FMJ 400 or 500

[TRAP]

I'm currently shooting FMJ 340s full length with about 275 gns up front out of my 55# Tall Tines.  28 1/2" draw most of the time.  

I know it goes against modern wisdom but I'd like to lose some of that weight up front and just go with standard aluminum inserts and a 145 gn head and get my total arrow weight back down around 500-550.

So my question is, which shaft? the 400 or 500. I can cut them down to about 30" but would prefer to leave them full length.  

The arrows will have 4-fletch, 5 1/4" feathers

What say you tuning gurus?

Thanks in advance

[JamesKerr]

I don't know what the center cut is on a tall tines but 340's out of most 55# bows are to stiff( a 340 spine shaft cut to 30.25" with 275 grains up front bareshafted great when I had my 60# longbow). A 400 spine would work better with that point weight up front cut to about 29-30" in my experience with most 55# bows. If I were going to use the 145 grain head and standard aluminum insert I would go with the 500 and see how they did.

[JimB]

Trap,not a tuning guru but I've found that jumping from one carbon spine group to another,over all weight changes 100-120 grs.I would try the .400's.

[damascusdave]

Trap I am not home right now but when I am I will weigh my FMJ 400's cut to 30.5 inches...I am thinking 350 grains total with aluminium inserts so would be right around 500 with those broad heads...if you have not tried the VPA two blades you should...I use the 175 and 200's but there is also a 150...very small looking heads...tough as they get

[damascusdave]

I also have some 400's left full length so will weigh them too...I am betting the 400's are the way to go if you leave them full length

[damascusdave]

Just did some calculating and your foc with 145 points will be 14%...that should be lots

[damascusdave]

One other thing to consider is going to shorter fletching...I shoot 3 2inch Razr and 4 of them would be even better...that would give you a bit more FOC...just something to consider

[Steve O]

400s Trap.

[damascusdave]

Just got some weights...bare shaft with nock and aluminum insert...cut to 30.25 inches, 335 grains...full length of 31.75 inches, 350 grains...will give you that 500 grain arrow that you are looking for

DDave

[jonsimoneau]

Hey Daryl, I'm pretty sure you will want a 400 especially if you prefer to leave them full length.

[TRAP]

Thanks Guys, I'll try the 400s and adjust length or point weight as needed.

Trap

[Stixbowdrew]

Trap I shoot a similar setup to you with my draw being longer my arrows are cut to 31.5" with standard inserts and 200 grain tips, and for arrow weight around 550 and the flat out smoke!  Oh shoot I run the 400s btw