jonnys Posted April 27, 2015 Report Share Posted April 27, 2015 Hi folks I'm looking for some thoughts on pellets drop that I'm experiencing please... I have recently bought a new AirArms S510 FAC Xtra it's 28lbs pressure. I zeroed it into 40m and it grouped nicely, but when I moved the target out to 60m the drop off on the pellet was unreal. By the time it got to 60m it was dropping by about 12 inches. I'm using .22 Bisley Magnums which I think are about 21 grain. I mainly use a 17hmr for my shooting and just wonder if I've got so use to shooting a flat trajectory gun, that I need to get use to a FAC air rifle OR if somethings not right??? Many thanks in advance, Jon Quote Link to comment Share on other sites More sharing options...
robbiep Posted April 27, 2015 Report Share Posted April 27, 2015 A 21 grain pellet with 28 ft/lb works out at a muzzle velocity of (roughly) 775 fps. So even if the pellet isn't losing much velocity it's still going to take an extra 1/10th of a second to travel that extra 20 metres. Which will be a considerable drop. I'd suggest trying a lighter pellet - 15 grain or so. You'll have a much higher mv, meaning that drop will be far less. Quote Link to comment Share on other sites More sharing options...
chrisjpainter Posted April 27, 2015 Report Share Posted April 27, 2015 (edited) I've just put it through Hawke's Chairgun pro (worth downloading; it's free) and whilst it's not foolproof, it reckons your drop off should be about 4.25" @ 66yds from zero of 44yds (I had to convert from metres). It's not 100% accurate, but it would say that a drop off of 12" is a problem! Are you able to check the power of the gun? Interestingly, you get a drop of 12" give or take if it's running at 11.5ft/lb. Probably a coincidence, but it sounds like you should get the power looked at! http://www.hawkeoptics.co.uk/chairgun.html Edited April 27, 2015 by chrisjpainter Quote Link to comment Share on other sites More sharing options...
Biffo Posted April 27, 2015 Report Share Posted April 27, 2015 Try a lighter pellet, as suggested above. Try AA's own Diablo Fields - the trajectory will be much flatter as they are 15.9gn and as long as they group well it will be a nice set up. I don't us 21gns in any of my FAC airguns. Quote Link to comment Share on other sites More sharing options...
Longbower Posted April 27, 2015 Report Share Posted April 27, 2015 You may as well throw boulders, As suggested, use a lighter pellet. JSB Exacts ,RWS Superfield, AA Diablo. I have been trying Bismag in my .177, and at the found similar, sudden drop at the end of their trajectory. Quote Link to comment Share on other sites More sharing options...
jonnys Posted April 29, 2015 Author Report Share Posted April 29, 2015 Thanks folks, I will try using a lighter pellets, I thoughts those magnums were heavy but everyone seemed to recommend them for FAC air rifles so just went with them. Chris - thanks for taking the time to look that up for me All the best, Jonny Quote Link to comment Share on other sites More sharing options...
peek-at Posted April 29, 2015 Report Share Posted April 29, 2015 (edited) Does it have adjustable power? Check the adjuster knob as 12 " drop is not right......(I also use Bisley mags with a 40yard zero ) Get your rifle chrono'd to check its power Edited April 29, 2015 by peek-at Quote Link to comment Share on other sites More sharing options...
chrisjpainter Posted April 29, 2015 Report Share Posted April 29, 2015 Just pm'd you Jonny. Peek-at's got a point! If yours has a power adjustment, I think one of the settings is about 12ft/lb. that might account for the graph I sent you... Quote Link to comment Share on other sites More sharing options...
peek-at Posted May 4, 2015 Report Share Posted May 4, 2015 Did you get to the bottom of this issue? Quote Link to comment Share on other sites More sharing options...
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