Author Topic: Arrow Speed?  (Read 2162 times)

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Offline pathfinder

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Arrow Speed?
« on: August 02, 2008, 12:53:42 PM »
I'm a newbie Bowhunter.  I picked up a PSE Nova bow and the sticker says its set at 70 pounds, 28" draw which I assume is an estimation.  I shot some 125 grain tipped arrows through my chronograph at 219 fps very consistently about 5' in front of my bow.  Does that sound right?

I've read that a lot of bows advertise they will shoot over 300 fps and I think the Nova claims 265 fps.  Do they use a lighter arrow?  Is a 125 gr broadhead going 219 fps enough for Elk hunting?

Offline mg66

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Re: Arrow Speed?
« Reply #1 on: August 03, 2008, 12:33:39 AM »
A chrono doesn't lie. Just sounds slow to me. You sure it's 70lb draw weight? What is total weight of arrow? A lot of factors come into arrow speed like draw length, draw weight, total arrow weight, type of cams, etc. Also peep sight, string silencers, spiders, etc will rob fps.

I set the chrono about 12" - 18" in front of the bow. Not sure if this is correct but an arrow will start losing speed almost immediately upon leaving bow. Gravity and all that you know but physics was never my strong point at school  ::)

A bow is rated in fps using usually IBO standard or AMO standard. All is explained here http://www.bghi.us/index.php?x=bowspeed

Now my bow is a Mathews Ultra2 and rated at 320+ fps .... yeah right. Here is what is really gets.

Arrow and Speed Spec using Gold Tip 5575 XT Hunter Carbon Shafts

Total Arrow Weight = 375 grains
Draw Weight = 70 lbs
Draw Length = 30"

Chronograph Speed = 283 fps
Kinetic Energy = 66.71 ft/lbs

Kinetic energy is the real figure to look at. About 40-45 ft/lbs is the minimum for Whitetail and I think around 65 ft/lbs (correct me if I am wrong here people) for Elk.

There are kinetic energy calculators on the www but you MUST know draw length, draw weight, arrow weight, etc precisely to get accurate figures.
mg66 - "every deer you legally take with a bow is a trophy"


Offline bscman

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Re: Arrow Speed?
« Reply #2 on: September 16, 2008, 09:51:44 AM »
I know this is EXTREMELY late, but I thought I could throw a few things out there.

#1. What model PSE Nova is this?
Is it the single cam nova, or the older "round wheel" type dual cam nova?
The older is a bit slower than the newer.

#2. What is your draw length?
IBO testing is done at 30" draw length...it seems most shooters are shooting closer to 28" of draw length.
For every inch you decrease draw length you're going to lose in the neighborhood of 10-14fps. So if you're shooting at a 28" draw, you can immediatly expect your arrow speeds to be down to 240 from the established IBO speed of 265.

#3. Draw weight
As established above, IBO speeds are tested at 70lbs.
Are you shooting at 70lbs? A 70lb bow typically has 10-15lbs of adjustment. If it isn't maxed out, you aren't shooting at 70lbs. Also, when you shorten your draw length an inch you typically lose about 2lbs of draw weight. These 2lbs can sometimes by made up my tightening the limbs, but sometimes cannot without changing string or cable length.
Every 1lb of draw weight is good for about 1.75fps change in arrow speed.

#4. Arrow weight!
IBO testing is done with a 350gr arrow.
The "average" carbon arrow is going to weight 285-300grs at a typical 29-30" length...this does NOT include the tip...which in your case is adding another 125grains. If this is the case, your arrows likely weight over 425grains.
You're shooting an arrow that is ~20% heavier than the arrows used in IBO testing...so subtract that much more speed!

Last but not least, most IBO testing is done by the manufacturer...in their facilities...with their people!
--They usually test their bows in a machine rest--you will lost a small amount of energy while holding the bow simple because of body mechanics.
--They sometimes test with bare shafts--no fletching to drag speeds lower.
--They usually test from the "hard wall." This means they draw beyond the "valley" of the let-off, which usually means they pick up at extra few FPS from a slightly longer powerstroke.
--They test the bow with a bare string--no nock point, no peep sight, no dampeners/leeches. Everything you add will slow down your arrow speed.
--Last but not least, they also test the bow a zillion times, and only report the "best" test rather than the average numbers.

FOR THE RECORD
I believe statistics show that somewhere in the neighborhood of 35 ft/lbs of kinetic energy is all that is required to make a pass-thru shot on a typical deer. IIRC, the numbers for elk were in the neighborhood of 46-50ft/lbs. I used to shoot an old PSE Nova (60lb, 27" draw) that sent my 530gr aluminum arrows a little under 200fps...and was still getting pass-throughs on deer at 40+yds.

You have plenty of bow for elk--keep your shots true and don't take unnecessary risks.
Best of luck! Our elk season is already underway, as I imagine yours is as well!

Offline Graybeard

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Re: Arrow Speed?
« Reply #3 on: September 16, 2008, 11:49:00 AM »
I've never owned a bow that shot an arrow even that fast but I've killed a bunch of deer with my bows over the years. It's not about speed so much as it is quietness and accuracy. Put that arrow where it belongs with a proper broadhead and it will do the job. Don't worry so much about speed. I think the fastest I've ever clocked an arrow from one of my bows was 210 fps. Mostly I shot 80-85 pounds of pull and 2315 arrows with 125 grain Thunderhead broadheads. Never had one stop in a deer yet.


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Offline JonD.

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Re: Arrow Speed?
« Reply #4 on: September 29, 2008, 02:50:53 PM »
Mostly I shot 80-85 pounds of pull and 2315 arrows with 125 grain Thunderhead broadheads. Never had one stop in a deer yet.

Talk about kinetic energy... man that hit a deer hard.

Your gonna laugh....Back when I was shooting 3D shoots weekly, I used to shoot 84lbs with a 2213 on an overdraw, and was getting about 260fps from an old York Bushwacker. I shot one deer broad side(and this is funny) square thru the back hams, it zipped right thru him. I trailed this deer.. and shot him again, at 15 yards he stood up standing straight away from me. I shot him square in the hind end and the arrow went all the way thru him lengthwise. ;D ;D

Offline squirrellluck

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Re: Arrow Speed?
« Reply #5 on: September 29, 2008, 04:59:53 PM »
Makes me curious about my 29 in. 2315s and 165 grain zwickeys. kinda slow out of my 54# damon but the deer and hogs seem to fall down just the same.

Offline glockman55

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Re: Arrow Speed?
« Reply #6 on: October 01, 2008, 09:47:33 AM »
I'm a newbie Bowhunter.  I picked up a PSE Nova bow and the sticker says its set at 70 pounds, 28" draw which I assume is an estimation.  I shot some 125 grain tipped arrows through my chronograph at 219 fps very consistently about 5' in front of my bow.  Does that sound right?

I've read that a lot of bows advertise they will shoot over 300 fps and I think the Nova claims 265 fps.  Do they use a lighter arrow?  Is a 125 gr broadhead going 219 fps enough for Elk hunting?

Sounds slow to me, the sticker on your bow doesn't mean it is set at 70#, just that it should max out around 70#. My Mathews Legacey is set at 70# I shoot a 28" gold tip ultralight 22 series with 100 tip at 294 fps. total arrow wt. is 355 gr.
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Offline billynwtf

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Re: Arrow Speed?
« Reply #7 on: October 03, 2008, 05:41:11 AM »
 Forget about the speed. It is about how well it shoots. If you can hit the heart/lung section of a deer or elk with a broadhead you will make a killing shot. Your bow setup will be fine. Just practice and make sure you can hit your target at the range you will be hunting. And be honest with your self and dont make shots that you know you cant make. Back in my early years bowhunting I killed alot of deer with bows only shooting 220 to 230. And I have had friends kill elk with the same bow and nearly the same setup. Practice is the best advice.

Offline T.J. McSuds

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Re: Arrow Speed?
« Reply #8 on: October 05, 2008, 01:48:06 AM »
  I just chronoed my PSE Triton. At my draw(26ins) it is 49-50lbs pull. Using Gold Tip Carbon arrows with a total weight of 329 grains. it shot 213 fps.
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