Shocking Discovery With New Chronograph!

[OkXbowHunter]

So I got my new ProChrono chronograph in yesterday. Set it up today and wanted to see what the TB (Turd Brown) Vixen and my Axiom would do.

The Vixen is shooting 2216's with QuickSpin QuickFletch 2" vanes and a 125 field point. Total weight is 450 grains (also bought a new digital scale while I was at it )

I'm using the original Dacron string. Sticker on the stock says 285 with FF string and 350 grain arrow. So I wondered how this set up would perform.

My first three shots were:

257 - 260 - 259

I consider that pretty darn good with the Dacron string!

Next up was my Axiom with the Excalibur FFF string.

My GT II's with the 2" QuickSpin Quickfletches and a 125 grain field tip weigh 445 grains.

The first three shots were:

284 - 283 - 284

To say I was sorely disappointed is an understatement!

I thought for sure I'd be nudging 300 fps with my set up. The Axiom has 25 lbs over the Vixen and it's using a FF string to boot. I know this isn't that bad...in fact the accuracy more than makes up for it in my book...but you know...we've had this fps thing drilled into our minds from birth...so it's hard to shake it...

The only thing I can think that might be slowing me down is that I have the stoppers on my STS just touching the string. When I get more time to play...umm... I mean "test"...I'll back them off around 1/16th to 1/8th from the string and see if that makes a difference.

Anyway, I am delighted with my Chronograph. The results I got with my Axiom is one reason I have never bought one before now...they don't lie often

[secret]

Throw a couple of twists in the string and you will be fine!

[bkisel]

Frankly I'm hoping that backing off the STS does not make a dimes worth of difference. Man, could you imagine if it did? We'd all be out buying chronos in order to fine tune our CBs for that extra fps.

Bill K.

[OkXbowHunter]

I guess I should have mentioned that my brace height on both bows is at the upper mark (the one closest to the trigger).

[Pydpiper]

There is absolutely no possible way that the string stoppers are affecting the speed, by the time the string gets to those bumpers the arrows destination and speed as already been determined.
The few things that can affect speed are brace height (draw length), string material and thickness and of course arrow weight.
There is also the batch number of the limbs, but that should not alter the speed too much.
My Exocet (200#)shoots 300FPS every single time, my wife's Ibex shoots 300FPS(175#) every single time, the only way to change that in a noticeable way is to alter the weight of the arrows, I use brass and she uses aluminum.
Brace height can have a small bearing, but not noticeable until 40+ yards.

[Pydpiper]

Through a couple of twists in the string and you will be fine!

That will reduce the speed.

[bkisel]

I guess I should have mentioned that my brace height on both bows is at the upper mark (the one closest to the trigger).

Ah, then you've got a bit of brace height to play with. Why not drop it to the middle of the lines right off the bat and see what you get? Should tell you whether messing around anymore with brace height is worth the effort.

Why not try 100 grain heads? That'd probably get you close to 300 fps and if the arrows are still flying good you might want to keep it set that way.

Bill K.

[wabi]

A general approximation of velocity loss with increased arrow weight is 1 fps for every 5 grains of arrow weight increase.

A bow rated at 305 fps with a fastflight string and 350 grain arrows would loose somewhere around 19 fps with 445 grain arrows (95/5=19) which would reduce velocity to 286 fps.
Sounds like a 350 grain arrow would get you right up there where is should be.

The brace height will account for a few fps (3 to 5 probably). I'd guess with the brace height lowered to the mark farthest from the claws and a 350 grain arrow you should get very close to 305 fps.

[Dereck]

Your speed sounds about right I was only getting 291 fps with a 370 grain arrow and a flemish string from my Phoenix.
I would not be disappointed with the performance you have a moderate weight arrow which will give awesome penetration and most likely a pass thru if no bone is encountered.

The speeds you quoted are lightening fast for hunting.

[Michael Stogre]

It's the weight as noted above. There is a loss of 5 feet per second for every added 25 grains of weight. Your bow is
right on. I shoot a phoenix and I have a chrono. I have verified this ratrio many times over the years.

MJS

[awshucks]

A general approximation of velocity loss with increased arrow weight is 1 fps for every 5 grains of arrow weight increase.

A bow rated at 305 fps with a fastflight string and 350 grain arrows would loose somewhere around 19 fps with 445 grain arrows (95/5=19) which would reduce velocity to 286 fps.
Sounds like a 350 grain arrow would get you right up there where is should be.

The brace height will account for a few fps (3 to 5 probably). I'd guess with the brace height lowered to the mark farthest from the claws and a 350 grain arrow you should get very close to 305 fps.

Leave it to the 'Birthday Boy' to make the post of the day!! LOL. If y'all are hunting max fps, get some Gt's L II's w/ alum inserts and 125 gr points, so close to 350 gr it will scare ya! You may need to switch to mech due to lower FOC, however.

[vixenmaster]

So I got my new ProChrono chronograph in yesterday. Set it up today and wanted to see what the TB (Turd Brown) Vixen and my Axiom would do.

The Vixen is shooting 2216's with QuickSpin QuickFletch 2" vanes and a 125 field point. Total weight is 450 grains (also bought a new digital scale while I was at it )

I'm using the original Dacron string. Sticker on the stock says 285 with FF string and 350 grain arrow. So I wondered how this set up would perform.

My first three shots were:

257 - 260 - 259

I consider that pretty darn good with the Dacron string!

Next up was my Axiom with the Excalibur FFF string.

My GT II's with the 2" QuickSpin Quickfletches and a 125 grain field tip weigh 445 grains.

The first three shots were:

284 - 283 - 284

To say I was sorely disappointed is an understatement!

I thought for sure I'd be nudging 300 fps with my set up. The Axiom has 25 lbs over the Vixen and it's using a FF string to boot. I know this isn't that bad...in fact the accuracy more than makes up for it in my book...but you know...we've had this fps thing drilled into our minds from birth...so it's hard to shake it...

The only thing I can think that might be slowing me down is that I have the stoppers on my STS just touching the string. When I get more time to play...umm... I mean "test"...I'll back them off around 1/16th to 1/8th from the string and see if that makes a difference.

Anyway, I am delighted with my Chronograph. The results I got with my Axiom is one reason I have never bought one before now...they don't lie often

I think they're both right on the money! Vixen gets 285 fps with 325gr arrow & FFF string the Axiom gets gets 305 fps with 350gr arrow & FFF string, plus yer up on high B-height instead of low one. Now Miss Vixen shoots 245 fps she still kills tick toters by the truck load

[Cossack]

The only thing that made a meaningful difference is installing my own made 32 strand Flemish on my bows. Picked up an average of 15 fps over factory string.
That's the problem with chrons (I use one for reloading), folks are perfectly happy with the speed of their gear (bow or gun) until they chron, then they start to wonder how to up the speed. In reloading its called hotrodding a load; for crossbows it's arrow weight reduction, brace adjustment,thinner strings. IMO 10, even 20 fps, won't make any difference either way. If you killed deer before (which you have) they won't be any deader if your arrow is 10 fps faster. But it's sure fun to tinker, eh?

[OkXbowHunter]

That's the problem with chrons (I use one for reloading), folks are perfectly happy with the speed of their gear (bow or gun) until they chron

And that is the reason I haven't owned one before now! I once shot a favorite Trad Recurve of mine through a fellow archers chrono at a 3D shoot once. I thought this recurve was like greased lightning. It shot in the 180's (I would have sworn it was shooting around 210 to 220). I was floored and couldn't shake the thought of shooting a "slow" bow even though I had killed more than a few deer with that bow!! I ended up selling it before Deer season and getting a "faster" recurve...or at least I "think" it was faster...I "felt" it was faster anyway...and that's the real difference...and I've stayed away from Chrono's until now

[vixenmaster]

Nothing wrong with Chrony's, ppl just need to accept the reading & not let it upset their speed thinking. When i shoot my vixen i knowed it will shoot from 225 fps up to 260 depending on arrow weight