bullet travels down the rifling to flick the slower bullet higher so that it strikes the target in the same place as the faster. That is a rather simplistic explanation and I’m sure there are others that can explain barrel harmonics in greater detail but for us, that is all we need to know and we will use hard results to verify.
Its 9.00am Tuesday 24th May and I have arrived at Eley’s main gate - less than a half an hour drive from my home. I have with me Celia Topp, retired teacher and regular shooting companion. This is her first visit to Eley and she has come along (she thinks) just to take a look at the test facility. The security guard recognises me from the not too distant past and greets us warmly. We sign-in and proceed, as instructed, to Reception to await Martin who has gone to Birmingham airport to collect an Indian shooter - who I later learn has already qualified for the 2012 Olympics and has flown 10 hours to do a batch-test.
Martin arrives after a short wait and we make our way to the test facility. The last time I was here was December last year to do a batch-test. Now, I was absolutely stunned at the changes made - a new office had been installed, level access, a wide entrance door, complete with a kitchen, dining area and, most importantly for me, a fully wheelchair accessible toilet. An enclosed ramp now leads down to the test room.
Whilst Martin set up the Indian shooter, I removed my barrel/action from the stock and fitted the tuner ready for Martin to fit it to Eley’s dummy aluminium Anschutz stock. My action is checked by Martin and headspace recorded, then it’s torqued down to my
68 Target Shooter
preferred pressure. This assembly is then located in a vice and it is torqued to 50nm.
By bore-sighting, Martin soon has us set up and it is now that I spring my little surprise on Celia by calling on her to be my assistant. You see, I can’t reach the tuner to make the necessary adjustments - she happily accepts and we begin the quite laborious process of shooting ten rounds, recording the group size then moving the weights forward 5 turns.
Two cups of coffee, two trips to the loo, four hours and 300 rounds later, we had the data that we had come for and we can sit down to a little lunch provided by Eley - thank you. To the untrained eye, the list of numbers would mean little but to me, I knew then I had more than I ever expected.
After dropping Celia off and arriving home, walking my dog on took precedence to entering the data into Dr Clarke’s program. Needless to say, the dog had to run his normal one mile walk! It took some minutes to type in all the data, double checking that I had not made an error before finally switching to the graph. The smoothed graph told the story and the trend line backs it up - it depicts exactly what I had visualised in the raw numbers.
What are we seeing? The blue line is our smoothed graph, the black line the trend. Starting left with the weights near the barrel the group sizes are large because the tuner is having no effect but as the weights are moved forward, the tuning action tightens the groups but then they rise again from mark 8.
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