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Posted By: Gun_Geezer Carbon Arrow Grains/Inch - 05/20/20
So the 11 carbon arrows I have for my old Mathews Q2 are PSE Carbon Force Extreme 300. Not even made anymore so I weighed them to see what the grain/inch is. Without points, inserts, nock, vanes (bare shaft) they are 8.06 grains/inch. Using my powder scale and a decent tape measure, it's not hard to do.

I've checked PSE, Carbone Force, Victory, and others to find an exact (enough) match so I could have 18 arrows all the same. Closest I can find in the same 300 spine is about 8.9 gr/inch. For my 27.7" arrows, that's a lot of extra weight compared to my current arrows.

Question: When the arrow maker shows specs for the arrows "grains/inch", that is supposed to be for the bare shaft. Correct?
Yes for the shaft.

8 to 9 gr per inch is light for a hunting arrow.

Adding Brass inserts and a heavy broad head is going to make the spine weaker. So in my opinion you should just buy new arrows that are the correct spine for the amount of FOC you want if you plan to hunt.
With 100 gr broadheads those arrows weigh in at 380 grs, manage to fly straight and true to their field point mounted brothers, and have always acheived pass through. They are light, but surgery sharp at 330 fps works well for me thus far. I'd hate to toss away that many good shafts.

In any case, might not be able to replace the in-kind and have to move to a heavier shaft once a loose/break a few.

I used to know what the FOC was on them, but don't recall anymore. What FOC seems appropriate to you?
Originally Posted by Gun_Geezer
With 100 gr broadheads those arrows weigh in at 380 grs, manage to fly straight and true to their field point mounted brothers, and have always acheived pass through. They are light, but surgery sharp at 330 fps works well for me thus far. I'd hate to toss away that many good shafts.

I used to know what the FOC was on them, but don't recall anymore. What FOC seems appropriate to you?


I wouldn't throw them away. Just my opinion but 380gr is to light for my taste.

What FOC seems appropriate to you

That is something I find by trial and error. I tend to like around 20% or so on my wheel bows and on my stick bows up to 25%
Now you have me all curious. Eat dinner. Calculate FOC. They may be a tad light up front.

Post FOC Calc Edit:
FOC for my set-up with 100 gr points is only 10.0
FOC with my set up but with 125 gr points is 12.2
Originally Posted by Gun_Geezer
Now you have me all curious. Eat dinner. Calculate FOC. They may be a tad light up front.

Post FOC Calc Edit: FOC for my set-up is only 10.0


If they are blowing through game animals you are hunting and tune well it's fine. I like a heavy arrow with a little extra FOC.
I have never had a setup less than 15% FOC and that is usually on a target bow.
Thanks for input.

Going to try a few ends using 125 gr point to see the difference. 300 spine may be a bit iffy. Fun to find out.
Do you have room to trim the arrows? The 125gr head will put you over 400gr and in my opinion closer to where you want to be.
Originally Posted by MontanaCreekHunter
Do you have room to trim the arrows? The 125gr head will put you over 400gr and in my opinion closer to where you want to be.


No such luck. They're already just about too short. Should've left them longer when I made them years ago.

Did the FOC calc by adding a 25 grain washer at the insert/field point. Had to order some 125 gr field points. Should be here tomorrow night. Shoot them Saturday and see how things change.
Posted By: Bearcat74 Re: Carbon Arrow Grains/Inch - 05/21/20

I added 100gr brass inserts with 125gr heads to mine to get my weight up to 537grs. Arrow flight is incredible and tuning was easy, bare shaft, field point and broad head grouped 2” at 31yds, which is about as good as I can shoot. My FOC is 20%
Originally Posted by Bearcat74

I added 100gr brass inserts with 125gr heads to mine to get my weight up to 537grs. Arrow flight is incredible and tuning was easy, bare shaft, field point and broad head grouped 2” at 31yds, which is about as good as I can shoot. My FOC is 20%


That's a heavy arrow for sure. How much velocity do you get with weight of arrow?
Posted By: Bearcat74 Re: Carbon Arrow Grains/Inch - 05/21/20

251fps drawing 66lbs on an ancient Mathews Legacy.


I’d like a newer bow but this one is quiet and I shoot it good so I just keep it.
I hear ya. Mine is Mathews Q2, about maybe 22 or 23 years old? Just put a new string on it and having a fun re-learing all the "bow technology" about setting one up. Have not shot it in 6 or 7 years, so I'm having to work my arm back up to it!
Posted By: Bearcat74 Re: Carbon Arrow Grains/Inch - 05/21/20


Same here, I had bow hunted 2-3 times since 2011 so I had to relearn.

I had always shot around 400grs but tuning a broad head was a pain so I always shot expandables. I watched some videos from the Ranch Fairy on YouTube about high FOC arrows and I decided to try it this winter. I’m shooting Slick Trick magnums and they’re flying like darts with the heavy arrows where they flew like a turd with the 400gr set up.
I've killed at least 4 Bull Elk with arrows in the sub 400gr (down to 360gr) range. My hunting bows usually shoot about 270-280fps. I used fixed blade broadheads - specifically Muzzy 90gr 4 blade heads. No problems and will use again this year. Once I learned about yoke tuning, getting broadheads and field points to hit together has been a breeze.
Originally Posted by centershot
I've killed at least 4 Bull Elk with arrows in the sub 400gr (down to 360gr) range. My hunting bows usually shoot about 270-280fps. I used fixed blade broadheads - specifically Muzzy 90gr 4 blade heads. No problems and will use again this year. Once I learned about yoke tuning, getting broadheads and field points to hit together has been a breeze.


Doing something doesn't make it the right thing. If it works for you that is great, however it is not advisable. That is a very light arrow specially at that speed.

NO Broadhead will shoot exact same POI as field points once you get past a certain distance. Close but never exact. Usually starts to open up at or around the 45 to 50 yard range.
Suit yourself. My elk rig this year will be a 60# bow shooting 375gr arrows about 280fps. Any elk within 60 yards that presents a shot is in trouble. Most likely though the shot will be about 30 yards from a ground blind on a waterhole.
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