Change sometimes not as good as a holiday

With mid-week accessto ANZAC Rifle Range, Malabar now merely a memory, I drove thetwo-hour haul to the SSAA Benchrest Range at Silverdale recently totest some new .308 Sierra Palma bullets (coming issues of SportingShooter and GunsAustralia) and to check out my .223Varminter, which had yielded what I considered to be an unacceptablegroup at 200 metres a while ago, when re-zeroing it with 69gn SierraMatch Kings.

I suspected that theparallax was playing up in the 16x Super-Sniper riflescope but hadnot extensively shot it that day. Also, I had come across a verycheap bulk lot of 55gn Soft Points and early trials had not promisedmuch out of my little Mannlicher-stocked CZ; so I thought I’d givethem another chance with different propellent in the CZ Varminter aswell.

Well, I started offshooting the Varminter with the 55’s and they were so-so, puttingfive shots into two-inches and a second group at 1.75 inches didn’tlight my fire, so I went on to shoot the 69 Sierras, with which I hadhad great success in 300 metre scoped service rifle matches.

Well, the first group camein disappointingly at 1.28 MoA. In a diagonal spread (see pic of”Group 1″). “Poo-bum!”, I mouthed and I went onto shoot with the Omark .308, letting the Varminter cool. Then I cameback and put five Sierras into .39 MoA (see “Group 2”) andfelt most gratified.

Later in the session Icame back to the Varminter and decided to shoot a cluster using itssingle set trigger feature and garnered a pleasing .55 MoAfive-shotter (see “Set trigger” pic), but it laydifferently on the paper to the others – WHY? – I don’t know forsure, but I think there are a couple of phenomena at work here.

Lesson 1.I believe that the first Sierra group was not up to scratch for onereason and it wasn’t parallax. When you change loads mid-shootwithout cleaning your barrel, your barrel will have to iron out thefouling from one form of copper and propellent before it starts toshoot well with another set of variables. This is a common occurrencein .22 rimfires and I have seen it often enough to believe it is thecase with many centrefires as well. Similarly, a cold clean barreloften needs from one to several shots to settle down to its normalzero.

Lesson 2.The experience with the set trigger group, while pleasing, did notyield as good a group as the standard, heavier trigger group. Thisproves to me that a trigger does not have to be very light to producethe best groups, rather it has to be consistent and predictable.

Lesson 3.The set trigger group was vertically strung while the standardtrigger groups were laterally spread. This proves one of two things:either the release action of the shooter’s finger is different withthe small difference imposed by the increased length of pull, therebyspreading vertically – or – the striker falls differently, setting upa different ignition dynamic in the whole system. I don’t know whichis more likely or whether it is a combination. What I do know is,I’ll leave the set trigger and use the standard one routinely. Onething I did read years ago on fault finding in smallbore shooting wasthat variable strength of ignition caused by a weak striker springcaused strung out elevation from 6 to 12 o’clock.

Lesson 4.When you start getting barrel heat induced mirage drifting up infront of your scope’s objectives, it is most disconcerting whileaiming. I just grab a light piece of cloth and drape it over thebarrel from just under the scope’s front to several inches up thebarrel – it’s a cheap mirage band and it works. Otherwise, you cansponge it down with a wet cloth to reduce the time gap betweengroups.

So, to summarise, Ibelieve I have reinforced my conviction that in shooting, once youhave a combination of factors working, change is your enemy andconsistency is your friend.

A littlefootnote. When I was packing my carbehind the range, hearing the loud, clanging reports of the remainingshooters’ rifles, I happened upon this beautiful blue wren near thecarpark. He moved so quickly, I couldn’t take a really sharp photo ofhim but here he is anyway. Funnily enough, the most prolificpopulations of wildlife I have seen in recent years are either on oradjacent to outdoor rifle ranges; the McIntosh Rifle Range at Majuraoutside Canberra is a case in point – it has the largest populationof kangaroos in the ACT. Then I was reminded of Darryl Kerrigan’simmortal words when taking his family to their holiday house atBonnie Doon, “Ahhh! Serenity…” I hope we never haveshooter-style serenity taken away from us.

Keep ’em in the bullseye.

Marcus O’Dean