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Thread: 12fv build w/ pics

  1. #101
    Basic Member DesertDug's Avatar
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    The cases were virgin hornady brass, sorted to within 1 gn and all trimed 1.114". I am thinking this had the most effect on the tight SD results. I hope now that I have the fired form brass I can get my form in line to start being these groups even tighter.

  2. #102
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    If one of the many steps wasn't done well, you wouldn't have see those results.
    No doubt your trimming and sporting helped eliminate some of the variation but so did your attending to all of the steps with the same amount of attention.
    All of your steps during reloading taken together achieved that reduction.
    And maintaining that attention during your next session might further reduce that SD.
    That's what should make the results so satisfying to you.

  3. #103
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    I measured up the shoulder of all the once fired brass and not all measured the same where would you numb the shoulder to on resize?

    [IMG][/IMG]
    1.538" was the most common. Shoulders were 1.531 when sized prior to reload.

  4. #104
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    Doug,

    I don't know how you use your calipers but you can easily shift the readings by 0.001 or even 0.002 if you press too hard as you close the calipers on the brass.
    If your pressure is inconsistent, you can skew the distribution, mostly toward the low side readings.
    Another factor is a slight imbalance in the shoulder expansion that can add a few thousandths depending on where you measure.
    To see if that might be affecting the measurements, try measuring again being careful not to put strain on the arms of the calipers and flex them. And this time rotate the brass and measure twice to see if the shoulders are still level.
    The shoulders don't have to be level.
    After all, they were just stretched by an explosion and exposed to a sudden high temperature transition.
    If I were you, I wouldn't expect the results of such a violent expansion to be always be consistent.

    However, the distribution you have would indicate that your shoulders grew by at least 0.005 to 0.009 inches. That's good information but not unusual.
    You probably want to set the shoulder back at least 0.002 below the low reading (or 1.534) to be on the safe side until you get a lot more data.
    Actually, if you left the dies set to the original shoulder and got the same results again, you could feel more confident of the decision.
    You are still very early in your period of getting used to a new barrel/stock combination and, if you are at all like me, you will get better results as you get used to the changes and get more consistent and confident in your set up.

    If you are uncertain about the adjustment in the shoulder, you can always adjust the shoulder out on one or two brass and check the fit to be sure you weren't setting the shoulder out too far.

  5. #105
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    Thanks CFJ that all seems to make sense.

  6. #106
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    Shoulders bumped to 1.536" and all cases retrimed to 1.914"
    Ifound this interesting sorting the weight's of the unfired cases "virgin" with 1 time sized and trimed.
    5 of the case above the mean that weighted 148grains moved into the mean column of 147. Two cases still weighed 146 grains.
    All fired formed cases required some trimming.

    [IMG] [/IMG]

  7. #107
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    That is about as good as you can measure.
    Good job, Doug.

  8. #108
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    My most consistent loaded rounds yet. Only 9 out of 36 not 338gn's and they are all +1gn.

    [IMG][/IMG]

  9. #109
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    got out to range Sunday. Are is the best of 5 shot groups, 5 in all.
    [IMG][/IMG]

    These were the first 5 shots that day.
    I then shot 10 shots to get crono results avg velocity of 2841fps.
    Went on to shot 4 more groups. These opened up some. shooting form was not up to par. Mean group results were good, but not overall MOA's.[IMG][/IMG]

    Need more practice.

    I am thinking that this will be the last post on my build since for now it is done. I will update if I choose to change anything on the riffle. thanks for following along.

    I will continue to record my shooting results and may just need to start a new thread on the reloading or range report page.

  10. #110
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    Doug,

    After I had my set up routine pretty well grooved, I have been able to call each shot that goes awry.
    Did you get any ideas on why the two bottom groups had several shots escape your group.

    If you were aiming at the center of the red dots for each group, you POI seemed to move from right to left and higher on two the top groups and change from low to high left with the two bottom groups.
    Were you adjusting your scope?
    That might cause the first shot after adjustment to be off.
    If the loads were all the same, I wouldn't expect you to have to adjust your scope. All the groups should have been in about the same POI given a center dot POA.
    If you were aiming in the same relative position with each group and didn't adjust your scope, the changes in the POI would indicate that your are shifting your position when your set up for a group.

    This is what one of my 25 round groups looks like with the same load - although I adjusted the aim point slightly and the POI dropped a bit as the barrel got really hot.
    The horizontal line is 2.017 inches and the diamond diagonal is 0.989 inches. Each side of the diamond is just about 0.7 inches.
    This particular set of shots with the 12 FV 6.5mm Creedmoor in the original factory plastic stock, shows the amount of drop I get when the barrel gets really hot. The groups started with the barrel temperature strip at 85 degrees. By the 18th shot the barrel temperature had pegged the temperature strip reading at over 140 degrees. I let the barrel cool back to about 130 degrees and shot the last 6 shots.

    Click image for larger version. 

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    The cold barrel groups were about in the low center of the diamond and the hot barrel groups were just under the horizontal line.
    The initial 6 shots were slightly to the right of the vertical center line of the diamond - the high set of holes on the right.
    I moved my aim point about 1/2 inch to the left and the second group of 6 shots was just to the left of the aim point and slightly lower as the bullets dropped as the barrel got hotter.
    One shot got away to the left (That thrown shot was on me - I didn't finish my natural point of aim check before I let the round go. I knew it as soon as I fired and sure enough the POI was to the left. Sometimes I get too sure I myself and do something stupid like that. I usually have one out of 25 that I screw up or have one fouled barrel shot that is out of the groups.)
    I shot one more round into the ragged hole to finish the group.
    Then with the barrel heating up even more, I shot the third group of 6 shots on the second aim point and the group was low by about 3/8 inches.
    I let the barrel cool off a bit after it got over 140 degrees on the temperature strip and I moved the aim point back to the cross point of the horizontal and vertical lines for the last group of 6 shots and the POI was again to the right, about in line with the original group but about at the same level as the third group.
    The last group of 6 shots might be a bit further right than the original because I had some difficulty sighting on the precise cross hairs because the bullet holes had obliterated the original aim point.

    The center to center measurement of the entire 24 shots,
    excluding the one thrown shot that I called, is under 1 inch
    even with a 1/2 inch difference in aim point for half the shots and a drop in POI due to barrel heating.
    The cold barrel groups were about 1/2 inch higher than the last hot barrel group on the right.
    The second group with the aim point to the left by 1/2 inch dropped about 1/4 inch.
    The third group with the same left aim point dropped another 1/4 inch.

  11. #111
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    I did adjust scope between groups. Chasing the center . Scope and I did not track correctly.
    All groups were same load.
    Some of the out shots I did not feel right on in one way or another. My rests are always shifting around. I understand the talk on other threads regarding a customs actions advantage of being able to cycle the bolt with out set up change. Not that this come into effect with where I am at this point. But it is cool when all things come together like the fist five shots of the day.

  12. #112
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    I sent you an e-mail with some more detailed pictures. I hope it helps.

    Changing your scope adjustments in the middle of a group will often cause big impacts in group sizes. That might have caused more variation in your groups than you think.

    First, I hope you don't adjust your scope after a single shot. You need to allow the scope to settle after every adjustment. Also, one shot doesn't tell you much because it could have been effected by shooter induced variation. Make a move based upon one shot that was moved by your set up and you'll be chasing you mistakes in an aimless effort.

    I don't touch a scope until I have shot a group and seen where the center of the group is.
    Then I base the adjustment on the position of the center relative to my point of aim.

    As for hoping to be able to cycle your bolt and hold your set up undisturbed:
    One of the reasons for having a consistent set up routine is that you won't be as impacted by moving the bolt or changing a magazine.

    Trying to shoot really small groups, I found that even if I operated the bolt keeping my cheek weld 'undisturbed', a recoiling rifle still moves me a bit so my 'undisturbed' cheek weld was actually still being disturbed.
    Custom actions that are smooth as butter can't eliminate the fact that your rifle moves under recoil and your body moves with it.
    As the recoil dissipates and the rifle moves back and then forward, your body moves with it.
    Even if your stock is perfectly matched to your arm length, your set up position will have changed.
    I am convinced that, even if you can operate the bolt smoothly as butter, you won't be maintaining your original set up position.

    Therefore, I go through the same set up routine every time for every shot regardless of whether the bolt is smooth or difficult to operate.
    The recoil always does some damage to my set up even if I didn't think it did.
    If I don't reset, I see the result in the next POI.

    The realities of trying to optimize everything:
    I realize that when hunting, you sometimes will have to take a shot almost as a reaction.
    In those cases, do what you must and do the best you can.
    Your repetitive shooting training will help you get the results you desire.
    You have already proven that you are very capable at doing that.

    When you are trying to figure out what your rifle can do and what loads are most accurate, I would suggest you need to try to minimize the majority of variations in set-up position.
    Then you'll have the most accurate loads and rifle settings in place for when you see the game and make your decision to take the shot.
    You'll have the best tools at your disposal and your repetitive disciplined approach to shooting will come to the fore and get you set up as well as you can in the hunting situation.
    I don't know about you, but I never counted on having a second shot available when hunting so I planned on making the first one count every time.
    I can count the number of times I got to take a second shot on one hand and still have a few fingers left over.

  13. #113
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    Back out. Some 3 shoot groups while adjusting scoope. Then out to 200 yards and I got lucky with 3 rounds touching. Disbelief in my eyes. Was last 3 shoots of the day right after a down pour or rain stoped. Other shoots where in the rain.

    10 round 100 yard group was during the rain pour. The only cloud in the the sky. They were delaying the ceasefire, waiting it out and these rounds were intended for the 200 yard. The fist five were all in that mean area.

    It it feels good to watch my own progress and confidence improve.
    [IMG][/IMG]


    [IMG][/IMG]

    [IMG][/IMG]

  14. #114
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    Good job, Doug.

    You're clearly getting comfortable with your new chassis set up.
    Lots of progress with accuracy and good consistency, even with the weather changing and interrupting things. That kind of stuff doesn't help your concentration but it didn't seem to cause you any real problems.

  15. #115
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    Reloads were not trimmed on that round. Adjusted setting depth to maintain 12th refraction exit time.

  16. #116
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    I agree that is the method to gain accuracy over the life of your brass without having to trim the brass. That approach appears to work well for you.

    I haven't trimmed my current set of 6.5mm Creedmoor or .223 brass in 20 and 19 reloads respectively and have adjusted the seating depth with each cycle to adjust for changes in trim length.
    I haven't seen any loss of accuracy using that technique during that time. Actually with a change to a new Oryx chassis, I have gotten an improvement in accuracy because the chassis is stiffer than the factory plastic stock.

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