A good day shooting leaves me with some serious ladder test questions.

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by 4ked Horn, Feb 12, 2006.

  1. 4ked Horn

    4ked Horn Writers Guild

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    Well today was fruitful to say the least. I did a break in on my nephews gun that went surprisingly well. I shot a 300 yard group with Wildcat 169.5 grain ULD RBBT HPs and the ULD flat base HPs. I will post the pictures of this in another post tomorrow. I have to say I am EXCEEDINGLY happy with the group made with the RBBTs.

    The topic of this post is, at the least, perplexing. We shot a ladder test with my brothers .338 win mag and had surprising results. The velocity increased with the increase in powder for the most part but the impact string went up and down. Alot. I was expecting something that resembled the velocity string. I expected the bullet holes to rise and settle then rise and settle. No such luck. In fact the last shot was only an inch and a half higher than the first shot but the extreme high and low shots were over 6 inches apart.

    I will post pictures of the actual target and the velocity and shot graph tomorrow (it is too late and I'm too tired to mess with it right now) but I wanted to get all you experienced ladder testers on stand by for this one. I have no idea what is hapening on this one. I actually have a theory. I am wondering if the gun was taking a toll on my brothers shoulder. He said that he was doing fine and he did keep shooting in a group (somewhat) or rather the shots were coming out near each other. They just weren't rising up the paper.

    Please keep an eye on this post for the incoming info. I really dont want to shoot this ladder twice if we can put together a satisfactory node from the info gathered.

    Thanks guys. /ubbthreads/images/graemlins/wink.gif
     
  2. royinidaho

    royinidaho Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    [ QUOTE ]

    The topic of this post is, at the least, perplexing. We shot a ladder test with my brothers .338 win mag and had surprising results. The velocity increased with the increase in powder for the most part but the impact string went up and down. Alot. I was expecting something that resembled the velocity string. I expected the bullet holes to rise and settle then rise and settle. No such luck. In fact the last shot was only an inch and a half higher than the first shot but the extreme high and low shots were over 6 inches apart.

    [/ QUOTE ]

    NOthing unusual about that, at least in my experience. Post the pics and velocities and I'll willingly post my ever so humble opinion. Yah, right.

    Include Powder, primer, stock/bedding type, etc.

    Waitin' to hear.
     

  3. Michael Eichele

    Michael Eichele Well-Known Member

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    Barrel harmonics have more to do with where the bullet will strike more so than inconcistent velocity string. Up to 600 yards or so, then good old gravity and time of flight will really do its damage and you WILL notice bullets high and low due to bad velocity strings.
     
  4. 4ked Horn

    4ked Horn Writers Guild

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    Here it is. The raw target. Components are new win brass, wrm primers, 250 gr SGKs, H4831sc powder. Rifle has the rear tang and front of reciever and lug bedded. BBL is free floated but not by much. Rifle was shot from front rest and rear bag. Trigger pull is a light 3.5 to 4 lbs (it will be used while traveling cross country sometimes). Rem 700 stainless. 40 deg. 3100 ft ele. mild 90 deg cross wind (5mph or less) coming from l to r. 10 rounds through bbl since last cleaning prior to starting test. No less than 1 minute between shots. Often more.
    [​IMG]

    Here is the graph showing the actual height relation of the shots. The first shot in the above picture was a test shot that was given #1 so shot #20 is actually #19 on this chart.
    [​IMG]

    Here is the velocity graph. The red vels (8,18) were "no reads" so I put them between ajacent shots. The green vel (16) was identical to shot #15 and we didn't notice if the chrono beeped or not.
    [​IMG]

    Velocities are as follows:
    1 2341
    2 2320
    3 2365
    4 2398
    5 2413
    6 2422
    7 2476
    8 no read (2500)
    9 2526
    10 2559
    11 2554
    12 2568
    13 2583
    14 2603
    15 2645
    16 2645?
    17 2626
    18 no read (2640)
    19 2660

    OK lets see if we can make heads or tails of this. Maybe a reccomendation on a next step.
     
  5. ss7mm

    ss7mm Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    4kedHorn:

    What is the powder charge increment for each load?
     
  6. 4ked Horn

    4ked Horn Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    .4 grains starting at 64.3 and ending with a published max of 71.5 from hodgdons "05 manual.
     
  7. royinidaho

    royinidaho Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    Which choke tube are you using? /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

    I'm thinkin! I'm Thinkin!

    How are you holding the rifle as in shoulder pressure, hand on forearm? That is, are you pulling in snugly into your shoulder with your trigger hand with your other hand on the sand bag?

    The reason I ask is that when my bbl was "barely" floated I was pulling it down against the stock sometimes when shooting off of pedestal rest. Then I got my handy dandy inletting tool and hawged things out so now you could drive a humvee in there.

    Check the free float while at the shooting bench. You get in your shooting position get your buddy to run a business card all the way to the recoil lug. If any resistance at all, consider some work on it.

    My standard for free floating is 5-1s together all the way to the recoil lug. Depending on the rifle I some times fold the 5 1s long ways.

    I've found that a good solid hold into the shoulder, the other hand squeezing the sand/beanie bag and letting the muzzle do whatever it wishes has been best for me. It also more closely duplicates conditions when shooting prone from bipod.

    You're not using REM 9 1/2 Primers, are you?

    I'd consider starting the test @ your #10 load and go up from there.

    In my Win. which seems to be a bit unusual as I can approach RUM velocities I got the following results with REM Cases and 4831sc:

    71.5 gr = 2596
    74.7 gr = 2788

    Mine didn't like SC as much as it liked some other powders.

    Also, 20 shots in less that say 30 minutes @ 40 degrees temp. your bbl should have been pretty darn warm. Remember it will be warmer on the inside than on the outside. I'd consider shooting it, removing the empty, pointing it in the direction of the wind, leave the bolt open, then walk down to the target, kick some dirt/sand/snow/etc, then come back and shoot the next shot.

    I'm a bit confuxed regarding the relationship between trigger pull and traveling across country? [pull is a light 3.5 to 4 lbs (it will be used while traveling cross country sometimes).

    I wouldn't switch powders, but may consider switching primers, unless you're using Feds, until the randomness is removed and more consistency is achieved. Then consider changing powder if you think you need to.

    Another thought. Stand the rifle on the recoil pad. With screw driver in one hand and your other hand (dail indicator works better but your hand will be pretty sensitive) loosely holding the rifle around the barrel and fore end tip, loosen and tighten the receiver screws in different combinations. If you feel any movement or hear the stock squeeking as the action moves, then you may wish to revisit the bedding.

    I'm not sure who I'm talking to, thus may have covered some stuff that you already have considered. Hey, just trying to help.

    Good shootin'
     
  8. 4ked Horn

    4ked Horn Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    [ QUOTE ]
    Which choke tube are you using?

    [/ QUOTE ]
    Hardy har har. /ubbthreads/images/graemlins/smirk.gif

    [ QUOTE ]
    How are you holding the rifle as in shoulder pressure, hand on forearm?

    [/ QUOTE ]
    My bro was pulling the poll of the grip hard against the heavy( heavy ) rear bag and then putting his shoulder against the butt with a full grip from his trigger hand then letting gravity do it's thing. Several times he said he wasn't sure of the quality of the shot but he also stated that he was getting a good surprise break. He attributed his doubts on the shots to the gun disrupting it's self on the recoil. The times I actually watched him take the shot they looked stress free and no flinching was detectable. Shot 15 was the only one he called as a "bad shot" but that was only because the break happened much sooner than the others.

    [ QUOTE ]
    Check the free float while at the shooting bench.

    [/ QUOTE ]
    Biz card goes OK on the work bench. I'll check it next shooting session.

    [ QUOTE ]
    You're not using REM 9 1/2 Primers, are you?

    [/ QUOTE ]
    Winchester large rifle mag.

    [ QUOTE ]
    Also, 20 shots in less that say 30 minutes @ 40 degrees temp. your bbl should have been pretty darn warm.

    [/ QUOTE ]
    I don't know exactly how long it took but it was much longer than 30 min. I feel confident that the BBL didn't get too warm. I remember seeing him touch the BBL a few times and he never mentioned it warming up. I'll keep an eye on this next time as well.

    [ QUOTE ]
    I'm a bit confuxed regarding the relationship between trigger pull and traveling across country?

    [/ QUOTE ]
    It is crisp and reasonablt light but I purposely left it heavy enough to prevent an accident if he was moving and bumping about with the safety off. Light hunting weight (3.5 - 4 lbs) instead of heavy target weight(2-2.5 lbs).

    [ QUOTE ]
    I wouldn't switch powders, but may consider switching primers, unless you're using Feds,

    [/ QUOTE ]
    I'm strongly considering going to Fed mag primers for the next test if for no other reason then the wimpy feel the win primers gave when seating. If I get better groups with them, all the better.

    I really appreciate all the help. Thanks for sharing your ideas.
     
  9. 4ked Horn

    4ked Horn Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    OK. This might just be my imagination but the longer I stared at this the more clear things seemed to get. This is what I saw.
    [​IMG]
    It seems like a definite set of small and large patterns.

    The first picture is almost a perfect mirror image with #14 smack dab in the middle. Upper node perhaps?

    The second picture seems to show more of a recurrence. Several shots to build an upward leg (red). Then some rapid fluctuations up and down (down is blue) then several shots to build another upward leg followed by rapid fluctuations again. Funny both the left and the right pictures show #14 in the same place in the pattern and the second recurrence.

    Am I smoking crack or what? (really, am I interpreting this right or am I just seeing what I want to see?)
     
  10. 4ked Horn

    4ked Horn Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    ss7mm, Where did your post go? The one where you suggested shooting .1 gr increments of the different sections of the ladder.

    I didn't get a chance to respond. Throw it back up here. /ubbthreads/images/graemlins/wink.gif
     
  11. royinidaho

    royinidaho Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    Nah, you're not smoking crack /ubbthreads/images/graemlins/crazy.gif /ubbthreads/images/graemlins/crazy.gif

    I took your thoughts and went spinning off on my own. Here's what I came up with. Just to let you you're not the only one who thinks hard about these things. /ubbthreads/images/graemlins/grin.gif

    I picked the consecutive shots that show a definite trend in your above Pics.

    Shots 1 through 4 do what is expected, a nice vertical rise w/velocity (except for #1 which I'll check off as a cold/maybe clean barrel). But nevertheless a vertical string.

    Then shots 4, 5 & 6 produce a nice horizonal string. Hmmmmn

    Shots 8, 9 & 10 produced a triangle, I'd call that a group. Look at the velocity steps between 4/5/6 and 8/9/10. About 12 FPS compared to closer to 30 FPS per step change. But still nevertheless a 'group' maybe about 2 1/4".

    Then look at shots 13 thru 16. Back to horizonal string again.

    Considering the shot placement along with the velocity trends gets a little more interesting.

    Seeing as it is your brother that's taking the punishment, I'd consider doin' it again. But as suggested above, start at Load #10 and go up. You can always stop when the loads get too hot.

    Before you shot them though, I'd consider spinning the loads to look for out of roundness. A spinner would be useful but not absolutely necessary. Just roll them on a flat surface and if any are out of round you'll see it. (Just a tho't).

    Here's my prediction. I'm going way out on a limb here. Credibility gonna go down the tubes. /ubbthreads/images/graemlins/blush.gif /ubbthreads/images/graemlins/frown.gif

    As testing is continued you will continue to see alternating patterns of vertical then horizonal stringing. There will be another vertical and horizonal pattern above the shots 13 through 15 sequence. Then, finally 1/2 way between the next vertical and horizonal pattern's is where it will shoot the best symetrical groups.

    This may be all out of wack but it's a pattern that I've seen too many times to dissregard.

    Good luck and have fun.

    PS: I'd consider cutting the powder change steps at least by 50%.
    [​IMG]
     
  12. Buffalobob

    Buffalobob Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    4ked horn

    Is the scope adjustable for paralex?
     
  13. 4ked Horn

    4ked Horn Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    Yes. It was set for 300.
     
  14. royinidaho

    royinidaho Writers Guild

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    Re: A good day shooting leaves me with some serious ladder test questi

    was parallex set by the number on the ring or until parallex is removed by adjusting until you can't see it any more?

    I haven't had a number on any scope even be close?

    Just another tho't.