Gary73 62 Posted August 24, 2016 Report Share Posted August 24, 2016 After initially trying Fap's in .22 through my hw100kt I kept getting the odd flyer so moved on to JSB jumbo exacts in 5.52. Roll on 12'ish months later and boredom got the better of me so tried them again. This time they were spot on so cleaned the barrel and they are still on the money, so adjusted power up 10fps so they are doing low 618fps and 625fps max avg being 622fps. I then put my chrono 18.5 yards away and did a 10 shot string 7fps spread again with the average being 584fps. So at distance 0 yards being 622fps avg and 584fps avg at 18.5 yards the bc calculator is showing a BC of 0.366 which seems wrong. Anyone see any issues with my logic. https://www.airgunsofarizona.com/Calcs/BCcalc.html Accuracy is very good which I cant explain after 12 months and 4000-5000 Jsb jumbo exacts. Just the BC not adding up. Anyone have any suggestions both chronos are good and checked. Quote Link to post
jonnie bravo 572 Posted August 24, 2016 Report Share Posted August 24, 2016 The result it gives me is 0.037, think you might have overlooked a zero perhaps? I think I remember seeing a bc of about 0.023 for faps, so even 0.037 does seem high, I think jsb exacts are around 0.032. If I were you I would try it again at min and max hunting ranges, I.e. 5-45yds or something similar, I think that would see the bc drop a bit more Quote Link to post
Gary73 62 Posted August 24, 2016 Author Report Share Posted August 24, 2016 After initially trying Fap's in .22 through my hw100kt I kept getting the odd flyer so moved on to JSB jumbo exacts in 5.52. Roll on 12'ish months later and boredom got the better of me so tried them again. This time they were spot on so cleaned the barrel and they are still on the money, so adjusted power up 10fps so they are doing low 618fps and 625fps max avg being 622fps. I then put my chrono 18.5 yards away and did a 10 shot string 7fps spread again with the average being 584fps. So at distance 0 yards being 622fps avg and 584fps avg at 18.5 yards the bc calculator is showing a BC of 0.0366 which seems wrong. Anyone see any issues with my logic. https://www.airgunsofarizona.com/Calcs/BCcalc.html Accuracy is very good which I cant explain after 12 months and 4000-5000 Jsb jumbo exacts. Just the BC not adding up. Anyone have any suggestions both chronos are good and checked. Quote Link to post
Gary73 62 Posted August 24, 2016 Author Report Share Posted August 24, 2016 The result it gives me is 0.037, think you might have overlooked a zero perhaps? I think I remember seeing a bc of about 0.023 for faps, so even 0.037 does seem high, I think jsb exacts are around 0.032. If I were you I would try it again at min and max hunting ranges, I.e. 5-45yds or something similar, I think that would see the bc drop a bit more Sorry my mistake 0.036bc. I will try it at 40 yards and see what happens. Quote Link to post
villaman 9,983 Posted August 24, 2016 Report Share Posted August 24, 2016 Most BC i have seen has given .030 - .031. I did a BC on them through drop in pellet from 30 yard zero to 60 yards and that gave me .0365 bc Quote Link to post
Gary73 62 Posted September 5, 2016 Author Report Share Posted September 5, 2016 Hit the range today. Had to turn the power down on the .22 Hw100kt, now doing 576ps max with 15.9gr Jumbo exacts these are the most powerful in my gun. So about 11.72ft/lbs now. This leaves the Exact Rs /faps doing about 617fps max and 610fps min. 11 to 11.3ft/lbs. The faps shoot really flat compared to the jumbos and h&n ftt pellets. I cannot run them any faster without going over the top with the most efficient pellets 15.9gr jumbos. I recalculated the faps bc which came back as 0.026, this was backed up when using chairgun and the clicks required out to 55 yards that it calculated. They all tallied up. Groups were very good and the pellets handled the wind without any issues. After 30 yards they out shot jumbos and ftt with the ftt being the worst. BSA R10 super carbine .177 Most efficient pellet is exact heavy 10.34gr running at 11.7ftlbs Pellets tested Exact 4.52/4.53 Express 7.9gr Bisley magnums 4.52 Exact heavies Easy winner was the exact heavies 4.52 10.34gr Tightest groupings at all ranges and handled the wind the best. bc worked out at 0.027 with the exact heavy pellets. Today the R10 out shot the Hw100kt but a nice calm day is needed to have another try. Quote Link to post
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