I wanted to share what I believe to be the best way to tune the HW45 pistol after approx 30 years of owning and tuning.
First, you can just leave it stock and shoot it. If you resist adding any additional lubrication, it will eventually expel, or burn off the excess lube put into it by the manufacturer. It will take a few tins of pellets to do this and will finally settle down. The components are built to last a lifetime and can be run relatively dry with no excess wear noticeable.
However, if you have the relevant skills to tune one, this is the method to use.
HW placed the rolled steel guide rod down inside the piston (opposite to any other gun) to increase the weight to the piston. This is to overcome the excessive cushion of air coming from the restrictive TP which bends through 90 degrees. It is also this restriction which generates heat which effects any lubes placed into the gun. However, having the guide down inside the piston means that there is no guiding at the loose spring end to control it where it is needed at the muzzle end. Tuning companies then supplying Delrin kits which have a shortened guides which can then be fitted at both ends to help smooth the gun and control the spring at both ends.....This is a mistake!
In this particular gun, if we make the guide/Top hat out of Delrin, we lose the valuable inertia to drive through that restrictive TP and lose a good 1ftlb or more (the whole point of owning a HW45 being its power) Such a move turns the gun into a benign 4.5 ftlb Tempest.
What we need to do is, machine the Top hat/guide and another to fit in the opposing end just the same, but out of steel. I have found if you machine a shorter guide of 30mm long, it will still weigh the same as the originally rolled steel guide because that is hollow, not solid. You require a good 20 grams and this will achieve max velocity. The shorter steel guide at the muzzle end, will stop the mainspring flailing around, prolonging its life and keeping from canting over against the wall of the piston, also increasing velocity a touch. As a bonus this muzzle end guide can act as a beneficial muzzle weight.
If you follow this advice, your HW45 will approach 570 fps with 7.8 grainers and can give 10mm groups after plenty of practise and most lube removed.
First, you can just leave it stock and shoot it. If you resist adding any additional lubrication, it will eventually expel, or burn off the excess lube put into it by the manufacturer. It will take a few tins of pellets to do this and will finally settle down. The components are built to last a lifetime and can be run relatively dry with no excess wear noticeable.
However, if you have the relevant skills to tune one, this is the method to use.
HW placed the rolled steel guide rod down inside the piston (opposite to any other gun) to increase the weight to the piston. This is to overcome the excessive cushion of air coming from the restrictive TP which bends through 90 degrees. It is also this restriction which generates heat which effects any lubes placed into the gun. However, having the guide down inside the piston means that there is no guiding at the loose spring end to control it where it is needed at the muzzle end. Tuning companies then supplying Delrin kits which have a shortened guides which can then be fitted at both ends to help smooth the gun and control the spring at both ends.....This is a mistake!
In this particular gun, if we make the guide/Top hat out of Delrin, we lose the valuable inertia to drive through that restrictive TP and lose a good 1ftlb or more (the whole point of owning a HW45 being its power) Such a move turns the gun into a benign 4.5 ftlb Tempest.
What we need to do is, machine the Top hat/guide and another to fit in the opposing end just the same, but out of steel. I have found if you machine a shorter guide of 30mm long, it will still weigh the same as the originally rolled steel guide because that is hollow, not solid. You require a good 20 grams and this will achieve max velocity. The shorter steel guide at the muzzle end, will stop the mainspring flailing around, prolonging its life and keeping from canting over against the wall of the piston, also increasing velocity a touch. As a bonus this muzzle end guide can act as a beneficial muzzle weight.
If you follow this advice, your HW45 will approach 570 fps with 7.8 grainers and can give 10mm groups after plenty of practise and most lube removed.
