Point of diminishing return ?? Where ya think?

[madtinker]

I get the calculated equation for force and momentum on paper and agree with it.

However, it would really be interesting to see a measurement at the actual impact of the target. Then can compare from arrow to arrow, speed to mass weight, etc. Then you can actually see how the momentum equation actually works. How more mass and less speed compared to higher speed and less mass…when those two show momentum the same.

There has to be a more simple than you think way to do that. Kind of like the sledge hammer force hitting the bell gag at the fair.

Measuring electronically has many challenges, the cost of the equipment and the speed it has to operate being only two. Using a pendulum and a mechanical device to mark the highest point of the pendulum’s swing after impact would be much simpler and allow you to compare impact energy between any number of bow set ups.

The finer points of lowering friction to make it operate consistently would take some work, but it’s certainly feasible. There would always be some error in the measurement because the arrow would always dissipate some energy as it punctures the pendulum, but I think you’d still get a useful comparison between setups.

 

[Arcus Venator]

A quick perusal showed only one mention of gpp. When I got into Trad 30 years a ago, the recommendation was for 8-12gr per pound.tried super light, makes for a noisy bow. Super heavy makes for an efficient quiet bow, but trajectory suffers.

Anymore, I try to get in the 10-11gr per pound for my setups. That seems to be my sweet spot. Have completely passed through deer and broken bones.

Heavy is nice shooting until the distances stretch out.

I have

 

[Sapcut]

Regarding the GPP sweet spot, It greatly depends on the bow. I have heard 10 gpp from everyone and their brother for years. I only have one bow, a Black Widow PSAX, [email protected]. A 700 grain arrow is waaaayyy too light to consider it efficient from any angle of thought. Too much hand shock, too much wasted energy, inability to see the arrow fly like it want to (which is imperative for instinctive shooting) and will stop quicker upon resistance compared to the more efficient arrow for this bow, which is right about 875-900 grains, when considering all things other than penetration potential. However, so far, a 1200+ grain arrow is not less efficient once impacting an animal under 18-20 yards or so with my bow.

In comparison, my last bow many moons ago was a Bear hunter takedown, 70@28 It had a dacron string and although I didn't know much at all about it back then, it shot a much lighter arrow really well. I'm guessing it was closer to 600 grains.

So I think the 'high performance" type bows with FF strings will have a sweet spot at a significantly heavier arrow mass than less quality bows.

When, and IF, penetrating animals, bones and all, is paramount and a genuine interest to a bowhunter, increasing arrow speed by decreasing arrow weight is not the answer. There is a very sound reason why bowhunters hunting water buffalo, elephant, etc build arrows that are much heavier than used for other game. Never is arrow weight decreased in order to gain speed.

 

[Arcus Venator]

Just got a Widow PSAX with carbon limbs and have been playing around with quite a bit 46@28 and I draw 29. The arrows I have tuned right now are 520gr. Shooting good, but I also tuned some heavier arrows that I had in the 650gr range.

The heavier arrows sure calmed/quieted the bow down, not that the lighter arrow are bad at all. But when I stretched the distance they were dropping off pretty fast.

May cut another 0.25-0.5 inches off the lighter arrows to add another 50gr to the tip. Might be a happy medium.

Any of them will shoot through a deer, and hopefully a black bear this spring.

I did a study once where I shot longbow, recurve, and compound. INcreasing arrow weight as I went. Every increase in arrow weight, increased momentum.

If I remember correctly from 20 years ago. When looking at the graphs of arrow weight vs momentum. There was a significant jump around 400gr with a non linear increase from there.
All bows were 60lbs, shot out of a shooting machine with release.

 

[Medic77]

I just think there is waaaay too many variables to come to a conclusion. Depends on what animal you're hunting for me. I used to shoot 60-70 LB bows exclusively with heavy ol FMJ arrows. I would get a pass thru no problem. Fast forward a few years, went to a 55lb bow with those same said arrows (different spine but same weight basically) and I would still get a pass thru. Fast forward to today, after several western trips for elk and muleys while still hunting big Midwestern whitetails, I am shooting an arrow that is more than 100gr lighter than the FMJ out of a 50lb longbow and the results are the same.

I realized that I didn't need to pull all that weight to still give me my desired same outcome and now benefit from a much flatter trajectory at 30 and 40 yds (not that I've shot an animal past 30).
If I lived in Texas and was hog hunting all the time, I would go back to the heavy arrows in a heartbeat. If I was Moose hunting.... heavy arrow. Realistically, I hunt deer and elk. My 550gr Day Six or Gold Tip pierce micro diameter with 300gr up front will do the trick every single time I do my part. (As long as they're tuned correctly)

 

[Sapcut]

I just think there is waaaay too many variables to come to a conclusion. Depends on what animal you're hunting for me. I used to shoot 60-70 LB bows exclusively with heavy ol FMJ arrows. I would get a pass thru no problem. Fast forward a few years, went to a 55lb bow with those same said arrows (different spine but same weight basically) and I would still get a pass thru. Fast forward to today, after several western trips for elk and muleys while still hunting big Midwestern whitetails, I am shooting an arrow that is more than 100gr lighter than the FMJ out of a 50lb longbow and the results are the same.

I realized that I didn't need to pull all that weight to still give me my desired same outcome and now benefit from a much flatter trajectory at 30 and 40 yds (not that I've shot an animal past 30).
If I lived in Texas and was hog hunting all the time, I would go back to the heavy arrows in a heartbeat. If I was Moose hunting.... heavy arrow. Realistically, I hunt deer and elk. My 550gr Day Six or Gold Tip pierce micro diameter with 300gr up front will do the trick every single time I do my part. (As long as they're tuned correctly)

To clarify… “same desired outcome”. Are you referring to soft tissue rib cage shot placement penetration or big bone penetration?

 

[Medic77]

To clarify… “same desired outcome”. Are you referring to soft tissue rib cage shot placement penetration or big bone penetration?

To be fair, I tend to stay away from the shoulder on deer but have had the same quartering to shot with both arrow setups. Both under 15yds, shot in front of the shoulder in that pocket, thru the brisket and clean out the other side. Obviously I don't get a pass thru on every animal I've ever shot and have had a few that have broke the opposite shoulder or other factors like a poor shot.
I used to use VPA 3 blades (the cool red ones) with the heavy arrow setups but have since gone to Iron Will wides with the lighter arrows (I went with the wides because I do tend to stay off the shoulder). I know that makes a difference.

When I first started my trad journey and was completely lost, I shot two hogs with a standard light arrow shaft, standard insert and 100gr head (I'm sure my arrows were tuned horribly as well). I had little to no penetration but still, by the grace of God, killed the hogs. It was complete luck but made me start investigating a different way when the hunt was over.

On a side note, if my bows were/are loud with the lighter arrow setup I wouldn't even consider shooting them and would try to find that happy medium

 

[Medic77]

To clarify… “same desired outcome”. Are you referring to soft tissue rib cage shot placement penetration or big bone penetration?

By the way, your arrows are cool as can be and I bet they hit like a sledgehammer. I love how everyone does things differently and proves to me, there are plenty of ways of shooting and hunting styles to get the job done. It's awesome

 

[Beendare]

Sorry Sap, but There is more to your question of diminishing returns here.

I shot a heavy compound for decades. I worked up to a heavy recurve when I started.
I finally realized;
Both of those ‘Heavy’ bows had diminishing returns…in fact, there was wayyyy more disadvantages than advantages. Its the same with very heavy arrows.

When we are getting incredible performance from 45-50# bows and 10gpp-12gpp…how much further past the animal do we need the arrow to go?

I can shoot a field round, a 3d shoot….and essentially easily draw, hold and aim my 50# recurve whenever I need to. A bow that is easily controlled is consistently more accurate…that matters in the woods.

Personally, coming from heavy fast compounds and mech heads….I was convinced that heavier is better. Nope, its not.

 

[Sapcut]

My interest in diminishing returns has nothing to do with anything other than penetration. I realize lots of guys hunt with the same setup they can shoot three rounds of 3D per day in a three day weekend. That certainly has nothing to do with my initial post.

If all personal preference bias can be set aside here and If you have seen diminishing returns where an arrow is so heavy it stops penetrating, please share. You know, the same exact reason arrows stop penetrating because they are too light. And we see that every where we look. And I am referring to resistance that will actually stop arrows like animal bones.

All else equal obviously, we could Inject broadhead style, etc but that’s another conversation as is being physically able to shoot a light bow all day long.

 

[Arcus Venator]

I think a person would have to go to an awful lot of work to get an arrow weight up so high that it would cause diminishing penetration.

I actually went back to three blade VPA's because my 50 lb bows were blowing through deer with two blade heads.

If I did a bunch of hog hunting, I would probably lean toward heavier,

 

[Beendare]

Ok gotcha.
personally I haven’t see that much difference in penetration between the middle of the road recurve setups Ive used- namely because of the 2 blades. I dont know how one can exclude the BH from a penetration discussion…its an over riding factor.

I have seen light fast arrows from a compound literally stop dead with shallow penetration on critters that are nothing special…but again, its a combo of things…not just arrow weight.

Physics explains this. Its the same reason the space capsules heat up on reentry- friction. The faster arrow creates more friction…and that higher friction is noticeable on an animal without much arrow behind it.

edit; i should have added that this was with an Inefficient BH, mech or short/wide chisel head. I have a buddy shooting 400g arrows in a 50# recurve and he gets great penetration using 2 blades. IME, Arrow weight helps when we hit something hard….otherwise its less of a factor with the right head.

The physics on an arrows diminishing returns is wayy up there in the 1500g range ( I cant remember exactly) per the excellent tests done by an engineer that went by Widgeon, he used to have it on an internet site And posted it on AT decades ago.
.

 

[Sapcut]

Ok gotcha.
personally I haven’t see that much difference in penetration between the middle of the road recurve setups Ive used- namely because of the 2 blades. I dont know how one can exclude the BH from a penetration discussion…its an over riding factor.

I have seen light fast arrows from a compound literally stop dead with shallow penetration on critters that are nothing special…but again, its a combo of things…not just arrow weight.

Physics explains this. Its the same reason the space capsules heat up on reentry- friction. The faster arrow creates more friction…and that higher friction is noticeable on an animal without much arrow behind it.

The physics on an arrows diminishing returns is wayy up there in the 1500g range ( I cant remember exactly) per the excellent tests done by an engineer that went by Widgeon, he used to have it on an internet site And posted it on AT decades ago.
.

Agree. Broadheads these days are certainly a game changer regarding traversing thru animals with any weight arrow. Another conversation that is extremely important when it comes to making animals dead is the lethality of arrow building (not only mass) and how that can make tremendous differences pretty much with any weight bow. When its truth time, the arrow is the killer.

 

[Arcus Venator]

I think Monte Browning used fiberglass fish arrows in the 1200gr range, but he also shot heavy bows.

There is no doubt that modern carbon arrows, FOC physics, , heck for stout broadheads and improved performance traditional bows have certainly upped the penetration game.

As to my personal opinion on where the diminishing returns is? I can only speculate. I think it may be higher than 1500gr.

 

[Sapcut]

Well so far, 1361 grains or 19.44 gpp from my bow wasn’t even close to slowing down thru deer matter. Although it was a easy peezy rib cage shot.

 

[Arcus Venator]

I can not imagine a rib cage shot deer slowing down a 1361gr arrow very much.

All this talk and I am going to have build up a super heavy arrow just to play with. ;-)

I can certainly tell the difference in penetration from heavier arrows out of my 50# bows on my target butts. Even more so when shooting 60# and 600-850gr.

 

[Beendare]

I’m with Arcus on the 10-11gpp….and maybe a liitle more to 11.5-12gpp. Its a sweet spot for all around performance.

When I can blow 2 arrows through an 800# moose at 30y with a 47# bow, any additional arrow weight just gives me less accurate gaps.

 

[Seeknelk]

If your shooting that much weight at little deer , may as well put a 4" cut broadhead on it instead of shooting a foot into the dirt. Short blood trails I bet

 

[Beendare]

Look shoot what you want…but some of this internet stuff is getting ridiculous….many get lost in it. So what if physics says more weight is better? Its a tiny incremental difference…not even measurable on game.

Its not like we are trying to pierce Armored soldiers at Agincourt….grin

 

[GLB]

The demising returns is when you start shooting under stuff. If you hunt deer from a tree stand 20 yards and in with predictable shots you can get by with extremely heavy arrows. Out west and open country with shots that are unpredictable and 20-35 yards something in the 9-11 grains per pound makes more sense.