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what’s the fastest shot you’ve chronyed?

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Viewing 11 posts - 1 through 11 (of 11 total)
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  • #22788
    miksatx
    Participant

    this morning jsb 10.3 .177 regged 1600 psi. new build disco based air tube, new magnum airpower disco modified valve.

    #270847
    rrdstarr
    Participant

    Faster is great ONLY IF accuracy is still great! What’s your group like?

    I used to shoot .17 Swift. Bullets were moving at 4300FPS. Accuracy was poor until bullets were slowed down to 3950. Some bullets tore themselves apart from torsional rotation!

    #270848
    miksatx
    Participant

    I wasn’t shooting groups Rrdstarr. I had just put the gun together. Added 2500 to the bottle. First shot 886, second 1081 3rd 1025 4th it shot the 1754 popped up I couldn’t believe it! I don’t plan on shooting it that fast lol. Right now it’s still work in progress. It has a pretty light valve spring and I found that most light springs I’ve tried in a disco valve. I’d get hammer resonance producing a machine gun type air dump of the tube.

    #271349
    leadbetter
    Participant

    Fastest chrony numbers I’ve seen was 5200fps on
    a .22-284 with zero freebore shooting 35gr slugs. Guy was hitting egg size water ballons at 300 yards. The ballons would pop before you heard the report.

    #273746
    bountyhunter1976
    Participant

    Is there such a thing as the chrony making a fluke measurement? But three times in a row? I had my condor in a ledsled secured so as not to move. I moved my condor after the third shot to topoff the tank and make some other change after this. Chrony was about 4 feet from the end of the barrel. I can not remember which setup I was using at the time, whether the .22 barrel or the .25 barrel but i am pretty sure it was with either a 14.3gr if in the .22, or the 25gr in the .25 but here are the measurements my chrony gave me: 1st shot 2630, 2nd shot 2553, and the 3rd shot 2326. All I now remember is I was playing around with the tophat and power wheel. This took place on May 14th 2017 and I have the pics of the chrony since I could not believe it. I did have one prior time right after getting the chrony where it showed 2178 and I know I had the .22 barrel on as it was shortly after getting the condor. I did not have the tt tophat but had the power wheel turned up to max.
    Anyone tell me how this could happen? Could it be correct?

    #273809
    miksatx
    Participant

    Hey bountyhunter1976 what chrony were you shooting over? I have a pro chronograph thought they were supposed to be better then say my old green chrony. I accidentally shot one of my green ones really felt bad about that . But this pro pos has had me seriously thinking bout shooting the hell out of it on purpose lol!

    #274721
    fomen
    Participant

    When you’re shooting a lead pellet that fast, it will tear itself apart within 15-30 yards from the muzzle. Even if it tore itself apart at the muzzle, the inertia of the fragments and proximity to the chronograph will give you a reading. Chronographs read hyper-sonic rifle rounds, so a fast moving pellet is nothing. Pellets are much more fragile than a cast bullet or a boat tail round. Most bullet manufacturers don’t use 100% soft lead in their rounds either. Even if they’re copper jacketed. They will use a 10% alloy to 90% lead to lighten and harden the projectile. Pellets are 100% soft lead. There is a MASSIVE amount of physics that goes into ballistic coefficients. You have the shape and weight of the projectile. The amount of initial energy exerted to project it to a specified velocity. Then you have the amount of barrel twist required to stabilize the projectile in accordance with the two aforementioned characteristics. Even center fire rounds can shoot too hot and rip themselves apart in flight. So I can tell you with 99% confidence that a pellet shot string shooting that fast at a 50 yard target would look like an un-choked shotgun shooting a target at 75-100 yards. There would be zero consistency in groupings. That’s if the pellet ever even made it there in the first place. It would be going 2x’s the speed of sound. The instability would be massive! But I guess it’s cool to see how fast it can travel at the barrel. But IMHO, it’s a waste of air. I know you can shoot .177 pellets faster than their bigger brothers and maintain stability. But I wouldn’t shoot a .22 or larger pellet any faster than 950 FPS. Ideally around 900. This by and large seems to be the sweet spot for stability with domed pellets. When you start nearing the supersonic range, the energy required to propel the pellet may damage the pellet. You will often times waste air by blowing it around the pellet, and potentially blow out the skirt on the pellet.

    #274728
    iride
    Participant

    Forman
    So the idea FPS speed of a 22 is 900 FPS give or take a few,
    and the 25 is about 930 give or take a few .
    The 177 is up to about 960 give or take a few ,
    PLEASE correct me if I am wrong any where.
    Mike

    #274735
    fomen
    Participant

    This is my disclaimer:

    BY NO MEANS am I an expert. But I have a very analytical mind. I research the CRAP out of something before I commit to it (sometimes to my own demise). But…… Of the research I have done, I can say that the FPS you referred to for the .22 and .25 pellets seems to be accurate. But then again, it depends on the twist rate of the barrel. The LW barrels that Air Force uses have a twist rate of 16:1. If you’re gun has the 24″ barrel, the pellet is rotating 1.5 x’s before it exits the muzzle. Some gun manufacturers use a twist rate of 17:1. In this instance the pellet is rotating 1.4 x’s before exiting the muzzle. This difference in twist rate seems insignificant. But if the rotation of the pellet over distance followed the initial 16:1 twist rate at the muzzle (which it will in accordance to a physical law called the Law of Angular Momentum), the over a distance of 100 yards the pellet will have twisted 225 times. With the 17:1 twist rate, the pellet will have rotated 211 times over the same distance. Although this seems minuscule, it can effect accuracy hugely. True air gunning is a sport that deals with fractions of an inch. We are using projectiles that are lighter and less stable than cast bullets, so if improperly placed they will not accomplish what you sent them out to do.

    So here is my suggestion…… Play with your power wheel. That’s why AF has it there. Chrony and sight in your scope simultaneously. Ideally you want to use a bench rest to ensure that the scope and gun give each pellet equal opportunity. I recommend doing this at 50 yards as the groupings diminish over distance. If your groups are tight (say the size of a dime to a quarter) then I think your settings are ok. But if you see them start to spread and scatter, play with your power wheel. The 24″ barrel coupled with the power wheel give you a significant range of adjustability regarding your FPS. Faster isn’t always better. If you’re shooting a .22, 18gr JSB pellet at 930 FPS, on your groups seem a little inconsistent, then slow the pellets down a little. Drop them down to 900-905 FPS. Then replicate the same scenario. See if your groups tighten. DON’t ADJUST YOUR SCOPE! Regardless of where it’s sighted in, your goal is to observe and maximize groups. Once you’re satisfied with the groupings, THEN sight the scope in.

    Also, if your AF is unregulated, you should probably discard the first 6-8 shots in the string after filling the tank to 3000 psi. They will be effected by the bell curve and the readings will be slower than then next 15-20 shots after the tank settles in. For maximum accuracy, I ALWAYS recommend purchasing a constant air pressure regulator. You can get them from PCP Tunes for $198. It is perhaps the single most effective purchase I’ve made for my AF Condor. You eliminate the bell curve, and you maximize the air to pellet ratio by avoiding the dreaded air “dump”.

    Regulator: http://pcptunes.com/airforce-condor-regulator-with-dual-gauge.html

    This is a GREAT video to explain and understand the bell curve and why it happens on non regulated air rifles.

    #275041
    pablouk
    Participant

    It is possible to get a decent string off the rifle unregulated. Takes a lot of fucking about, many strings, lots of pellets but it can be done. I’ve shot 1″ groups at 100 yards unregulated. That being said one of the best purchases i made was a reg.Takes all the hard work out and gives you a level of certainty when taking a shot. But I’ll tell you what, getting a good string unregulated is VERY satisfying.
    When it comes to accuracy here’s my tuppence worth…
    Always use a JSB pellet, diablo is best. The Walther Lothar barrel and the BSA( if you’re lucky enough to have one) barrel like them.
    Anywhere between 850 and 950fps is the ideal speed, .22 and .25 Of course you’re looking for the highest speed whilst maintaining accuracy.
    Simples.

    #275115
    fomen
    Participant

    Couldn’t agree with you more. Especially about the regulator. The majority of the shots through my gun have been unregulated. However, since the purchase of the regulator (4 months ago) I’ve found myself saying “Why the heck didn’t I buy this thing sooner?” You get maximum efficiency and maximum consistency in fps and fpe. This equates to maximum accuracy. I see a lot of guys on videos shooting at targets down range (various distances) railing on their guns regarding their shot spreads and accuracy. If you’re shooting a regulated, high end PCP air rifle, and your shots are all over the place, it’s more than likely YOU and not the gun that is the problem. The only way to truly get a gauge for what your gun is capable of is to tweak the gun to achieve the aforementioned speeds with the aforementioned pellets. Once you’ve chronied your gun and you can attest that the regulator is working, and there is consistency with the shot strings, get your gun on a GUN VISE and sight it in. Not on a bag! Not on your bipod! On a gun vise. The gun vise will ensure that your cross-hairs are on the exact same spot every single time. Also, sort your pellets. Make sure they are consistent in shape. No deformations. Let your gun prove itself. You will be AMAZED how a regulated PCP air rifle can put multiple pellets in the same hole over and over again. This way you can truly sight your gun in.

    Also, if you’re using a AF platform (Talon, Escape, Condor) you can significantly improve your accuracy by getting a 1 piece stock (like from Mad Dog Rifle Stocks). AF guns are very hold sensitive. Most other gun manufacturers use bull pup designs with solid stocks. These stocks have picatinny rails on them for a bipod to be mounted. The minute flex of the stock has no bearing whatsoever on the driving components of those rifle. They are somewhat independent of each other. But on an AF, the gun is long, and it’s conjoined in the middle. When you utilize your bipod (which is attached to the rail system build onto the shroud frame) the weight of the front of the rifle combined with the shooter resting his cheek on the tank to take aim downrange will cause flex at the joint. It’s very small, but it does happen.

    But a regulated AF rifle with a 1 piece stock is a small, furry, woodland creature slaying BEAST! Evan at epic distances!

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