Neil Price works his magic on a German classic
Final part of Neil’s improvements to a friend’s Weihrauch HW97, in .177
16 Smear a very light coating of the supplied moly grease onto the outside edges of the power seal and onto the rear of the piston. Make sure that none of the grease goes on the front of the seal. When lubricating a spring-powered gun, less is more, so do not overdo it with the grease.
17 Place the spring with the top hat and spring guide inside the piston.
18 Carefully insert the piston and spring assembly into the compression cylinder, easing the seal over the edge of the cocking slot with the blade of a small screwdriver to stop it from snagging. Make sure that the cocking slot in the piston is in line with the cocking slot in the compression cylinder.
19 Lightly lubricate the front and rear of the compression cylinder and slide it, and the piston and spring assembly, into the rifle action. It can be seen that there is even less pre-load on the V-Mach spring that there was on the standard one.
20 The threads on the trigger block can easily be started by hand without the need of a spring compressor.
21 With the same bar and mallet used for taking the trigger block out, gently tap the trigger block around until the slots in the trigger block and action are exactly in line.
22 Smear some moly grease along the cocking slot in the action, on the hook of the cocking arm and on the ‘ears’ of the cocking arm.
23 Locate the hook of the cocking arm in the slot in the compression cylinder. Slide the ears of the cocking arm into the barrel block. Line up the fulcrum pin holes and knock in the pin. Press down on the top trigger sear.
24 The top sear will then lock into place, cocking the trigger unit.
25 Slide the safety button into the left-hand side of the action and hold it in fully whilst sliding the trigger unit into the slot in the trigger block.
26 Line up the holes in the trigger block with the corresponding holes in the trigger unit. Fit the two cross pins, the longer one at the front of the unit and the shorter one towards the read. Now press the trigger to de- cock the trigger.
27 There is an M4 nut that should be held captive in the trigger case pressing, but sometimes this is loose. This nut is what the rear trigger guard screw tightens into. It was loose on this rifle, so it has to be pressed back into position within the trigger housing.
28 Pull the anti-bear trap slide toward the rear of the action until the holes line up with the pillar nut screw hole. Place the pillar nut spacer in the hole in the smaller bear trap slide. Replace the pillar nut and tighten with the 13mm A.F. open- ended spanner.
I initially fitted the mainspring with one washer in front of the spring to act as a bearing, and no spacer behind it. I know from previous experience that this assembly configuration usually gives between 10 and 11 ft.lbs.. I did this to give me a base line for setting the power level, fully expecting to have to strip the mainspring out again in order to pack it, to give me the power setting for which I was aiming. I refitted the stock and then did a 10- shot string over the chronograph. I was pleasantly surprised that this gave me the power level of exactly what I was aiming for, so there was no need to strip it again.
That’s a lot better, a total of 7 fps variation over the ten shots with unweighed pellets, and a muzzle energy reading of exactly where it should be after having this work carried out. It is well below the UK legal limit of 12 ft.lbs., having enough leeway for the power to increase by up to 0.5 ft.lbs., as the new components bed in, and the rifle still being legal.
It has a considerably quieter and smoother shooting action. It now fires with just a dull thud and with hardly any recoil, which comes straight back into the shoulder with no discernible muzzle f lip.