Which arrow would you shoot KE Momentum updated numbers

[bigcountry25]

I finally got my weight tubes in and done some testing for speed ke and momentum I figured this numbers at bowjackson.com(thanks aurthurp). I will be hunting with a 4 Blade mechanial broadhead the rocket hammerhead 4L. I am shooting 28.5" carbon express cx300 3D Selects fletched with 3 2" blazers with 100gr feild tips out of a Bowtech Allegiance 29" draw and 70lb draw weight.


I went to an archery shop 40miles away because the number just were not adding up I think these number are more righ than the ones I had before. Let me know what you folks think.


Arrow 1. Speed: 305.1fps Arrow wieght: 372gr. KE: 77lbs Momentum: 0.5032240lb-sec

At 30 yards Speed: 294fps KE: 71lbs Momentum: 0.4856529lb-sec Vertical Drop: -18"

Arrow 2. Speed: 288.8fps Arrow wieght : 420.5 gr KE : 78lbs Momentum: 0.5384428lb-sec

At 30 yards Speed: 275fps KE: 73lbs Momentum: 0.5221888lb-sec Vertical Drop: -19"

Arrow 3. Speed: 281.0fps Arrow wieght : 453gr. KE: 79lbs Momentum: 0.5643921lb-sec

At 30 yards Speed: 273fps KE: 75lbs Momentum: 0.5485427lb-sec Vertical Drop: -21"

[walks with a gimp]

I think that if your arrow weights are correct, something is wrong with your chrono

[bigcountry25]

The arrow speed at 30 yards is done by the calculator at bowjackson. WWAG what do you think is wrong with the chrono? I shot each arrow 10 times and averaged the speeds and the most varance was 3fps on an arrow. I also shot a 356 gr arrow at 312fps 5 times in a row.

[walks with a gimp]

Your bow lost 21 fps by shooting an arrow that weighed 47.5 grains more; 372 grain arrow and 305 fps and a 420.5 grain arrow with 284 fps. Then your bow lost only 4 fps by shooting an arrow that weighed 32.5 grains more; 453 grain arrow at 280 compared to a 420.5 grain arrow at 284 fps.

[PABowhntr]

I think that if your arrow weights are correct, something is wrong with your chrono

I think what WWAG was making reference to was the 4 fps change in arrow speed for a 32.5 grain change in arrow weight. Normally an arrow loses 1 fps for every 3 to 4 grains of arrow weight increased considering this specific grains per pound of draw weight ratio. Operating under the assumption that the second arrow speed is the correct one I would expect an arrow speed of around 274-275 fps with the 3rd arrow. That would lower both the KE and momentum figures for the 3rd arrow.

Edit: Sorry Russ. We were posting at the same time.

Come to think of it though, the change in speed versus change in arrow weight from the 1st to 2nd arrows doesn't necessarily jive with accepted ratios either. I am not doubting the genuiness of the post just the results.

[bigcountry25]

I checked the arrow wieghts and they are correct.

Walks: I know I found that very very odd but it repeated it's self over and over and this chrono has been very reliable but it may have something wrong with it. But I don't know anyone else with a chrono to chech it.


Also would you go for the speed or the momentum with the type of broadhead choice I made? The bow shots very well with the 372gr arrow.

[Kanga]

From the figures you posted I would opt for arrow number 3.

This is the one that gives you the best KE and Momentum.

[walks with a gimp]

Chronos can be picky about lighting conditions, mine is and it likes for the sun to NOT be shining into the slots. Also the height the arrow passes above the screens seems to make a difference also. I only shoot over my chrono outside.

[Arthur P]

What you could do: Arrow #1 for deer and antelope. #2 for elk, wild hogs, black bear. #3 for moose and big bears. Since I like keeping things simple, I'd just use #3 for hunting everything.

Be careful not to confuse arrow drop with trajectory. If you sighted in each one of those arrows at 30 yards, there wouldn't be an inch difference in midrange trajectory.

[bigcountry25]

I went to a shop about 40 miles away and got some different numbers I guess mine my be off a bit.


Arthur P: I agree the drop would not be what the chart says but I put all the info the chart gave me.