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#4001947 - 04/16/10 03:07 PM Arrow weight VS speed
JJHACK Offline
Campfire Tracker

Registered: 01/30/01
Posts: 7222
Loc: Touchet Wa. & Ellisras South ...
I was testing a bow today that has been used as the most successful hunting machine I've known in my life. There has never been a lost or wounded animal with this bow, and it's taken several hundred head of big game from Small deer and African Antelope up to American Bison in size.

Here is the data from my freshly back from the factory calibrated Chronograph.

This was with a 63lb Switchback 28.5" draw

330 grain arrow with 100 grain point 280fps
355 grain arrow with 125 grain point 270fps
375 grain arrow with 100 grain point 266fps
400 grain arrow with 125 grain point 260fps
417 grain arrow with 125 grain point 254fps
450 grain arrow with 125 grain point 244fps

I have killed big game with every one of these combinations. The majority have been with the 400 grain weight. I have strayed from that over the years but I always seem to come back to this combination.

When I see how pathetic the speed is with this compared what others are getting I feel embarrassed! like I'm shooting a kiddy bow. The 280fps seems good but it's with a light weight 330 grain arrow.

Is it worth going down in weight to 355gr to get to the 270fps speed? That is a 45 grain weight loss from the 400 grain weight.

What is worth more 45 grains of weight or 10 fps?
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#4001957 - 04/16/10 03:10 PM Re: Arrow weight VS speed [Re: JJHACK]
JJHACK Offline
Campfire Tracker

Registered: 01/30/01
Posts: 7222
Loc: Touchet Wa. & Ellisras South ...
An interesting look at Foot Pounds of Energy here. I decided just out of curiosity to calculate this to see what it looked like. As a side note, let there be no doubt that 60fpe with a Slicktrick will kill any animal under 2000lbs without any problem at all.
-------------------------------------------------------------------
330 grain arrow with 100 grain point 280fps 57fpe
355 grain arrow with 125 grain point 270fps 57fpe
375 grain arrow with 100 grain point 266fps 58.9fpe
400 grain arrow with 125 grain point 260fps 60fpe
417 grain arrow with 125 grain point 254fps 59.7fpe
450 grain arrow with 125 grain point 244fps 59.5fpe
---------------------------------------------------------------------

It would appear that the 400 grain weight is the best combination for Energy with this bows draw weight and cam curve.

Also funny to me that it's the combination that shoots so well and has been the primary combination used for well over 100 big game animals( hunting and culling). Guess I should not have been surprised by what I already knew from experience, but it was a little surprise to see this work out with the math formula's as well.
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#4001996 - 04/16/10 03:30 PM Re: Arrow weight VS speed [Re: JJHACK]
SAVAGE14 Offline
Member

Registered: 03/04/10
Posts: 53
Loc: michigan,wayne county
your draw lenght hurts you . plus shot placement is more important than speed . think about recurvesand long bows

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#4002065 - 04/16/10 04:02 PM Re: Arrow weight VS speed [Re: JJHACK]
Tom264 Offline
Campfire Kahuna

Registered: 12/19/06
Posts: 21541
Loc: above you.....
JJ I personally think 400 grains is about the perfect weight in any speed for archery.

I myself shoot 417.? grains (I know what your saying, .?) yeah, I weigh all my arrows and broadheads to the tenth of a grain = anal...I know.

Anyway I shoot at 299-300 fps, never had a problem with blowthrough with any broadhead and would use this combo for any game I encountered with the exception of Africa big 5 and NA Grizzly.
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#4002573 - 04/16/10 06:46 PM Re: Arrow weight VS speed [Re: Tom264]
B_Lance Offline
Campfire Regular

Registered: 04/08/08
Posts: 396
Loc: Out West- between liberal heav...
I'll always choose the heavier arrow-within reason.

With penetration being the critical factor and you always get better penetration with the heavier arrow...its simple for me.

Every accomplished bowhunter I know who has killed a pile of animals uses a heavier arrow [425gr+] And the funny thing is they ALL started out with light fast arrows.
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#4002679 - 04/16/10 07:12 PM Re: Arrow weight VS speed [Re: B_Lance]
JJHACK Offline
Campfire Tracker

Registered: 01/30/01
Posts: 7222
Loc: Touchet Wa. & Ellisras South ...
My Glen Del buck is pretty new and I never shot from the back. So today I shot it from the back for a little off the cuff test.

I shot three weights ( 355-400-450) five times at 25 yards.

The deepest penetration 100% was the 400 grain arrow, then the 450 grain which was about 1.5 close to 2" less and then the 355 which was between 2" and 3" less.

All very close but it's again kinda interesting that the penetration meets the exact result of the calculated amounts of FPE. There is something really great about having seen this for many years and many dozens of animals. Then to drag out the tools, science and math with the calculations only to find that what I knew from experience was matched up with the engineering we have all been taught all along.
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#4003135 - 04/16/10 10:47 PM Re: Arrow weight VS speed [Re: JJHACK]
krp Offline
Campfire Outfitter

Registered: 01/04/05
Posts: 8841
The 400 grain arrow is spined the best, therefore hitting square the best, shooting the straightest, penetrating the most.

You are shooting 125s on all three.

put a 100 even 85 on the 355 and a 150 on the 450 and see if it will bring them into spine.

400 is not a magical number, just with that arrow spine, with the length cut and the 125 used.

Use an arrow that weighs 300 instead of 275 and add a 100 head, still 400 total and see if it shoots as well and penetrates as much.

you are most likely underspined on the 355 and overspined on the 450. Either means the energy in the arrow is not square behind the broadhead, losing penetration.

KE is dictated by poundage/energy. As you show, a difference in 35% of arrow weight only loses 5% of KE, not enough to worry about. The small percentage you gain in momentum from a heavier arrow will only be realized if the spine is correct on all compared weights.

This all relates to tuning issues people have because they buy a bow a set it at 70 lbs or whatever, cut arrows and buy a head weight. Then try to adjust nock and rest. Sometimes it's close and others it isn't because one of the three do not work with the other two for spine. You have three different weights that probably all were charted for your poundage and yet your numbers prove that it's just a start on spine and not an endall.

Spine effects arrow flight more than any other factor.

Kent

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#4003152 - 04/16/10 11:14 PM Re: Arrow weight VS speed [Re: krp]
CRS Offline
Campfire Ranger

Registered: 12/21/05
Posts: 1946
Loc: Black Hills of Dakota
When I did KE and momentum testing on longbows, recurves and compounds, without a doubt, every time I incresed weight, this lead to increased energy, and decreased velocity.

Started at 270gr and went all the way up to 1300gr. There are some flatter and steeper sections when I plotted the data. I attributed it to the changing in dynamic spine.

So I agree with krp above.
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#4004121 - 04/17/10 11:31 AM Re: Arrow weight VS speed [Re: CRS]
kenner Offline
Member

Registered: 01/02/09
Posts: 65
Loc: SoggyFoot, Oregon
"Pathetic speed"?.... What's pathetic is seeing 15-20" of penetration from these super-bows, at close range....

Go with the added weight. Shoot a narrow, cut-on-contact, two blade. Read the "trad" articles/forums and see what the other side is doing. We're shooting much heavier arrows at much reduced speeds and the arrows go right through and out the other side.

Arrow penetration: If there's a problem,there are several factors:

I. Too light of arrow. (425grains is a light arrow.) Stick with the old idea of 10-12 grains/pound. (500-550gr would be ultra-efficient with a 63# compound) I think "Uncle Ted(Nugent)" has even dropped his poundage down and will tell you that a 50# bow, with a two-blade broadhead, will get the job done... But then, every "50#" bow is different... it's about what speed the arrow leaves the bow.

II. Broadhead has too much resistive, or cutting surface/too steep angle and/or too many blades.

III. Poor arrow flight. Your arrow should look like a torpedo in flight, going straight towards the target.

If not, you need to tune your arrows by changing the head weight, the length, or the amount and angle of fletch.

(krp is spot-on!)... when you changed your head weight, you changed the way your arrow flew and how it entered the target. An arrow is a system, a bow is a system, the archer is a system,, and any change in this ecosystem, can do a lot of change. I'm glad you're asking the question!!.. It'll lead you to a whole new dimension of archery and obsession.

Broadheads require more fletch. They also can come off a rest differently. The height of your nock point will make a radical change in flight as well.

In order to get penetration, your arrow has to be going straight and not slam into the animal sideways. One needs a sharp, narrow broadhead, on a heavy arrow... One doesn't need speed.

Good shootin'.... Ken

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#4005780 - 04/17/10 09:34 PM Re: Arrow weight VS speed [Re: kenner]
CRS Offline
Campfire Ranger

Registered: 12/21/05
Posts: 1946
Loc: Black Hills of Dakota
Quote:
When I see how pathetic the speed is with this compared what others are getting I feel embarrassed! like I'm shooting a kiddy bow. The 280fps seems good but it's with a light weight 330 grain arrow.


JJ,
I hunt with a 60lb recurve and longbow, 600-620gr arrows, COC heads. (Magnus Journeyman, Eclipse, Bear super razorhead)

I use wood arrows painstakenly matched for spine and weight. I also like the skinny carbons like Beman MFX and Easton Axis with weight tubes for my desired weight.

The setups are tuned to perfection using the bareshaft/fletched method described on OL Adcocks website.

I know that neither of these setups are over 200fps.

I have to go back quite a few years to remember any animals I have shot that were not complete pass throughs. I also have to go back to the early 90's to recall the last shot I took over 20 yards.

IMO arrow flight is utmost importance to aid penetration.

As far as the embarrassed statement. I don't think you really mean that. Do you feel embarrassed using your plain jane 30-06 when someone else is using a magnum?
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