FOC Field Application?
 

After talking to quite a few archers and archery shop employees, it seems like the majority of the compound shooters use arrows that weigh around 400 to 430 grains total weight - and most use 100 gr. heads. (Guess this would be a good poll question)

I'm wondering why more shooters don't use 125 gr. heads for hunting. An arrow that weighs 9.4 gpi with a 100 grain broadhead will have a total weight of about the same as an arrow that weighs 8.5 gpi with a 125 grain broadhead. If the arrow diameter is the same, the lighter arrow with the heavier head should have better broadhead flight and better penetration - based on FOC principles - right?

Only downside I could see to all this would be that the 125 grain point might require the next stiffer spine rating, and subsquently move you into an arrow shaft that is heavier and/or fatter. My 61 lb. bow, for instance,can use the3-39 series arrows with 100 grain points; but actually needs the 3-49's for 125 grain heads.

But otherwise, why don't more folks use 125 grain heads?

RE: FOC Field Application?
 

'Cuz 125 grain heads have got cooties.[8D]

Being right on the top edge of a shaft's spine rating and not wanting to buy more arrows is a good reason to go with 100's over 125's. Or maybe a preferred broadhead only comes in 100 grains and not in 125's. Other than that, I doubt anyone could give you a semi-coherent reason.

RE: FOC Field Application?
 

The 'need for speed' all but requires the use of light broadheads. Far too many people are looking for this over all else. For guys like myself, speed never enters the equation, but we are far and few between. Manufacturers cater to the masses.

RE: FOC Field Application?
 

I usually don't use a 125 grn fixed blade because most of them have a larger cutting diameter. I have a fairly light set up so I try to go with a better penitrating smaller diameter head most of the time. It also makes them easier to tune and a tadd more forgiving in the wind.

If I want to add weight to my arrow I do it inside the arrow most of the time.

Paul

RE: FOC Field Application?
 

Roskoe,

I've been wondering that since I got back into shooting and it seems to baffle me.Arrow manufacturers even offer add on 25 gr weights. Why not just get the 125 gr tip. Which it seems are harder and harder to find in the newer designs.

I like the additional weight up front to help with penetration and right now my 421 gr arrow isabout 293 fps which his fast enough for me and I have an FOC over 12%. I gain about 1 fps for every 5 gr I remove from my arrows. With the 100 gr tips I'd be at 299 with the FOC dropping by 2%.

RE: FOC Field Application?
 

I'm wondering how much 2% increase in FOC would stack up against 6 fps in terms of real world penetration? Everyone talks about FOC . . . . but if it was that big of a deal, I would think we would all be shooting very lightshafts with fairly hefty broadheads.

I was doing a little broadhead testing this afternoon - upped the pull weight 6 lbs.on my Hoyt a couple of weeks ago, and wanted to see what effect it had on the point of impact of various heads. I was somewhat surprised to find that the 125 gr. Muzzy and the 145 gr. Bear Razorheads both hit the same point of impact (20 yards) as the various 100 grain broadheads/field points - even though the spine charts show I should be going to the next stiffer shaft with heads this heavy. I could nock one of these without changing much of anything - at least out to 40 yards or so. The 75 gr. broadheads, however,all hit several inches high at 20 yards.

RE: FOC Field Application?
 

Roskoe, on the 75 grain head that hit high, if you were to move your gang adjustment to compensate, I would be willing to bet that your pin gap wouldn't change very much at normal hunting distances..

RE: FOC Field Application?
 

Probably not. Awhile back, I was playing with some lighter 3-D type carbon arrows. They had 75 gr. field tips, and weighed only 320 grains total. My regular arrows weigh almost400 grains total. There wasn't much difference in point of impact, even with this light of an arrow, until you got past 50 yards. At 60 yards, the light arrow was about 6" high.

RE: FOC Field Application?
 

One of my arrows has a Muzzy Phantom 220 grain tip (242 w/insert). I practice with a 200 grain field tip. There is a 17% FOC on my 534 grain arrow. Now, this is totally UNscientific, but when I switched to these 534 grain, 17% FOC arrows they penetrated very differently than the lighter arrows I was using with a 125 grain tip (about 140 w/insert) with a 11.5%FOC. The 17% FOC arrows routinely come 6+inches out the back of the bag targets and also penetrate the rinehart deeper. Like I said totally unscientific but from what I have seen with the heavy arrows with a larger FOC % I am sold. The other day I was measuring the speed and the numbers went like this:
[ol][*]0 yds - 234FPS[*]20 yds - 228FPS[*]30 yds - 225FPS[*]40 yds - 222FPS[*]50 yds - 219FPS[/ol]
I like these arrows and I am sold on a heavy arrow with a high FOC.

RE: FOC Field Application?
 

I'm not sure myself to be honest what the difference will make. I've just always shot 125 grains and have no problem with how they perform. Though it limits my broadhead choice unless I use the 25 gr inserts.

By going lighterthespine would be stiffer which would aid in penetration and offset the weight penetration. I'd probably have to go up 50 grains or more to see a diference. I can shoot my 3D Select 300's at 73#'s and they shoot fine even though the arrow is way underspined.

I switched to the GT 7595's though to stiffen the spine.

RE: FOC Field Application?
 

I'm not so sure it works that way. A fair number of people online talk about it, but relatively few of the total bowhunters seem to know anything at all about it. Just look at how little involvement the technical forum gets compared to the "bowhunting stories" forum, and one gets a feel for the lack of interest in this type of thing. Certainly, less than 1% of bowhunters have ever read Ashby's studies involving FOC and only a portion of those believe what he has concluded.

Is it a big deal? Well, I doubt a 1-2% increase in FOC will make much of a difference, unless it just happens to get your arrow out of a super unstable range. However, when you get into the extreme increase range, then the difference is profound in my opinion. Still, how many people have even experimented with 250 grains on the tip? I'm including bow shop owners in this. I'll bet 90% of those haven't even tried it, much less studied the available data on it.

You also have to know how to arrive at proper spine when using heaving weight on the front. You can't just add the weight to an arrow and expect it to work. Most don't know this. They go to a chart, read the variables and choose the recommended head. They don't even know how inaccurate those charts can be, and the charts typically don't go past 125 grains. Heck, none of the charts even take into account the difference between draw length and arrow length when determing spine.

In my opinion, the bowhunting public has a long way to go before a majority understand what proper arrow design consists of. Bowhunters tend to be wrapped up in annecdotal evidence - 'light-weight, low FOC worked for me, so why change?' The bow industry will have to make a change towards promoting stable arrow flight, vs 'this is the fastest bow on the planet'. I don't see this happening anytime soon. At this time, the industry seems to be predicated on what bow manufacturers do - and they promote faster bows than the 'other guy' has.

RE: FOC Field Application?
 

Straightarrow,
And to think that a few months ago when I was asking all of the technical questions, I was told that I was being too technical, both by the archery shop owner and some of the members here. I didn't stop learning, though. I just stopped talking about it. I'm one of those guys who isn't satisfied that it works.... I want to know how and whyit works.

RE: FOC Field Application?
 

I'd really like to experiment with light arrow shafts and ultra high FOC's but that right there is what keeps me from it. My arrows are too long (32"). Even at 125 grains, the charts show me needing a shaft with .300 spine deflection. That's pretty much as stiff as it gets with carbon. At least, so far as I'm aware.

Maybe I just need to break down and find myself an overdraw so I can shorten up my arrows.

RE: FOC Field Application?
 

Great discussion guys. I really have to agree with Straightarrow when he talks about how the vast majority of bowhunters really have no clue what should be taken into consideration when building a shaft. Whether it is for 3-D, Hunting, Target, etc.

While I am just starting to get into bowhunting, and have a long ways to go, I learned quickly on the affect a poorly "thought-out" arrow and how broadhead flight can be dramatically affected.

Just look at the forums right before hunting season. Tell me what you see. Many are left with poor broadhead flight due to poor tuning (both bow and arrow).

While I have no dabbled into 125 grain heads, through this discussion, I am thinking about setting up arrows for both 100 grain heads and 125 grain heads to really dig deeper into trying to find better accuracy and penetration.

RE: FOC Field Application?
 

Arthur, I think guys like yourself can dabble a bit in the extreme FOC arrows under some situations. There's always the option of the arrows like Carbon Express' Maxima arrows with the built-in FOC, but if you're like me, you want the extra weight of the heavy tip on a carbon arrow. I personally have little interest in a light weight arrow, so I'm staying away from the tapered shafts.

Gold Tip's Big Game 100 arrow has a .280 spine. If you're willing to shoot it at around 45-50 lbs, I'd bet you could get somewhere in the 200-250 gr weight on the tip on a full length arrow. Lower draw weights are not a big drawback for guys like yourself. Your arrow has so much power that I'd bet most big game would fall if you were shooting 35 lbs. I'm using this arrow with my compound at 62 lbs at around 31" with 250 grains on the tip. My draw length is only 29", but like I said, if you get down into the lower draw weight ranges, it should work just fine.

You don't need all that extra power anyway. ;)