Just got my new Extreme VFT in and set up at my local shop. The Birth certificate from BT said they got 306 fps using 300 gr. arrow, 61 lbs., and 28.5" draw. We changed my draw to 29" , added a string peep, string loop, and shooting a 383 grain arrow off of a Mirage fallaway rest. The bow now shoots 273 fps through the shop chrony. Should I have lost this much speed? The KE is pretty good, 63 lbs. I just hate seeing that much of a speed loss.
Any ideas and/or comments?
Thanks

You increased your grains by a lot and your crony may not be exact but it sounds like you are not too far off.

From what I have read, every addition of 30 grains of arrow weight reduces the speed of the arrow by 10 f.p.s. That would put you right around 26 f.p.s. loss from the gain in arrow weight. That would put you at 280 f.p.s. That extra 1/2 inch of draw length isn' t going to add much speed, a couple feet per second. Well, then, you add in your string accessories, and you are right on track. Heck, you might be exceeding the expected performance of your bow at that set-up.

I' d say your bow is where I' d expect it to be. Think of this. There are alot of 70# bows that are slower, set up the same as yours.

Uhhmmm,
Does your birth certificate indicate THEY shot your bow under 5 grains per pound of draw weight???
61# x 5 gpp= 305 grains

Don' t they mention somewhere that shooting under 5 grains per pound is a no-no??
I know it' s not by much, but 4.91 grains per pound is what it is. If you ever have ANY warranty issues I' d be quick to show them THEIR birth certificate.

They' re not trying to pull High country tricks are they???

Dave.
What BT does is list the 5g/p speed rating so the bow shot a 300gr arrow at 60lb.
They then also list the max poundage of the bow thus the 61lb.

Meomako
I would say you are well and truely in the ball park with those figures.

Nope. Our Extreme VFT shot 423/425 fps. set up with the 2.5 gr. per pound arrow.

At the plant they don' t have an arrow that weights exactly 5 gr. per pound for every draw weight. Some bows peak at 61 so they use a 300 gr. arrow.

Hmmm, I' ll have to inspect my birth certificate when I get home, but I could have sworn it said " 350 grain arrow @70.2# @30" draw = 323fps"
If so, they did it to me too.......[:@].
I' m not really complaining, just pointing out that if it' s so " what' s up wit dat?"

With my Pat Dually I have seen an average of 1 fps lost with every 3.88 grains of aditional arrow weight.