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Thread: New to using a 'F-CLASS BR' at 50 yards...

  1. #241
    Boolit Grand Master 303Guy's Avatar
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    Well, I got to the range today. I must say, my groups look a lot like yours, only mine were shot at half the distance.

    But the similarity lies in some nice groups then a wild flyer and then some spread out groups, plus the moving around the POI. I was wondering what could be going on with my guns so I looked down the bore of my 510 and it looks terrible. It has what looks like greasy patches which made me wonder whether those odd flyers out of a seemingly tight group, could be the proverbial purge flyers?

    The other oddity I found was a nice centered group followed by an attempt to 'prove' that group. The first shot goes to the center then the range gets closed. On resuming, the next shot of that group goes wild but then the rest fall back into the POI. Barrel and greasy lube cooled down resulting in a purge flyer maybe? I'm just wondering about it.

    The guy shooting next to me with his CZ target rifle was shooting flies off his targets at will. No flyers (excuse the pun). He literally put ten shots into one hole - not a group - a hole. But then he was shooting 'cheap' SK Target ammo at NZ$15 a box. I couldn't find any when I looked. Ordinary CCI sub-sonic HP ammo costs NZ13 a box, just for comparison.
    Last edited by 303Guy; 05-02-2021 at 12:48 AM.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  2. #242
    Boolit Grand Master tazman's Avatar
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    You wouldn't think higher end match target ammunition would be as affected by the shortage as cheaper plinking ammo, would you?
    Seems that everything has become difficult to get.
    Makes it hard to perform any serious testing when the ammo to test isn't available.

  3. #243
    Boolit Grand Master OS OK's Avatar
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    Got my flags calibrated... I put a 22 grain piece of Gorilla tape on the end of the 24" yellow tape, folded so it's on both sides...



    I thought if it's too heavy, I could trim it off a little at a time to reduce weight but I was lucky and it worked just right at that weight...when the tape is 90º to the staff the wind is 5 & 6 mph like the foreground flag...the one behind is at 45º and the wind there is 2 & 3 mph...the flag on top of the backstop is not calibrated, a light breeze will show it at full 90º deflection...all it shows right now is wind direction.



    I moved the flags so I can peek around the scope & see the both of them without wrecking my cheek weld and eye relief from the lens...I couldn't get the camera to stay focused in the scope and show both flags as I see them but this is the idea...looking on the left of the scope.



    The wind was cooperating today for the first of several tests with the tuner reinstalled.
    I understand the method suggested for sampling 2 shot groups throughout the range of the tuner. That is a total of 1/2" minimum to maximum adjusted in .001" clicks. I decided to start at the minimum, '0.0-0' and do the first .025" without skipping any settings.
    I hoped that following the 2 shot groups from one target to the next (.001" increases of barrel length), I could get some idea of just how the barrel is oscillating from the harmonics. I can't say for sure but it looks like a vertical oval shape.
    This is something I have heard described in several ways...from a circle to straight up and down...obviously where the 'mean center' of each 2 shot group is located, the barrel was pointing at that 'mean location' for that adjustment. me thinks?



    I was surprised to see that the tuner shifted my POI down by 3/4's inch and left by 1/8"...I readjusted the scope on targets 3 & 4. The top left is the warmer spot...top right is the tuner testing at '0.0-0'.
    I started the test at '0.0-1' so that the target numbers would reflect the tuner setting. Did that so I wouldn't get confused, it is marked like a dial micrometer on the tuner. The major lines are marked '0' ~ '5' with 3 lines between each major marking, the first line represents .025" then the 2'nd line is .050", the 3'rd is .075"...then the next line is a major line representing .100", it continues like that up to the .500" mark at the maximum setting.

    With all that explained...I intend to take several of these settings and do several 5 shot groupings of each to prove them out and determine what the group looks like, whether or not it is tight and symmetrical or whether it proves to be something like a cloverleaf or...it may well be a group that is one of those 303Guy was describing with the one single flier in each proof set of 5 shots?
    I wish I could explain that but can't at this point in testing. It may be just a different barrel time on that flier that causes it but if that is true then we shouldn't see but one or two happen in a total of 5, 5 shot groups. I hate to think I will have to get the chrony and monitor each and every shot speed in each group....Man that sounds like a lot of work!

    So . . . if this barrel 'is oscillating in a vertical oval', which pair of 2 shot groups (side by side with no vertical dispersion or 1 hole 2 shot groups) would you choose?
    If the 2 shot pair appears to be at the top or bottom of the oval, it seems that when the barrel is changing directions we should have a wider barrel time in that node. Does that make sense to you?
    a m e r i c a n p r a v d a

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  4. #244
    Boolit Master Forrest r's Avatar
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    Typically when you see too much side to side movement of the bullets poi when adjusting the tuner. It's caused from bedding issues or torque setting on the hold down screws.

    !/8" is nothing.

    A chronograph would make choices a lot easier. Namely the group that has the largest difference in fps that have the tightest group. That's what a tuners does after all, reduce the vertical spreads.

    The 3/4" down is interesting, that means the bbl had to move .006"+.

  5. #245
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by Forrest r View Post
    Typically when you see too much side to side movement of the bullets poi when adjusting the tuner. It's caused from bedding issues or torque setting on the hold down screws.

    !/8" is nothing.

    A chronograph would make choices a lot easier. Namely the group that has the largest difference in fps that have the tightest group. That's what a tuners does after all, reduce the vertical spreads.

    The 3/4" down is interesting, that means the bbl had to move .006"+.
    That's confusing for me. You can see a 'ES' (10 fps spread) difference within the two sets of numbers in the chrony work from the first target I posted. That ammo was the same lot, same box of 50 rounds.
    Those numbers came from 10 shots each, both groups shot back to back.



    I first placed the chrony at the target, shot 10 rounds...next moved the chrony to the muzzle +10' and shot another 10 rounds...notice the ES & SD numbers?

    Wouldn't we see that happening each time giving us a false sense of actual 'ES's'? It all depends on the luck of the draw each time with the rounds and their individual speeds as they're shot & calculated.
    It keeps varying test to test within parameters I'm sure...but depending on ES for choosing a node had not really occurred to me.
    I thought we might be looking for a spread of 2 shot groups that are very similar in elevation...like this series here.



    It seems to have less vertical displacement over a .005" increase of barrel length than any of the other settings below...



    Somehow I relate that to having a wider node, tolerating wider extreme spreads within these adjustments because the barrel is actually changing direction across these adjustments....I can't say for sure. If only we had actual high speed video slowed enough to track the barrel oscillations and see the exit of the projectile.
    The computer simulations on Al's Varmint Page are just that...varying numbers & his video simulations are the same.

    http://www.varmintal.com/a22lr.htm
    a m e r i c a n p r a v d a

    Be a Patriot . . . expose their lies!

    “In a time of deceit, telling the truth is a revolutionary act.” G. Orwell

  6. #246
    Boolit Grand Master 303Guy's Avatar
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    Something I found interesting this past Sunday at the range. I was shooting my Toz-17 (which I am becoming quite fond of), and with a very relaxed hold, the gun was 'jumping' with each shot. My targets are 1/3 of a A4 page apart and the scope would jump from the target aimed at to the adjacent target. That's at 25m, moving in the rest. Recoil is significant! The movement was made possible by the thinner fore-end in the rest channel. I wonder what a heavier stock would do for accuracy. It wasn't stellar.
    Last edited by 303Guy; 05-03-2021 at 11:44 PM.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

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  7. #247
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by 303Guy View Post
    Something I found interesting this pas Sunday at the range. I was shooting my Toz-17 (which I am becoming quite fond of), and with a very relaxed hold, the gun was 'jumping' with each shot. My targets are 1/3 of a A4 page apart and the scope would jump from the target aimed at to the adjacent target. That's at 25m, moving in the rest. Recoil is significant! The movement was made possible by the thinner fore-end in the rest channel. I wonder what a heavier stock would do for accuracy. It wasn't stellar.
    I can see the same thing happen with the .22lr. It is not as significant of a shift as yours but sometimes 1/2 to 1" to the right or left.
    I can catch myself steering the wind-age with a slight effort in my shoulder, if I steer for wind-age alignment I see it happen most often.
    Lately I have been backing off from the rifle and re-engaging it from a straight line from the rear, when I relax the rifle stays on POA...that's how I keep track of my errors and try to get rid of them.
    a m e r i c a n p r a v d a

    Be a Patriot . . . expose their lies!

    “In a time of deceit, telling the truth is a revolutionary act.” G. Orwell

  8. #248
    Boolit Grand Master 303Guy's Avatar
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    The Toz is a 22lr. That's what made it so so significant. I was aware of pressure on the stock. My rest arrangement is actually quite easy to keep minimum pressure on the stock but is not all that secure but I am confident that I am not adding more than a bullet diameter error in aiming to each shot.

    I saw a very neat rest on Sunday, one that I am going to copy, but in wood. It's a one piece with a but cradle. My idea is to to have only trigger finger contact with the gun. We'll what that does. But if the gun is jumping then maybe it needs to be preloaded onto the rest to at least provide consistency.

    My thinking is that how firmly or not the stock is held will effect the barrel oscillations. Hence my thoughts on a heavier stock. It's been a long time since I made a rifle stock - the thought is daunting! But doing that without changing anything else could be educational.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  9. #249
    Boolit Grand Master OS OK's Avatar
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    I try to just be there behind the butt, sorta like a door stop...in contact & no pressure forward.
    I use cheek weld pressure on the comb & that's straight down.
    I built a front rest to fit the forestock...



    Made from oak & covered with leather...fit's snug side to side, no slop.
    Lately I have been resting my non trigger hand across the top of the scope, gently & not much pressure...mostly to stabilize the rifle up straight. That's more important on the MKII than the CZ as the MKII has a rounded bottom to the forestock and it fits that other pad in the top right side of the picture. That's the pad that came with the Caldwell rest.

    I think that every subtle little thing we do in contact with the rifle affects the resonance. We have to be consistent.
    a m e r i c a n p r a v d a

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  10. #250
    Boolit Master Forrest r's Avatar
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    You and I test differently

    I don't care about 10-shot strings nor do I care about what the bullet's speed is at the 50yd line.

    I will record every shot to get a larger more realistic idea of what the sd's & more importantly what the es is for that ammo. I record the speeds of the 2 shot groups. When you have 2 shots with a spread of 2fps it doen't mean much if the bullets are in the same hole. Get a spread of 14/15fps and they're still in the same hole. Now you have something to work with.

    Really don't know what to expect from the modern eley ammo. Never liked seeing anything in the double digets.

    When I'm saying the bbl had to move .006"+ to have the bullets impact 3/4" away/differnet. I'm saying the actual bbl's muzzle had to move 6/1000th's of an inch. Not the tuner, the end of the bbl itself.

  11. #251
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by Forrest r View Post
    You and I test differently

    I don't care about 10-shot strings nor do I care about what the bullet's speed is at the 50yd line.

    I will record every shot to get a larger more realistic idea of what the sd's & more importantly what the es is for that ammo. I record the speeds of the 2 shot groups. When you have 2 shots with a spread of 2fps it doen't mean much if the bullets are in the same hole. Get a spread of 14/15fps and they're still in the same hole. Now you have something to work with.

    Really don't know what to expect from the modern eley ammo. Never liked seeing anything in the double digets.

    When I'm saying the bbl had to move .006"+ to have the bullets impact 3/4" away/differnet. I'm saying the actual bbl's muzzle had to move 6/1000th's of an inch. Not the tuner, the end of the bbl itself.
    I keep mentioning & nobody's picking up on it...I'm trying to get into a 2 hole series of groups that are occurring when the barrel is changing directions in oscillation, if that were the case I would have twice the normal time to accommodate those ES's.
    I'm postulating that those groups, shot so close together (.001" barrel weight-length between groups) have to be tracing the barrel's POA upon release...regardless of the type of circle, oval or straight up and down, it is showing us where it's pointing.
    I am a Neophyte at this so I have to try to prove things for my own understanding that the rest of you ole'Salts learned decades ago.
    a m e r i c a n p r a v d a

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    “In a time of deceit, telling the truth is a revolutionary act.” G. Orwell

  12. #252
    Boolit Grand Master tazman's Avatar
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    I understand what you are describing and attempting to quantify. I am just not certain how to go about it.
    Sorry, that I can't really help. That's why I didn't respond.
    I sound stupid enough when talking about things I think I know without spouting off about things I am certain I don't know.

  13. #253
    Boolit Master
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    It may be better trying to get the barrel on a upswing .
    That way the slow bullet will exit later and the faster bullet earlier so as they both end up falling into the same hole.
    You would have to cryno each shot and take into account.
    That was what he was trying to say I think.
    Something like that.

    Me I just shoot till it gets smaller and say ghee thats better. Note that point and move on till I find a setting that dwells there the longest.

    I did it years ago and went through some ammo thou.

    Hope you find it one way or another.
    Last edited by barrabruce; 05-03-2021 at 08:57 PM.

  14. #254
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by tazman View Post
    I understand what you are describing and attempting to quantify. I am just not certain how to go about it.
    Sorry, that I can't really help. That's why I didn't respond.
    I sound stupid enough when talking about things I think I know without spouting off about things I am certain I don't know.
    Isn't this why we are having such a good time here? All of us...well...some of us 'flailing' around and digging deeper for clues? Getting lots of data, discovering subtle little things that trim a little overall group size...you know a person can learn from getting it 'right & wrong'...all depends on what you take away from something...right?

    I remember a couple years ago when 'milk jug busting' was fun to watch on video...some very big explosions & some not so big but everyone having a good time watching. Some folks putting little yellow rubber duckies on the jug top and seeing how high they'd launch...I used ping pong balls for a good effect...
    Several people started guessing at how much velocity a typical .45ACP HP would loose going through the first jug...well...I mulled on it for a while and came up with a hair-brain experiment.
    Why not put the chrony behind the jug and clock it on the exit...sure enough I got the numbers. 908 fps going into the jug and 450 fps coming out with a perfect mushroom, kept all it's weight and we discovered that the first jug consumes 1/2 of the energy in that short little distance from front to back, providing your blend was good.

    In a round about way, that's what we are doing here...looking under stones that haven't been turned over in a while or ever? Can't have more fun that that unless we get some one-holers once and a while for a bonus for our efforts.

    I appreciate everyone's input especially since we have gone this long without any big arguments from anyone...that's saying something right there!
    a m e r i c a n p r a v d a

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  15. #255
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by barrabruce View Post
    It may be better trying to get the barrel on a upswing .
    That way the slow bullet will exit later and the faster bullet earlier so as they both end up falling into the same hole.
    You would have to cryno each shot and take into account.
    That was what he was trying to say I think.
    Something like that.

    Me I just shoot till it gets smaller and say ghee thats better. Note that point and move on till I find a setting that dwells there the longest.

    I did it years ago and went through some ammo thou.

    Hope you find it one way or another.
    We can't depend on that exact sequence every time...what if it's reversed or the rounds are close or the same in speed...now we are looking at vertical stringing.
    a m e r i c a n p r a v d a

    Be a Patriot . . . expose their lies!

    “In a time of deceit, telling the truth is a revolutionary act.” G. Orwell

  16. #256
    Boolit Grand Master tazman's Avatar
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    Quote Originally Posted by OS OK View Post
    Isn't this why we are having such a good time here? All of us...well...some of us 'flailing' around and digging deeper for clues? Getting lots of data, discovering subtle little things that trim a little overall group size...you know a person can learn from getting it 'right & wrong'...all depends on what you take away from something...right?

    I remember a couple years ago when 'milk jug busting' was fun to watch on video...some very big explosions & some not so big but everyone having a good time watching. Some folks putting little yellow rubber duckies on the jug top and seeing how high they'd launch...I used ping pong balls for a good effect...
    Several people started guessing at how much velocity a typical .45ACP HP would loose going through the first jug...well...I mulled on it for a while and came up with a hair-brain experiment.
    Why not put the chrony behind the jug and clock it on the exit...sure enough I got the numbers. 908 fps going into the jug and 450 fps coming out with a perfect mushroom, kept all it's weight and we discovered that the first jug consumes 1/2 of the energy in that short little distance from front to back, providing your blend was good.

    In a round about way, that's what we are doing here...looking under stones that haven't been turned over in a while or ever? Can't have more fun that that unless we get some one-holers once and a while for a bonus for our efforts.

    I appreciate everyone's input especially since we have gone this long without any big arguments from anyone...that's saying something right there!
    I understand and agree. If I come up with something, even a small detail, that I think might help, I will post it here.
    For the moment I am at a complete loss.

    quote---We can't depend on that exact sequence every time...what if it's reversed or the rounds are close or the same in speed...now we are looking at vertical stringing.

    Temperature or screw tension could change that equation so it doesn't work correctly. Also variations in ammo for sure would change it.
    Deep rabbit hole here. Watch your footing. And your wallet.

  17. #257
    Boolit Grand Master 303Guy's Avatar
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    I had a hair brain idea this morning and have been thinking about it on and off all day. I get what Forrest r is trying to say and I get what OS is trying to achieve and that is to have the boolits exit the muzzle when it is changing direction as that is when it is moving slowest for longest. That is actually what Forrest r is alluding to. Find the point of exit that has the least influence on POI, regardless of velocity spread. And that is where the chrony comes into play with two shot groups.

    So, getting to my hair brained thought - fit a laser to the muzzle and video the movement on firing. Chronograph at the same time of course. If it could be done - well it can be done of course but maybe not by everyone - we might learn something and perhaps find that sweet spot of best accuracy with a tuner. The laser would need to be very light so as not to influence the result appreciably.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  18. #258
    Boolit Grand Master


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    Reading this thread I realize how little I know. I was fat, dumb and happy in my ignorance.

    I would test ammunition, get an acceptable result and be done. Never thought about how the load shoots at 20*, 65* and 95*. But if .001" of barrel length affects groups, even those temperature swings will have an impact. I missed it completely as I never checked it. And I never checked and verified what the action screws were torqued to.

    In practical terms, what do I do if I need a different barrel length for different temperatures? Assuming I do not have a tuner? Would I need different ammunition for different temperatures? Use electrical heating to keep the barrel at say 125* all the time? Well...that is too much for me. It is not practical. I can live with a situation where the gun shoots 1/2" groups at one temperature and 1" groups at another. But then again, I am not competing...just looking for practical precision. POI is a bigger concern but I honestly do not know if POI is affected by a temperature swing of 75*. That ignorance is a result of laziness....I test under good conditions and do not verify under the extremes...now I know I better start doing that.

    As to the 2 shot group discussion. I agree with what Forrest is saying if I understand correctly. If you get two bullets that have a large ES in the same hole that is the place to be. That assumes that the bullets themselves are "perfect" and true, and the shooter did his job of executing a perfect shot for each, and the wind did not impact bullet flight. But that will require burning up a lot of ammunition. Conversely, a one hole two shot group
    from two bullets of the same velocity tells you nothing....you expect them to have the same barrel time so the barrel will be in the same spot for each bullet. In my mind, if you do not get an extreme spread of say 20 fps you need to repeat the two shot group or the result from that tuner position is irrelevant.
    Don Verna

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  19. #259
    Boolit Master Forrest r's Avatar
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    Typically I test with ammo that has es's in the 30's. And yes I chronograph every shot. I look for setting that get the largest difference in velocity of those 2 shots and puts them in the same hole/next to each other.

    Once you find where that tuner needs to be the setting will not change that much from lot to lot, velocity differences with ammo in the 1060fps to 1085fps.

    "rounds are close or the same in speed...now we are looking at vertical stringing"
    Nothing could be further from the truth!!!

    The bbl's osculation will end at the same place (muzzle in same place/same angle) with identical or close velocities.

  20. #260
    Boolit Grand Master tazman's Avatar
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    Just how fast and far does the barrel muzzle move during a shot?
    The idea about the laser is interesting but I don't know how fast your camera needs to be to accurately record the oscillation.
    If it only takes .006 to make an inch difference downrange, where do you need to record the images of the laser?
    How many times does the barrel oscillate during firing?

    Deep rabbit hole with way too much specialized equipment to figure some of this out.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check