I am new to traditional this year so I appreciate all the info you all are sharing. This answer to this question may be obvious, but never working with Zwicky Eskimo's before I have to ask.

125 grain should weigh 125 grain, correct? I recently purchased my first 6 to tip some cedar arrows I made and tuned to where I am happy with bare shaft and fletched arrows with 125 gr field tips.

After mounting the Zwickys all of a sudden my shots are knock left of target point. I am RH shooting a Bob Watkins Viking Longbow 52# @ 28, so knock left of target point should signal not enough spine, correct? (Or too heavy head?). After scratching my head and looking at retuning I decided to pull them off to weigh. All weigh 137-139 gr. ? on a Hornady scale.

Did I get shipped incorrect / mispackaged gr weight from this retailer or is this the manufacturing tolerance with these? And in that case start retuning to these? Thanks all in advance

Zwickey heads usually weight a tad more than the package ad weight. And I'm glad they do....once you sharpen them, you're removing material. Zwickeys should be sharpened before hunting with them (and they sharpen easily). I have found once I put each head on the sharpener, the finished weight is not far off. If they weighed exactly what the packaging says, they would now be too light. I'd rather them be a tad over than under.

I ordered some eclipse heads this year that were all way over weight. Similar to what yours are. Being this was my first time dealing with them I assumed it was to allow for sharpening. At the same time I found it hard to believe one would remove 15-20 grains during the sharpening process. I ended up calling the company and he said they definitely shouldn't weight that much over the intended weight. He ended up sending me another pack free of charge and they all were all within 5 grains of what they were supposed to weigh. Maybe give Zwicky a call and see what they say. Good luck

Shawn

I think the weight should be close but if the mfgr had to hold every head to exact weight, those nice inexpensive Zwickey's would cost 3 times as much as you paid. I think the weight is a "range" of a few grains either way. I have noticed 125gr field points are 6 or 8gr heavier than stated. Plus there could still be some glue inside the ferrule, making them a bit heavier too. I don't think 6-10 gr is going to make your arrow that much weak. BTW, did you spin test your broadheads to make sure they spin without wobble?

140 grains is too much variation for a broadhead that is supposed to weigh 125. I too have a weighing balance and all of my broadheads weigh within 1-2 grains of the advertised weight. This includes a few Zwickey Eskimos. I would not hesitate to return the broadheads and ask for replacements of the correct weight if that is what you want to do. That said, 15 extra grains on the point end should not throw your arrow off balance. I find that it takes closer to 50 grains before I see a significant difference in arrow alignment on impact.

You may have to cut the tip a little shorter and then re-taper to make the arrow a little shorter and stiffer. Or play with your brace height a little. I think lowering your brace height a little might do the trick. I'd try that first before cutting the arrow.

Two standard questions that nobody has asked yet:

Are they hitting Point Right, or just sitting Nock Left? (JMO, nock orientation is only useful in the air)

and

Where do they hit RELATIVE TO bare shafts & field points?

Also, you didn’t mention the range(s) at which you’ve been testing; in tuning and spine testing, you are trying to calibrate your system, and JMO you cannot REALLY call yourself calibrated against a single point of reference. Yeah, you could check your scale against a single, 150 grain reference weight every time, but (just the way I was trained) you’re much better off checking at 25 and 250 in addition to the 150. You can connect any two dots with a straight line; it’s harder with three.

I just ran the specs for a wood arrow through the spine calculator, and 140 vs 125 grains works out at a difference in spine of #3 1/2.... That doesn’t seem like a lot, unless you're really VERY good at this stuff.

How do they spin-test?

if 15 grains throws your arrows off, you weren't tuned to begin with

I with rusty. If 15 grains throws you that far off, your arrows were up against it to begin with.

If you can take 1/2" off your arrows, you'll probably be okay. Not that it's right or wrong, but I've always made sure my hunting arrows were a tad stiff--never a tad weak.

Agree with Rusty as well. You are also weighing the glue residue since the head you have on the scale shows burn to get it off the arrow. Heads that need sharpened should weight a bit more since you remove metal to sharpen. That itself would lower it by maybe five grains. If you are kicking, then it's a spine issue too close to the borderline for your bow. And, I don't see where you mentioned what spine your arrows were, how long....and what type of string you are using...and center shot of bow. All of those things impact spine need in the dynamic equation.

I agree there is a spine issue here, that little weight difference should not effect arrow flight. Need to know the answers to the question George asked "....and what type of string you are using...and center shot of bow. All of those things impact spine need in the dynamic equation."

Bob

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