View Full Version : Cam Rotation
11-21-2007, 10:53 AM
If anyone here has a bow with the new MPro cam that is shooting the advertised IBO speeds, can you post a picture of the cam orientation.
I have a brand new MOAB and it is only hitting 296 fps. That is at 70lb, 30", 265 grain arrow with a loop on the string.....
11-21-2007, 03:03 PM
You must mean 365 gr. arrow. 265 is WAY too light. IBO is 5 gr. per lb., or 350 gr. MINIMUM. Any less is a dry-fire. There is no way the bow would only be doing 296 fps. if that were the case. Thus, I will assume you mean 365 gr. not 265 gr.
What accessories do you have on the string? Peep sight (esp. the ones that require tubing), nock point, silencers, cushion button and/or string loop, kisser button, and the like can take up to 10-25 fps. off in my experience.
Also 365gr. arrow vs. 350 gr. arrow will be costing you 2.5-3 fps., as will using a single caliper and/or retractable sear design release.
This all adds up to 15-31 fps. lost. If they are instaled correctly, this will be closer to 15 fps. If poorly installed, it could be up to the 31 fps. lost mark.
Also bear in mind that Martin bows, like most other brands, probably record IBO in "optimum conditions" to gain every possible fps. for public appeal and an edge on the competition. these days, the maxim is "SPEED SELLS".
eg. lubricated dropaway rest, no fletchings, arrow not even .1 gr. over 350 gr. and very low FOC, no other accessories, unwaxed string, lubricated serving where released from, chroneyed 2mm from the chrony, etc...
11-23-2007, 04:48 PM
Arrow was 365gn.
Nothing on the string but a d-loop. Rest was a TT spring steel.
11-25-2007, 08:17 AM
Justin, Nuts and Bolts had a thread on them awhile back, I can see if I can locate it for you. The M-Pro cams he said should be 1/8of an inch from the end of the groove, if that helps
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