THE LATEST AIR ARMS TDR principle but how does it work? In a ‘normal’ PCP, the main cylinder is charged to around 190bar – the filler at one end, the firing valve at the other, with no air going anywhere. On firing, a weight, commonly called ‘the hammer’, moves forward and hits the back of the firing valve; the valve opens for a brief period of time, letting out a small blast of air, which is channelled to the back of the pellet, which moves it up the barrel. The valve is kept shut by the back pressure in the cylinder, so as the cylinder pressure decreases, the hammer has to overcome less pressure, which in essence, means that the valve stays open a little longer, delivering more air and thus more power. This principle accounts for the power curve, where the power is lower to start, rising to a maximum, before dropping off as the cylinder empties. REDUCED PRESSURE The addition of a regulator between the cylinder and firing valve produces a secondary chamber of lower pressure air, typically around 100bar, which means the firing valve is dealing with the same pressure of air, until the main cylinder pressure drops below the regulator pressure. This means that there is never a compromise in function, leading to no power curve, and more consistent power delivery. The regulator fitted to the TDR is the AA series 7, which was developed, and is built in-house. The gun itself has been designed for regulator use, so it will be more efficient than a rifle with an added after-market unit. Next month, I intend to explore more fringe benefits of the regulator, and get on with some shooting in the field to see how this rifle performs under the conditions it was made for – until then, stay safe and well. CONTACTS Air Arms. Unit 5/6, Hailsham Ind. Park, Diplocks way. Hailsham. East Sussex. BN27 3JF. Tel. 01323 845853. www.air-arms.co.uk. S510R TDR tactical black £1,129. Available in walnut £1,099. I 67 www.airgunshooting.co.uk AIRGUN WORLD
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