Optimal velocity for sub-20 FPE AA s510 .177 with AA 10.3s?

Discussion in 'Air Arms' started by Blind Squirrel, Oct 9, 2018.

  1. Blind Squirrel

    Blind Squirrel New Member

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    Good evening from The Colonies...

    Paul from the Republic of Texas here wondering if I might reap the benefits of others' hours of experimentation...

    I have an AA s510 FAC Ultimate Sporter .177 and love it as an all-rounder. I have been attending benchrest as well as Field Target (Hunter PCP, US AAFTA rules require less than 20 foot pounds of energy). I tried a few different pellets and think it shoots pretty well with AA Field Heavy 10.3 grain pellets. (FYI, I use the magazine even in HFT matches because I find I gain a great deal of confidence when I can simply cock and shoot a second time after finally finding a comfortable shooting position. I know, single shot is far superior...but not if I lose confidence so that can be a separate thread once I get everything else sussed...)

    My observation is that, in a recent chronograph session with a friend, when I turned the power dial to near 875 fps the groups tightened up a bit. With my setup at closer to 920 fps the groups seemed to open up a bit.

    Is anyone able to lend his or her experience to suggest an optimal velocity for accuracy for this combination of pellet and rifle? (If you have found another pellet that you simply must recommend then I suppose I would be up for a little more testing to vet your suggestion. At this point upgrading the rifle is not an option.)

    Thank you for your thoughts and for the fantastic reading (amusing as well as informative) this forum offers.

    Cheers! -Paul
     
  2. Conor

    Conor Never been banned from sales Staff Member

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    Paul, as strange as it may seem to you but the 20ft/lb .177 set up is rather alien to the U.K. and even here in Ireland it’s mainly .22 at 30ft/lb and above.

    My advice is run the fun at its sweetest, I.e. grouping and consistency and stick with the pellets that really suit the barrel (sane batch).
    Then learn it through extensive shooting.
    The 10.3grn is probably your best option. A heavier pellet may give the trajectory too much loop. I don’t know how a lighter pellet like 8.4grn holds up accuracy wise at the velocity you run at, it would probably be bordering on supersonic?
     
  3. Tone

    Tone Active Member

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    Hi Paul

    I guess you have a shrouded barrel as moderators are not easily allowed in the US of A?

    I have found that manufacturers use compact barrels when using a shroud, and i have found that compact barrels shoot very well with the Bisley Magnums at 10.65 gr in .177

    This would be my go to choice without a doubt: Bisley Magnum Pellets

    By the way Bisley is a place and the home of British Shooting.

    Cheers

    Tony
     
  4. Slip Stream

    Slip Stream Experienced novice

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    Hi Paul,

    From personal experience I've found that a air rifle pellet losses stability the closer you get to the sound barrier , and the pellet weight doesn't seem to make any difference.

    This was confirmed by Phil Price ( editor of Air Guunner magazine ) Who found his 0.177 28ft/lb was more accurate running at 820 ft/sec then 900 and above.

    I have my 20 ft/lb 0.22 Set at 780 ft/sec , using JSB exact heavy 15.8 grain.
    And get a good group out to 75 yds , though I limmit my shoot range to 50 yds max.
    Hope this helps.
     
  5. Pepone

    Pepone WFTF World Champion 2010

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    I use to shoot with my steyr and hw100 in .177 the jsb hvy at 260ms with superb accuracy. Both with hw barrels in 24".
    With the hn barracuda match you could obtain similar groups only with no wind, the bc is a bit lower, and they drop a bit more and are not very good in windy days.
    Maybe with a bit more power, the jsb .177 monster or jsb .177 monster redesigned could be an option.
     
  6. Blind Squirrel

    Blind Squirrel New Member

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    Thank you for the quick responses, gents. As you have surmised the barrel is the fully shrouded 19.5" model. And I do appreciate that a 20 FPE setup is far outside the standards you have set in the UK. (Americans always have to go too far, right?!)

    What I wish we had nearby is a dedicated indoor air range instead of standing lanes restricted to 25 yards...

    I have tried JSB Monsters with decent results but not quite as good as the AA 10.3s (but I may test again with more stringent controls).

    Sounds again like slower can be better and I need to continue to experiment with that sweet spot.

    I have never heard anyone in my nearby clubs using Bisley Magnums but sounds like they are worth a tin or two to try out, thank you!

    Again, thank you for your recommendations and I look forward to hearing even more. -Paul in Texas
     
  7. Conor

    Conor Never been banned from sales Staff Member

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    Bisley Magnums are made in Germany by H&N, they are basically the Baracuda Match pellet but not produced and selected to the same tolerances.
    I believe in your neck of the woods they are the Beeman Kodiac
     
  8. scrane

    scrane Member

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    I read some time ago that 870 fps is the optimal speed for airgun accuracy. I've since used that as my target velocity on a number of airguns without a problem.

    At the moment, in the states, there are numerous sources to buy silencers, both name brand and homegrown models. The federal government has not contested so we are in a kind of "don't ask / don't tell" mode. The law is somewhat ambiguous, outlawing silencers for firearms. The question is how does an airgun silencer differ from a firearm silencer. Silencers for firearms are legal in states that permit them after a federal / local approval process and the payment of a $300. tax.
    There recently was a movement to remove the restrictions on silencers that was cut short by one of our periodic massacres.
     
    Last edited: Oct 23, 2018
  9. Conor

    Conor Never been banned from sales Staff Member

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    Careful what you read and where you read it.
    All different calibe, rifles and most importantly batches of pellets have their preferred velocity.
    870fps is just too specific IMO. It’s possibly a benchmark future for the 20ft/lb brigade as faster velocities can and do introduce stability issues with the smaller caliber .177 however there is no holy grail figure for velocity.
     
  10. Spray1Mark

    Spray1Mark Member

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    What I find bizarre with the AA FAC guns is the short barrels, I had the S310 EXTRA FAC years ago, everything seems to work at between 860-880FPS.
     
  11. Dale

    Dale Active Member

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    Mainly sturdiness of construction, a sound moderator for airguns does not need to cope with the pressure, volumes and temperature of the propellant gasses generated by firearms, so the construction is much lighter in most cases, particularly when looked at in contrast to moderators for centre-fire guns.
     
  12. Conor

    Conor Never been banned from sales Staff Member

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    With a shorter barrel you have to work the gun harder to achieve the higher velocities. It’s a balance between hammer spring tension and either reg pressure or the bottle pressure if there’s no reg.
    shorter barrels are louder and have more muzzle flip and may not achieve the required velocity. Longer barrels will achieve a higher velocity with less torque adjustment in the hammer spring.
    I’ll stick to 760-770fps with my 8.4grn JSB Exact
     
  13. Spray1Mark

    Spray1Mark Member

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    "Silencers for firearms are legal in states that permit them after a federal / local approval process and the payment of a $300. tax."

    $300? when did the NFA CLASS 111 tax stamp go up from $200?
     
  14. biwain

    biwain Tree bark and paint chipper Champion

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    Airguns in the US are not classed as firearms. But you're not allowed a removable "silencer" if it can be removed and fitted to a firearm.
    That's why the silencers or moderators are integral ,either moulded to the barrel or in the form of a shrouded barrel.
     
  15. Scott Hull

    Scott Hull Member

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    Here are some match results that shows velocity for a number of 20fpe competitors:

    http://www.slsba.org/airgun/results/results08-17-2018.htm

    If shooting 10.3gr, the consensus seems to be about 870-890fps for best accuracy. But if you are limited to 16x on the scope, 900-920fps might make up for the lack of ranging precision while still being accurate enough. It's a trade-off.
     
  16. Blind Squirrel

    Blind Squirrel New Member

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    Thank you again, gents, for the recommendations. I have reduced spring tension to achieve ~875 and am hoping for an improved performance in our local AAFTA-rules HFT match Saturday (if it ever stops raining!) Regarding "Lead Dust Collectors" they are completely unfit for firearms and I have no sympathy for the consequences if someone were to try to affix one. That said, my understanding is that they are currently not regulated like firearm Silencers nor do they need to be integral. The integral shroud on my s410 Ultimate Sporter FAC is already extremely effective but my Clague LDC fits perfects to the female threading on the muzzle and reduces even that little remaining mouse flatulence to a nearly inaudible level. Backyard-friendly is an understatement at 17.51 FPE.

    Anywho... thank you again and I will update this thread based on my indoor practice session Friday and, ideally, stellar results Saturday morning once again in the great Texas outdoors. Cheers! -Paul
     
  17. scrane

    scrane Member

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    Oops, sorry, you are correct. Although I imagine $200. no longer covers the paperwork and background check.
     
  18. Spray1Mark

    Spray1Mark Member

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    Yes as I understand it was implemented when $200 was an awful lot of money!

    But hey what do I know I live in little old England LOL, you may catch a glimpse of me on TV one day when you see Wayne La Pierre debating in England, if only we had him here gun ownership would be a lot easier, silencer ownership for your firearms here is however legally very easy!
     

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