Nicholal

I just had my bow crono'd and paper checked
27' draw length
PSE carbon force dominator 300's 28 inch arrow
hoyt ultra mag 300 ibo
shot an average speed of 260 fps
would this be about right.

some of the boy's say that seems a little fast other say should be 270?

So if I went to another place to do a crono would the munber be the same?

AL

zak123

That seems about right. What is your total arrow weight, and what accessories do you have on the string? How many pounds are you pulling?

Nicholal

Sorry Zak
63 pounds draw weight
I think my arrows weigh 363 grams

on the string just the factory leches

adams

27" draw. This is where you're losing the IBO speed. Unless27" is the max draw length for that model bow, when it was tested it was shot at a dl longer then 27" and if the bow iscapable, it was shot at 30".

If you're happy with your set up, RULE 1: Stay away from a chrono!!!

Paul L Mohr

Yes chronos can be off. It is not uncommon to go to two or three different shops and get two or three different readings. That is also why you should shoot more than one arrow thru it. Shoot at least three and take an average. Most of them are made to check the speed of something small like a bullet, not an object that is 20 some inches long. And some are just cheap and don't work very well from what I understand. From what I have heard lighting plays a big part as well.

The worst are the techno hunt set ups from what I understand. They usually give readings different than a true chrono does. I don't remember if they are slower, or faster though. I think slower.

Bow scales are the same way. Getting an accurate reading off from a compound bow with a hanging scale is a little tricky. I bet you could have three people check a bow on the same scale and you might get three different readings. Not to mention if you are using a scale made to weigh things around a hundred lbs or more the scale will not be that accurate on the lower end. And some don't get calibrated very often.

If you are using a scale and a chrono to track the tune of your bow, like checking if from time to time to see if anything changes you should frequent the same shop and use the same equipment.

And I agree with the others, I don't think you are going to see 270 out of that bow with a 27 inch draw length and 63 lbs of draw weight. Unless you are shooting an extremely light arrow, which you are not. They tested the bow at 70 lbs, a 30 inch draw and a 350 grn arrow with nothing on the string. And they may have even fudged the numbers a bit to get 300 fps. You are losing around 20 fps alone just for your lower draw weight. Then add in your shorter draw length and heavier arrow. I'm actually surprised you are getting 260. If you shoot it thru a different chrono you may be dissapointed.

Paul

Sylvan

It really doesn't matter how long the object is. Chronographs sense only when the leading edge of the object passes over each detector however the shape of the object can make a difference. A blunt object casts a shadow that is easier for the instrument to detect the precise instant that it arrives than a pointed object.

PABowhntr

I don't have an estimate on your speed but the chrono definitely could be off. I once sat three "chronographs" side by side and shot the same three arrows repeatedly through them. There was a variation of 8 fps between the slowest and fastest chrono. Not significant in some people's book but enough for me to take notice.

Paul L Mohr

Some chronos are designed for archery I thought. One of the shops I go to they have to input the length of the arrow into the machine, so it must make a difference to some extent. You are talking about the difference between 200 fps and 3,000 fps and a projectile from 1/2" to 30 inches long. I can see where there would be room for error somewhere.

Paul

Bowhntr6pt

With a 2 window unit, the front window "STARTS" the timer and the rear window "ENDS" the timer. With the more expensive units, 3 windows are used as a "CHECK AND BALANCE". It's all a matter of START/STOP time as measured against a known distance between the timers.

Length of the object does not effect the START/END of the timing session. I have a very cheap "CHRONY" that I have used for years with firearms, shotguns, and bows with no problems.

kevin1

260 FPS isn't fast enough to kill what you normally hunt ?