

    barefooter56

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    Jeff,
    Its been my experience that the bullet seating depth accuracy node stays pretty static in regards to velocity.
    see here: http://www.bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf .
     
  9. SteveOak

    SteveOak Silver $$ Contributor

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    <strike>Hey barefooter56. The link didn't work for me. Could you repost it please</strike>

    Nevermind. It autodownloaded and I didn't see it.

    Thanks!
     
  10. Don

    Don Gold $$ Contributor

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    No ice water here But ?
    I shoot Palma and F/TR = .308 .
    Lapua Brass runs a weight difference .
    I weight separate all my Brass ..
    Lapua , Winchester & Peterson .
    I have shot Wining scores with Winchester .
    I have never thought my Brass was holding me back .

    168 gr. Sierra Bullets are good to 600 yards .
    If you wish to step out on the Town with your rifle ? I would try Berger 175 OTM they make it to 1000 yards.
    Good Luck
     
  11. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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    seating depth affects the barrel harmonic node. think of rolling a marble down a 4' pipe while youre shaking it up and down then the same with a 5' pipe. the balls will exit at different spots on the up down track. if you fine tune the seating depth to where the bullet at a certain speed exits the barrel at the same exact spot on the barrel's path youll shoot smaller groups than if you have the bullet exit on an upswing then on a downswing. that's why seating depth AND powder charge has to be consistent. also think of that case as a pressure vessel and the volume of it affects the internal pressure and that particular powder charge on that day at that time may need a little tweaking to have a perfect pressure that can be duplicated on the next shot- like fine tuning a carb- you get the perfect burn ratio
     
  12. jeff423

    jeff423

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  13. jeff423

    jeff423

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    Thanks Don,
    I'm sticking at 100 yds. for now. I've got plenty of Lapua Brass and I believe if I used the Winchester brass I would have to get a different neck bushing. I'll keep it on hand though.
     
  14. Shynloco

    Shynloco You can lead a horse to water, but ........ Silver $$ Contributor

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    Jeff,
    I just came across your post and have a few suggestions that may help you. When it comes to "accuracy shooting" and testing for the best load, there are a few imperatives and rules that are time proven that assists in getting you the best accuracy out of a specific rifle. One of those rules is that whenever you test, only change ONE component at a time. By that I mean don't jump around testing different makes of brass. Settle on one (lapua) and use that make. Then figure out which bullet, powder and even seating depth to use and load three/three shot test groups that are all identical in load and seating depth. Start first with a powder load and seat to whatever SAMMI spec appears in the given manual you are using. Also look for the "Accuracy Load" that some manuals offer as they give to good idea of where that best accuracy lies. But start below that powder load and "ladder" up to it. Having loaded for various .308's, I can tell you that some .308's like a 168gr bullet to be jammed, while others like a jump. So to figure out what your rig likes, by use a SAAMI spec length. Then work your way both toward or away from the rifling to see how much difference there is in group by changing the seating depth by .010, Then narrow to .05 as the groups get better. Also know and remember, that Seating Depth is usually the final step in finding/tuning your accuracy load for your rifle. Also know that since you are shooting at 100 yrs, 44grs of Varget at that distance IMHO is too much powder. In my .308BR, 42 grs of Varget, RE 15 or IMR4895 usually has given me my best groups (@100 yds) regardless of the bullet manufacturers. However, I would recommend using ether Sierra or Berger bullets that I've found work best in several different make .308's. And BTW, some loved the jam, while other hated it. So I have found starting at .030 off the lands has been a good starting point for me.

    Good Luck and have fun. Accuracy reloading/shooting is both challenging but loads of fun. So be patient and be sure to write down every load you test to better track your testing. And remember to ONLY change one part/setting of a test load at a time. Changing more than that makes is more difficult to pinpoint specific likes and dislikes of your rifle, sometimes known as "variables."

    Alex
     
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  15. joshb

    joshb Gold $$ Contributor

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    ^^^^^^:):):):):):):):)^^^^^^^^^ This just saved me a whole lot of writing. Ditto. Except "narrow to .005"
     
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  16. jeff423

    jeff423

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    Thanks Alex,
    You've helped me on my way. I picked 44gr. from the Nosler data as being the most accurate charge for Varget. (They claim BL-C2 as the most accurate overall.) Based on an earlier post I'm going to drop the Varget down to 38 gr and work up from there. From my hand gun and rifle reloading I've got about 15 powders so I'm trying to restrict my purchases because I've got a lot of "orphans". I've got H 4895 and IMR 4895 too. If I try another powder it will probably be VV N140 or (RE 15 - Sierra's recommendation.) As soon as I use up my HDY 155's and my Sierra 168's I'm going to try some Bergers.
     
    Last edited: May 16, 2018 at 10:23 PM
  17. joshb

    joshb Gold $$ Contributor

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    Oh, don't veer away from trying the H4895 just yet. It's one of my favorite for the 308. You have the viht 140, which is a good powder that I haven't used. I use the viht 135 for my best 308 loads. It's a great powder, but expensive these days. Maybe the 140 would work too. I don't have my book in front of me. The 308 can shoot very well with a variety of powders. You just have to test, test, test. For a retired guy like me, that's just plain fun. You're good with the Varget , too. It's my primary powder for the 308 because I bought a ton of it when powders were getting scarce and I couldn't get the H4895. I ran the 168 Sierra pretty hot when I was getting started. I was at 2.96 COAL for a long throated factory Remington, just touching the lands with 44.7 Varget. I learned a lot from the guys here and lowered my charge weight to a slower node which is more accurate and less brutal on my brass. Might have saved me from blowing my face off, too.:eek: I think I ended up between 40 to 42. I'm speaking in general terms because you have to test your gun. Using someone else's load might get you close to an accurate load in your gun. It might also blow your gun up.:mad: As always, start low and work up. Watch for over pressure signs. Good luck!
     
    Last edited: May 16, 2018 at 10:35 PM
  18. Rsadams

    Rsadams

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    So much good info above , especially about changing only one thing at a time.... My suggestion would be if your going to use Sierra bullets , buy a Sierra manual.... I use the specific manual for the bullet I am using... Do to different bearing surface's etc I have found it to work better , plus you can't really have to many manuals or data... I use the correct manual after loading some bullets from a different manufacturer and at half way up the charge scale on a manual from a different bullet maker they were already as fast as factory loads.. I know you work up but I normally start in the middle because I find starting with the minimum charge a waste...
     
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