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

  1. #361
    Boolit Grand Master tazman's Avatar
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    What you are doing is working. Keep it up.

  2. #362
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    Quote Originally Posted by OS OK View Post
    Got out early today . . . to catch that lull in the morning breeze and I missed it.
    Oh well...now we are going to deal with it. Even going to try to use a little Kentucky Wind-age. At this wind speed & direction I feel fairly confident that I can shoot into the wind almost a full bullet diameter. We'll see how that worked in a minute.

    One of the new things I am incorporating into my setup is to place that right hand down on the base of the rear bag after I have the elevation adjusted on the front rest...this is how I'm holding that bag and putting a small correction to the windage, it doesn't need much when moving the rear end of the rifle.



    Another little change, I hope for the better is that in 'pinching off the rounds', I am using a tiny bit of thumb pressure forward on the rear of the trigger guard.



    So...those are the only changes and this is today's progress. Some of the rounds worked and some didn't. Right as I touched them off the wind died, either died back a little or I had a sudden lull that lasted about 15 seconds.
    Anyway...I got what I got.



    I kinda like this setting, still wanting a good day, a day of lull & slack wind to be sure...we'll see?
    You should consider shooting a sigher every once in an while during the string to gage the windage.
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  3. #363
    Boolit Master
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    nice shooting

  4. #364
    Boolit Grand Master OS OK's Avatar
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    Some time ago... several of you mentioned using the chronograph to verify the speed of each and every shot...I think to do this to see how the speed would make the POI change within a 'suspected good node'.
    I also wanted a good day with little to no wind to better evaluate this 4.75-10 setting on the tuner...today is the day...I set the chrony out front of the bench, took a pad & pencil and went to work this morning...



    It was almost a perfect zero-wind morning but not quite...good enough though after waiting through some windy days and stormy weather lately.
    Here's what I got this morning...



    I haven't had the time to sit and study these shots considering their POI & speed on the chrony. All the 'wind + direction & speed' & 'FPS' information is on each individual target.
    I thought I would see the POI above & to the right of the node group if the round was faster and see the POI either to the left and or above to the left if the round was slower.
    This I thought would be the case if my tuner setting is actually at the bottom of the barrel oscillation.

    What is your take on all this data? Anything significant in all this data or just the happenstance of POI's around a suspected node?

    EDIT... I ordered this ammo at 1,055fps and you can see that I am getting more speed from this barrel and chamber ... I think I am still flirting with that pressure wave here at 2,000' ASL?

    Last edited by OS OK; 05-22-2021 at 03:06 PM.
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  5. #365
    Boolit Grand Master 303Guy's Avatar
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    Nice Shooting! The velocity doesn't seem to make any difference. What was the air temperature? It looks to be quite warm although that could be deceptive. Warm for me would be 65 F and up. At 70 F the speed of sound is 1130 fps and at 65 F, it's 1122 fps and at 50 f the speed of sound is 1106 fps. One of your rounds was 1117 fps and that one shot high. That may have nothing to do the sonic velocity though. I see your first warmer was 1151 fps!

    I would suggest recording air temperature. In cooler weather those rounds won't be sub-sonic anymore. Have you noticed an improvement in group sizes since your weather has warmed?
    Last edited by 303Guy; 05-22-2021 at 04:57 PM.
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  6. #366
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by 303Guy View Post
    Nice Shooting! The velocity doesn't seem to make any difference. What was the air temperature? It looks to be quite warm although that could be deceptive. Warm for me would be 65 F and up. At 70 F the speed of sound is 1130 fps and at 65 F, it's 1122 fps and at 50 f the speed of sound is 1106 fps. One of your rounds was 1117 fps and that one shot high. That may have nothing to do the sonic velocity though. I see your first warmer was 1151 fps!

    I would suggest recording air temperature. In cooler weather those rounds won't be sub-sonic anymore. Have you noticed an improvement in group sizes since your weather has warmed?
    I'm not really warm here yet, today it was 55ƒ 1/2 hour before I went out to set up & shoot...maybe 57ƒ by then but that's only a little difference in fps to that wave.
    We have only had a few days in the 80's this year, it's been pretty cool so far.

    This is a good page on all this ... https://www.engineeringtoolbox.com/e...ir-d_1534.html
    https://www.engineeringtoolbox.com/a...und-d_603.html
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  7. #367
    Boolit Grand Master 303Guy's Avatar
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    I did find that second one this morning which is where I got my figures from. So, if you were 55 F or maybe 57 F then those rounds are bordering on the sound barrier. It's a pity they are not doing the 1055 fps that you had wanted. Once it gets warmer you will be below the speed of sound.

    This morning I found a research paper talking about the unstable zone which begins at Mach 1.2 and shadow graphs show what they mean.

    https://www.accurateshooter.com/ball...-stability-bc/

    I'm wondering just how much the transonic velocity range affects us.
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  8. #368
    Boolit Grand Master tazman's Avatar
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    303Guy--- I was studying the pictures in that article and reading what he said. I got the impression the worst problem was going from having the major wave in front of the bullet(mach 1.3and above)to having only the wave at the rear of the bullet(mach 1.03 and lower). Most of the problem should occur at speeds above mach 1.02. His velocities are well under the mach 1.02 numbers.
    Other than the wave being less strong under mach 1, there wasn't really much difference.
    The velocities we are talking about with match 22lr ammo and the numbers OS OK posted, should be just under mach1.
    Given the accuracy OS OK is getting, I would say that the mach zone is having very little, if any, effect on his bullets.
    Another thing mentioned in the article was shorter, flat based bullets are bothered less by the turbulence than longer bullets. Our 40 grain bullets fit right into the shorter bullet profile the author was talking about.
    If we were shooting higher velocity rounds, such as bullets going around 1300fps, I could see the turbulence being a much bigger problem.
    I really don't believe the velocities OS OK is showing are going to put him in any danger of losing stability and accuracy because of the speed of sound. His accuracy would tend to prove that point.

    I would have been interested to see that video but it seems to be unavailable.

  9. #369
    Boolit Grand Master 303Guy's Avatar
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    True. It did surprise me that the troublesome range was as high as that. Thing is though, one of the rounds was sonic or even supersonic at 1117 fps (sonic at 60 F is 1117 fps, less at lower temperatures) was off target which is interesting.

    A question I have is that trans-sonic typically refers to Mach 0.8 to Mach 1. Indeed, Doppler radar chronographing has shown that a bullet's BC drops to a minimum at about Mach 0.83 and rises to maximum at around Mach 1.2.
    Last edited by 303Guy; 05-23-2021 at 01:12 AM.
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  10. #370
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by 303Guy View Post
    True. It did surprise me that the troublesome range was as high as that. Thing is though, one of the rounds was sonic or even supersonic at 1117 fps (sonic at 60 F is 1117 fps, less at lower temperatures) was off target which is interesting.

    A question I have is that trans-sonic typically refers to Mach 0.8 to Mach 1. Indeed, Doppler radar chronographing has shown that a bullet's BC drops to a minimum at about Mach 0.83 and rises to maximum at around Mach 1.2.
    That sounds like the report/article I read also...for the life of me I can't find the bookmark. Like a BoneHead I prolly didn't save the link!

    Harry Tobin . . . and I talked today. Harry mentions that back in the day when they were first breaking the sound barrier, as the plane went through the pressure wave, it lost control on it's control surfaces. I suppose as the wave passed along the fuselage to the rear of the plane.
    In the same way, as it passes along the body of our little pills, I think they loose their stability to some degree even though they have adequate spin stabilization. Now I'm just spitwadding again but I thought that the low pressure drag at the base of these lil-short projectiles aided in its ability to track, both in sub and sonic rounds...it's the passing through, it's the pressure wave transferring from rear to front as the round goes sub-sonic that causes the disturbance (me thinks)? That's why I'm guessing that as the round approaches sonic flight, there's destabilization happening even when it doesn't reach the sound barrier.

    I think too that as the round approaches sonic flight that the drag in the rear is affected also (?), not sure though.
    There seems to be an incredible 'lack of published information' pertaining to these rounds we shoot.
    With all the high speed photography available, all the dopler radar out there, that nobody has addressed this and made their work public.
    All the places I go to read about this stuff all I see is 'general information', nobody specifying their elevation where they shoot or temp. or humidity...everyone just comments in general. That's frustrating and dang hard to learn from.
    I have been searching the sites for folks posting targets like I use (or any of the various targets from the different associations), I wanted to see if any of the better targets had groups that roamed around like mine seems to do...roams around in the 10 ring. All I find is pictures of their favorite hole-shooter and one tight picture of one tight group they have shot...that doesn't help at all, we have all had 'one tight group' but that doesn't represent what a rifle does with a string of groups...it's a 'happenstance' if you ask me.

    I'm getting frustrated but I ain't quitting or giving up on this search to understand this phenomena.
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  11. #371
    Boolit Grand Master 303Guy's Avatar
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  12. #372
    Boolit Grand Master tazman's Avatar
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    Quote Originally Posted by OS OK View Post
    That sounds like the report/article I read also...for the life of me I can't find the bookmark. Like a BoneHead I prolly didn't save the link!

    Harry Tobin . . . and I talked today. Harry mentions that back in the day when they were first breaking the sound barrier, as the plane went through the pressure wave, it lost control on it's control surfaces. I suppose as the wave passed along the fuselage to the rear of the plane.
    In the same way, as it passes along the body of our little pills, I think they loose their stability to some degree even though they have adequate spin stabilization. Now I'm just spitwadding again but I thought that the low pressure drag at the base of these lil-short projectiles aided in its ability to track, both in sub and sonic rounds...it's the passing through, it's the pressure wave transferring from rear to front as the round goes sub-sonic that causes the disturbance (me thinks)? That's why I'm guessing that as the round approaches sonic flight, there's destabilization happening even when it doesn't reach the sound barrier.

    I think too that as the round approaches sonic flight that the drag in the rear is affected also (?), not sure though.
    There seems to be an incredible 'lack of published information' pertaining to these rounds we shoot.
    With all the high speed photography available, all the dopler radar out there, that nobody has addressed this and made their work public.
    All the places I go to read about this stuff all I see is 'general information', nobody specifying their elevation where they shoot or temp. or humidity...everyone just comments in general. That's frustrating and dang hard to learn from.
    I have been searching the sites for folks posting targets like I use (or any of the various targets from the different associations), I wanted to see if any of the better targets had groups that roamed around like mine seems to do...roams around in the 10 ring. All I find is pictures of their favorite hole-shooter and one tight picture of one tight group they have shot...that doesn't help at all, we have all had 'one tight group' but that doesn't represent what a rifle does with a string of groups...it's a 'happenstance' if you ask me.

    I'm getting frustrated but I ain't quitting or giving up on this search to understand this phenomena.
    I have been watching a number of you tube videos of people testing various brands of ammunition in their rifles. They are using rifles like mine or, at least, very similar. While I realize their rifles are not my rifle, I can get a feel for what to expect as far as group size.
    During their tests, they fire strings of five shot groups. All of them wander a bit from the first to the last group as far as where the center of the group is located.
    Something I have noticed is the wandering tends to go to the right. Initial group would be either in the center or the left of the bullseye and the rest of the groups would work their way to the right of center by the time they finished shooting(normally 5 five shot groups). Sometimes, the speed with which they shoot their groups makes a difference on how pronounced the shift is.
    It may not be much of a movement, but it is there if you watch closely.
    Now for the spitballing. I suspect the cause may be the barrel heating up on the inside due to friction and the temperature of burning powder. This temperature change may cause the lube to change properties slightly and perhaps change the friction/drag on the bullet as it passes through the barrel. Whatever effects this will have on group consistency, I have no idea....Yet.
    Just something else to think about.

    I doubt there would be much of anything that we, as shooters, could do about this except just to observe and collect data so we could anticipate this occurring.

  13. #373
    Boolit Grand Master OS OK's Avatar
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    Quote Originally Posted by tazman View Post
    I have been watching a number of you tube videos of people testing various brands of ammunition in their rifles. They are using rifles like mine or, at least, very similar. While I realize their rifles are not my rifle, I can get a feel for what to expect as far as group size.
    During their tests, they fire strings of five shot groups. All of them wander a bit from the first to the last group as far as where the center of the group is located.
    Something I have noticed is the wandering tends to go to the right. Initial group would be either in the center or the left of the bullseye and the rest of the groups would work their way to the right of center by the time they finished shooting(normally 5 five shot groups). Sometimes, the speed with which they shoot their groups makes a difference on how pronounced the shift is.
    It may not be much of a movement, but it is there if you watch closely.
    Now for the spitballing. I suspect the cause may be the barrel heating up on the inside due to friction and the temperature of burning powder. This temperature change may cause the lube to change properties slightly and perhaps change the friction/drag on the bullet as it passes through the barrel. Whatever effects this will have on group consistency, I have no idea....Yet.
    Just something else to think about.

    I doubt there would be much of anything that we, as shooters, could do about this except just to observe and collect data so we could anticipate this occurring.
    Remember this test from the 'Peep & Globe' thread? I walked away from this thinking that this minimal temperature rise couldn't have much of an effect on a bull barrel. I was thinking only of the barrel physically moving from temperature expansion of the steel...like hotter and more expansion along the part on top 'heated by sunlight' or the whole barrel heated from the .22lr ammo.
    This is another 'DUUUUUH' moment for me...I never considered the interior surface and the lube quality changing from shot to shot!
    We can certainly see that lube can/is causing a round to build more pressure...as in that first shot of the warmer target the other day at 1,151fps...



    I definitely heard that sonic crack first shot of the morning. (Because of that first shot on the warmers target spot each day being 'out of group' so far & more times than not, I notice that sonic crack, I've had it in my mind that the lube in the barrel has 'changed' somehow from the last shooting session from a day (or longer) before. Perhaps it crusts-over or has some oxidation process going on we don't know about (or needs a quick re-heating and smoothing)?
    It certainly holds the first round back and makes more pressure & speed as the barrel lube is refreshed for the current session...notice how the following rounds dropped back in speed and started trying to group from the 2'nd shot on-wards.)

    I get focused on something in my mind and my tunnel-vision kicks in...sorta like being focused on a small section of bark on a tree with with whole forest before me.

    I think that I don't collect enough data in any one particular test...seems like I'm always focusing on 'one' thing at a time . . . to do this data collection right we'd need a team of people working together at the bench. I should have had the chronograph running for every shot here also...but that's hind-sight now, "20-20 as they say!"

    Here's that posting from... https://castboolits.gunloads.com/sho...0-yards/page22 post number 437...

    Let's see what we can see here... Barrel temperature - Test 1

    This first test will be me shooting the warmer spot and 5 more spots for group measurement, for barrel temperature & for time elapsed, just as I have been doing (except for all this added data).
    But...dangit...I have a DISCLAIMER... When I set this multi-meter up with the thermocouple and tested it in the 'shade' of the early morning shop, I noticed that the barrel temperature was 69.
    I loaded the gear in the push cart and posted my target, then I pushed the cart out to the 50 yard line. The rifle had sat in the 'direct sunlight' for about 12 minutes as best as I can estimate.
    By the time I had the rifle set up on the bench (in the shade of the umbrella) I noticed that the barrel had increased in temperature to 75. This is my 'blunder for today' & whether or not this blunder fouls the test I'll leave that up to you boys to consider.



    The ambient air temperature was 58 and I allowed that rifle to sit in the shade approximately 40 minutes and the barrel temperature did not drop before I started the test.
    I set up the iPhone as a running timer, started it and then went to the 10 shot warmer target and proceded on to the next 5 spots without stopping for anything but a photo like the one below to note the time elapsed and the barrel temperature,
    This photo was taken within a half minute after the 10 warmers...



    From the warmer spot I went to the top middle target (working top to bottom, going left side to right) shot 5 rounds and immediately took a photo, this is the second spot shot...barrel temperature & time elapsed recorded...the temperature was reading 78 and toggled back to the 77 just as I snapped the photo.



    I did this the same spot for spot until I had finished all 6 spots...this is the last picture showing total temperature climb in the barrel and total time elapsed in shooting the 6 spots...



    From here I referenced all the photos and recorded the group size/ barrel temperature/ and time elapsed beside each spot on the paper. Below is that target session...



    After the 10 warmer shots it looks like I spend aproximately 3 minutes on each spot.
    Thinking about this blunder I made, I left the rifle in the direct sunlight when I returned to the shop, seems as though it sat there for about an hour (guessing) as I tended to the target marking and a couple other things.
    This is the maximum temperature the barrel went up to in that time lapse and in ambient air of about 59-60 by this time in the afternoon.
    The end of the thermocouple is bent 90 and poked down in the threaded hole for a scope base mount and it is directly above the forcing cone of the bore. If any place on the barrel could show us any temperature readings I suspected that this hole would be the place.
    Under the chamber there at the front of the receiver is the 'front-most' barrel contact with the stock and it is solid...I did not think that wrapping this electrical tape there would affect the barrel harmonics in the least.



    SO that's the whole thing wrapped up nice and neat with an official blunder to consider. What do you boys think about this?
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  14. #374
    Boolit Grand Master tazman's Avatar
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    I have to wonder, just how deep is this rabbit hole going to get?

    From your test results, we can see the barrel temp is increasing during shooting. We assume this is from the firing of the rifle. Not a major change, but the temp is measured on the outside of the barrel.
    I don't know of any good way to measure the temp of the inside of the barrel. Anything put inside the barrel between shots will have some effect on the conditions due to it's presence there. If nothing else, it would disturb the condition of the lube coating in the barrel however slightly. We would be introducing another variable which we really don't want to do.

    I think testing and recording data over time will give us the best view of what is happening. Position of groups and any other tendencies we can determine and record will help.

    This is all going to take time and attention to detail to figure out. Not something that can be proven by a single test sequence.
    I don't get to shoot as often as I would like. I have been concentrating on consistent technique. I think I am going to need to spend more time setting up for recording other data than I have been.
    Last edited by tazman; 05-23-2021 at 01:08 PM.

  15. #375
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    Quote Originally Posted by OS OK View Post
    Some time ago... several of you mentioned using the chronograph to verify the speed of each and every shot...I think to do this to see how the speed would make the POI change within a 'suspected good node'.
    I also wanted a good day with little to no wind to better evaluate this 4.75-10 setting on the tuner...today is the day...I set the chrony out front of the bench, took a pad & pencil and went to work this morning...



    It was almost a perfect zero-wind morning but not quite...good enough though after waiting through some windy days and stormy weather lately.
    Here's what I got this morning...



    I haven't had the time to sit and study these shots considering their POI & speed on the chrony. All the 'wind + direction & speed' & 'FPS' information is on each individual target.
    I thought I would see the POI above & to the right of the node group if the round was faster and see the POI either to the left and or above to the left if the round was slower.
    This I thought would be the case if my tuner setting is actually at the bottom of the barrel oscillation.

    What is your take on all this data? Anything significant in all this data or just the happenstance of POI's around a suspected node?

    EDIT... I ordered this ammo at 1,055fps and you can see that I am getting more speed from this barrel and chamber ... I think I am still flirting with that pressure wave here at 2,000' ASL?
    Nice shooting. Sad about the dropped point. I don't think sonic ammo is causing you problems. I think you should recalculate the velocity numbers without the first shot from cold barrel.

    You seem to be getting one "bad" shot in every line/group of 5 shots. Target 12 you came close to dropping another point. I don't think target 4 miss is anything to do with the velocity. Target 2 is just as big a velocity difference. Unless that node was not quite rightly centered and the slightly higher velocity put you off the node. I wonder if the node might move one click with a small change in conditions, like temperature or barometric pressure. Centerfire guys used to load ammo at the range to match the conditions, they did not have tuners.
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  16. #376
    Boolit Grand Master OS OK's Avatar
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    dtknowles . . . That's an interesting observation.

    Do you have any suggestions as to how you would monitor the conditions? What equipment you'd use and how you might apply it?
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  17. #377
    Boolit Grand Master 303Guy's Avatar
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    Quote Originally Posted by dtknowles View Post
    Nice shooting. Sad about the dropped point. I don't think sonic ammo is causing you problems. I think you should recalculate the velocity numbers without the first shot from cold barrel.

    You seem to be getting one "bad" shot in every line/group of 5 shots. Target 12 you came close to dropping another point. I don't think target 4 miss is anything to do with the velocity. Target 2 is just as big a velocity difference. Unless that node was not quite rightly centered and the slightly higher velocity put you off the node. I wonder if the node might move one click with a small change in conditions, like temperature or barometric pressure. Centerfire guys used to load ammo at the range to match the conditions, they did not have tuners.
    Tim
    I do tend to agree. However, target 2 is in the subsonic direction while target 4 is right on Mach 1 at 60 F. OS has said he thinks the air temperature may have been 57 F in which case the speed of sound would have been 1114 fps.

    Of course, target 4 could be just a coincidence. One would need a reasonable number of rounds at that same velocity to be able to make any kind of assessment and that would include the possibility that as you say, the slightly higher velocity might have put the shot off the node.

    I must say that the speed of sound effect does not look too convincing but shouldn't quite be ruled out at this point.

    Here is a nice speed of sound calculator if anyone might be interested;

    https://www.weather.gov/epz/wxcalc_speedofsound
    Last edited by 303Guy; 05-25-2021 at 04:10 AM.
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  18. #378
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    Sonic, or when the bullet snaps or cracks, is not a function of the velocity of the bullet related to the speed of sound [1117 fps at 50*], but rather is when the speed of the compressed air moving around the nose of the bullet approaches or exceeds the speed of sound. That is when the disturbing buffeting effect on the bullet occurs.

    At a given bullet velocity the speed of the air moving around the nose is always faster than the bullets velocity. The more air streamed the bullet the less the speed the air has thus the higher the velocity of the bullet can be before going sonic.

    For any ammunition to be truly subsonic [the bullet not to crack or snap on muzzle exit] the highest velocity of any round fired must be below that bullet velocity where the air breaks the speed of sound moving around the bullet. That bullet velocity is always below the speed of sound. This is easily verified with a suppressed firearm as the load is increased until there is a "snap" on bullet exit the chronographed velocity will always be less than the speed of sound.

    This is why all quality match 22LR will have a velocity considerably less than the speed of sound as will other truly sub-sonic ammunition. Thus, regardless of the rifle barrel length, the velocity of the bullet will not enter the buffeting trans-sonic area where the air speed around the bullet approaches the speed of sound.
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  19. #379
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    You write:
    EDIT... I ordered this ammo at 1,055fps and you can see that I am getting more speed from this barrel and chamber ... I think I am still flirting with that pressure wave here at 2,000' ASL?
    ---------------------------------------------------------------

    Yes. That makes me wonder as well. I shoot a lot of Eley Match too and have tested the velocity in the past and order by velocity, or did when I could. I have never run into lots that went this fast.
    ????

    I agree with the above post that it is the air moving around the bullet rather than simply the bullet speed V supersonic that is the factor. Often we simply say the bullet is SS when we really mean the displaced air around the bullet.
    Chill Wills

  20. #380
    Boolit Grand Master OS OK's Avatar
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    Dec 2015
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    El Dorado County, N. Ca.
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    They had a limited supply of ammo rated at 1038 fps but I wasn't fast enough on the order to get any, that was sold within about 15 minutes and 1055 was the next choice.

    Another unusual thing about this order is that I have had prolly 8 or 10 FTF's from the first brick of this Match. I checked the strike & it's deep & pronounced as all the others are but 'no bang' until I rotate it 90 ~ 180...then bang.
    I have a suspicion that perhaps quality controls have been lax to some extent while this ammo grab is on & they're just pumping them out ASAP.

    Don't know this for a fact, as this problematic brick is only the 5'th of the Eley tenex (2) & Match (3) since I began this journey..I'm just spitwadding here.
    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

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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