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Thread: Please recommend .22 PCP rifle for heavy aerodynamic pellet development project

  1. #1
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    Default High BC pellet development project: Please recommend .22 PCP rifle for testing

    Greetings,

    Matt Dubber of Air Arms Hunting SA fame regularly shoots edible and pest birds with .22 cal PCP rifles; at ranges from 50 to 150 yards.

    In the video below, Matt asks pellet manufacturers to step up and develop high ballistic coefficient pellets, that deliver flatter trajectories with less wind drift, for better accuracy and energy retention at extended ranges.

    While I am not a pellet manufacturer, I have decided to take up Matt's challenge. I am presently making custom swaging dies to produce test pellets. See image below of two different nose profile pellets that I produced so far, as "proof of concept" for my process.


    Proto pellets.jpg proof of concept pellet.JPG



    After that lengthy introduction, the reason I am posting this is to pick your collective brains.
    I am looking for a PCP air rifle with the following capabilities/characteristics:

    1. It can shoot .22 "pellets" weighing 25 to 35 grains at 900 FPS.
    2. Has an un-choked barrel (as the projectiles have rather long bearing surfaces compared to diablo pellets, they don't benefit from choking and will potentially suffer accuracy-robbing distortion from passing through a choke).
    3. Has a twist rate in 1:14 to 1:16 range (while the intention is to support more than one maximum pellet length, longer "tail heavy" pellets will require a faster twist to stabilize.)


    My intentions are to verify that my proto pellets "work", before making them available to Matt for serious testing. As such, I am looking for a PCP rifle as described above. Matt, will have access to Air Arms rifles, with a range of twist rate barrels to test, among others.

    As I am new to PCP rifles, I though you guys might be able to point me in the right direction.

    Thank you for any suggestions.



    Matt's challenge is voiced here from 18 minutes and 34 seconds (click on link):
    https://www.youtube.com/watch?v=7IjK...tu.be&t=18m34s


    From full video. below:





    Discussion of Matt's experimental FX barrels:
    https://www.youtube.com/watch?v=0B2d...tu.be&t=10m56s


    FX barrels.jpg
    Last edited by subscriber; 04-24-2017 at 04:20 PM.

  2. #2
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    For a starting point, buy and look at 22LR ammunition for their projectile shape and weight. There are some very light (20+gr) to 60gr bullets available in various shapes.

    Example: 22LR Stinger ammunition has a 32gr hollow point projectile that is rated at 1645f/s. I have shot them and they are reasonably accurate.

    A comment, the STANDARD projectile used by the British and Germans in the late 1800's to develop ballistic tables looks much like the ones you show. The point was a curved surface that was twice the radius of the bore and 3 radii long. That means the curvature on the pointy end would have a radius of .22" and a length of .33 inches for a 22cal. See Hatcher's Notebook 3rd Edition Ch 23 Pages 549 and following. These were used to develop tables for rifle and cannon shells.

    Another thought to get the mass forward and to provide a skirt would be to mimic the Minie ball that has a hollow base.

    Sounds like a fun project.

    Sorry I have no knowledge of PCP's as I shoot springers. RWS54 is about the best I know of for power and accuracy in springers. .177 and .22 are available.
    Last edited by dtdtdtdt; 04-21-2017 at 12:43 PM.
    Dave Thomas

    Shoot safe. shoot straight, have fun
    Teach a kid to shoot

    RWS54, 4.5mm, RWS 4-12x50CI
    FWB300SU, 4.5mm, Clearidge Ultra RM 3-9x32

  3. #3
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Quote Originally Posted by dtdtdtdt View Post
    For a starting point, buy and look at 22LR ammunition for their projectile shape and weight.
    ...
    Another thought to get the mass forward and to provide a skirt would be to mimic the Minie ball that has a hollow base.
    Thanks for the reply Dave.

    RWS actually sell 40+ grain airgun pellets modeled on their rimfire bullet. Pulling bullets fom loaded ammo will be too expensive, except on a very limited scale; but contacting CCI to ask if they would sell 29 or 32 grain Short or Stinger bullets is an excellent idea! Thanks for putting that into my head.

    You may be amused at how close my first attempt ended up to a .22 LR bullet profile:

    heavy pellet.jpg


    I have done several pellet designs that optimize aerodynamics by mimicking spitzer rifle bullets. More pointy implies longer; but the snag is that due to magazine depth limits, I can't make the projectile that long.


    sample design.JPG

    sample design2.JPG


    Longer also implies heavier, unless the projectile is hollowed out; so that is what I have modeled. I played around with several hollow base designs that enable me to achieve the target weight.


    sample design3.JPG



    This design looks a lot like a "Minie ball". This is in part to reduce its weight, and in part to move the center of gravity forward. The latter should make it easier to stabilize at slower twist rates.

    sample design4.JPG



    Now, if you scale these images down to life-size, you realize that actually making dies to produce them is going to be a little harder than designing them. As such, I decided to first make some simple flat-base punch and die, as a proof of concept. I will be adding some hollow base punches to the mix, but figured that starting with a flat base would educate me about how little I know about swaging pellets.

    So, the first pellets look more like handgun bullets than rifle bullets. That is OK, as these have a much higher BC than diablo style pellets.

    I have to guard against wanting "perfection or nothing"; as I will end up with nothing...
    Last edited by subscriber; 04-21-2017 at 05:40 PM.

  4. #4
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Suggestion: make life a bit easier. Don't mess with hollow points or hollow bases until you have the basics worked out. Staging a shallow thin edged base to give a skirt to seal on is important. Take a look atmy recent posts on pellet testing on the gateway to air guns German gate site and the brief summary here. Can't get the whole data set here as too big.

    I wasnt suggesting that you buy and pull a bunch of 22lr for testing but was suggesting a serious look at their profiles and design. 150 years of experimentation probably has optimized the design.

    Also, I went to the South African guys site and listened to his presentation. A follow up video gave bad news. YouTube has made decision to not allow advertising on gun related videos so his income will quickly dry up. Lots of gun related stuff will likely disappear. Reaction to the dimwit who randomly shot a retiree on live Facebook last week.
    Dave Thomas

    Shoot safe. shoot straight, have fun
    Teach a kid to shoot

    RWS54, 4.5mm, RWS 4-12x50CI
    FWB300SU, 4.5mm, Clearidge Ultra RM 3-9x32

  5. #5
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Thanks for the clarification, Dave.

    A thin skirt seal is important for low pressure/low power airguns. The .22 "pellets" I am trying to make are for 30 to 50 ft.lb applications. These guns can handle/require the additional initial resistance on "take-off", that such long bearing surface solid base projectiles infer. Their operating pressure is also well above the swaging pressure of pure lead...

    As I stated near the bottom of post # 3, the first pellets will have flat bases, just to keep things simple.

    The demonetization of youtube videos started before the facebook incident you referred to.

  6. #6
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    I wasn't aware of the demonetization issue until the hue and cry over the shooter here in the Cleveland area (he and his lady friend lived within 15 miles of where I do.) Apparently he was a gambling addict, owed every payday loan place and probably not just a few loan-sharks (we still have Mafia here!) She broke off their relationship as a result of his problem.


    ANYWAY.

    I am not a pcp shooter, and certainly don't have anything that generates 30-50 fpe so am not up on the needs that you are addressing.

    Does look like fun though!!

    Cheers
    Dave Thomas

    Shoot safe. shoot straight, have fun
    Teach a kid to shoot

    RWS54, 4.5mm, RWS 4-12x50CI
    FWB300SU, 4.5mm, Clearidge Ultra RM 3-9x32

  7. #7
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Quote Originally Posted by dtdtdtdt View Post
    I wasn't aware of the demonetization issue until the hue and cry over the shooter here in the Cleveland area
    Just because we learn about two things on the same day, does not mean those two things are connected:

    Look at the publish dates for these two videos. They precede the FB shooter by more than a week.

    https://www.youtube.com/watch?v=gWlBFxxr7aI
    https://www.youtube.com/watch?v=moI-figYGuo


    Thanks for looking at my pellet thread and trying to help.

  8. #8
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    After a lot of research, with not a lot of available info, I ordered the Cometa Lynx V10 from Straight Shooters:

    http://www.straightshooters.com/come...-.22-wood.html




    What sealed the deal on this somewhat obscure choice was the responsiveness of Cometa Spain to my questions about its specs. So, unless something was lost in translation, its rifling twist is 1:15.75" (1:400 mm); and the hammer forged barrel is un-choked. While I would have liked a bit more power for heavy projectile testing, the fact that this pressure regulated air rifle produces consistent velocity and accuracy is a huge plus for me.

    When I asked for the same info from other brands, I got some of it, while most of it was"proprietary". All anyone would need to do to copy parts or systems that perform really well is to buy a sample and reverse engineer it. Reluctance to share info suggests a lack of patent protection...

    I was tempted to buy an Air Arms with a full length Lothar-Walther barrel; then cut the choked portion off... The snag is that the barrel's twist rate is only 1:17.7" Reference: http://www.lothar-walther.com/457.php . This is fine for diablo pellets, but probably not for long tail-heavy pellets at 900 FPS or less.

    Next, I hope to ask Cometa how to get a bit more power out of the Lynx...
    Attached Images Attached Images

  9. #9
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Looks like a good choice for starters. When I was thinking about pop I was looking at the Cometa Lynx. Decided that I had too many toys already so didn't jump into that.

    As to information about pcp air guns. There is a guy, Gary (?) Quackenbush, in Missouri that makes high power and high caliber air rifles that have been used to kill both American Bison and some African game. While his are big bore, you might try to contact him for his views on high energy small bores too. He may have made some 22's along the way and have knowledge he would be willing to share.

    Also, several years ago, I saw advertised, or described, a Korean air rifle that was designed to shoot regular .308 bullets used for deer hunting because civilians in South Korea are not allowed powder firearms. They might have something on a website that might be helpful.

    I'll be following your exploits with interest. Good LUCK
    Dave Thomas

    Shoot safe. shoot straight, have fun
    Teach a kid to shoot

    RWS54, 4.5mm, RWS 4-12x50CI
    FWB300SU, 4.5mm, Clearidge Ultra RM 3-9x32

  10. #10
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    Default Re: High BC pellet development project: Please recommend .22 PCP rifle for testing

    Thanks Dave.

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