mooster 1 Posted July 31, 2010 Report Share Posted July 31, 2010 Hi folks. I'm a long time ferreting man and 12 bore owner who acquired a weihraught HW80K .22 a couple of years ago. A mate of mine who is a real techy on air rifles took it to his club and measured it's velocity on a chronoscope and reported back that he suspected the wrong spring had been fitted or it had been illegally altered as the velocity is too high. He has let me borrow his chronoscope to sort the matter out and has explained how I can either remedy this by grinding a bit off the spring or by heating it up and decreasing the spring length slightly. I intended doing this tomorrow and have just read the instructions for the chrono but I have omitted to ask him what reading I am looking for to make this thing legal. I am unable to contact him for a few weeks so wondered if anyone could give me quick bit of advice on what the reading should be. If not I will trawl through the Weihraught websites to see if I can make sense of the inevitable "technical info" page! Just a figure would be fine as I have read the moderators intro and can see that this is a touchy subject-I just want to get it sorted as I am trying to be a good citizen!!(and have a more accurate bunny shooter) Many thanks in anticipation. Mooster. Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 Hi there Do you know what pellets he tested it with? Phantom Quote Link to post
pest hunter 151 15 Posted July 31, 2010 Report Share Posted July 31, 2010 We cant tell you fps with out knowing pellet Quote Link to post
mooster 1 Posted July 31, 2010 Author Report Share Posted July 31, 2010 I'm using superdome 0.94g. 5.5mm. Cheers. Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 I'm using superdome 0.94g. 5.5mm. Cheers. Using the data from Weirach (max fps is 722fps) and 0.94 (14.51grains) pellet weight has your gun running at 16.6 ft/lbs and is indeed over You would need to have the gun running at about 11 to 11.5 ft/lbs to be safe so using those pellets you want a max velocity of 597.3 FPS better to run with 11 ft/lbs(more than enough) at 584 FPS velocity Hope that helps Phantom Quote Link to post
matt_hooks 188 Posted July 31, 2010 Report Share Posted July 31, 2010 RWS Superdome? To calculate the energy of your pellet, the calculation is (velocity x velocity x pellet mass)/450240, where velocity is in feet per second and mass is in grains. The RWS superdome are 14.5 grain, so your max velocity will be just slightly over 610 fps. To be on the safe side you shouldn't be shooting over 600fps with them, and remember the law says that it should not be capable of firing any projectile at over the legal limit, so a bit of space to spare is necessary. Best to get a competent gunsmith to do it for you, as altering the internals on a gun can be dangerous, and you risk damaging the gun! Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 610 gives 11.98 ft/lbs 600 gives 11.59 ft/lbs Matt, did you do the math yourself? And did you take into account the BC of the pellet I went the easy route and used CGP Phantom Quote Link to post
mooster 1 Posted July 31, 2010 Author Report Share Posted July 31, 2010 Many thanks gents. You seem to know what you are talking about so I can impress my mate when I tell him how I've sorted it! Thanks again for the figures. Mooster. Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 The Pleasure is ours, apparently were the boyscouts of the entire forum Phantom Quote Link to post
mooster 1 Posted July 31, 2010 Author Report Share Posted July 31, 2010 Well if any of you chaps ever get a ferret problem I can help with...just ask. I will try to remember to let you know how I get along with the improvements. Summer bunnies here we come! Mooster Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 Well if any of you chaps ever get a ferret problem I can help with...just ask. I will try to remember to let you know how I get along with the improvements. Summer bunnies here we come! Mooster Funny you should say that I've got a severe Ferret problem I can't get any and after last weekend I really fell in love with them Plenty of kits about I'm told, but not around here I'm after a couple of Polecat type kits. Shame your not a lot closer to me Don't suppose you know anyone up this end of the country do you? Phantom Quote Link to post
matt_hooks 188 Posted July 31, 2010 Report Share Posted July 31, 2010 Phantom, I used my Excel spreadsheet that I have set up for doing those calculations. And the BC makes no difference to the ME, it's purely a function of mass and velocity! Mooster, pleasure mate. I'd note that down as this thread will probably get pulled when the mod sees it. Quote Link to post
Phantom 631 Posted July 31, 2010 Report Share Posted July 31, 2010 Phantom, I used my Excel spreadsheet that I have set up for doing those calculations. And the BC makes no difference to the ME, it's purely a function of mass and velocity! Mooster, pleasure mate. I'd note that down as this thread will probably get pulled when the mod sees it. I know I'm just in a funny mood and fancied pulling your leg buddy Phantom Quote Link to post
matt_hooks 188 Posted July 31, 2010 Report Share Posted July 31, 2010 (edited) Weeelllllll, if you want to talk about the BC, we could get into sectional densities and ogive angles. I'm more used to things running 1200 ft.lb's! Edited July 31, 2010 by matt_hooks Quote Link to post
mooster 1 Posted July 31, 2010 Author Report Share Posted July 31, 2010 You boy scouts are getting far too technical now....stop! I've written all the info down,so thanks for the tips. Sorry Phantom but I'm the other end of the country(down at the pointy end in Devon). Get yourself a couple of ferrets from someone local maybe on this forum and you will never look back.They really are infectious and great sport. Cheers.Mooster. Quote Link to post
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