Bow weight and FOC

[jpcarlson]

#3302

I am a believer in high FOC arrows and bevel sharpened broadheads. My question is this; I have two hunting bows. One is 65# and throws my UFOC arrows at around 700grs and 32% FOC very efficiently and with a fairly flat trajectory. My other is 51ish #, (48@28. I draw 29+). I have been shooting the same arrow setup out of this bow too, weighing in at 720grs, and 32-34% FOC on a tuned arrow. It shoots them well, but after shooting a new batch of the same tuned arrows out of the heavier bow, I wonder if reducing the overall weight while trying to maintain high FOC for the lighter bow would be a good idea for white tails? The lighter bow is very comfortable to shoot with that weight, and much easier to shoot when sitting in a stand with cold muscles and lots of cloths on:) I was hoping those who hunt with a bow in the low 50s could share their thoughts and experiences here.

Thanks,

Jans

[mhay]

#18871

Let me begin by saying I stumbled onto the Ashby Studies in 2012 and quickly became convinced of the need for a better arrow and broadhead set up . Later I found this website and the knowledge I have obtain through both places has been terrific .

I shoot a Super Kodiak 64 inch recurve ,,45# @ 28 inches . My draw is 30.75 , so I’m pulling about 51-53 pounds . My arrows are 2216 Legacy aluminum with 289 grain up front and three 2 inch fletch on the rear . It is not the HOT ROD of some bows but it is super quiet ,,,both bow and arrow .

Other than the fletching (was still 5.5 inch last season ) this is the same set up used last year to take a whitetail doe from the ground at about 12 yards . She and he yearling were feeding just across the creek from where I stood . Finally after 30 minutes of watching and waiting as they fed on the lush fescue she offered a shot thru a window in the sycamore limbs . The arrow passed thru and buried into the bank . She knew something happened but only made one jump, never flagged , and the yearling never stopped eating . She stood there a few seconds , made one more jump and just stodd there looking around . Then fell dead .

That doe was the first and only deer I have seen shot with anything that didn’t run . The silence of the bow and the

efficiency of the arrow made it possible .

I would rather have a lighter arrow and more EFOC but at this time the funds aren’t there for the upgrade . But , then too , I know that my set up is more than enough for quick clean kills on whitetail.

Best of hunts to ya .

I forgot to mention , total arrow weight is 697.5 grain.FOC is 20 %

[Doc Nock]

#21016

This is a question I debate constantly with others.

I shoot high 40’s (now a 47# 2X carbon Bigfoot that truly SPITS an arrow faster and harder than any other I’ve owned.)

I have striven to limit my overall arrow weight to under 600 gr. total. I have 28% FOC with 100 gr. insert and 200 gr. head. I could ease up the FOC if I went to 50 gr. insert and 250 gr. head, I think.

More weight that is in front of the shafting, not inside, the higher FOC seems to go for me.

Shooting lighter draw, I want a heavier arrow, higher FOC, but feel that there is a ‘point of diminishing returns‘ with heavy arrows and lighter draws.

At some point, it becomes personal. I do see a bit more drop when I get to 30 yards, alas, my eyes don’t see tiny deflections at that distance in the woods, so I limit my shots to 20 and under except in ideal conditions! So the point gets somewhat moot.

I’m all eyes on this one!

[jpcarlson]

#21455

Yes, I too am waiting for the “experts” to chime in here:) I think part of the “problem” may be my old 1971 Bear take down. These old bows did not have very efficient limb designs. I’m sure this bow would really spit out one of my heavy arrows if the limbs were built by a modern bowyer at this draw weight and I wouldn’t be here asking questions. I’m considering taking the 300 TuffHead off and trying the 190gr MeatHeads on this setup for white tails, along with a double footing up front to strengthen the shaft. I worry about deer jumping the string on this one. I had no problems with my 65# Bob Lee recurve, but that is a whole different beast. I like the ease and comfort of shooting the old Bear at around 51-52#s and would really like to fill one of my other tags this fall with that bow. It was passed down to me from my grandfather who was an avid trad hunter and who corresponded with ol’Pappa Bear a bit.

I definitely notice much more of a parabolic curve in the arrow trajectory with this lighter bow vs. my heavier bow, and I want an efficient arrow to reach my target quickly. I’m still going to try and keep my arrow weight up around 650gr as that is the magic bone breaking number for FOC arrows. I will most likely hunt with my 720gr arrows with the 300 Tuffy up front at 32% FOC with the old Bear and see how it goes.

Jans

[mhay]

#21584

JP , I am shooting a very similar bow to your old Bear . All summer I was shooting 877+ grain , 24% FOC . Arrows flew perfect . Arrows fell short at target though . Kept thinking the eyes and muscules would catch up but never did . I removed the 180 grain bullet from the shaft ,,,,returned to 20% FOC ,,,,and all has been SWEET .SPOT ON SHOOTING AND I know the arrows capabilities on whitetail .

Slow at 152 FPS , but very quiet ,,,and arrows are perfect in flight .

Full length 2216 Legacy,,,12 gpi

255 grain in front of shaft

2.5 inch ,,,3 fletch

697.5 grain total wgt.

[jpcarlson]

#22786

I shot the old Bear today with my heavy arrows. 810gr, 34%FOC, 52#@29″. Then I shot my setup for my Bob Lee. Those are about a 750gr, 32%FOC. The lighter FOC arrows flew fairly good out of the Bear which they are not tuned to, with fairly good penetration. I didn’t notice any large speed increase. I think I will keep shooting those heavier arrows for now because they are tuned to the Bear and fly really well. I also love how quiet they are, and how much penetration I get! I may play with a lighter setup by using the 190gr Meatheads at some point and see how they do.

Jans

[Doc Nock]

#23215

I wonder how much less weight one would need in a give pair of shafts to start seeing increases in speed?

If…IF an arrow is not tuned to a given bow, the oscillations would potentially ROB any latent increase in speed, due to lack of proper tune.

Lastly, amidst my random thoughts, I would think that lightening an arrow other than at the tip or head weight would have advantages….

I’ve been pursuing lighter GPI shafting to do just that in the past couple years… 8.1 gpi shafts or less are available in carbon, but then need some over-footing to strenthen the lighter wall thickness at the vulnerable point of impact and behind the head. FWIW

[James Harvey]

#28967

mhay wrote: Arrows flew perfect . Arrows fell short at target though . Kept thinking the eyes and muscules would catch up but never did.

Jimmy Blackmon did a neat little vid on youtube where he shows his method for plotting the trajectory/ballistics of a given bow/arrow rig. I’ve been playing around with that and arrows seem to have a gentle rise up from the bow to a ‘sweet spot’ where the trajectory is almost flat for a while (mine is about 15-32 yards) before plummeting rapidly.

I reckon that sweet spot is what makes instinctive shooting viable and effective, once I get past it I have to do a reasonable JD and gap to be consistent.

Why does that matter? The heavier and slower an arrow, the shorter that sweet spot is and hence the shorter your effective instinctive range. I think you’d have to be quite a gifted individual to make the instinctive JD’s and elevation adjustments required for the steep drop at the end of flight. I’m certainly not up to the task.

Jim

[David Petersen]

#29046

When it comes to arrow weight vs. FOC, in my experience here again Doc Ashby is right when he says, as I interpret and use it, “get the minimum weight first, then worry about FOC.” That minimum weight to assure sufficient penetration for lethality assuming the worst-case scenario of a heavy bone hit, is 650 grains. For white-tailed deer and other smaller big game, I try to hold total arrow close to that in order to boost speed. With today’s increasingly lighter and stronger carbon shafts it’s entirely possible to have a total arrow weight of 650 as well as EFOC, simply by using heavy broadheads. For elk and such I prefer around 800 grains total and with light carbon shafts can attain UFOC. But the bottom line remains weight before FOC. The original Natal Study didn’t address FOC but concentrated on total arrow weight and broadhead design. Using 843-grain total arrow weight (compressed hickory) with a tiny 125 grain broadhead I shot completely through two elk with the same arrow (not at the same time of course). On the third elk I hit the scapula and utterly destroyed the broadhead (Wolverine) with only skin-deep penetration. The point being that without broadhead integrity no amount of arrow weight or FOC is going to help us with heavy bone hits, but in fact promotes broadhead failure. Not a single piece of the puzzle can be left out. I currently shoot a 52# r/d longbow.

[Bruce Smithhammer]

#29256

David Petersen wrote: …Using 843-grain total arrow weight (compressed hickory) with a tiny 125 grain broadhead I shot completely through two elk with the same arrow (not at the same time of course). On the third elk I hit the scapula and utterly destroyed the broadhead (Wolverine) with only skin-deep penetration. The point being that without broadhead integrity no amount of arrow weight or FOC is going to help us with heavy bone hits, but in fact promotes broadhead failure.

Dave –

Your post just made me ponder something. Obviously, broadhead integrity is critical, but I wonder if an additional contributing factor to broadhead failure in the example above (an 843 grain arrow with a 125 gr. head) is exactly that – 718 gr. behind the head. This means that upon impact with an object solid enough to stop arrow travel, you have significant forces impacting the head from both ends.

In other words, even a broadhead with plenty of integrity to withstand impact with heavy bone, might still not have enough integrity to withstand impact with heavy bone, and having to stop 700gr. with its arse end simultaneously. 😉

Just a thought, and another good reason for getting as much of the total weight in the head as possible…

[David Petersen]

#30014

Bruce, thanks, you have clarified my point better than I did. Those three consecutive years’ experiences provided an abrupt learning curve for me. First, I ended a long troubling history of poor penetration on elk by going from 550-grain total arrow weight with aluminum shafts and 125-grain Thunderheads (replaceable-blade three-blades) to 800+ total weight and a narrow two blade. That combo worked great so long as I didn’t hit heavy bone, which I didn’t on the first bull and cow I took with that combo. The second step in the experience/learning process was precisely as you spell out–learning the hard way that a light thin head driven by a heavy shaft is a very weak link. So yes, precisely as you suggest, Bruce, the ticket is to get as little of the total weight as possible from the shaft and as much as possible from the point. (Another reason that heavy heads are preferable to internal weights: strength.) Back then, and this was many years ago, no such as the Tuffhead or its growing number of well-built contemporary counterparts existed, because there was no demand … and no demand due to the widespread and tenacious lack of knowledge in this arena (pre Ashby). The recent and ongoing increased availability of Sherman-tank broadheads following the widespread dissemination of the Ashby reports is the single best example I’ve seen of industry paying attention and providing what is truly needed to maximize success. Knowledge prompting innovation.

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