Too heavy? Arrow building

[Keedman]

I know that the trend is to run heavy these days the 500+grains. I can understand why it makes sense. However at what point is the arrow too heavy?
My current arrow 28" is a 445 @245fps. 27 inch DL. Off hand im getting 56ke.
If I bump to a 600 estimated speed at 213fps so it would be roughly 50ke. I have some 500grain builds but haven't shot them or ran numbers yet.

Will the heavier arrow still give the penatration benefit even tho it has less energy at the gate?

 

[Brendan]

Everyone always forgets to list or talk about their draw weight, draw length, and poundage when they say - "Run a heavy arrow".

Take guys like Dudley - pretty sure he's running 70# and 31# draw. Aron Snyder is 80# with a compound, and 29" draw. Both of those guys have said - "Run a heavy arrow", but they've also said that they prefer an arrow speed of 275-285 fps or thereabouts (Which, coincidentally they get with a 500+ grain arrow). Two of my arrow builds are 505 grain, and 518 grain. But I get from 272 - 280 ish with those arrows with a draw length of 29.25" and a draw weight of 73#.

So, my opinion for you is - Yes, too heavy unless you're taking short range shots only. No way I'd be going up in weight, I'd stay where I was or even potentially consider going down depending on what I was shooting and at what ranges. Not going to matter at 30 yards and under, but pin gaps, sight clearance, errors due to being off on range estimation are a problem with a heavy, slow arrow.

 

[jpe5714]

I'm shooting 260fps with my 425 grain Victory (27"DL, 67lbs)
My pro shop owner said 450-500 grain is the sweet spot for compounds
said you don't need a real heavy arrow unless your shooting a stickbow

 

[Brendan]

My pro shop owner said 450-500 grain is the sweet spot for compounds

This is exactly the issue I have. I know you listed yours, but the sweet spot for what draw length and draw weight? It matters.

If you're shooting 40-50# and a short draw length, it is absolutely NOT the sweet spot. If you're shooting long draw lengths and heavy poundage, again - NOT the sweet spot.

Another reason why I don't trust 99% of "Pro" shops...

 

[wayoh22]

It's all relative no matter which way you swing it. What works for someone won't always work for another. Literally called a local shop to see if they had any match-grade Axis in 300 spine yesterday and was told word for word: "Woah, no. That's a really heavy arrow for us to be dishing out. Don't think we've ever carried anything that heavy let alone the match-grades. We usually use 400 or 340 as a last resort"....

Brendan is 100% right, need to know the variables in play here

 

[Billy Goat]

Sweet spot is a grains per pound, not an actual weight. I think it's around 7-7.5 grains per pound to maximize the energy of a compound bow. Get past 30" draw and it will be more than that.

I generally go lighter than that. I like to have some speed for open country. I like to be at least 285. Last year I had a heavy arrow setup that was turning low 260's and hated hunting with it. It was accurate and quiet. If something moved on you after you ranged it you had problems. Few yards made a pretty big difference. Let something walk away from you on angle while at full draw, animal covered 10 yards, but it was at a low angle to you. Is it 2 yards further or 5?

Currently I'm shooting 492 grains at 283 fps.

 

[Dwnorton1]

I have a hoyt that would not tune until heavy arrow. I shoot 650g plus. 109ke at 0 97ke at 60myards.
Heavy only means slower with different POI. I have no fear of releasing an arrow on an animal in about any position When I release I know I am getting pass thru even if it means destroying both shoulder blade on pretty much any bone on about any North American game.

The bonus was it quieted the bow. A loud fast bow cannot out shoot an animals reflex. I do have a long draw 31" and 69lbs so I do start with mechanical advantage

 

[Bmoore]

It's all relative no matter which way you swing it. What works for someone won't always work for another. Literally called a local shop to see if they had any match-grade Axis in 300 spine yesterday and was told word for word: "Woah, no. That's a really heavy arrow for us to be dishing out. Don't think we've ever carried anything that heavy let alone the match-grades. We usually use 400 or 340 as a last resort"....

Brendan is 100% right, need to know the variables in play here

I put up a post last week or so about this exact thing. Shops just don’t seem to care about your bow spec. They hand you a 340 spine and assume your good to go.

 

[Bmoore]

To the OP original question, penetration is more dependent on momentum than kinetic energy. There plenty of info out there in regards to this but a good analogy I’ve heard is you can get a 22 bullet flying at tremendous speeds and show higher KE than a slower 30 caliber bullet. But no one should be shooting an elk with a 22. The 30 caliber bullet moving much slower has a higher momentum, meaning it takes more energy to slow the projectile down. That equates to better penetration. So don’t get lost on the numbers there.
Secondly, as others have mentioned it’s really a preference thing. Basically shoot as heavy as you can go that still allows you a trajectory your happy with. There is no speed or weight number that works for everyone. It’s what makes you comfortable. If you can be happy with the trajectory that the arrow produces for you at ranges you will shoot, then it’s heavy enough. If it’s getting too slow and you uncomfortable woth drop at yardages you plan to hunt, then back the weight off a bit. It’s all a balance.

Im personally shootingIn whitetail country and won’t take a shot over 40 period. That’s my comfortzone for white tails on the east coast. So I’m not worried a kit trajectory at all. My arrow weight is gonna be 575 and I don’t know the speed at all. I’m 30” draw at 65 lbs. I’mhappy woth my trajectory out to 40 and confident as I can be that the arrow is gonna make a clean pass through on any deer I shoot at. So I’m at My sweet spot.

 

[N2TRKYS]

Sweet spot is a grains per pound, not an actual weight. I think it's around 7-7.5 grains per pound to maximize the energy of a compound bow.

Good case in point, that hard and fast numbers don’t work across the board for everyone. Even using that method is way too heavy for me.

 

[5MilesBack]

However at what point is the arrow too heavy?

For me, my arrow is too heavy when I can't get all 7 pins set in my sight anymore.......and that's keeping my middle pin (50) in the middle of the sight guard.

 

[Greenmachine_1]

A few things:

1. Figure out what shoots best out of your bow with your hunting style. 70# 30in. Draw people are probably going to find success using a 500+ grain arrow. As you lower your draw weight and/or draw length, you are likely going to need to lower your arrow weight or effective range. This is purely due to the fact that they don't have enough energy to be effective.

2. You didn't mention what you were hunting or how far you were planning on shooting, but a couple of things to consider. With a shorter draw length, I would definitely want you to know your effective range and understand that you are likely to have issues at longer ranges. Not saying it will happen, but is possible.

3. I would not expect your KE to decrease as arrow weight increases. Without going into a long rant, KE is an indication of bow efficiency and typically as you add arrow weight, bows become more efficient since they are moving slower. Underspined arrows might lose more energy, but it shouldn't be significant. Your estimates do appear correct on velocity though.



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Edit:

4. I'm not sure you would pick up enough momentum to be significant depending on your range. I would expect a slower moving arrow (245 fps feels slow to me) to lose less momentum during it's flight than a faster moving arrow.

 

[Mighty Mouse]

Arrow speed vs. weight is a trade-off between the flatter trajectory and tighter pin gaps of a lighter/faster arrow vs. greater penetration potential of a heavier/slower arrow. Where along the spectrum you choose to land is largely personal preference based on a combination of factors such as max shot distance, hunting style, and the animal you're hunting. There's no "correct" arrow weight, just a wide range of options bounded on the low end by avoiding damage to the bow (minimum 5 gr per pound of draw weight). "Too heavy" is wherever you decide your max range has become too short and/or pin gaps have become too large.

Not to imply that kinetic energy should be the determining factor, but your KE calculations are off. With arrow weight in gr (W) and speed in fps (S), KE in ft-lbs is calculated as W×S²/450,240, so 445 gr @ 245 fps = 59.3 ft-lbs and 600 gr @ 213 fps = 60.5 ft-lbs. KE increases slightly as arrow weight increases because the bow gets slightly more efficient at transferring the potential energy developed during the draw cycle from the bow to the arrow.

 

[Sled]

I know that the trend is to run heavy these days the 500+grains. I can understand why it makes sense. However at what point is the arrow too heavy?
My current arrow 28" is a 445 @245fps. 27 inch DL. Off hand im getting 56ke.
If I bump to a 600 estimated speed at 213fps so it would be roughly 50ke. I have some 500grain builds but haven't shot them or ran numbers yet.

Will the heavier arrow still give the penatration benefit even tho it has less energy at the gate?

for me, my arrow is too heavy when the spine is too weak or the trajectory is unsuitable for the distances i may need. mine all end around 420-450gr on my 65lb 30" draw bows (give or take). i haven't had a lack of penetration issue but then again i don't shoot leg bones. what i do pay attention to is where the weight is. if i can keep my FOC in the 10-18% range then i'm happy. yes, more can be better but i'm not forcing the issue.

if i get good flight, acceptable trajectory and the weight is suitable to the game i'm after...i'm going hunting and thinking about it anymore.

 

[406unltd]

I feel like everyone within the wide but normal parameters of draw length/pounds should try for a certain speed of 265-285 coupled with a good head and proper arrow build with weight where it needs to be. Smaller people/ children should consult professionals and or people with real world experience with those special circumstances. For the rest of us whatever weight you end up with to achieve that speed will likely yield you the optimal setup that tunes well. Add a awesome head on the top and all should be well for the hunt given the proper steps were taken and accuracy has been achieved. Happy mediums are what I preach for almost everything in life.

 

[Keedman]

Wow didn't expect this many responses!
1. To start my draw is a 27" @70lbs. My max effective range is 50 yards.
2. I live in cali chase mules and bears. Hopefully next year I'll try my hand at elk
3. @Bmoore that makes a ton of sense thanks! Never thought of comparing it to a 22 vs 308
4. For the most part I have been looking at ways to increase my arrow performance. I would love to be able to consistently get pass through shots an if I hit bone know that there is enough juice to punch through and still put the animal down.


Again thank you guys for responding this is my go-to place for anything I have questions about.

 

[Dwnorton1]

I Shoot and HHA site. With it at max range I can shoot 62yards. Anymore and fletching and nock hit site ring.

Read this in article for perspective. which would be easier to stop? A 16penny nail at 400fps or a railroad spike at 250fps.

Shoot heaviest you can that does not effect your comfortable range. I leave my site on 30yards
Guess what if animal is at 20. dead. 40 dead. one a liitle high one a liitle low. Past 40 drop get pronounced.
The super light super fast was selling point. IMO My bow is slow got to get new......

I Teaxs heart shot a doe,( that had busted me for years had it coming) busted through pelvis passed full length of body through front shoulder and stuck in ground in front of her along with about a gallon of blood.

I have to be careful what kind of targets I use as the material often sticks to shaft and PIA to pull arrow. If they do not sink to fletchings.

 

[fwafwow]

[snip]

Im personally shootingIn whitetail country and won’t take a shot over 40 period. That’s my comfortzone for white tails on the east coast. So I’m not worried a kit trajectory at all. My arrow weight is gonna be 575 and I don’t know the speed at all. I’m 30” draw at 65 lbs. I’mhappy woth my trajectory out to 40 and confident as I can be that the arrow is gonna make a clean pass through on any deer I shoot at. So I’m at My sweet spot.

Not to diverge too much from the OP's post/thread, but I "run" a similar setup (73#, 29.5", 286fps and 492 gr) for elk. When some people find out I shoot the same arrows for whitetail, they say that it's overkill. Not sure I understand the opinion, as it's not like using a 300 WM when a 243 would do (thereby possibly destroying more meat), as I can't "over penetrate" when my goal is to always have a complete pass-through on any type of animal.

 

[MattB]

Sweet spot is a grains per pound, not an actual weight. I think it's around 7-7.5 grains per pound to maximize the energy of a compound bow. Get past 30" draw and it will be more than that.

I am interested what you mean by that? On a couple of occasions, I have run a variety of arrow weights through a chrono and even at 9+ grs/# draw weight, the KE was still increasing. Maximizing is probably in the 10-12 gr./# and maybe more. It is just a matter of the heavier arrow capturing more of the bow's energy versus that arrow being lost through noise/vibration.

I do believe that 7-7.5 gr/# (or maybe 6.5-7.5) strikes a good balance between energy and trajectory.

 

[Billy Goat]

I am interested what you mean by that? On a couple of occasions, I have run a variety of arrow weights through a chrono and even at 9+ grs/# draw weight, the KE was still increasing. Maximizing is probably in the 10-12 gr./# and maybe more. It is just a matter of the heavier arrow capturing more of the bow's energy versus that arrow being lost through noise/vibration.

I do believe that 7-7.5 gr/# (or maybe 6.5-7.5) strikes a good balance between energy and trajectory.

That seems to be where I have found the sweet spot for energy with ke. It will vary depending on the setup, but it has held true for a lot of bows around 70# and 28-29 inches. You start getting too heavy and you loose ke.

Momentum will keep increasing with weight, but your ke will start to fall off with the reduction of speed.