Arrow Penetration

[dbHunterNY]

Basically I'm looking to be able to use a two inch cut mechanical broad-head with correct penetration. I have a 60lb bow at about 28.5 draw so i know my bow with current arrows at 8.1 GPI is shooting them at about 268 fps, but i'm wondering if a arrow in the 9+ GPI range is needed....

 

I shot deer last year with one of my bows:  PSE Bowmadness (330 fps IBO), 29" draw, 60lbs, Rage 2 blade titanium with a 2" cut @100gr, Hexx 400 arrow at 27.5" long and 7.2 gpi with blazer vanes.  deer were anywhere from 10 to 31 yards away and I got an entry and exit hole for each of them.  one doe at 23 yards even spun toward me at the shot, that was probably already slightly too far back and slightly quartering toward me.  arrow went in 3" behind the front shoulder and came out through the opposite hind quarter.  normally I've found they spin away so I thought that was weird.

[The_Real_TCIII]

Easy answer....... Would you rather get hit with a ping pong ball or a golf ball?

how fast is each going?

[JimMac]

that calc is a need little tool, not sure just how accurate it is , i pluged in my numbers

for my new bow 55lbs , 25 draw and it was saying my arrow speed should be in the 220 area

hit the chron with my bow but my arrows are cut at 28 (freebies) and chron was sayin

190 but was having issues with the chron giving Errrrrr on most of the shots.

 

cuttin my arrows down to 26.75 and the will clear the riser by a inch for a broad heads

then back and try the chron again and see what it says.

 

i figure i should be good when seasion gets here , up the bow to 64(max)lb , 25"DL

easton bloodline 400 7.7 gpi , 125 grain broadhead

 

 

[Lawdwaz]

how fast is each going?

87.5 mph

[The_Real_TCIII]

87.5 mph

Titleist??

[The_Real_TCIII]

The important thing is to make sure your bow is tuned, field tips hitting with fixed blades. A lot of KE is wasted if your arrow is fish tailing or porpoising, or your spine is incorrect for your setup.

[moog5050]

Basically I'm looking to be able to use a two inch cut mechanical broad-head with correct penetration. I have a 60lb bow at about 28.5 draw so i know my bow with current arrows at 8.1 GPI is shooting them at about 268 fps, but i'm wondering if a arrow in the 9+ GPI range is needed....

8.1 may work, but a little more weight certainly won't hurt and should help. I used 2" rage hypos last year and they were devastating. I shoot a heavier bow and arrow than you though. I think at your specs, you may be on the edge for a large cut mechanical.

[Hock3y24]

Sometimes that extra 25 grains on the broad head wil

Help of it isint to much for your arrow spine.

[chiefbkt]

Basically I'm looking to be able to use a two inch cut mechanical broad-head with correct penetration. I have a 60lb bow at about 28.5 draw so i know my bow with current arrows at 8.1 GPI is shooting them at about 268 fps, but i'm wondering if a arrow in the 9+ GPI range is needed....

 

I think as long as you shoot an arrow that is over 350 grains you will be fine.  You could always shoot a heavier arrow if you notice you aren't getting the penetration that you want.  My buddy that I hunt with shoots a 60 lb bow with 29" arrows that are about 370 grains.  He shot 2 deer last year and had complete pass through's.  One he shot quartering towards him and still got a complete pass through.  

[nyslowhand]

Lawdwaz...Think a better analogy would be to compare being hit by either a golf ball or a baseball at ~260/270fps. Which BTW equates to ~180mph. My choice would be neither!!

 

This is one of this forum's annual threads, that always seems to end up with no clear cut choice, other than personal choice! Much like discussions about the "best deer rifle"!

 

Think this discussion is overlooking the idea or theory of what is the appropriate penetration to get a quick & ethical kill on a whitetail sized animal with "cut on contact" archery equipment. Okay, so if your shot is less than ideal and hits a shoulder blade, granted a heavier arrow will compensate for a marginal shot placement. The type of BH also comes into play in these scenarios! No offense meant, I've been there & done that myself. Game bigger than deer would certainly need to be considered in choice of arrow wgt. Assuming all the s/u variables (and physics) mentioned in above posts are equal; my question is.... Aside from the obvious blood trails, is a complete pass thru a more lethal shot than one with only 1/2 the arrow (~13-14") penetrating the chest cavity?? As most will already know, another confusing point to some may be that the physics of Ke in "stick & string" relates only to penetration. Not to be confused with Ke in the ballistic comparisons of expanding projectiles, bullets.

 

If there were an obvious choice as to whether a lighter or heavier arrow were the better option, wouldn't there be only one available? Marketing & personal choice are the chief influences in arrow selection. I shoot a lighter arrow wgt for the benefits they offer and have been more than satisfied with their penetration. More power to those that choose heavier arrows, but they do come with their own drawbacks. In the end...chose what works best for you!

[Doc]

Ok.... let me slip in another dimension to this discussion about arrow weight and penetration. And I want to start off saying that I have no pre-conceived notions. This is truly just a question.

 

Does a lighter arrow react in a more exaggerated fashion due to slight form problems, or clothing contacts or marginal bow tuning than a heavy arrow, or vice-versa, or no difference?

 

I know that arrows that do not enter straight will effect penetration, so this aspect of the discussion is still truly on topic.....lol.

[nyslowhand]

I strictly shot 340 wgt carbon arrows, so I can't speak of your comparison. IMHO, the shooting issues you put forth would effect any arrow regardless of wgt or construction. Think a misnomer might be that lighter arrows are not as strong as heavier alum arrows. Also an arrows length (total wgt) effects penetration. The 340gr @ 30" is pretty comporable in total wgt to a heavier 400gr @ 26" length. Back to the Ke formula - the "v" component of the formula is squared for the slightly faster light arrow and will achieves an ≥ Ke in the comparison I suggested. BTW - yes, "v" of an arrow varies, but for Ke calc it is at impact. The construction of modern carbon arrows is a phenomenon of technology. But they will snap compared to alum arrows merely bending. Ever watch any YouTube slo-mo vids of an arrow's flight? Carbon arrows do flex and gyrate somewhat until the fletchings gain control and they stablilize in flight, even under ideal conditions. Probably more so the slimmer &/or longer they are or the size/length of the vanes.

 

Maybe we should suggest this as an episode for the Mythbuster to resolve by shooting arrows of different weights & BH types into those gel blocks! lol

 

Back to our regular programming, trade-offs & personal preferences! Mainly, as others have suggested, there is a sweet spot in arrow wgt for your scenario & equip. I know it's aginst the guy code, but bigger isn't always better! Yeah, still taking arrow weight.....

[wildcat junkie]

A 540gr arrow with a properly sharpened Bear Razohead will slice through a deer @ 25 yds like a hot knife through butter when the arrow leaves the bow @ 190 fps.

Kinetic energy @ the bow does not equal penetration @ impact yardage. The heavier arrow will retain more energy as the distance increases.

Edited April 18, 2015 by wildcat junkie

[NFA-ADK]

99% of the guys I shoot with that have a 60lbs draw use 400 's I used the 340 (heavier) for a long time and found the 400's with faster speeds penetrate the same in 3D targets.   

 

I am sure if I did a speed test on both and put in the calculations it would be about the same KE. 

340 at say 260 something fps is probably similar to 400's at over 270 fps.  Next time I test I will get the speed of both and post.

 

This calculator is a bit more simple.

http://archerycalculator.com/archery-kinetic-energy-and-momentum-calculator/

 

[The_Real_TCIII]

If you are over or under spined, or out of tune, penetration will suffer regardless of arrow weight. All that energy needs to be directly behind the shaft, fish tailing and porpoising misplace it

[biggamefish]

Doc I know a light arrow is far more likely to be pushed around by wind and have more of a deflection if it hits a leaf or small twig.  I would think form would also show up in a lighter arrow to some degree.

[beachpeaz]

My 340's go slower than my 400's and both penetrate about the same.  Heavy arrow shots slower and a light one shoots faster, both have about the same KE and are a pain in the neck to pull out of 3D unless you lub up the tips. 

 

If the speed was the same for both arrows then the heavy arrow has more KE.

Because you mentioned lubing the tip....

 

 

Edited April 24, 2015 by beachpeaz