check out Muzzy's selection, Mark (Land) has done more playing around and R & D with carbon arrows and inserts than anyone i know---i believe they offer 50 and 100 grain inserts for regular carbons and HIT (Axis, MX and FMJ) system arrows. i've used the regular carbon size in both 50 and 100 grain quite a bit and found them to be very uniform in weight and dimensions. He's also a good source of information about carbon arrows with regards to length/point weight/insert weight, etc.