Draw weight and fps question

[Don W]

This topic seems to have conflicting logic for me.

First it seems that if a 45#@28" bow shoots a 600 grain arrow at 160fps, and a 60#@28" bow shoots the exact same arrow at the exact same speed, everything we shoot a bow for (like penetration, cast, etc) is exactly the same, but the lighter bow would be more accurate for most people, more people could shoot it, it could be shot longer, it's probably easier to make and would likely be more stable.

The conflicting logic part is if this were true, anyone buying a bow would want to know the fps (based on a consistent # like 10gpp) and not just the draw weight like it typically is, any one making a bow would also be more interested than a lot seem to be.

Logic seems to play tricks on me with bow making sometimes, so I figured I had to ask. Maybe I'm missing an important part of the equation I get that for a hunting bow (and most bows for that matter) fps isn't the most important factor, but it seems it has a very big role in what is most important, no matter what that is to you.

What's youtr thoughts.

[Fox]

Well, obviously the 45# bow is a better design because otherwise, it would shoot much slower. I think that that would be a better way to market bows is with FPS. but now that is how modern bows are marketed so.......

[Fox]

When I say modern I mean compounds and crossbows

[Del the cat]

I think you are missing the inter-relationship of things.
More FPS is good in theory, but anyone who's made a flight bow can testify that they can be a bit twitchy... e.g they can start to bend sideways, loose tiller, explode, and are likely to be less rugged than an overbuilt bow etc.
A smoother slower bow may be more accurate and forgiving than a faster one of the same draw weight.
Heavier draw weight and more speed is fine if you are just taking a few shots, but would tire you if shooting all day or conversely waiting all day in a cold cramped position waiting for that one shot.
There is a sweet spot for optimum arrow speed, and manageability for any individual, for me it's about 45#... if I'm roving and need to get out to 200yards, then it's about 70-75#
It's about finding a bow that suits you, (and the use you are putting to) and I think that is often about the fiddling and fettling, adjusting the grip to suit your style and arrow pass to suit your preferred arrows.
That's why we make bows and don't just buy 'em.
Del

[bassman211]

Theoretically is goes like this according to what I have read. 45lb bow 450 gr arrow at 160.  60lb bow at 600 gr arrow 160 fps. Based on 10 GPP arrow. More energy foot pounds,and better momentum with the 60lb bow which means better penetration. More efficient weapon over all. My best sinew backed Osage bow is 45 lbs at 25 inches of draw, and with a 450 gr arrow shoots 162 fps.... Their is always acceptions to the rule, but it is not easy to make a 45 lb wood bow that will shoot a 600 gr arrow at 160 fps. Least not for me.

[mmattockx]

First it seems that if a 45#@28" bow shoots a 600 grain arrow at 160fps, and a 60#@28" bow shoots the exact same arrow at the exact same speed, everything we shoot a bow for (like penetration, cast, etc) is exactly the same

This is correct.

The conflicting logic part is if this were true, anyone buying a bow would want to know the fps (based on a consistent # like 10gpp) and not just the draw weight like it typically is, any one making a bow would also be more interested than a lot seem to be.

Your mistake is assuming we make all our decisions based on cold logic with maximum performance as the ultimate goal.

First off, we are mostly hysterical apes and our emotional responses dictate a huge portion of what we do and the decisions we make. Most of these emotional responses happen down near the lizard brain and we are not conscious of them or how they shape our responses/choices/etc. It is not a choice to be guided by deeply seated emotions, it is just how we operate as humans.

The second part is that we are not always searching for maximum performance. If you are archery hunting and not shooting a compound you have already decided that other things are more important to you than raw performance. As long as you have enough performance for your goal (in your case cleanly killing a game animal) then many other factors can come into play. It can be how a particular bow feels, looks, shoots, whatever that makes you choose it over others regardless of the performance differences among them.


Mark

[TimBo]

I was going to add, but Bassman already mentioned something similar...making a really good 45 pound bow that shoots as well as a mediocre 60 pounder is NOT easy!

[PatM]

Why are you comparing a good bow  to a bad bow? Compare apples to apples.

[Don W]

Why are you comparing a good bow  to a bad bow? Compare apples to apples.

Don't you need to know how well a bow shots to determine if it's a good bow or a bad bow? And isn't it possible to have two good bows, just on a bit better than the other?

[WhistlingBadger]

I was going to add, but Bassman already mentioned something similar...making a really good 45 pound bow that shoots as well as a mediocre 60 pounder is NOT easy!

That's kind of what I was thinking.  All else being equal, both bows being equally well designed, the 60# bow is going to shoot a 600gr arrow a lot faster than the 45# bow. 

Now, my 45# bow does shoot a lot faster than my wife's 55#er, but that's because their designs are NOT equal.  Her bow was designed mostly for looks and has taken several inches of set, and she also likes it braced really high.  The thing shoots trajectories like a rainbow, even at 20 yards.   

[Don W]

That's all my point. Someone asked "can I hunt deer with a 35# bow" and the answer should start with a question about fps. If that 35# bow shoot a 400 grain arrow at 130fps it's fine. If it lobs them like a rainbow, then it probably shouldn't go to the woods, no matter what the draw weight.

[Gimlis Ghost]

At this point in my re-acquaintance with archery it seems to me that acceptable accuracy trumps velocity. A highly accurate though low velocity bow would at the very least be excellent within its limitations for small game. A hard hitting heavy draw bow that you can't expect to keep hits within the kill zone of larger game is next to useless.

In the 60's this state had a draw weight lower limit on bows to be used for hunting Deer. If draw weight was below 45 lb it was illegal to hunt Deer with it. My 35 lb Bearcat fires the same arrows noticeably faster than my 40-45 pound Black Fox and always did.

At this point in time I myself can not shoot either bow with the accuracy I'd want to use for hunting either small or medium game, outside of turkey perhaps. I don't think either bow is at fault. I'm up to three to four dozen shots per session and have made quite a lot of progress since only a few months ago I could barely bring either bow to full draw after a bad reaction to my second COVID jab left my right shoulder very weak.

[superdav95]

Just to add what has been accurately stated.  I recently made a pyramid bow 66” ttt. that pulls at 60# at 28” and Speed is at 192fps with a 450grain arrow. That’s 7.5gpp.   It shoots awesome and I find I’m more consistent with it.  Arrow is little lite for hunting according to some out there but I figure if I’m accurate with it then shot placement is more important then speed to a point. As a comparison I also have a 50# bamboo bow 58” ttt that shoots the same 450grain arrow at 30” draw at 194fps. That’s 9gpp.  The energy behind the arrows from both bows is about the same.  Two very different bow designs.   One might say that the 50lbs bamboo bow would be more accurate as it’s easier to draw and delivers similar energy to the arrow.  When balance is struck between speed, kinetic energy behind the arrow and accuracy you get to a sweet spot. I do think speed is very important too in hunting also.  You don’t want to give the deer or game your hunting reaction time to get out of the way of a slow arrow even if the energy is there for good pass through.  In my compound days worrying about whether the deer would duck my arrow was not as much a concern at 300+fps.  When slinging arrows with a long bow for hunting purposes for example I’m looking to ensure good pass through or penetrate vitals accurately and decent speed so that it is less likely that the deer will duck my arrow.   A good hunting bow strikes a balance between accuracy of end user and kinetic energy it can put into the arrow.  The bamboo bow I mentioned shoots well but to my liking the heavier long bow feels more accurate to me.  This could be due to several factors in my abilities as an archer with each style of bow.  I say whatever bow you can shoot accurately that has decent speed and kinetic energy for hunting big game go for it.  Just my opinion. 

Cheers.  Dave

[Selfbowman]

 50@28 3” set. 67” longbow will take down a wilderbeast with 572 gr.

[RyanY]

First off, we are mostly hysterical apes

This is correct. 

I think anyone getting into hunting and asking these questions is guided to the answer buy someone more experienced. Probably rare that people just pull equipment off the shelf expecting to take game with no research. I would guess there’s also an assumption that commercially made modern bows are capable of taking game with the right setup given decades of proven use. We probably think a lot more about these things being homemade equipment with natural materials.