I'm going to be using a Martin X-200 45# at my 28" draw length, and arrows cut to 29 or 30" with 100gr. insert and 125gr. heads.  I'm looking at the Beman MFX 500 or Traditional Only carbon arrows.  Would 500 be good or would I be better suited with a lighter spine?

thanks,
Ken

You should be real close. Install your insert and point and bare shaft to tune the lenght. Cut from the nock end........

will do, thanks for the reply!

Another question:  I'm shooting GameGetter 500's right now, 30" with 100gr. insert and 125gr. heads and they fly perfect for me, but are pretty long because I only draw 27 1/2".  So if I cut them down to 28 1/2" will that affect the spine? since the extra 1 1/2" is just sticking out in front of the riser anyway I thought I could cut them and it wouldn't change anything.

It will effectively make the arrow stiffer if you cut them. I think the rule of thumb is a gain of 5# stiffness per inch you cut.

even if the extra length is sticking out in front of the shelf?  My bow likes a really light spined arrow and I can't get much lighter than what it is and they're already a bit too long.

You could buy 600 spine carbons.  In my findings, carbons are more affected by lenght than by point weight. When I bare shaft test I only cut a 1/4 inch off at a time. When I get the shaft flying perfect for me, I can add 50gr or more without alot of change to where my bare shaft inpacts right or left of center.

I may have to head to my shop and try some carbon to see if they spine the same as my aluminums do for me.  thanks for the advice,
Ken

I have had the same findings as Desert. You could change your anchor to your jaw ;D Personally I don't mind hang over if my arrow is flying right.

If I was you I'd probably put a brass insert in a 29" 500 with 125gr point. That should put you close and you'd have better FoC %. IMHO.

What does everyone else think?

47pronghorn,  I'm using the brass insert and 125gr. point now with Easton GameGetter II 500's and they fly really well for me, but I've bent a few of them so I'm gonna switch to carbons.  I think the Beman MFX 500 or CX Heritage 150 would be my best choices if I put around 200 - 250gr. up front.

Check out the arrow spine FOC calculator, it has worked really well for me and many others.