fixed vrs mech revisited

[bobcat]

i see a lot of post about not using mech broadheads in slower crossbows because of the loss of KE to open them. I get the theory, but what i dont get is this....
tons of guys including myself have shot mech out of vertical bows going way slower than even your low end crossbows and have no problems. my last vertical bow only shot around 250 fps.
enter the argument that vertical bow arrows are longer and heavier but is that really true? most vert guys are shooting 100 gr heads. i will use my boy for an example. he is 240lb at 5 foot 9. he shoots 65 lb vert. bow. from what i can find min arrow weight for vert bows is about 5gr per pound . 65x5=325
min for an Excalibur crossbow is 350.
the kid is shooting zombies in a 350 spine that are 8gpi. his 27.25 shaft is 218 gr add 100 gr for a bh and your at 318 add 18 for fletching , 14 for insert and 8 for nock and if i did my math correctly you have a 358 gr arrow. his arrow speed will be around 275 fps. for around 60lb of KE
no one shooting a set up like that would think twice about shooting a mech broadhead.

so what would the difference be in shooting a crossbow at 280 fps with a 350 gr arrow which is also around 60lb of KE?
what am i missing?

[Deaf jeff]

i see a lot of post about not using mech broadheads in slower crossbows because of the loss of KE to open them. I get the theory, but what i dont get is this....
tons of guys including myself have shot mech out of vertical bows going way slower than even your low end crossbows and have no problems. my last vertical bow only shot around 250 fps.
enter the argument that vertical bow arrows are longer and heavier but is that really true? most vert guys are shooting 100 gr heads. i will use my boy for an example. he is 240lb at 5 foot 9. he shoots 65 lb vert. bow. from what i can find min arrow weight for vert bows is about 5gr per pound . 65x5=325
min for an Excalibur crossbow is 350.
the kid is shooting zombies in a 350 spine that are 8gpi. his 27.25 shaft is 218 gr add 100 gr for a bh and your at 318 add 18 for fletching , 14 for insert and 8 for nock and if i did my math correctly you have a 358 gr arrow. his arrow speed will be around 275 fps. for around 60lb of KE
no one shooting a set up like that would think twice about shooting a mech broadhead.

so what would the difference be in shooting a crossbow at 280 fps with a 350 gr arrow which is also around 60lb of KE?
what am i missing?

this is the first time that I have seen it put this way and am very interested to see the replies

[xcaliber]

Voodoo! Too many variables for me to comment based on real world results! I have seen some crazy stuff, as many here have as well to say what is, and what should never be! (Led Zepplin) 1973, I think!
Read what the manufacturer says about minimum KE, and pick one you like, make sure it hits where you aim, and report back, pictures not necessary, but always appreciated!

[fuzzy]

...

[longbow joe]

Been down this road many a time.them fixed penitrate great but then you dont get that giant hole .that leads to a 30 yard easy recovery as with a giant expandable. Shot many a deer with a fixed but i slowly swayed to the spitfire .blood trails dont compare unless your shootin a giant fixed like a snuffer.then you got " plane" issues. Them slick tricks always left a big hole n flew good

[bobcat]

What you're missing is the difference in "acceleration" of the string upon release. Crossbow has half the power stroke (draw length), as much as 4 times more draw weight and is much more violent upon release as compaired to the vert bow. Crossbow does "twice" the work in "half" the space with 3 to 4 times more draw weight than a vert bow.Good luck.

right thats how it gets the speed.... but once they leave the bow they are the same weight going the same speed. how it got there no longer matters.

[xcaliber]

Well I beg to differ on that! Here is a buck I shot with a little Ole Vortex, NAP 100 grain T-Heads, Fixed, my shot was 29 yards, my buck piled up at 38 yards. He is right under my limb tip, I'm sitting in my stand. This is a Voodoo topic!
I'm always trying new broad heads, but fall back on these, and Cabelas Copper Heads, both have done me well, but I cannot say they are the best. I'm going to try Spitfire Heads this fall, and have read many great reviews, and seen a lot of killed deer photos to know they work. Next year there will be a new flavor of the month, and I'll probably try them, I think you have studied the subject well enough to draw your own conclusions, and there are positive results no doubt to steer you towards a great B-H. Just make sure you you shoot one to verify POI, and kill something.
Good Luck, hunt hard!

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[vixenmaster]

Some Mech. BH's do cause some loss of penetration as some of the bands used are tuff to break as the blades open. I have used a Vixen many times usin Mech. they worked well, the swhacker seems to need more arrow weight or poundage or momentum to get the same penetration as a Hammerhead or the Spitfire. I have used Spitfires on hogs several times n they jus eat'em up

[bobcat]

im not arguing for or against mech. i just thought i was missing something in the science. i know everyone has to draw there own conclusion. my conclusion is if a regular bow gets pass through with a certain mech with no problem then the same weight arrow going faster from a crossbow will do the same.
that being said i was going to go with fixed blades as there is less to go wrong but i couldnt find any i liked in 125 gr.
i bought the spitfire 125 because of all the good reviews and with over 80 pounds of KE i dont think there will be any issues if i do my part.

i have shot deer with rage and eastman first cuts that only went 50 -75 yards with double lung pass throughs and i shot a buck at 30 yards with a 260 rem right through both lungs and it ran 200 yards. every deer, every shot, every hunter is a little different but science is science.

[xcaliber]

Hysteresis I think it is called! Again, Voodoo. I have seen a 54 pound, 26" draw compound bow put a Rage thru a huge buck, and bury the arrow in the dirt, and a 74 pound, 31" draw compound put a Shwacker half way thru a small doe! No theory to explain to that!

[georgiaboy]

I don't know about all this KE vs speed vs fixed vs blah blah blah...
All i know is the first five deer i ever killed with a crossbow i took with an old Horton shooting a blistering 242fps using 100 gr spitfire's
My furtherest shot was 36yds...dropped in her tracks. The other four were from 12 to 28 yds...longest recovery was 60 yds.
Keep your shots reasonable and use a quality head & you will fill your freezer.
My 2 cents of redneck reason!!

[xcaliber]

I don't know about all this KE vs speed vs fixed vs blah blah blah...
All i know is the first five deer i ever killed with a crossbow i took with an old Horton shooting a blistering 242fps using 100 gr spitfire's
My furtherest shot was 36yds...dropped in her tracks. The other four were from 12 to 28 yds...longest recovery was 60 yds.
Keep your shots reasonable and use a quality head & you will fill your freezer.
My 2 cents of redneck reason!!

I checked your math, it's great!

[georgiaboy]

[racking up points]

I have killed deer with mechanical heads in vertical bows shooting anywhere from 250-275fps and got pass thrus. I see no reason why anyone wouldn't be able to use most expandables in any of the current crossbow models. (There are some exceptions, the FOC broadhead being one, it takes some KE to open those blades and then push 3" of said blade through an animal. After consulting forum members who have used them successfully, my baseline for using these would be somewhere around- 330fps/400gr/96KE.)

With models shooting with less KE, and using an expandable, the odds of a pass thru decrease, so that is a something to consider if you plan on using them.

With a crossbow, we have shorter power strokes and the arrow accelerates over a shorter span, so I am inclined to believe that this increases the chance for premature opening in flight. As it has been pointed out, using dental bands as a backup to the broadhead's blade retention system, if equipped, is a good practice.

To clarify, I have been a diehard cut-on-contact broad head shooter for the last decade and I'll be using 175gr Slick Tricks this season out of one of my bows. But I will experiment with the 170gr, 3" cut FOC after seeing the results from members of this forum. They appear to be devastating and true-flying.

[DuckHunt]

I think your original question was more about the speed and KE needed. I agree with your thinking. Although the arrows were different lengths and the crossbow has a more violent launch, the weight of my arrows were just above 350gr for my 70# vertical bow and crossbow. With equal speed, my KE would be the same with either once they were in the air.

I used Spitfires on a round cam Browning bow that could only muster ~220fps. They still passed through. I think you'll have plenty of KE with any of the current bows for a mechanical head. Though the ones with extremely wide cuts may need a bit more weight or speed. I know an ExoMax is enough bow for any mechanical.