Im not Mauser, nor am I an expert...but I view momentum like this.

Grab a rebar stake 3 ft long, and a heavy softball slugger bat, 3 ft long.

Your arm strength is the same, regardless of which item you swing, similar to how a bows stored energy is the same no matter what you sling.

Find a buddy dumb (drunk) enough for your science experiment. First walk up, and while he is facing away, swing the rebar stake with all your might and strike him in the back. It will sting like hell, but likely wont knock him down. the stake will stop at his back, or maybe push him forward a little bit.

Now get him to stand back in the original position, only this time reach for the slugger bat. Again, swing with all your might and strike him in the back. While your swing around wont have near the speed as the lighter rebar stake, you will knock the guy flat on his ass, and your swing will follow through all the way around.

Same energy applied, the heavier object has a greater tendency to keep on keepin on in the direction it is going.

Obviously there are extremes for both, a light paper clip extended out is not practical, nor is a 10" diameter metal beam.

I only shot 1 deer so far with the 2 blade rage at 28 yards, complete pass thru arrow stuck in ground about half way.Shooting a ross cardiac 76#.Never seen a hole or blood trail like it left, deer went 25 yards stopped and stood there for about 5 seconds and fell over.

No it's not that simple, Mauser. When you add weight, you lose speed. Simply adding weight won't do it. If it would....I'd be all over it. There comes a point of diminishing returns in regards to KE/momentum. Yes....adding weight sometimes equates to more KE (to a point)....even though speed is lost. So many other factors come into play with a hunting arrow, thogh (arrow spine efficiency, point of diminishing returns RE: speed loss, etc...), though.

TEmbry.....the MASS would help sell your rebar/bat argument more than momentum. Even using #4 rebar....they would weigh roughly the same. Anything over #4 and the rebar actually outweighs the bat.

I understand momentum as it relates to heavier objects traveling at the same speeds. What many overlook is......(relating this to a hunting arrow).....you can't get the same speeds out of a heavier arrow. At some point there becomes an "optimal" in both KE and momentum. I haven't met anyone versed enough to tell me what that is.....yet.

I only used rebar because it is thought of as stout....lets go with aluminum pipe then.

My whole point revolved around the fact that they arent traveling the same speeds. The lighter of the two will go faster, but it also wont knock the person down, meaning its travel path is stopped more easily...the heavier bat, will knock the guy out of the way and continue its path of swinging through. You are exerting the same amount of force with each swing, the speed is determined by the weight of the object...not how hard you are swinging.

It isnt that more speed equals more energy, which is how some guys (not implying you) look at it. The bow is putting out a set amount of energy at the shot, whether you are shooting a log or a feather. The lighter the weight, the greater the speed...BUT the heavier the weight, the more momentum...generally speaking.

momentum is an extremely simple formula, when looked at in Newtonian laws... P=mv. Mass x Velocity...the only two factors for momentum. Generally, more mass = more momentum when fired from equal initial forces simply because the mass increase is greater than the caused decrease in velocity..up to a point like you said. IMO, Momentum out weighs KE for arrow performance down range, but they usually go hand in hand.


In your case, yes it is as simple as adding 100-200 grns to your setup...it WILL give youmore momentum, how much could be figured by simple mathematics....whether it is worth it is up to you, the shooter. Your weight is more than ample for deer hunting though, especially with the numbers your bow can put out.

The thing I always think of, if mass and momentum arent important for penetration, why arent people using light arrow setups for grizzly, or buffalo, or moose hunting?

If you have an adjustable weight system for your arrow, a chrono, and a calculator you could probably chart your own KE & momentum values for your individual bow. And then you can find out where they are optimized. Time consuming, probably. But take a Saturday afternoon and you’d have it. Personally I am a fan of momentum over KE. But like jeff says that doesn’t tell the entire story. Take a heavy but weak spine arrow and you could probably get better penetration from a lighter/stiffer arrow, even if it may have less KE. You have to compare apples to apples. Momentum is the tendency to keep an object in motion. The longer it is in motion, the more it will penetrate. The way I see it, the best compromise is shooting the heaviest arrow one can use, while still being satisfied with their arrows trajectory.

Each side can come up with scenarios to make their points. Would you rather be hit with the bat traveling 10mph or the lighter pipe traveling 60mph.....if both have the same amount of force required to produce said speeds (which would hold true)? THAT'S getting closer to the hunting arrow scenario. It takes the same amount of force (DW/DL) to propel the lighter arrow at greater speeds as it does the heavier arrow at slower speeds. If we could propel heavier objects with no more force required.....hell we'd all be shooting logs. When speaking in hunting arrow terms (which is all I'm interested in, really).....you give up speed when you add weight....every time.

Exactly, and I dont think anyone knows the answer to this, whether they claim to or not. The reason arrow weight isnt proportional to speed loss, is because a heavier arrow will absorb slightly more energy from the bows potential energy, making the loss of speed not as great because it has a slight gain in initial energy over a lighter arrow. Extremes in either direction make using ONLY the momentum or ONLY KE to determine this pointless, like you said...its all about a balance between the two. Most hunting weights will fall into the acceptable range, if you arent getting pass thrus into the dirt, assuming this is better, then Id look to a smaller Diameter COC head than a 2" rage, if you are happy with having bigger gashes and the arrow remaining in deer, stay with the devastating rage. At over 70 ft/lbs KE, you are nearly double the required KE to deer hunt....I think ANY arrow weight would suffice.

Thanks. I've been saying this all along.

Hence my fact finding mission. And....the reason I purchased some fixed heads, today to test.

but the speed you give up is less than the weight you gain, up to a point....a heavier arrow absorbs more of the bows potential energy, instead of it passing into limbs and riser......this is why heavier arrows tend to be quieter on the shot.

This increase in initial energy for heavier arrows is why going up slightly in weight slightly increases your KE AND Momentum....again only up to a point before the advantage diminishes.

The energy exerted on the arrow isnt technically the same for every arrow from the same bow, it depends on the mass or weight of that arrow.

TEmbry.....what is your suggestion to allow me to shoot the rage heads.....and gain more momentum (which you seem to be touting)? If I go up in total arrow weight....what happens to my KE? WIll the additional momentum allow me to experience more pass thru's? How do/did you determine this?