I use on my 45 lbs at 29 inches (my draw) hybrid longbow with an 6 strands SBD string the following:
GT traditional 1535
Full lengh, so a BOP of 30,5
Standard GT nock and insert of 11.5 grains each
a 100 grains fieldtip
5 inch helical feathers
9 inch crown dip and cresting, which adds 10 grains app.
total arrow weight: 387 which gives me a GPP of 8.6
I am still plaing around with gluing a small screw in the nock, adding 17 grains to the back of the arrow. This stiffens the spine a bit and raises my GPP to 9.
I bareshafted this set-up and shot perfect groups on 20 yards.
It gives me a FOC of 9.3. Without screw around the 11.
( Psss:I believe Big Jim still has some GT 1535 blems, best deal you can get, don't tell anybody...
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