Jasonlester

Ok all. I recently picked up a Bear Instinct. I draw 29" and the actual draw wieght is 74#

Now. Unless I'm blowing the math. I cant seem to find a carbon arrow heavy enough to work for me without leaving it pretty long. I'd actually rather a heavier arrow anyway as speed isn't realy my concern as much asan acuratehard hitting arrow.

So what are my options. Weight tubes? I have heard some people useweights inside the shaft.Or amI blowing the math or missing ashaft that is heavy enough?

Thanks in advance.

Jason

BGfisher

Go to some carbon arrow manufacturers' websites and see what they have. You're missing something. There are actually carbon arrows made that can be beavier than aluminum. Py attention to spine first. You should have something with at least a 300 spine. After that look at grain/inch of the different shafts. Multiply gr/in times the length of the shaft. Add the weight of the insert, tip, fletching, nock, wraps if you will use them. This gives you total arrow weight. For 74# you need at least 370 grains.

Looking at the different shafts made you should have little problem getting something as heavy as 500 grains if you so wish. Whoa, I just saw the CT Safari shaft (70-95)---how's 15.5 gr/in sound?
29" shaft coms to 450 grains. Add 15 for insert, 30 for vanes, 10 for a wrap, 125 for a point., 12 for a nock. How does 642 grains sound for a heavy arrow.

Gold Tip 22 series is 7.3 gr/in. Gold Tip Big Game is 10.6/in. CT Hippo is 11.1/in. With all these options you can make an arrow anywhere from about 325gr to 640 grains. And these are all carbons. You just ain't lookin in the right places.

Jasonlester

Ok I saw some of the ones that were more and less gpi.

Here is my math.

5 gplb is absolute minimum So thats 370 at a minimum.

A 30 inch arrowfor the 5 gplb is almost 13 gpi just at the minimum.... Sure the point takes that down a bit as do the insert and nock/vanes.

...............................................

Actually now that I look at it again I think I just need to go back to math class.


Ok so next question is what is the normal range. something in the manual said something about 5 gplb being light or to light or could void the warranty....maybe it was less than 5...I can't seem to figure out where I put it right now.

I'm hunting deer with this bow so I want to make sure I have plenty of penetration. But I don't need to bury it half way in the ground either.

.....Ok now I'm thuroughly confused....now Iremember why I like Trad so much....Simple...

y2khog

Most bows require a minimum of 5gr/lb for warranty coverage. According to my math 74# @ 5.5gr/lb = 407grs total arrow weight. Subtract broadhead 125gr, insert 12gr, blazers 18gr, nock 12gr gives you a shaft weight of 240grs at 30". Or 8grs/inch. Sound about right guys?

BGfisher

Where id you get the 5.5 gr/lb? It's not critical, but it does change the math just a touch.

And fellow, my figures are based on manufacturers weights with a 29" shaft.

BGfisher

Jason,

It's good to scrutinize and learn, but you're overthinking your problem. Penetration will not be an issue with any properly spined arrow at 29" and 74#. You're familar with traditional equipment? A 74# compound is like shooting about a 100# traditional bow, so to speak. Forget penetration unless you are on your way to Africa. Not that it doesn't matter, but at your length and weight it's a non-issue.

The arrow you choose should be based on your desires of penetration/momentum and/or speed. What I was showing you were examples of the two extremes. If you're just going to hunt then something in the middle of these extremes would work well. Kind of the best of two worlds. A little heavier arrow will help to make the bow more quiet, too. There are always trade-offs. With a hunting bow I err on the side of quiet.

I just did some simple math. Assuming you use standard components, 4" vanes and 125 grain tips if you choose a shaft weight of about 9 gr/in then your total arrow weight would fall around 425 gr to 450 gr. This would make a real nice setup and give you what I called the best of both worlds---speed and penetration. Want more speed? Then lighten something up like vanes, points, shaft. Want more quiet and momentum? Heavier shaft.

Hey take your time and enjoy just learning this stuff. Give you credit. At least you have the intelligence to ask before you buy.

I also see that you are online right now.

Barry

bowdoc1

[quote]ORIGINAL: Jasonlester


Now. Unless I'm blowing the math. I cant seem to find a carbon arrow heavy enough to work for me without leaving it pretty long. I'd actually rather a heavier arrow anyway as speed isn't realy my concern as much asan acuratehard hitting arrow.





My carbon are 28 1/2 inchs, 419 gr, 100 gr, G5 Montec ,at 280 fps andI'mblowing through every thing I shoot targets and bucks. It would shoot through my truck door. Before hunting season when tunning broadheads I was shooting nock off and cutting vanes off at 60 yard with broadheads in a three arrow groups. Just how much harder hitting are accuratecan you I get

OHbowhntr

You said it. It's not that difficult, and it's okay to make mistakes.

Now a test for your spelling

"O-H.......???"

Jasonlester

Never been able to spell well....actually typing is more the issue....LOL


With my trad bows I tend to shoot heavy arrows so I know I'll have penetration. With my old compound (65lbs) with 45/60 CX Terminators I've had pass throughs no problem. Going up in weight I did not think I'd have a problem but I knew I did not want an ultralight arrow and risk damaging the bow.

As my math started to make sense to me I realized 400-450 is going to be my goal for these arrows. This bow seems fast so why not use it right...

I asked the questions because its been a long while since I figured this and arrows were a bit different. And I didn't want (and can't afford) to spend money and waste it.

Thanks for your alls help. It all makes sense now.

Jason

BGfisher

Jason,

Just as a matter of information you could log onto www.bowjackson.com and find what is called AMO Minimum Arrow Weight Chart.

What this basically does is compute safe minimums based not only on draw weight but draw length, too. Something the factories and very few other people take into consideration. Most don't know anything about it. Then there are those who think the factory 5gr/lb minimum is gospel.