6 mm Velocity @ 600

Forums Reese Bottom Chat Room 6 mm Velocity @ 600

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    • #6394
      Richard Slaton
      Participant

      One of interesting things that the Shot Marker does is give you the Bullet speed at the target along with SD. As I stated in my match report my 6 BrX with 107 SMK with a MV of 2750 (16” barrel) had an avg. velocity of 1863 @ 600. iStrelok (phone app) backs that up saying 1833 @600. Now I know we have a few 6 MM shooters @ Reece Bottom whether it be 6×47,Dasher,X or standard Br. I would be very interested in seeing what your MV vs. @ 600 with what bullet weight. For anyone that has that data and would like to share. Ok I don’t want anybody to feel left out of this game and data swap so feel free to post any cal. Also your feelings on your @600 SD
      Mr. Wynne gave us this place to chat so let’s chat He also got us the Shot Marker so let’s use the data that it gives us
      jrs

    • #6395
      Wynne Echols
      Keymaster

      Richard, I just logged on to respond and remembered that I shot the .223 last month. I am shooting 90 grain Sierras at the muzzle 2780 and the target info in the other thread said that they were getting to the target just over 1900 fps. I plan to shoot the dasher this month and we can see what is happening. WWE

    • #6397
      Steve Gilley
      Participant

      I will be shooting a brx with 30 inch barrel. 107 Matchkings at about 3020 Fps. Will be interesting to see the #’s compared to the dasher.

    • #6398
      Steve Gilley
      Participant

      I shot the 107’s last match with a standard Br load to fire form some brass. The Sd was like 7 which amazed me. Was using Norma powder instead of Varget!!

    • #6448
      Wynne Echols
      Keymaster

      Richard, this is my info from November. I was shooting the Dasher, H4895 = 31 gn, Vapor Trail 103 gn, 28 inch barrel and the muzzle velocity a few days before was approx.2925 fps. Saturday it was somewhat colder but at the target my first two targets avg.1835 fps and the second two targets a couple of hours later and warmer avg. 1856 fps. I appear to have a larger drop in speed than you do. Not sure what that is saying. WWE

      • This reply was modified 11 months, 1 week ago by Wynne Echols.
    • #6450
      Richard Slaton
      Participant

      Thank you Mr. Wynne for posting your #’s
      This give me something to compare to and somewhat of a base line as I plan for 1K.
      It is interesting that your mv is almost 200 fps faster but @ 600 only about 65 fps faster
      I guess it’s all about the Bullet (weight and BC), app say’s I’ll be at 1309 @ 1k. I’m still thinking the wind will deal the 107 fits between 600 and 1K. I would like to hear from anybody that has shot 1K with a small case 6mm.

      My #’s based on 107 SMK @2750
      1st. Target 1769 SD 12.9 Group 5.91”
      2nd Target 1770 SD 17.2 Group 6.44”
      3rd. Target 1779 SD 16.2 Group 7.37”
      4th Target 1783 SD 10.4 Group 5.10”
      So my 1st. target was my slowest had the second lowest SD and second smallest group
      My 4th target was my fastest , lowest SD and smallest group.
      Theoretically I guess lower SD should product smaller group but not necessarily in the real world
      The Aug. FC match my avg. @600 fps was 1839 avg. SD 24.3
      Oct. F C match 1864 SD of 15.1 this match avg. 1775 and SD of 14
      I hope others will post their #’s and thoughts on the #’s game
      jrs

    • #6452
      Wynne Echols
      Keymaster

      Not sure where this is taking us, but I am sure something can be learned. First off, a couple of weeks ago I tested a load of H 4895 for the first time trying to get the muzzle velocity up to 2925 fps. After a short ladder test we determined that 30.9 gn of the H4895 generated approx 2925 fps. I loaded up 5 and shot them on paper at 300 yards, no crony info and the five were the size of a dime. Friday the weather app said that Saturday was to be several degrees colder than the day that I had shot the group so I added another .1 gn which was 31.0 gn H 4895.

      Here are the results:

      Target 1: size 3.00, avg. vel. 1830 fps, SD 8.1
      Target 2: size 3.50, avg. vel. 1840 fps, SD 9.0
      Target 3: size 3.15 avg. vel. 1859 fps, SD 5.4
      Target 4: size 3.98 avg. vel. 1854 fps, SD 4.2

      I had tried to pay a lot of attention to how these 20 rounds were loaded and looking at the SD I think it paid off. Target 1 & 2 were shot probably 2+ hours before targets 3 & 4 and we know that the temperature rose quite a few degrees during that time so I think we see some temperature sensitivity in the powder. If SD indicates the node, I think we also see that the rifle liked being shot a little faster. The group had much more wind influence than vertical which leads me to believe that the shooter shot too slow allowing the condition to ‘take him to the cleaners’. Reese Bottom has no business being so difficult on the poor, old, blind, achy, stove up, no count shooter. WWE

      • This reply was modified 11 months, 1 week ago by Wynne Echols.
    • #6454
      Wynne Echols
      Keymaster

      I am going to attach a photo of my third target from last Saturday and for 600 yards I would think that the vertical is acceptable but you can see that the wind, I hope, was moving the 103 gn bullet around quite a bit or either I am a very bad aim.

      The date on the targets was correct so I assume the time is correct also. That being said target 1 was shot at 9:09 am and target 4 at 11:59. That is a 3 hour time difference in the information listed above and a pretty good increase in temperature.

      Everyone mentions velocity at the muzzle. These numbers at the target are so different that you cannot relate the two. To me that is a little confusing. WWE

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