This has certainly been asked before, so pls bear with me.

I shoot an AR 34 (2003, Ram Cam). The botom limb (with the sticker that tells the serial #, draw weight, etc.) says that you should shoot a minimum 420 grain arrow. My arrows w/o the crest (and with feathers instead of vanes) are 378 grains and my arrows with crests and vanes (instead of feathers) are 410. Both seem to shoot great for me. What gives?

BTW, I'm shooting PSE Carbon Force Extremes 400's (28") with 100 grain field tips/Muzzy 3-blades.

Also, what is an acceptable tolerance in weight for arrows? Mine seem to be +/- 5 grains or so.

Thx for the help.