November 30th, 2009, 07:35 AM
Crossbow bolt weight
My son and I were just shooting the breeze about crossbows and their +'s and -'s. It came to how loud they are when you shoot them.
My boy is "wicked smart" and came up with this (think about it).
Compound bows use a minimum of 5gr of arrow weight per lb of bow draw weight, right? 350 gr arrow for 70#. You can make a compound bow much quieter normally by substationaly upping the arrow weight, say to 450 gr or so.
Well how much does a crossbow bolt (arrow) weigh? Using a 20" 2219 shaft, I think we guestimated at around 250 to 300 grains total. Call it 300 gr. Now shoot that out of a 200# (cross)bow. That comes out to 1.5 gr per lb if my math is right. No wonder they are loud! You are almost dry firing them every time you shoot one.
We got to wondering if you could quiet a 200# crossbow with a 1000 gr arrow (.5 gr per # draw weight), and still have acceptable arrow velocity.
We thought of solid fiber glass carp shooting arrows cut down, filling a 2219 or 2315 aluminum shaft with epoxy/lead shot mix or sand, or salt. There's a lot of ways to get an arrow to weigh a lot.
My son called on of his college buddys that is now managing a Gander Mountain store and talked this over with him. Last I heard, this guy was looking to see if he had a solid fiberglass carp shootinig arrow that he could cut down and set up to shoot out of one of his store's crossbows. More to come when I hear the results.
I'm a tinkerer and this almost makes me want to go out and buy a crossbow just to see if it can be done.
You young people will never know the satisfaction of slamming down a receiver on a rotary phone
November 30th, 2009, 07:44 AM
yes I think you could make it quieter doing that but thats how crossbows get all there speed is from the light bolt and the heavy poundage . Put a 1000 gr bolt in that and you will likely be seeing less than 150 fps speeds out of a X bow that was shooting 350 fps with a standard bolt . only way to find out exactly is to get ahold of a chronograph and try it
November 30th, 2009, 07:47 AM
I shot PSE's new cross bow, the rep had some bolts called 15.75's
it was a thick carbon at 15.75 gpi looks like it will be a good bolt
for the cross bow guys.
November 30th, 2009, 08:13 AM
A 20" 2219 with a 125 grain tip will be well over 400 grains. Yes a heavy arrow will make it a tad quieter but at the sacrifice of speed. A 20" 2219 is not under weight for 99% of all crossbows and is the norm for a bolt and the recommend bolt set up.
Have a good day and a better hunt
November 30th, 2009, 10:14 AM
Keep in mind that the average crossbow also only has half the power stroke of a vertical bow, too. This is a big part of the equation. If you seriously increase the projectile weight it's gonna' be a dog.
November 30th, 2009, 10:53 AM
Maybe so on the power stroke but with that shorter power stroke it still has tremendous energy and speed. When was the last time you shot 150 to 200 pound limbs---need to take that into consideration
Originally Posted by Buster of Xs
Have a good day and a better hunt
November 30th, 2009, 11:34 AM
I have an Excalibur with the new string stoppers and it is considerably quieter. Also if you put beaver balls on the string it helps. I shoot a 20" bolt with a 125 on it and it is not bad.
Pat AKA VaDeerHunter
As with all things performance of people is based on thier gifts......Spock
November 30th, 2009, 11:35 AM
The Barnett Predator, with 175 lb. draw weight, specifies a bolt weight of 425 grains minimum. 369 fps. Kinda loud, though.
November 30th, 2009, 12:18 PM
Of course. It's the only reason Xbows have the high DWs anyway....short power stroke.
Originally Posted by Dale_B1
My point, though, was that 5gpp may not be soooooo bad because the power stroke is soooooo short.
November 30th, 2009, 12:30 PM
I have a Excal Y25(recurve) set at 200lb draw weight,My Lazer II arrows weight in at.....406.5(+/-).....with 100grn BH's.Iam getting around 405-408 thru my chrono,this can change depending where my string is set between the lines on the front rail,I tend to keep string in the middle of the lines.
Excalibur Y25. Excalibur Matrix 380 Blackout. Axiom SMF.
TenPoint Turbo XLT. TenPoint Stealth SS.
Mission MXB 360.
Arrows and BH = A lot.
Free Men Need Not Ask To Bear Arms.
November 30th, 2009, 12:37 PM
crosbow's strings also have a great amount of friction on the rail , that plus the short power stroke and you must shoot some light bolts to compensate .
we have a great bunch of crossbows enthousiast/builders in France and they are shooting 500# war crossbows ( medieval replica ) . the average bolt ( also replica ) weight is around 500 grains .
i'll follow this thread
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