FATBOY 500/400

[Mikelo]

Hi
I am currently shooting a Great Plains Black Hawk 60" with #55 @ 28, and I am in doubt with these arrows: Fatboy 500 with 125-grain points and Fatboy 400 with 100 grain-points. Both weigh the same, 363 grains, with 5" feathers, and I can hardly find any difference at all between them, but there should be some... or not?
I´d be so grateful if anybody could advise me.

[Blake Dustin Adams]

It's going to be rather dependent on your draw length and the length of the arrow.  However it does sound like you are rather light on that 400 spine shaft, it sounds like it should be quite stiff.  Also your shooting about 6.6 grains per pound.  You want to up that to at least 8-9 just to save the limbs of your bow.  

I'm no expert but if you give us more info we can give you more info.

BDA

[Mikelo]

Thanks, Blake, my draw length is 28" and the arrows are 29". Moreover, it sounds I am a bit low in weight, but they go pretty wel, and in 3D they fly really nicely, but maybe too light...?

[woodcock]

You will probably see almost no difference in the two.  Carbons are very broad spectrum in their spine.  I would think out of your bow the 400's are a little sweeter feeling maybe?  They are certainly more appropriate for that weight bow.  The weight is cosiderably lighter than I would shoot out of that bow.  Stick a 250 or 300 gr point up front and try it out.  You will be surprised at the result.  Particularly on penetration.  If you don't want to go 10 gr/lb for 550gr get at least 475-500gr total weight or thereabouts.

[Blake Dustin Adams]

It's going to be a question of bare shaft tuning.  Your arrows right now are so light that those feathers are making a huge difference, my opinion from my experiences, causing a lot of drag on that lite an arrow should really straighten it out.

I would suspect that those 400 at that length and bow combo would bare shaft fairly well with about 175-225 grains up front.  There are always going to be differences in how you shoot compared to somebody else, i.g.: your release, if you snap shoot or hold your anchor, three under or split finger.  Everything makes a difference and what works for others might not work for you.

If you have a shaft or two with no feathers put on some different weighted points and see what flies best when bareshaft tuning.  If you need more info on bareshafting go above the forum here by the sponsors adds click on the search function and type in something like "bareshaft", "tuning", or both at the same time.  There will be lots of results.

Everybody is different and has there own technique and style that is unique to them.  What matters is that they stay consistent with that style and have arrows that fly well for their style.

The 8-9 grain per pound is as much as anything else to save your limbs on your bow.  There is a lot of stored energy that must go somewhere and a heavier arrow will use that energy and quiet the bow.

BDA

[JimB]

If you are shooting both with fletching,you may not see a difference but there is about 20 lbs difference in spine.I see a big difference between carbon spine groups myself.If you take the feathers off a 500 and also a 400,you will see a difference.The 400 is stiffer and should require quite a bit more point weight.I would also want an arrow quite a bit heavier than that for that draw weight.That will put a lot of strain on the bow and I bet it is extremely noisy.

[Blake Dustin Adams]

Just found it on my Easton charts.  Their 2117 aluminum has a spine of .407, on the lb spine chart that equals 78lb spine.  So with a Fatboy 400 which of course has a spine of .400 you are looking at just a hair more than 78lbs.  In regards to a 500 spine arrow that equates out to close to 62lbs.

BDA

[huntmaster80]

are u having any trouble with ur arrows breaking? Fatboys have a very weak wall from my experience shooting them with wheel bows, I didnt like them cause they seemed to be breaking all the time with the slightest arrow strike.  but if they are working for u then shoot em up.  Good luck!

[owlbait]

Fatboys are large diameter shafts. Seems like those fat shafts might be hard to get clean flight with the limited amount of centershot on trad bows.

[Mikelo]

Thanks, guys, the truth is that they flight pretty straight, great for my 3D contests, but maybe a bit light... and for the noise, I put hair  silencers and it is terribly silent.
Could it be that large diameter shafts, as owlbait remarks, absorb more quantity of stored energy... or that is only a question of arrow weight? Because you have to try, men, they are accurate and fast as a missile...