Tuning FX impact spring tention Allen key size

[AzharDar]

Hi people need help I have FX impact and FX chronometer and I found velocity is 850fps I want to increase it just want to know which size Allen key works for spring tention adjuster wheel?

Help would be appreciated

 

[biohazardman]

Hammer spring adjuster takes a 1.5mm Allen wrench.

 

[Glem.Chally]

I believe 1.5mm.

 

[Saltlake58]

Hint - if you have the Harbor Freight allen wrench sets, don't use the 1.5mm. I've got several of the HF kits and the 1.5mm is undersized. Once I sprung for decent tools like the Bondhus wrenches, all the sudden I could adjust the spring tension. My frustration was all ' cause HF wasn't sized correctly. Live and learn

 

[AzharDar]

I have 1.5 Allen but I am unable to rotate it can't feel the turn with my Allen.

Does Allen has to have any speciy shape at the end?

 

[Glem.Chally]

It could be loctited, might need some heat to break it loose. Don't strip it.

 

[AzharDar]

Thank you so much I think that's the problem 

 

[AzharDar]

What maximum velocity we can achieve on by tuning it for 18.13gr jsb