Shooting the Girardoni

With all new guns comes tuning for performance and efficiency.  Various factors effect the tune,  some fixed, others variable.

6X6 bottom

This is a 6X6 Douglas fir post with numerous balls fired from 25 yards.

fused balls

The impact energy is sufficient to fuse balls together.

.279 vs .302 valve orifice

Valve orifice diameter is a variable which effects gas flow.  As can be seen above,  it is directly proportional to power (FPE) and and inversely to efficiency (FPE/CI).  The efficiency is how much power per volume of air at STP can be obtained.

Spring vs no spring

The valve spring slows the opening and speeds the closing of the valve.  Many have theorized that an airgun could be operated with no spring.  This graph shows that to be true.  However,  the power goes up disproportionately to the amount of air consumed per shot,  hence the efficiency is almost half without the spring.

cast vs swaged

The type, diameter and preparation of the lead ball have effects on performance.  All rounds shown are 100% lead.  The difference of .003″ is negligible between the .457 and .460 rounds.  The Swaged balls seem harder and have a pronounced decrease in performance.  Also note that the unlubed balls are more erratic and even lesser in performance.


Gir_HS lock

Here is a high speed video of the lock in action.  1000 fps – Casio EX-ZR1000

Hank HS shoot

Another high speed video of the gun being fired.  Note the oscillations of the hammer on the mainspring.

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