zak123

Will a 275 grain arrow penetrate better than a 400 grain arrow out of the same bow in the same target? I am not planning on going this light, I just plan on winning a bet!

BGfisher

All things being equal, the answer is "NO". The lighter arrow just doesn't carry as much momentum to the target.

OMHO though, if you are hunting critters the size of deer the worry about Kinetic Energy, Momentum, and such just gets too much press. Years ago (many years) we shot bows that produced speeds of 180-190fps. We picked an aluminum arrow that spined and tuned right, shot them for target and hunting using a good sharp broadhead and shot right through deer. No problem. We didn;t worry about how much energy was produced or anything else. We learned to shoot the bow. That is what produced meat-on-the-table.

Man, guys are getting complete passthroughs on game as big as elk with 55lb recurves---still.

gibblet

man, you know that's right.

Arthur P

Yeah, but they ain't using no 350 grain arrows to do it.

But you're right. We didn't start worrying about KE and momentum until they invented carbon arrows. And IBO had to make that 5 grains per pound rule to keep idiots from being a danger to themselves and everyone else on the range. They came up with these KE theories trying to prove they aren't complete idiots for hunting with those lightweight arrows.

Archery pro

it will penetrate at least as far as the 400 grain arrow because it will be going faster maybe just a touch deeper depending on the yardage shot.

zak123

But you would think that the heavier arrow has more momentum would push it through.

Cougar Mag

I give up on the speed/arrow weight/KE/momentum debates. Just shoot what works best for you and be happy.

A buddy of mine was at a pro shop yesterday buying arrows, and while I was in total agreement with the weight/spine of arrows he was sold, I disagreed with the pro shop owner's blanket statement. The owner said he has proven that the lighter faster arrows always penetrate farther into his targets! The owner also said that within 20 yards the penetration was the same but at longer distances the lighter, faster arrow always penetrated more. I didn't want to get into a debate at the time and just kept my mouth shut.

BGfisher

The whole point of my post was to say that if you are shooting anything about 50# and hunting deer, then it doesn't matter. If guys would spend as much time perfecting their shooting form and super-tuning their bows, and learning something along the way they wouldn't have time to worry about crunching numbers that don't really mean anything anyway.

And it's stupid to compare penetration differences in foam targets. Foam is not flesh.

bigbulls

To keep this only about winning the bet the following will apply.........

All other things being equal except the following variables...

A heavier arrow will penetrate better than a light arrow but there is a point of dimisshed returns when you can get too heavy.

A faster arrow will penetrate better than a slower arrow of the same weight.

A skinnier arrow will penetrate better than a fat arrow of the same weight.

A stiff arrow will penetrate better than a more flexible arrow of the same weight.

A shorter arrow will penetrate farther than a longer arrow of the same weight.

JOE PA

IMHO, it depends largely on what you are shooting the arrows into. If you are shooting into hard foam, then the lighter, faster arrow may penetrate just as well or even better. Does that traslate into better penetration when shooting at game? I would doubt it, but have no evidence to prove it. I know it is often irrelevant to compare archery equipment to guns, but here is a story with (to me) a surprising result. My buddy was shooting his 7mm Remington mag, and another "friend" who was a know it all type suggested he shoot it into a 1/2" steel plate. He said the 154 gr. bullets my friend was shooting could not "blow through" the steel plate, but his 75 grain bullets could. Sure enough, that was how it worked out. The sheer velocity of the lighter bullets blew through the steel plate when the heavier, slower bullets did not. However, Mr. 75 gr. bullet said that meant they would penetrate better on game. That is not the case, and I do have enough experience with various bullet weights and velocities to know that if I am hunting for Elk or Moose, I certainly would not choose the 75 gr. bullet.