Posting your "magic" group

Forums Benchrest Benchrest Talk Posting your "magic" group

  • Views : 2272
  • Link

    CampFussell
    Participant
    Member

    Nice shooting Chuck.

    Link

    Centercut
    Participant
    Member

    @campfussell This ones for you Fuss. Shot six 5 shot groups at 110 yards, wind 6 to 7 mph from my 10 to 11 o’clock, .22 EDgun R3 Long, NSA 20.2 grain HP DB slugs at 965 FPS. Here are the two best groups, and a third was right at one inch, the other three groups were between 1 and 1.5 inches. Best group below is 5/8 inch. I could have stopped after 4 shots with a 5/16 inch group, but 5 shot minimum is the current standard. 


     

    The second best group of the day at 110 yards is 13/16 inch. I’ve decided to do all my practice for the coming competition season at 110 yards. I figure if I can shoot competitive groups and scores at 110 yards then it’ll be easier at 100 yards. FYI, the calculated BC for these NSA slugs (done today) is 0.0735.  That is for the .217 caliber 20.2 grain NSA HP DB at 965 FPS and 110 yards.

     

    • This reply was modified 4 months ago by Centercut.
    Link

    CampFussell
    Participant
    Member

    Centercut

    @campfussell This ones for you Fuss. Shot six 5 shot groups at 110 yards, wind 6 to 7 mph from my 10 to 11 o’clock, .22 EDgun R3 Long, NSA 20.2 grain HP DB slugs at 965 FPS. Here are the two best groups, and a third was right at one inch, the other three groups were between 1 and 1.5 inches. Best group below is 11/16 inch. I could have stopped after 4 shots with a 3/8 inch group, but 5 shot minimum is the current standard. 
    The second best group of the day at 110 yards is 7/8 inch. I’ve decided to do all my practice for the coming competition season at 110 yards. I figure if I can shoot competitive groups and scores at 110 yards then it’ll be easier at 100 yards. FYI, the calculated BC for these NSA slugs (done today) is 0.0735.  That is for the .217 caliber 20.2 grain NSA HP DB at 965 FPS and 110 yards.

    Great green globs of spewed out pellet dust, mutilated target sheets, and two magic grouping feats! Don't know why that tune is stuck in my head?

    You are the "Master Slug Miester". Thanks for sharing man.  I'm gonna get the nerve to try some of those FX Hybrid slugs in my lil' .22 Firecracker one of these days.

     

     

     

     

    Link

    Centercut
    Participant
    Member

    A couple more groups today. Light breeze. 110 yards. EDGun R3 Long. NSA 20.2 grain HP DB slugs at 975 FPS. For reference, a quarter is 0.955 inches and MOA at 110 yards is approx 1.15 inches. Both groups are smaller C2C than the quarter. First group is 6 shots, second is 7 shots. I initially did 5 shots and kept going until one shot wasn’t “tight”. Both groups the low shots were 6th, or 6th and 7th. Five shot groups would have been just over 3/4 inch. 


    • This reply was modified 4 months ago by Centercut.
    Link

    Therealld
    Participant
    Member

    Our club used to shoot airgun benchrest matches at 50 yards for group for many years.  After months of trials, beginning with ten shot groups, then down to five shot groups, we finally settled on three shot groups, BUT, we fired THIRTY three shot groups per match, then measured all the groups ctc, with the winner having the best aggregate.

    The REASON for three shot groups was the difficulty in easily determining how many shots were really in a group when measuring them.  See, with tight clusters, its not easy to tell.  Yes, we DID use backers for awhile, and they do work, but its a pain to use em, and keep them changed, so we eventually found its darned rare that a three shot group is confused with one or two shots.

    Typical decent sporting airguns deliver around .75"-1.00" thirty group (90 shot) aggregates with decent ammo off the bench.  Good tuned sporting, or FT competition type airguns give .5-.75 aggregates.  Really well sorted dedicated benchrest rigs give .35"-.5" aggregates.  We found .22 cal rifles shooting around 30fpe generally the best, with the record setting guns here in Temecula over a several year period being USFT rifles using sorted .22 JSB pellets and Benchmark 2 groove barrels.  The record aggregate was a bit under 0.34" for the thirty three shot groups, with many groups under 1/16" ctc.

    When we began to shoot the International target (one shot per bull) we stopped group shooting competition, and, I suspect, have likely lost some of the knack of it.  It took better eyes and skill to accurately measure all those groups than it does the 25 meter International cards, so we haven't gone back to the "old game".

    Group shooting in competition is different than "Centercut" cites, since one normally "chases shots" to keep the group tight.  Our game required at least one shot to touch the black bull, but as with most group shooters, we normally offset the scope zero to avoid obliterating the actual aimpoint, which was typically at six or nine o'clock on the black. Ideally, one or two shots were in the black, but one or more could be in white without penalty.  Failure to "anchor" a group to a bull resulted in a 1" penalty added to that group.

    In general, if you shoot enough groups so the AVERAGE is good, its impressive, but one TINY group is really not too much rarer than the occasional HUGE group, if you do your part.  To prove out a rig, I think ten five shot groups is enough to show potential.

     

    Link

    nomojo65
    Participant
    Member

    Therealld, did the 2-groove barrels have a choke and were they SS? I have a lt. varmint  taper Kreiger I believe is 5R “no choke”, since this is cut rifled I can turn it down? Don’t know if it’s worth the time? I guess I could sell it to fund another barrel?

    • This reply was modified 4 months ago by nomojo65.
    Link

    Centercut
    Participant
    Member

    20.2 NSA slugs at 975 FPS

    Link

    tommyb
    Participant
    Member

    Mike 

    Tom B here…

    247 Meters 15-18 mph wind?   Amazing, why are you experimenting with these distances and excessive wind?

    i know there is a good reason..

    does this help you for 100y BR?
     

     

    Link

    Centercut
    Participant
    Member

    Tommy, it’s a bad joke. It was intended as a “spoof” on other posts discussing 300+ yard shots in cold blustery conditions hitting 12 ounce coke cans 9 out of 10 times. That is obviously a figment of someone’s imagination…  The guys at the club and I (Temecula Airgun Club) were all joking and laughing about those types of posts, and I decided to write a fictional yardage on the target box just to be funny ;)

    The actual distance was about 115 yards in howling winds. 20 shots. No one can group like that at 275 yards in that wind… No one.  Sorry about that. One thing to note about shooting and practicing. If you only shoot in calm conditions you’ll never be a good 100Y BR shooter. Calm conditions are only for sighting in and testing. Practice even more on days where the wind seems ridiculous. You’ll be S.O.L. when you shoot in competition if you’re not ready for heavy variable winds. A few of the relays at RMAC last year were just horrible. Not all, some relays were lucky, plus the finals weren’t that bad. The 2nd qualification round where my gun broke, I had about a 14 inch drift right to left at 100 yards with the .30 Bobcat…

    One take away from the spoof post above, since the winds were gusting to well over 20 mph, is the vertical dispersion of the shot pattern. Only about 1.5 inches which is very good considering the conditions. I kept my POA the same for all shots despite the varying winds just to test the gun and the vertical dispersion which tells me I have very consistent slug speed and an amazingly good barrel. Oh, and lest I forget, high quality NSA slugs, in this case the .22 caliber 20.2 grain HP DB version. 

    • This reply was modified 4 months ago by Centercut.
Viewing 9 posts - 101 through 109 (of 109 total)

You must be logged in to reply to this topic.