The 75 Gr. Steel BH Adaptors

[Dr. Ed Ashby]

Just a heads-up. Until recently I had not done any testing with either the 75 or 100 grain BH adaptors; only the 125 grain versions. The adaptors in this recent testing are all ones I bought from 3 Rivers.

There appears to be a fatal weakness in the 75 grain version. Several have broken, with the threaded section breaking away from the taper. I think the counter-bored hole in the taper on the 75 grain adaptor simply goes too deep, weakening the connection at the threaded shank. These breakages are occurring frequently enough that I think it is significant a arrow-integrity issue.

Ed
TGMM Family of the Bow

[Russ Clagett]

I can see how they might break being shot into heavy buffalo, but do you think they might be strong enough for lighter weight animals like deer?

[luv2bowhunt]

Interesting find. I have only used the 125 grain versions myself... looks like I will keep it that way.

Kevin.

[Dr. Ed Ashby]

Russ, the problem was noted during some Georgia whitetail testing! I've not tried them on a buffalo - and don't intend to, after what the whitetail bones did to them.

Ed
TGMM Family of the Bow

[SlowBowinMO]

Interesting info.  At the time the 75's were getting a work out, were you also testing the 100's?  I wasn't entirely clear on that from your post.

We have sold the 75's by the bucket load, all we've heard of is one fellow breaking one like you described hitting a rock.  If I understand you correctly they were actually breaking in the animals?

[Dr. Ed Ashby]

Tim,

Yes, but we haven't done as many shots with the 100 grain adaptors as with the 75 grain adaptors. However, no damage was encountered with the 100 grain adaptors in the initial whitetail testing. For sure, no more chance for whitetail testing until next year, but I have a dozed 100 grain adaptors I intend to 'punish' on some buffalo in this year's testing; to see if they hold up as well as the 125's.

Just FYI, both the 75 and 100 grain versions were tested with 100 grain brass inserts on Extreme FOC setups. They were used from a longbow and compound. Had multiple adaptor breaks on the 75 grain version from both bows.

Ed
TGMM Family of the Bow

[robtattoo]

How odd.....

Makes building 200gn broadheads awkward now, doesn't it?

Funnily enough the 75s is all I've ever used & I've stump-shot hundreds of them into trees, rocks, earthbanks & even one or two into animals! Never had one break/bend/fail yet.

Could we see some pics please?

[BobW]

It is all just a ploy to get us all shooting extreme FOC (I"M KIDDING!!!!!).

Thanks for the info Doc.  Something to look into.  Lots of us use 75's.

Not sure what this does to my arrow selection process.

BobW

[SlowBowinMO]

Thank you Dr.Ed, fascinating.  I wonder if it's possible you have a batch with a hardness issue or something?  I've simply not heard that before but once.  I can see what you're saying though, the hollow cut out does go deep.

My limited first hand experience with them is similar to robtattoo's, I've not broke or bent one.

I have no idea how to test hardness myself, although I can perceive it fairly well when filing broadheads.

Interesting stuff indeed, thank you for the information.

IF ANY OTHER USER OF THE 75 GRAIN STEEL ADAPTERS HAS HAD SIMILAR FAILURES PLEASE POST ON THIS THREAD OR PM ME, I WOULD LIKE TO KNOW ABOUT IT.

Thanks, Tim

[Russ Clagett]

DR Ed, thank you sir. I normally use the 100 grain adapters with 100 grain inserts, and a 125 broadhead, but was thinking of switching to the 75 grain adapter. It sounds like you were testing a setup just like mine, and on whitetails too.

I'm very interested in how this thread turns out.

[Dr. Ed Ashby]

Okay, here are photos of one of the inserts. Every one looks like a carbon of the others. I double-checked the weight, and they are 75 grains (just being sure that the hole hadn't been accidentally bored too deep).




This is the typical break. None of the adaptors show any bends to shank or taper. Note how thin the metal was at the area of break, shown by the width of the break line (Blue Arrow).




This is the inside of the shank; the portion that would be inside the hollow taper.





This shows what the taper looks like after the break; just a tapered hollow tube.

Ed
TGMM Family of the Bow

[Richie Nell]

Dr. Ashby,
I have the 190 and the 160 Grizzlies.  I am thinking that the 160's with the 100 or 125 grain adapter will be a better choice.  I say this because it appears that the shape of the 160 is more like your modified 190.  Narrower and still pretty long.  The adapter makes up the difference in weight between the 190 and the 160.    
Is there a reason not to go this route based on the research?
Richie

[Dr. Ed Ashby]

Richie,

Because of being shorter, the 160 has a somewhat lower MA than the 190, and much lower than the Modified Grizzly. In fact, if you modify the 160 by taking the cut-width to 1" and reducing the rate of blade taper by keeping the Tanto width the same, you end up with a minature El Grande - the exact same MA as the unmodified 190. Both have good MA, but the 190 is the higher of the two.

Ed

[SlowBowinMO]

Dr. Ed, the pictures are great.  Thank you for posting it really cleared it up for me.  Based on your pictures my perception at this point is that it is an inherent design flaw.     It appears from your pictures there is very little steel at that breaking point.

[Dr. Ed Ashby]

Tim, that's my take on it too. It appears that the hole is just too deep. I think they would have been better off to reduce the length of the taper a tad more, and not have to make the hole in the taper so deep. For lower mass adaptors, sure would be nice if someone made one in titanium. Could be 'beefier' at the same mass.

Ed
TGMM Family of the Bow

[J-dog]

I was just thinking that the 75 grain ones I bought would do well for some Wensel woodsman BHs I was gonna try! LOL not now!

Will get the 100 grain ones? are they still good or just go to the 125s?

J

[Dr. Ed Ashby]

Jason,

I haven't tested the 100 grain adaptors enough to be certain yet. They did fine in what little whitetail testing has been done with them. However, that is less than the testing on the 75 grain ones. I bought some 100 grain adaptors to take back with me, and will be doing some 'truly hard' testing on them this year, on some buffalo. If they stand up there, they won't have much problem on deer! All I can say for sure right now is that I noted no problem in the testing so far; which is too limited to make and conclusions.

Ed
TGMM Family of the Bow

[Richie Nell]

Thanks Doc....Then I will really need to use the 125 adapters due to the weight the dremel will take off modifying the 160.  I will probably end up with around 275 grains.  And a total arrow weight of 740 grains pulling 66 lbs.

Thanks again as I charge the dremel battery
Richie

[Dr. Ed Ashby]

Richie, I've mentioned that modification on the 160 to a few folks, but I'm not sure anyone has taken an animal with the 'Mini El Grande' yet. Let me know if you do, and how it performs for you.

Td
TGMM Family of the Bow

[Benny Nganabbarru]

I haven't broken any 75s yet (my arrow required 200 grains from bareshaft tuning)... I've taken down pigs (including a couple of real nice ones), a camel and a brumby. Some hits were pretty tough bone hits.