A TWIST. OF.. FATE

A TWIST. OF.. FATEEver sincé news of Ben Tay,lorls revolutionary SmosthTwist bariéls first cámethrough, Jim Tyler haS wahted tó gét his hánds on one... and now hé haS|:*-5an with a telephone message submitted to me for testing, because| ;=" 'g me to call Ben Taylor, the field has a north/south orientation,:,:::-se he wanted to submit his so that I'm normally testing into aSr*:,:rrTwist barrel for a thorough headwind or with a tailwind and, toresl zrd he specifically wanted mef u :: t. 'Flattered'doesn't make matters worse, I'm shootingbegin to diagonaliy acrols the field, so theI =o,-- De my feeling at being singled wind is at an angle to the trajectoryi' i-:'lr this privilego; ar'td by one of of the pellet. The field is also halfway':-= -JSt knowledgeable and up a steep hill, very éxposed, andes:-rned true airgun gurus, at that. perfectly still conditions occur with&'""'3.lg€rTrertts were made for me to the frequency of blue moons. That,:: ::t the rifle from the Milbro stand as you can imagine, plays havoc witht:-2 2O1O CLA Game Fair. accuracy, and really shows up pelletsls we chatted, it became apparent that don'take the wind too well.ungm&.{ **$ruq#Wffiffiffitu€*,€7ám ffi€Xffiffiffiffi WZé= ffi#&ffiffi:WTE'ZL*="==, o .-"rVEIGHE THE MORE NESISTANT TO I,{TIND THE PELLET 1,VIL.|",. ffiffi'::-z: Ben was far more interested:-= 'esults of my testing the barrel:*¿r in getting a review into print,;-1 I suggested that both me and my+:nd Professor Mike Wright, who'=¡ders will be meeting for the first: re in the following pages, carried:-t our own tests independent of each::-er. When I explained Mike's::sting qualifications to to Ben, heN,?s fTlofe than happy to proceed.!l,ty test range can be: nightmare for theranufacturers of rifles¿'id pellets that areHappily, my time with the MilbroElan to which the SmoothTwist barrelwas fitted, followed a period in whichI'd been helping Mike Wright to testa theory regarding a pellet'ssusceptibility to being steered offcourse by wind. What we proved wasthat there is a correlation between apellet's ballisticoefficient (BC- ameasure of the rate at which it slowsin flight) and its weight on the onehand, and its susceptibility to windon the other. In a nutshell, the higherthe BC and the lower the weight, themore resistant to wind the pellet willbe. In Mike's review of the Elan,you'll see reference to the 'WSF' -that's the Wind Susceptibility Factor,which is the square root of the pelletweight divided by the BC. The higherthe WSf, the more susceptible towind the pellet will be.In order to test Mike's theory, wehad to measure the BC of the pellets,and we separately (and quickly) cameto the conclusion that the BC of apellet depends on the barrel it's shotthrough, and'some barrels givesignificantly higher BCwith a particularpellet than others. I think I know whythat is and, although the jury is stillout on whether my theory is correct(a lot more testing remains to bedone), but the theory suggested thatthe SmoothTwist barrel shouldproduce higher BC values, and hencepelletshot through it should bemore resistant to wind than pelletsfrom conventional rifled barrels. Theproof would be in the testing.The testsMy tests really are at the mercy ofthe weather, and my first test sessionwith the ffi73

Elan was in a force 5-6 and a meaning that they weré ai! withingusting, crossing tail wind that,would three-quarters of an inch centre=to=normally be disastrous to accuracy. centre (c-t.c), at 50 yards, into aTo make life easy, I shot a magazine variable crossing headwind. Like the(17 pellets) of each of the three earlieresults, the group sizes are allpellets I tested, which were the roughly similar in size,,where a rifledMosquito, Bisley Long Range Gold barrel would normally print groupsand RWS Superdome. The group that varied much more.sizes were, respectively, 35rnm wide The SmoothTwist barrel is the leastby 34mm, 37mm by 34mm, and pellet-fussy barrel I've ever used, and36mm by 22mm. Those figures more testing with a wide range ofmight not look much until you :factor pellets during the time:l had the EIanin the atrocious conditions, and that Iwas shooting at a range of 50 yards,That's impressive, but what is mostremarkable is that the group sizes,obtained with three very differentpellets, are all fairly similar in size.Try it with conventional rifled barreland see what happens.My nextest session was the sameday, but during the evening, and thewind had not only eased to a force 3-4, but had gone around, so that Iwas shooting into a crossingheadwind, still at 50 yards. I shotgroups of ten pellets to speed thingsup, and the results were: RWSSuperfield, 24.5mm x 18.75mm. AirArms Field, 20,5mm x 11,9mm.H&N FTT, 16.63mm x 19,3mm.Those figures are edge-to-edge,the same POI relative to the aimpoint as they d:h when I'd shot awhole magazine of them. 'With the test rifle, 1980s EleyWasp had the same POI asAccupell, and ,l was able to get verYcreditable groups with magazinescontaining a mixture of them.served only to reinforce that. Then Shooting eight Falcon AccuracYthe thought struck me that,Plus, each separated b¡t alternatelythroughout the testing, whenswapping pellets, I'd not once ',a Wasp and an Accupell, Producedcleaned the barrel, nor had I shot'X' two nice groups (one from theAccuracy Plus, the other containingnumber of pellets through to re-lead the Wasp and Accupell) at 35 Yardsit, which would have been essential into a headwind.with a rifled barrel. ¡'¿,justreloadedwith another pellet and continued Wd$r''accuracy testing. That is nothing I believe that the SmoothTwist'sshort of remarkable.remarkable tolerance of pellets is dueto that fact that it sizes them;i:tily:;ü*.',,'r'examining shot pellets reveals thatWith every quality round head pellet the entire perimeter of the Pellethavingiven good accuracy through head has been:profiled, and thethe SmoothTwist, I decided to carry result is a slightly higher BC valueout a test that I'd never contemplate than I'd expect:from a rifled barrel.with a rifled barrel, which was to More important than the BC figure isshoot magazines containing a mixture that every pellet exits the muzzleof pellets, The pellets all landed with exactly the same size and withexactly the samé profi,le, regardthe pellet's head size. With a riflbarrel, a larger pellet exits the mwith deeper rifling indentation(which decreases BC),, and a smpellet with less pronouncedindentations, and I think that alsexplains why most, if not all, riflbarrelshow a marked preferenpellets of a specific head size.Wtrm¡ml'The question on everybody's lipsgoing to be 'Where can I get aSmoothTwist barrel?', and the shanswer is that you can't, and necan | - yet. You can, however, buair rifle fitted with the SmoothTand that's the FX IndependenI have no doubthat theSmoothTwist barrel is a winner.tjust to make sure, when I'd finiswith it, I passed the Elan on to IWright, who carried out his owntests. Look to the feature on theto see whether a Professor Emeof Electromechanical Engineeagrees with me. ffifu74m