A little confused.

Discussion in 'Long Range Hunting & Shooting' started by shooters, Nov 23, 2011.

  1. shooters

    shooters Well-Known Member

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    Hello. I've just started re loading and am a little lost. I don't think this belongs in the reloading section though. I have a Sendero ll 300 RUM. Loaded to book. 3.600 OAL, 94 gr Retumbo Powder, 200 gr Accubond, Fed 215 Primers, Rem brass full length resized. Brass extensivley preped. De burred, primber pocket uniformed, weighed, etc.. I started with 94 gr, not sure why, but did. Book says 95 is max and 91 was most accurate load tested. Here's where I'm lost. With that caliber and bullet, does it take a certain distance for that bullet to stabilize, or is there just simply fine tuning to be had with bullet seating and powder? Here's why. I chronoed the rounds, got temp, elevation, humidity, etc.. all the works. Went to several ballistic calculators and printed out dope charts. Each bullistic calculator was about the same. I went to the range. Wanted a zero at 275 yards. Said I should be high 1.0 inches at 50 yards. So, I got on paper, got to exactly 1.0 inches high at 50. Shot 2 rounds. Punched paper in exactly the same hole. Thought, good start. Went to 100 yards. Dope chart said should be 2.5 inches high. I put 2 rounds touching right at about 2.25 inches. Roughly, hard to measure 200 gr bullet hole when talking half inch size holes. Ha ha. Anyway, I was like, wow, first time reloading and everything is amazing. Then, go to 300 yards. Chart said I should be 1.5 inches low at 300 yards. I was 3.5 inches HIGH. I shot 1 round, let barrel cool for about 5 min. Shot another, let cool. Shot another again. 3 total. All rounds could be covered with a copenhagen lid I would say. So, now I was wondering if I fouled my barrel up with a little copper. I spent the next hour running patch after patch of Tetra gun until there was no more blue to be seen. Went straight to 300 yards, same thing. 3.5 or so inches high. Went to 50 yards, 1 inch high. Whats the deal??? Why am I shooting high??? Is that bullet not stabilized yet, or does that round just not work out of that rifle and I need to do some fine tuning? I haven't tried 4 or 500 yards yet. I checked scope mount and everything felt tight as can be. Shooting a Sightron Slll 6-24X50. Can't remember the scope mount. Thanks for the help.
     
  2. WildRose

    WildRose Well-Known Member

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    What velocity are you getting from your Chrono?

    Do you have your scope height correct? Measure center of bore to center of scope tube.
     

  3. Scot E

    Scot E Well-Known Member

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    Assuming 3100 fps, your numbers correlate to what my program says as well so you should be hitting low by 1.5 inches or so.

    If you are getting tight groups then stabilization, rings and bases isn't likely the issue. Have you checked your parallax? How tight is your group at 300 yards?
     
  4. shooters

    shooters Well-Known Member

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    Chrono is 3104. Scope height, I measured 2" which is where I probably went wrong. Thought it was 1.5". There Seekins rings and base. They sent me what they said were the correct height, which I think are medium for that contour barrel.
     
  5. WildRose

    WildRose Well-Known Member

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    Plug that into your program and see what it does.

    Remember ballistics programs are limited in effetiveness/accuracy by a number of factors. The more correct your input data is, the closer it will give you to accurate info out.

    Even at that you may end up needing to tweak your velocity and/or ballistic coefficient to narrow things down further.
     
  6. Bravo 4

    Bravo 4 Well-Known Member

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    You are getting good groups and velocity with a proven bullet. The rifle/load seems fine, either your adjustments in your scope are way off or you and the ballistic calc aren't jiving. I doubt the your scope height being off 1/2" is gonna throw you off 5" @ 300 yards, maybe 1000. That just isn't helping. Check the scopes adjustments, then make sure you have the correct adjustments in the calculator.
     
  7. paphil

    paphil Well-Known Member

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    I would do a 100 yard test to verify true click value. "0" the scope at100 an a tall target and then crank on 50 or 75 clicks and shoot again at the same spot. Measure the distance from the low group to the high group and divide the distance by the number of clicks. 1/4 minute clicks should be 1/4 of 1.047 inches or .26175 inches per click. More or less needs to be corrected for in the program. That is the great thing about the Best of the West and the G7 programs. You use what you have done so far as a guide to shoot data that is entered back into the program to give you a perfect chart for your gun and load. BC, velocity, click value and all the other variables must all fit togather to give you a good chart. All the programs depend on exact data to function properly .
     
    Last edited: Nov 24, 2011
  8. Sully2

    Sully2 Well-Known Member

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    I cant help ya with the actual ballistics without shooting it myself...but if it were me Id go and get the medium height rings. You wont have to lift your head up as much and it might just keep ya from getting slapped by recoil sometime.
     
  9. jabey9210

    jabey9210 Well-Known Member

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    Also target height will make a difference as in if you are laying prone and the target is 3 ft high vs shooting same target height from a bench. Why don't you try zeroing it at 275 then check your 50 and 100 yrd heights....
     
  10. Scot E

    Scot E Well-Known Member

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    At the distances we are talking, 50 -300 yards, errors in velocity, BC, scope height, incline and atmospheric conditions are not going to be the problem. They just make too little of a difference that close in to really be a factor.

    Plus, if you are really zeroed at 275 then you have to be shooting low at 300 yards. So I would start there. Be sure to zero at 275 yards. Make sure your rangefinder is accurate and ranging in yards. I have thrown a meter measurement in before myself and screwed everything up. Adjust the parallax so you get no reticle jump at your zero range then don't change the magnification setting or parallax while you are sighting in at 275

    My guess is that it is either
    1. scope click value errors or a defect. (verify that your scope clicks are working properly)
    2. A bad parallax issue (check parallax issues)
    3. You aren't zeroed at the correct distance. (verify zero)
    4. A combination of the above.

    When you are zeroed at 275 you can also do some other tests to make sure your scope is up to snuff. Once zeroed shoot a group at high and low power to make sure POI isn't changing as you adjust the magnification. This can happen with a QC issue or with scope failure.

    Also, adjust the parallax to 100 yards and maybe infinity and see if there is a drastic change in POI. When a scope's AO goes haywire I have seen it affect all kinds of different issues. And IME a scope's AO can be one of the weak links to today's scopes.

    HTH,

    Scot E.
     
  11. 4xforfun

    4xforfun Well-Known Member

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    Where, exactly are the "clicks" and scope error comming into play? He is not adjusting his scope....1" high at 50, 2.25 high at 100 (instade of the predicted 2.5 high), and 3.5 high at 300 (instade of the predicted 1.5 low)....he did NOT dial his scope.....so trash that idea.

    Scope height off by 1/2 inch..... 0.05 inch difference in impact between 1.5 and 2 inche scope height at 300 yards with a 275 zero...trash that idea also.

    Being a foot or two above or below the target will not make a difference. I mean really. What would the up/down angle be?? Something like .01 degrees. Not sure about the math on that one. I punched in 10 degree angle and got an impact difference of .02 inches at 300 with a 275 zero. I say...trash that idea also.

    Now the sad part....It makes no sence...and I can not answer your delema. It all should all go as planned...exterior balistics is all math and science and can be predicted to , well, lets just say "several" decimal points to the right of the zero. Paralex could be the culpret, I supose. Set your gun up on rests/bags/bipods.....whatever, so the gun holds zero without your aid. Now, while looking through the gun, wiggle your head around and see if the cross hair "floats' around on the target. If it does, you got paralex issues. The cross hair shold be locked on the mothball no matter where your head is at ...if you can see the target and the cross hair is on target, it should be a hit. I can easily see how a paralex issue would/could put you off by 4" at 300. When I set up at the bench at a match, the FIRST thing I do is check paralex....just as I described above. I do not depend on weather or not the sight picture is in focus....I have seen scopes that can be blury and have perfectly adjusted paralex......focus that same scope in so the sight picture is clear, and POOF....paralex is way off.

    Good luck!! I hope some of this helps, and let us know what you find. I think you should retest.

    Let us know.
    Tod
     
  12. shooters

    shooters Well-Known Member

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    I will take all the advice given and apply tomorrow once again. Unfortunately, I opened way to many threads in a panic and some in the wrong sections all on this issue. Sorry for the multiple threads.

    Went to the range once again earlier up until dark. Here is exactly what I've done today, some I may be repeating over and over, but its so someone may catch a mistake I've made. Sorry, archer by trade, but doing everything I can to learn here.

    A friend here in town is a gun smith, and being Thanksgiving day, his shop was closed but he allowed me to swing over to his place for him to double check my scope set up and install. Everything was taken apart and reinstalled and torque to correct tightness. I have Seekins Medium base and ring set up on a Sendero ll rifle. Scope is the Sightron Slll SS LRD with Parallax.
    Remington brass once fired. Full resized with Redding dies. Brass cut to 2.840 precisely. All weight sorted within .5gr. Primer pocket uniformed. Flash holes debured. Neck's turned. All exact. Fed 215 Primers set .010 under flush. All 200 gr accubonds weighed to exact weights and sorted like the brass. OAL of final founds 3.600. 94.0 gr Retumbo powder. 3104 average fps from 5 rounds.

    Range. I do NOT have a 275 yard target just yet, so I was relying on ballistics calculator. I didn't miss a single step in putting info into calculator. I knew all the information exactly at that exact time. Sight height at 2" if I measured correctly. I shot 3 shot groups each time, waiting 5 min before each shot for cooling. After each shot, I cleaned with Tetra gun until all blue copper was no longer visible. Just to be safe, I used Sweets as a back up to see if there was any left that the Tetra missed. None.

    Targets are perfectly horizontal to my shooting bench as best I could tell. No tools to measure, but I would say damn near perfect. Bench is stable, zero movement. Set up on a led sled that has two ratchet straps holding it tightly in place to the concrete bench. Gun was NOT strapped down, it was free to move about. Nothing under the forearm of the rifle that would maybe affect accuracy. Each shot felt excellent when trigger was squeezed. Jewel trigger I might add has been installed and I believe set at around 3lbs. Not sure if that is too heavy, but gun smith said not to go too light for a hunting rifle.

    50 yards. Scope on 24 power, parallax adjusted. Don't notice any side to side movement out of the dot when I move my head. 3 shots, same hole. Literally.
    100 yards. Scope still on 24 power, parallax adjusted. Didn't seem to notice any movement side to side from scope. 3 shots. 2 touching, 1 about 1/16 off from touching.
    200 yards. 24 power, parallax adjusted to infinity. When I moved my head side to side or up and down, I did notice the dot slightly moving. VERY little. Instead of 2.7 inches high, I had 1 4 inches high, 3 inches left. 1 3.5 inches low, 2 inches left, and 1 horizontally correct, but 4.24 high.
    300 yards. 24 power, parallax not adjusted. Noticed a little movement from DOT when head moved side to side and up and down, but not enough to throw me off as far as shots were, at least to what I thought. 8.5 inches low and 3 inches right. 11 inches low, 6 inches right, and 3 inches low, 1 inch left.

    What is the deal? I should have just stuck with archery. I am so frustrated. I have been trying to do everything so precise and its just not working. Someone at the range told me that the led sled is the culprit, yet I thought I read a thread on here one time discussing the sled and someone said that bullet is long gone from the bore way before the recoil has even started. So either the parallax is causing my problem like another member said, the led sled is, or??? I'm so lost. I have loaded up everything the same as before, except this time I will try 5 shot groups at 91 gr, 92 gr, 93 gr, and then max at 95 gr. This is my 3rd RUM. The first one I had, Kirby, or FiftyDriver loaded up for me, all max loads and specs to the book. Nothing fancy. Winchester gun. That was the most amazing factory rifle as far as accuracy I've owned. Second was the Sendero l 300 RUM. My buddy loaded exactly what Kirby did. What a dream. Groups to 400 were amazing. Now this one, I just cant figure out. This is the first Seekins setup I've had and the first Sightron. The other 2 RUM's had mid level Leupolds and plain Jane rings and bases on them. I'm so bummed out. Thanks again guys.
     
  13. Korhil78

    Korhil78 Well-Known Member

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    Well in your last post you stated that you had the parallax adjusted correctly with the 50 and the 100 yard shots and from what you are saying, they shot well. Now on the 200 yd shots, you say that you had the parallax adjusted to infinity which in my opinion is not the adjustment setting that you want. You want the adjustment for 200 yds. And on the 300 yard shots, you didn't adjust the parallax at all and it shot poorly so you need to adjust the parallax for 300 yds on that one. I am just going off what I am reading.

    And for goodness sake! You are not shooting out to 1000 yds so take it off of 24 power! :D Try a lower power on the scope and that might help as well as adjusting the parallax.

    If nothing else that you are trying works, then try switching out scopes to see if that is the problem.
     
  14. shooters

    shooters Well-Known Member

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    Gotcha. When I purchased the scope, I was lost on how to adjust parellax in a hurry up and shoot situation, so I called Sightron. Their tech said that from around 200 yards, set parellax on infinity and you will be able to clearly see your target from 200 yards out without the need to adjust parellax and POI will not be affected. They also mentioned that whether I had the scope set on 6 power or 24 power, it made no difference on POI as well. They informed me that that with parellax adjustment, scope magnification did not matter. Ok, so basically they told me two different things. When using parellax, scope power does not matter, but yet again, I can set the scope parellax to infinity from 200 yards out and POI will not change? I'm confused...again. Sightron said whether I was at 50 yards or 1000 yards, magnification would not change POI. They also informed me that, say I was set up at 300 yards and adjusted the parellax while looking through the scope. If I seen the DOT retical move through the scope and leave the tiny dot on paper I was aiming at, to just move the scope DOT retical back on target and it would be right on. Again, now I'm lost. Sorry guys.