Mecanical heads opening up upon firing

[dpoisson]

Hi gang, for those that can understand french, there is a great article in Aventure Chasse & Pêche (french magazine) about mecanical boltheads.

They tested several (I believe they had 15 different heads) with 3 crossbows of different strength (fps). With the most powerful crossbow, all heads opened up upon firing (or right after leaving the crossbow). Same results with the mid-speed crossbow. Even with the slowest of the crossbow, a lot of them opened up.

They calculated the group size and when the heads opened up, the group size with certain heads was huge. They gave a couple of pointers on how to test for these and listed a couple of solutions.

It was an interesting read!

Anyone else catch a glimpse of the article?

David

[mchurch]

High poundage recurves are a particular problem. Some good ones I have found even for the matrix mega 405 ate excalibur x act, g5 t3 crossbow version, nap killzone crossbow head and the grave diggers

[StormDragon]

I plan on dental banding my Grim Reaper X-bow Razortips for my Micro just in case.

I havent tried it yet but i think I have the banding procedure concept after reading about it so I will try it out on a live broadhead and see how things go.

[Shotnbeer]

I missed a nice buck with a mechanical opening up in flight. Never again. Fixed for me.

[bob1961]

why i only use fixed head slick tricks, nothing to go wrong ....

[flinthead]

yup... it's hard to beat the 150 grain Slick Tricks or Boltcutters.

[dpoisson]

Do the boltcutters have a good reputation?

I hate when things can go wrong, since they always seem to go wrong at the worst possible time (damn you Murphy!). This is why I was eyeing fixed blades as well, long before I read that review.

The fix is usually simple though, simply adding an extra o-ring will usually do the trick for most mecanical heads.

David

[bob1961]

I went to tricks after I could not get my bolt cutters to fly anyway good ....

[hankenhunter]

I've been using the boltcutters since I bought my bow in 2010. Have never missed a
shot on big game. It is a very robust broadhead. In fact, I still have two of the original boltcutters that I bought with the bow. One went into a tree after a passthrough and I couldn't dig it out. You don't get field point accuracy target practicing with a boltcutter, but will still hit a two inch circle at 50 yards. For me, the top selling point of the boltcutter is the ease of blade changing. No teeny tiny screws to fart around with. The tip unscrews, slide new blades in, screw tip back in and your done. I once shot a boltcutter through the doors of an old import beater car and only had to replace the blades.
Hank

[Riflemanz]

I use two bands on my rocket hammerheads! They open when they impact the deer! Very easy fix! My 355 shoots pretty fast too.

[Riflemanz]

I'm going to try this dead ringer trauma 3 1/8" cut 125 gr head this year, notice the thick band on it. I tested it a 30yds and it flies dead nuts!

[vixenmaster]

This topic can go on n on. Best is to use what you feel most comfortable usin. The only Mech. i have ever open on me in flight was a rage! Cost me a nice 8 pt. I don't feel bad about Mech. BH's i jus don't use Rage BH's anymore. I have killed a dump truck load of tick toters usin the Mech. BH's n will continue to use them. Jus need to put yer bands or o rings on them fer the speed yer shootin. Or in case of the Spitfires don't use past a certain speed

[racking up points]

This topic can go on n on. Best is to use what you feel most comfortable usin. The only Mech. i have ever open on me in flight was a rage! Cost me a nice 8 pt. I don't feel bad about Mech. BH's i jus don't use Rage BH's anymore. I have killed a dump truck load of tick toters usin the Mech. BH's n will continue to use them. Jus need to put yer bands or o rings on them fer the speed yer shootin. Or in case of the Spitfires don't use past a certain speed

Good advice there^^^^

[Outback]

Tried the Rage and won't never use mechanicals again, nope not none of them. Montec G5 is all I use now and will continue to use.

outback

[tomcat]

Had this problem with NAP Spitfires when shot out of Excal and Speed Vertical bows. Spitfires used a dimpled friction shim to keep blades closed instead of rubber band. The friction was pretty good on brand new blades and shims, but the problem was that once it was opened/closed a couple times the force to do so diminished slightly. The fast loading of the Recurve and high poundage speed vertical bows simply overcame that friction upon firing.

I discovered this during paper tuning them with a Hoyt Supertec one year. I noticed one or 2 blades were open as it passed through the paper. I also confirmed this with my Excals. There were 3 solutions:
1. Put blades on and never open them...(somewhat impossible given storage in quiver and a million other reasons why they might accidentally be opened.)

2. Take shims out and dimple them even further with a matching small cylinder shaped punch. This definitely worked perfectly and allowed you to reuse the shims indefinitely simply by performing this when changing out blades or resharpening them.

3. Remove the shims altogether and simply use the rubber bands that other expandables used(aka dental brace bands). This was absolute, and the route I chose simply because...it was simple and I believe it requires the least amount of force to open the blades.

The way to find out if this is an issue for your setup is to simply shoot through paper. It's easy to tell the difference between a fletching tear and an opened blade, but if that's confusing, shoot an un-fletched arrow..

If you discover it's happening, there are all kinds of ways to remedy this with each type of mech, or you can just give up and switch back to fixed blades and accommodate the slight variance they might have in flight vs field points.