The perfect arrow/broadhead combination?

[Todd_ID]

I've been looking for the perfect broadhead and arrow combination.  I know that there are many good options, and I've killed lots of critters with many different combinations.  The time I lost an elk by not breaking bone was when I said, "Enough".  There has to be a better mousetrap.  Following the teachings and research of Dr. Ashby has led me to big, heavy, single-bevel broadheads.

So here's the results of this morning's testing (playing).  I shot these results using 125 grain and 300 grain field points on a FOB-steered .300 spine Easton Axis Arrow at 29" with a Mathews Switchback (2004) at 72# and 30" draw length (advertised IBO speed of 318 FPS).
 
The .300 spine Axis arrows seemed to be stiff enough to be able to shoot that massive head, and they are also the right spine for the 125 grain broadheads I've been using.  The Tissue Penetration Index (TPI) is the end goal according to Dr. Ashby's work; his TPI findings are at the bottom.
 
The results are:
 
Magnus Snuffer SS 125 grain 3 Blade
1.44" cutting length
1.0625" cutting diameter
.9035 Mechanical Advantage (MA)
11% FOC balance
487 grain mass weight
269 FPS speed
78.235 foot pounds KE
.582 slug-feet momentum
Final TPI of .526
20-30 yard drop: 5.5"
20-40 yard drop: 12"

Grizzly El Grande 190 grain 2 Blade with 100 grain adapter
3.125" cutting length
1.1875" cutting diameter
2.6316 MA
22% FOC balance
658 grain mass weight
236 FPS speed
81.361 KE
.690 momentum
TPI 1.814
20-30 yard drop: 7"
20-40 yard drop: 20"
 
Formulas:
 
KineticEnergy=Weight*Velocity*Velocity /450436
 
Momentum = Weight * Velocity / 225218
 
Mechanical Advantage = Length cutting edge/(cut diameter*.5) * number of blades)

 
TissuePenetrationIndex=Momentum*MA*ShaftDragFactor

 
Shaft drag factor for both arrows was 1.0 because Axis diameter was less than broadhead ferrule
 
TPI findings from Dr. Ashby's research
TPI of 0.62 unable to ever penetrate
TPI of 1.27 penetrated scapula +5-8" flesh
TPI of 1.50 penetrated scapula and broke offside ribs on pass-through every time

 
 
The end result is that the big, heavy broadhead is 3.5 times better at penetration and bone breaking than a standard 125 grain head.  I think I may have found my new setup for big game.  I hope to test it out on a bear soon!

[boneaddict]

going to have to study that to figure it out, good information.  One thing of note, is that I have been steering towards two bladed heads as well versus the ones with bleeder blades etc.for elk.  After busting a shoulder on my NM elk, I am convinced that if I had been using a three blade, I wouldn't have split through it. 

[Todd_ID]

That's what happened to me last year, but I was using the 3 blade head.  The shot was only 6 yards, and I put the arrow on the exact hair I wanted to, but I didn't get through.  I think the heavier FOC on the heavy heads will help that: Dr. Ashby's stuff says that the extreme FOC arrow will recover faster out of the bow.  I think my shot last year was too close to break bone because the arrow was still oscillating when it hit.

[Ray]

What is an 100 grain adapter? Is that an insert near the tip or something attached to the broadhead itself?

?

[bucklucky]

Great info. Ive been contemplating my broadhead / arrow set up. I got a Mathews Reezen now since I ran over my XT after killing my bull last year. I went to the full metal jacket this year, the 340's. Uped my draw length to 28 inches to gain about 10 fps, which I gained already another 34 plus the 10 ish with draw length going to the reezen 6.5. That's a huge gain for a short draw feller. I went from 263 fps with a hunting arrow to 297 plus the 10ish would put me at about 307 with the same arrows. That was like a 390 gr arrow. I haven't been able to crono my new bow with my new setup since the crono is down but with a 100 grain tip and the FMJ's mt arrow weight is 463 grains. With guestimations we figured my KE would be around 80. I was really thinking about going to the new Muzzy phantoms with the bleeder blades and cut on Impact blades that are .40 thick instead of .20 like my original blades that would break. I think my new setup will way out penetrate my old set up by far and seems to shoot way flatter. I don't have all the info down like you , wish I could figure it all out . I think my FOC was like 10 % ??

[bucklucky]

My arrows are right AT 28 INCHES ALSO.

[boneaddict]

I was looking at the grizzly stix or whatever those big beasts are.  I'd like to shoot them to see what happens.  I'm probably already at a disadvantage shooting Trad, but withthe poundage I am winging them things ans at max arrow length.  good thread to start, because I'm pondering myself. 

[boneaddict]

single bevel broadheads are sure the hype.

[Todd_ID]

What is an 100 grain adapter? Is that an insert near the tip or something attached to the broadhead itself?

?

Yep, that's exactly what it is.  It brings us compound guys up to the level of using the traditional guys' equipment.

[Todd_ID]

single bevel broadheads are sure the hype.

There're lots of good reasons for that!  Dr. Ashby's research on them was fantastic; basically it was solid enough logic and physics that I switched to them.

[bucklucky]

single bevel broadheads are sure the hype.

Whats that?

[Todd_ID]

Single-bevel is a 2 blade broadhead that is sharpened on only one side of the blade.

Think of the cheap steak knives we all have at home; the ones with seration on one side and flat on the other.  Try cutting a slice of cheese off a thick block.  You pretty much can't cut straight!  This is because the angle of the blade is causing the knife to turn.  The knife that is sharpened from both sides will cut straight every time: the same is true of broadheads.  When you put that single-bevel on both sides of the broadhead, then the head will rotate as it cuts.  This rotation will cause bone to split and break instead of simply trying to cut through it (double-bevel heads have to push/cut through bone).  Once the bone breaks, then there is very little resistance left, and the arrow can continue on through the animal.

The next thing is that since the broadhead continues rotating as it travels through the animal this creates an L shaped wound channel instead of an I shape that a double bevel head makes.  The tissue/vessels/skin twist onto the head as the are being cut creating much more damage than a standard double-bevel head.

[Ray]

Single bevel (one edge) Link to product example

[bucklucky]

Now I have to rethink my broad head choice.......what are some good manufacturers of those type of heads? And do they make them in the 100 grain catagory. That info makes real good sence to me.

[WDFW-SUX]

I got some 300 spine ACC pro hunters and 100gr silver flames.........they seem pretty lethal