Neil Price works his magic on a Ger­man clas­sic

Air Gunner - - Contents -

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.








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