An easy way to tell how the rotational tuning of the bundles is proceeding, is to turn oneself into a human torque meter.  As can be seen in the following vid, it helps not only to have eaten your wheaties, but to have retained a few of them to act as protective padding. 20100207201050

The degree of torque seen in these bundles has reached the point where I am only able to lift the limb off the stanchion by an inch or so.  With another 7 1/2 degrees of rotation, I will barely be able to move it a 1/4″.   Another 7 1/2 degrees after that,  and it will be impossible for me to shift it at all using this technique.  Past experience has shown that at that point, the velocity of the bolt will climb dramatically for every new 7 1/2 degrees introduced into the bundles.   Along with the rise in velocity will be a concomitant rise in the draw weight.    At this time, I have no desire to push Firefly much beyond 4,500 lbs of draw weight.   As soon as I can make up some new bolts, we will see what kind of velocities  can be recorded as she approaches that limit.  Today we managed two shots and were able to get the old 5,000 grain Gallwey bolts up to a sedate 220 fps.  However,  at this stage the bundles have barely started their rotational tightening sequence,  and today’s draw weight was only 2800 lbs.   Compare this to when the bundles were made from 3/8″ double braid.  The average velocity then was a miserable 200 fps,  while the draw weight  hovered around  3, 700 lbs.

These new “magnum”  springs have a long way left to go before they top out.   I am increasingly hopeful that we can work up to 320 fps with the 5,000 grain Gallwey bolts, and hit 400 fps with  the lighter 3,000  grain Dura’s.  That will be more than enough to justify all those Wheaties.

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