LR 308 is finally done

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Replies

  • ZeeZee Senior Member Posts: 20,564 Senior Member
    edited August 2018 #32
    Jay said:

    308 gas guns tend to be over-gassed and as a result, have a tendency to beat themselves to death.  An adjustable gas block is just good insurance, allowing the user to tune for just the required amount of gas to the BCG to do the job.
    This
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • ZeeZee Senior Member Posts: 20,564 Senior Member
    edited August 2018 #33
    Jay said:
    JKP said:
    Add $100 for a decent BCG. Still good pricing. 
    Heck, I'd just double check head spacing using the BCG from the existing upper and swap it back and forth between the two uppers.  Can only use one upper at a time, with just one lower...

    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • ZeeZee Senior Member Posts: 20,564 Senior Member
    Nice group!! 
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • Diver43Diver43 Senior Member Posts: 8,525 Senior Member
    Good shooting
    You built yourself a keeper
    Logistics cannot win a war, but its absence or inadequacy can cause defeat. FM100-5
  • JayJay Senior Member Posts: 3,319 Senior Member
    Thanks guys. I’m very satisfied with 1/2 MOA, to say the least. Just hoping velocity will be acceptable. Which shouldn’t be a problem, since I don’t plan to shoot this thing far enough to need top end velocity. 
  • knitepoetknitepoet Senior Member Posts: 18,658 Senior Member
    Couple of things....
    I seem to remember someone saying something about a H4895 load making you smile :smiley:

    Concerning adjusting the gas block. I like the instructions that came with my Superlative Arms adjustable block. I'll paraphrase them here
    Load one round in a mag. Fire, if bolt locks back, close block 1 click. Repeat until you get to the first failure to lock back. Then open it 2 (yes TWO) clicks and call it good for that load
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • JayJay Senior Member Posts: 3,319 Senior Member
    edited August 2018 #38
    knitepoet said:
    Couple of things....
    I seem to remember someone saying something about a H4895 load making you smile :smiley:

    Concerning adjusting the gas block. I like the instructions that came with my Superlative Arms adjustable block. I'll paraphrase them here
    Load one round in a mag. Fire, if bolt locks back, close block 1 click. Repeat until you get to the first failure to lock back. Then open it 2 (yes TWO) clicks and call it good for that load
    You were definitely correct on that. 😎 Thanks. 

    Sounds like that procedure should work on mine. Although, all of the test loads I tried today pretty much landed in about an 8” circle at my 4 o’clock, a few feet away. That’s with the gas block almost half open and not a single malfunction so far. Once I get an allen wrench long enough to reach the gas block, I might try closing it down a click at a time as your instructions state. 
  • knitepoetknitepoet Senior Member Posts: 18,658 Senior Member
    edited August 2018 #39
    Superlative includes a 6" allen wrench with theirs :p

    And you're welcome
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • Elk creekElk creek Senior Member Posts: 5,725 Senior Member
    Nice! That will work. Well done. 
    Aim higher, or get a bigger gun.
  • JayJay Senior Member Posts: 3,319 Senior Member
    Thanks guys. 👍
  • JayJay Senior Member Posts: 3,319 Senior Member

  • ZeeZee Senior Member Posts: 20,564 Senior Member
    Motivation. 



    Killed a pig with mine tonight. 
    220yrds w/ Sierra HPBT-GK
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • JayJay Senior Member Posts: 3,319 Senior Member
    Nice!

    My pig wasn’t nearly as big and was funny looking... And it wasn’t edible.

  • JayJay Senior Member Posts: 3,319 Senior Member
    Jay said:
    A couple of days ago I loaded some test loads for the 308. After getting some advice in my thread about gas gun loads and consulting my Hornady manual, I came up with 40.5, 41, 41.5 and 42 grains of H4895. I got out this morning before the heat got too bad and tried them. The gun did ok with the 40.5 grain loads. The hole to the left was my third and I felt like I pulled it just a touch before I saw it on the board  I think that one could have been a little better. I didn’t take my caliper with me, but comparing it to the 1” paster, it looks to me like it’s pretty close to 1” even with the flier.

    The next two loads opened up pretty dramatically. I won’t even bother posting pics. 2”+ groups. It definitely didn’t like those loads. I had a feeling it would find another accurate spot somewhere higher and was hoping the 42 grain load would be it. I wasn’t disappointed. 


    I cut that section of the target backer out and out and took it home to measure it. .49” center to center. Thats at 2.175” BTO length. I’ll take that. Now, I need to load up the rest of my brass with that load and check velocity next time out. Then I can get my initial ranges on the BDC reticle marks and verify them. 
    Just as a follow up to this, I was finally able to get out and chronograph this load. I went out yesterday afternoon, only to find that my chronograph battery was dying and wouldn’t read anything. Not having a spare 9v battery, I had to go out again this morning. My load of 42 grains of H4895 and a 168 Amax averaged right at 2500 FPS out of my 16” barrel. 
  • JayJay Senior Member Posts: 3,319 Senior Member
    I used that velocity and the following info in the Vortex ballistic calculator;
    Elevtion-2500 ft
    temp- 80 degrees
    humidity- 40%
    ballistic coefficient- .475
    50 yard zero
    3” sight over bore

    The Vortex ballistic reticle look so like this, with the MOA noted for each mark. 


    Based on the ballistic calculator info and those MOA measurements on the scope, it gives me the following. 
    Main reticle- 20-220 yards (+/- ~1.5”)
    2.4 MOA mark - 280 yards
    5.6 MOA - 375 yards
    9.5 MOA - 480 yards
    14.6 MOA - 595 yards

    Whether or not that is correct, I’ll have to find out. Next trip out, I’ll check and verify and adjust as needed. 
  • JayJay Senior Member Posts: 3,319 Senior Member
    FWIW, I was able to shoot steel at 270 yards this morning. Holding the 2.4 moa mark just under the center of the steel had it ringing with every shot with ease. 

    300-600 yards should really start getting interesting. 
  • ZeeZee Senior Member Posts: 20,564 Senior Member
    Hopefully, the reticle is not to thick to make shooting your target at 400+ yards a trying task. 
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • BigDanSBigDanS Senior Member Posts: 6,788 Senior Member
    I have a theory about load development.  Have you ever noticed most “ best” loads are at the higher end?  We get more used to shooting the rifle and when we get to the top end we have “got it”.  Great fourth group by the way!  
    "A patriot is mocked, scorned and hated; yet when his cause succeeds, all men will join him, for then it costs nothing to be a patriot." Mark Twain
    Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
  • ZeeZee Senior Member Posts: 20,564 Senior Member
    Most of my “best loads” are at the top end with ALL of my rifles. Regardless of how “used to” the rifle I am. 
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • JayJay Senior Member Posts: 3,319 Senior Member
    Zee said:
    Hopefully, the reticle is not to thick to make shooting your target at 400+ yards a trying task. 
    I don’t think that will be as much of a problem until past 400. At least not for MOA hits. Just guessing. The reticle on this scope is actually surprisingly sharp from what I’ve seen so far. Not a thin reticle, for sure. Aiming st those 1” pasters at 100 yards, I can actually aim at the center circle and use the cross hairs on the paster, rather than just aiming at an orange dot. But, guess we’ll see. The steel target I’m using is 10”x12”. Going to try that out to 600. 
  • JayJay Senior Member Posts: 3,319 Senior Member
    BigDanS said:
    I have a theory about load development.  Have you ever noticed most “ best” loads are at the higher end?  We get more used to shooting the rifle and when we get to the top end we have “got it”.  Great fourth group by the way!  
    For the most part, I’ve seen good accuracy at the lower end, then it comes apart a little, then better groups at the top end again. Doesn’t always work that way. But I see it quite a bit. This load is approaching the higher end, but still could go higher. For what I’m doing, out to 300 reliably with up to 600 as the top end goal, I’m good with 2500fps right now. 
    Thanks. 
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