HW110 Hammer Spring Adjustment:
As there is not a lot of information on the HW110 in the US. I thought I would create a tutorial for this forum on how to adjust pellet speed via the adjuster on the HW110’s hammer spring shuttle.
(This should also be relevant to HW44 pistol owners.)
I also created instructions for how to adjust regulator pressure and how to change out the hammer spring shuttle (if you want to swap the sub-12 shuttle for the FAC shuttle or vice-versa)
ADJUSTING HAMMER SPRING TENSION:
First some Important Things to Note (to avoid breaking your hammer spring adjuster):
#1: When adjusting the hammer spring tension in these HW110 shuttles you turn the 4mm Allen adjustment screw in (clockwise) to REDUCE pellet speed. You turn the 4mm allen adjustment screw counterclockwise to INCREASE pellet speed. Trust me, I have both versions (FAC and sub-12) of the hammer spring shuttle and have done this countless times.
#2 - MAJOR NOTE: You MUST loosen a little Torx T-8 lockdown screw that is INSIDE the 4mm Allen key adjustment screw hole. If you don’t loosen (counterclockwise to loosen) this little T-8 lockdown screw BEFORE attempting to adjust hammer spring tension with the 4mm Allen, you will BREAK your hammer spring adjuster. Trust me, I got bad information from some UK sites and broke one of mine. Weihrauch actually emailed me and informed me of the T-8 lockdown screw. After you complete adjusting your hammer spring, you should tighten the T-8 lockdown screw back down - just finger snug - don’t overtighten. Both the FAC and sub-12 versions of the hammer spring shuttle have the T-8 lockdown screw. I own both versions (FAC and sub-12) of the hammer spring shuttle and have confirmed this. (I purchased both 2022 versions - FAC & sub-12 - from a UK store called AirGunSpares.com).
New HW110 rifles sold in the UK have a plug in the hammer spring adjuster port - that prevents any adjustment. I’m not certain if Weihrauch has the T-8 screw installed under the plug.
#3: The FAC hammer spring shuttle has 6.5 turns of adjustment available. The UK sub-12 version has 6.5 turns of adjustment available. (edited from my original post - I loosened the torx 8 lockdown screw a bit more and was able to verify 6.5 turns of adjustment available on the FAC hammer spring shuttle- same adjustment range - in turns - as the sub12 version)
#4: Only adjust the hammer spring tension when the rifle is UNCOCKED. If you attempt to adjust when cocked, you will notice it won’t turn easily- don’t turn or you will likely break your adjuster.
Steps:
Step 1: Remove two stock bolts - the shorter bolt is towards muzzle
Step 2: Remove trigger guard. Remove Allen screw and then tap out pin.
Step 3: when adjusting (remember to loosen the T-8 locking grub screw BEFORE turning the 4mm allen adjustment).
I recommend installing the rifle back in the stock WITHOUT the trigger guard. This allows your to adjust your hammer spring tension while shooting - i.e. shoot a group, evaluate results, adjust tension, shoot another group, etc.
If you use my method, you will have to be careful not to bump the trigger, as the trigger guard in not in place to protect the trigger from damage.
Step 4: Once you have the desired hammer spring tension, you can take the stock off, reinstall the trigger guard and then reinstall back into the stock.
Results (updated with more pellets as of September 20, 2022) with regulator at 150 bar (factory FAC reg pressure) and FAC hammer spring shuttle:
14.66g pellet H&N FTT: Min Velocity = 382 fps Max Velocity = 965fps
15.89g pellet JSB : Min Velocity = 335fps Max Velocity = 925fps
18.13g pellet JSB: Min Velocity = 318fps Max Velocity = 889fps
21.14g pellet H&N: Min Velocity = 277fps Max Velocity = 847fps
I hope this helps HW110 / HW44 owners who want to tune their pellet velocity. The rifle is noticeably louder at max velocity with the factory regulator setting of 150bar for FAC.
As there is not a lot of information on the HW110 in the US. I thought I would create a tutorial for this forum on how to adjust pellet speed via the adjuster on the HW110’s hammer spring shuttle.
(This should also be relevant to HW44 pistol owners.)
I also created instructions for how to adjust regulator pressure and how to change out the hammer spring shuttle (if you want to swap the sub-12 shuttle for the FAC shuttle or vice-versa)
ADJUSTING HAMMER SPRING TENSION:
First some Important Things to Note (to avoid breaking your hammer spring adjuster):
#1: When adjusting the hammer spring tension in these HW110 shuttles you turn the 4mm Allen adjustment screw in (clockwise) to REDUCE pellet speed. You turn the 4mm allen adjustment screw counterclockwise to INCREASE pellet speed. Trust me, I have both versions (FAC and sub-12) of the hammer spring shuttle and have done this countless times.
#2 - MAJOR NOTE: You MUST loosen a little Torx T-8 lockdown screw that is INSIDE the 4mm Allen key adjustment screw hole. If you don’t loosen (counterclockwise to loosen) this little T-8 lockdown screw BEFORE attempting to adjust hammer spring tension with the 4mm Allen, you will BREAK your hammer spring adjuster. Trust me, I got bad information from some UK sites and broke one of mine. Weihrauch actually emailed me and informed me of the T-8 lockdown screw. After you complete adjusting your hammer spring, you should tighten the T-8 lockdown screw back down - just finger snug - don’t overtighten. Both the FAC and sub-12 versions of the hammer spring shuttle have the T-8 lockdown screw. I own both versions (FAC and sub-12) of the hammer spring shuttle and have confirmed this. (I purchased both 2022 versions - FAC & sub-12 - from a UK store called AirGunSpares.com).
New HW110 rifles sold in the UK have a plug in the hammer spring adjuster port - that prevents any adjustment. I’m not certain if Weihrauch has the T-8 screw installed under the plug.
#3: The FAC hammer spring shuttle has 6.5 turns of adjustment available. The UK sub-12 version has 6.5 turns of adjustment available. (edited from my original post - I loosened the torx 8 lockdown screw a bit more and was able to verify 6.5 turns of adjustment available on the FAC hammer spring shuttle- same adjustment range - in turns - as the sub12 version)
#4: Only adjust the hammer spring tension when the rifle is UNCOCKED. If you attempt to adjust when cocked, you will notice it won’t turn easily- don’t turn or you will likely break your adjuster.
Steps:
Step 1: Remove two stock bolts - the shorter bolt is towards muzzle
Step 2: Remove trigger guard. Remove Allen screw and then tap out pin.
Step 3: when adjusting (remember to loosen the T-8 locking grub screw BEFORE turning the 4mm allen adjustment).
I recommend installing the rifle back in the stock WITHOUT the trigger guard. This allows your to adjust your hammer spring tension while shooting - i.e. shoot a group, evaluate results, adjust tension, shoot another group, etc.
If you use my method, you will have to be careful not to bump the trigger, as the trigger guard in not in place to protect the trigger from damage.
Step 4: Once you have the desired hammer spring tension, you can take the stock off, reinstall the trigger guard and then reinstall back into the stock.
Results (updated with more pellets as of September 20, 2022) with regulator at 150 bar (factory FAC reg pressure) and FAC hammer spring shuttle:
14.66g pellet H&N FTT: Min Velocity = 382 fps Max Velocity = 965fps
15.89g pellet JSB : Min Velocity = 335fps Max Velocity = 925fps
18.13g pellet JSB: Min Velocity = 318fps Max Velocity = 889fps
21.14g pellet H&N: Min Velocity = 277fps Max Velocity = 847fps
I hope this helps HW110 / HW44 owners who want to tune their pellet velocity. The rifle is noticeably louder at max velocity with the factory regulator setting of 150bar for FAC.