I thought you fellow HW110 owners would enjoy the results of my experiment tonight.
My HW110 .22 caliber started life as a “FAC” full power model with 30ft/lb hammer spring shuttle and 600mm barrel. The factory regulator setting was 150 bar.
I’ve since tuned it down by installing the 410mm barrel, installing the UK 12ft/lb hammer spring shuttle (both purchased from Airgunspares.com in the UK) and reducing my regulator pressure to 90bar.
Experiment #1: Max Velocity with H&N FTT 14.66g pellets & 410mm barrel.
I maximized the hammer spring preload and achieved a 5-shot average of 761 fps. Note that this is 18.86 ft/lbs - so there is a LOT of headroom in the “12 ft/lb” UK specification hammer spring shuttle.
(You have to loosen the Torx T8 locking grub screw BEFORE turning the 4mm Allen key to adjust hammer spring preload - or you will snap the adjuster bar inside your shuttle. Remember to tighten the Torx T8 back down after adjusting, or the hammer spring preload will slip and you will experience velocity change over time. This is what UK guys mistakenly refer to as “power loss” over & over again. UK rifles may have a plug in the adjuster port that must be removed before adjusting.) Both the Torx T8 tool (silver) and 4mm Allen (in rifle) are shown in my picture.
Experiment #2: Max Velocity with H&N FTT 14.66g and 600mm barrel.
I simply unscrewed the 410mm barrel and screwed in the 600mm - then ran 5 shots through the gun. The 5-shot average velocity was 805fps. So, about a 45fps gain just by switching barrels. Note the this is 21.1 ft/lbs - with the “12 ft/lb” hammer spring and the mild 90bar reg pressure!
So, UK guys have a LOT of power headroom in your UK specification HW110s - if you know how to adjust them. This is an EXTREMELY simple air rifle to adjust hammer spring tension so “get the plug out”, lol.
Finally, I reinstalled the 410mm barrel and adjusted velocity down to 700fps with the 14.66g pellets. This is about 16 ft/lbs. I’ve found the HW110 to be most accurate at around this power level.
If you remove the trigger guard, you can access the hammer spring adjuster port while the rifle is in the stock - so shoot, adjust, shoot adjust - until you’re satisfied.
You can see the 1st 11 shots I took after reinstalling the 410mm barrel (I pulled the 1st shot high as rifle moved - then took 10 more after getting rifle properly back into tripod.
I hope that you find this info helpful for tuning your HW110.
My HW110 .22 caliber started life as a “FAC” full power model with 30ft/lb hammer spring shuttle and 600mm barrel. The factory regulator setting was 150 bar.
I’ve since tuned it down by installing the 410mm barrel, installing the UK 12ft/lb hammer spring shuttle (both purchased from Airgunspares.com in the UK) and reducing my regulator pressure to 90bar.
Experiment #1: Max Velocity with H&N FTT 14.66g pellets & 410mm barrel.
I maximized the hammer spring preload and achieved a 5-shot average of 761 fps. Note that this is 18.86 ft/lbs - so there is a LOT of headroom in the “12 ft/lb” UK specification hammer spring shuttle.
(You have to loosen the Torx T8 locking grub screw BEFORE turning the 4mm Allen key to adjust hammer spring preload - or you will snap the adjuster bar inside your shuttle. Remember to tighten the Torx T8 back down after adjusting, or the hammer spring preload will slip and you will experience velocity change over time. This is what UK guys mistakenly refer to as “power loss” over & over again. UK rifles may have a plug in the adjuster port that must be removed before adjusting.) Both the Torx T8 tool (silver) and 4mm Allen (in rifle) are shown in my picture.
Experiment #2: Max Velocity with H&N FTT 14.66g and 600mm barrel.
I simply unscrewed the 410mm barrel and screwed in the 600mm - then ran 5 shots through the gun. The 5-shot average velocity was 805fps. So, about a 45fps gain just by switching barrels. Note the this is 21.1 ft/lbs - with the “12 ft/lb” hammer spring and the mild 90bar reg pressure!
So, UK guys have a LOT of power headroom in your UK specification HW110s - if you know how to adjust them. This is an EXTREMELY simple air rifle to adjust hammer spring tension so “get the plug out”, lol.
Finally, I reinstalled the 410mm barrel and adjusted velocity down to 700fps with the 14.66g pellets. This is about 16 ft/lbs. I’ve found the HW110 to be most accurate at around this power level.
If you remove the trigger guard, you can access the hammer spring adjuster port while the rifle is in the stock - so shoot, adjust, shoot adjust - until you’re satisfied.
You can see the 1st 11 shots I took after reinstalling the 410mm barrel (I pulled the 1st shot high as rifle moved - then took 10 more after getting rifle properly back into tripod.
I hope that you find this info helpful for tuning your HW110.
