Today, for the first time I shot over my chrono. I've used it while reloading for firearms many times but it just never really occurred to me that I might want to send an arrow over it. Anyway, I changed arrows recently and decided to go heavy (Carbon Express Piledriver). Since I'm cranking up the weight of my arrows I figured it would be nice to calculate my KE.

Out came the chrono, set it on a 4' step ladder and fired 5 arrows over it from 5 feet back. I am shooting at 65lb draw, 29" draw, and my arrows/broadhead combos are weighing out right at 485 grains. All shots were consistent at 251-252fps and when plugged into the KE equation with my arrow mass that give me right around 68lbs KE.

I guess I am happy with that. Anyone else shooting arrows weighing well over the standard used to determine IBO speed? I believe they use a 350gr arrow, 30" draw length, and 70lb. draw weight. If so, what kind of numbers are you getting?

always figured I couldn't gain enough speed to keep em from ducking, so no use really.

The times I did many years ago, 220 to 230 was about a norm. Plenty fast if you take all the other things into consideration.

At least for me.

I haven't shot over mine yet, I'm not sure how far back you're supposed to get for a true reading. If too close will arrow paradox be a problem?

Many time, can be very enlightening.

I shoot firearms and my bow over a chronograph on a regular basis. It takes a lot of guess work and speculation out of things.

Shot over a wild boars back once. He was faster than my bow after that.

What speculation does it take out of the bow end of it?

I don't do much with bows like I used to... when younger shot a LOT and almost only bows... shot every day for sure...

With guns, the chrono only answers if I'm in my target range of velocity. Beyond that the chrono just doesn't answer any questions at all really. Of course thats when I was competition shooting and trying to see where I was speed wise in a load.

Now that I mostly only hunt, I use a chrono same, just on initial audette to see that i"m in the ballpark MV wise and never look at the chrono ever again.

I will have to dig the Oehler out for the subsonic work on the whisper though...

I bought a Shooting Chrony about 25 years ago and still have and use it regularly. Just another tool in the toolbox.....

I used to shoot over my chrono a lot. It was a very good training tool for me to make my release with fingers very consistent. Didn't really care how fast my bows were. But when you can stand out there and fire ten arrows in a row and the chrono reads the same velocity everytime...you've got a pretty good release with a recurve bow.

X2
With trad bows it's a better tool to train for consistency than anything else.

I shot three through today actually. I wanted to see what my new Obsession Phoenix was running. 29" draw, 65lbs...BloodLine 400's with a 125 practice tip. I've never weighed the arrows.

305, 306, 305

My son just shot some this morning using my pro chrono. Here's the e-mail I just got from him.

70# Hoyt with 450gr arrows...



0yds - 298fps 88.6KE .59 Momentum

50yds - 278fps 77.1KE .55 Momentum

100yds - 253fps 63.8KE .50 Momentum




60# Schafer with 578gr arrows...

0yds - 175fps 39.2KE .44 Momentum



60# Schafer with 534gr arrows...
0yds - 183fps 39.6KE .43 Momentum

Kind of depressing with most trad setups when looking a how slow they really are. My compound is 120fps faster than my trad bow!

What speculation does a chrono take out?
On firearms, velocity determines trajectory and over long ranges, that is big deal, so I like to know velocity so I have better accuracy at long range. Published data on velocity is often way off from actual.
Also velocity variation shot to shot impact accuracy. So if one sees that, it's a good time to change loads.

On archery, knowing velocity allows one to determine momentum and KE, among other things.That can be useful in selecting arrow weight especially in the case of dangerous game.

Wow. Never knew archery was so delicate.

We picked arrows by spine, and weight years ago. Knew that light anything is like the ping pong vs the golf ball on energy. Been books on needed total weight of arrows vs game size for years. You need a scale or chart for that more than a chrono.

Went even heavier with elk and such. Never knew much about KE or momentum. Never had a problem killing stuff either.

RE printed velocity in guns, yes, like I said, you can use it once or twice to see if you are close to book max but pressure signs have to be read, book max depends on SO many things, bullet coatings, throat design, land and groove diameter, case capacity, types of powder etc...that you are better off reading pressure signs IMHO than a chrono.

As to trajectory and groups at long range, I happen to know a hair about that, and I'll rely on paper over a chrono every last time. Especially with ES and SD and what they may or may not contribute to group sizes. Not sure how knowing velocity affects better accuracy at long range. If I think some more there I might be able to understand that one though. Long night with fire calls and such and I am not totally clear headed this morning. Off to get some more shredding done.

But it can be fun to calculate all that other stuff in the off season.

390gr carbon express maxima shooting 321fps
422gr gold tip shooting 311fps

Which of these would you prefer to shoot at whitetail deer.

422grn. 10 fps only translates into about 2" at 40 yds

So you think the heavier arrow would be better? I've always shot the lighter one but with my new bow I can shoot the heavier arrow faster than I could the lighter one with my old bow

Yes I do. The heavier arrow will penetrate better and quieten your bow which is never a bad thing.

I use what is probably an identicle setup, but I haven't timed them, though I could easily. Where I hunt, bow noise is far more important than arrow speed.

+1

Just shot my Sarrells blue ridge sr longbow over the chrono. 44#@28" with a 427 gr. Arrow, got 235,237 and 239 fps.

Be sure to tune your bow to eliminate fishtailing before you try the chrony. A whipping arrow can knock it clear off a tripod. I learned that 30 years ago.

I chrony'd my setup under an array of conditions:

4 settings up and down my "draw weight" scale.

100, 125 gr tips

then the topper.... when I cut the 4" of unnecessary arrow length off my arrows.

each of those had a fairly linear impact on my fps. Good stuff and WELL worth the data gathering. I put it in a pretty cool spreadsheet. (cause I'm a geek, and that's what geeks do)