Arrow Weight? Advice Please.

[ecfire1967]

I'm pulling 70 lbs and shooting a 395 grain arrow. I'm thinking about dropping to 350 grain to pick up some speed. Is that a good idea?

[Zen Archery]

your not really going to be gaining much speed. so unless you've got the money to blow no.

[awatsonjr]

Shoot heavier thinner shaft arrows get better penetration

[awatsonjr]

Speed is over rated. Except in football. In that case speed kills.

[fthoodhoghunter]

Shoot heavier thinner shaft arrows get better penetration

x2

[dustoffer]

X22

[ecfire1967]

What weight should I use?

[Bill]

What bow and how fast now?

Possibly for 3d competition, for hunting the only difference will be how deep it goes in the dirt coming out.

[ecfire1967]

What bow and how fast now?

Possibly for 3d competition, for hunting the only difference will be how deep it goes in the dirt coming out.

Bow tech assassin. 70lbs going 310fps

[agtex42]

I'd say if anything you need to increase your arrow weight. You're already sitting at roughly five and half grains per pound, going to a 350 grain arrow would put you right at five grains per pound which imho is much too light for any kind of extended use (hunting or otherwise). You have to remember that speed isn't everything when it comes to setting up your bow. I ran a few quick numbers based on your current performance numbers and assuming a 1 fps loss/gain per 5 grains in arrow weight here's what you can expect to see:

350 grains @ 319 fps = 79 ft-lbs KE
395 grains @ 310 fps = 84 ft-lbs KE
450 grains @ 299 fps = 89 ft-lbs KE
500 grains @ 289 fps = 93 ft-lbs KE
550 grains @ 279 fps = 95 ft-lbs KE

Now keep in mind that these are ballpark numbers and your real-world performance will probably be different. The point is that rather than focusing solely on speed it's probably a better idea to find the balance between arrow weight and speed that gives you a trajectory that you're comfortable with. A heavier arrow (at an acceptable speed) will produce better penetration on shots that are slightly off the mark, and you can expect your bow to be much quieter than it would be with a lighter setup. I generally tune my bows to shoot the heaviest arrow I can at 280 fps, this gives me a setup that provides plenty of kinetic energy for the animals I hunt AND I can roll right into/out of the 3D season without making any changes to my rig.

Your best bet would be to go to your local bow shop and see if they'll let you put a few arrows through a chronograph (at the above weights) to see what kind of results you get. Most places will be happy to oblige, just be sure to return the favor and have them build some arrows for you once you figure out what's going to work best.

[3children]

Too much focus on KE. Momentum is what you look for in archery. KE is what you look for in gun ammo. Remember that in order to get pass thru, you need push, that is momentum! Take a dart and throw it at a target, now go and push on the dart, it will go deeper into the target. That is the push you want on your bh setup. A heavier shaft will push a bh deeper. I hope that makes some sense. Now take that same dart and fill the tip flat and throw it at the target, when it hits that is KE and doesn't go as deep, but all the energy in done at contact.

[Mudslinger]

Go heavier. I increased my arrow weight from 410 grains at 314 fps to 560 grains at 260 fps and my KE increased slightly, my momentum increased drastically, the quietness of the bow was remarkable over the 410 grain arrow and my set up was more accurate and more forgiving especially at longer ranges. I acheived the 150 grain increase by adding insert weight to my arrows to increase my FOC from 8% to over 18%. I am a converted speed freak and will never go back to a light arrow again. My suspended bag target is still swinging from the 560 grain arrow smacking it! Big difference between the 2. Agtex42's numbers are very close to what you may be looking at.

[pblaetz]

I just increased my arrow weight by 100 grains by adding weight tubes and 125gr. broadheads. I did this for a hog hunt but I don't think I'll go back. They hit harder and are much more quiet.

[Bill]

Plenty fast as is. It will kill anything you'll probably hunt unless you go to Africa. I like a heavier arrow, CT Rhino but that's personal preference.

X2 on momentum vs KE above.

[agtex42]

Too much focus on KE. Momentum is what you look for in archery.

Excellent point and an even better illustration, there will be a point of diminishing returns when it comes to increasing your arrow weight. I should have ellaborated a little more in my original post when talking about having "an acceptable trajectory". You can quantify this by shooting through a chronograph at five feet and then again at your max hunting range, compare your numbers to determine what effect arrow weight has on speed loss downrange (momentum) and choose a combination that you're comfortable with.