actually, if maintaining 5 gr/lb you can go down to 275 grains and still be within warranty specs at 55#.
For those that don't know Martin bows, they have a 15# range, meaning 15# down from the peak. That being said, they have long enough limb bolts and threds can be seen through a barrel nut that they can be safely shot at about half their rated draw weight, although I wouldn't recommend it as a long term deal. If you want to shoot at some minimum weight then it's best to replace the limbs.
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