sproulman

have any of you used this system to increase your F.O.C?

i was looking at them and they come in weights from 10grs /50 grs that screw into back of alum insert.

if used, how would you know what weight to get or isgetting the point area as heavy as you can way to go .

i use 100 gr points on my 20 inch 2216.
i just put inside a 2020 shaft to stiffen the arrow and thisadded about 35 grs to point area,so i am up to around 435 grs on my arrows now.

Cossack

Here is a web site that has an FOC calculator:http: //www.goldtip.com/calculators/foc.asp
Hope that helps you determine yours.
It is for vertical bow carbon arrows but works for bolts too. (The formula works the same for aluminum shafts).
I have not used the system you mentioned, looks like to much 'putzing.'
I use 20" GT Lazer II (carbon) shafts, 110 gr brass inserts, 2" Blazer vanes (no wraps) and the stock GT rear alum. Tipped with a 100 gr Slick Trick I get a FOC slightly more than 20%.
The stuff I've read says around 12% for arrows and "higher, perhaps as much as 15% for bolts." This sounds like the author wasn't too sure about the latter , so I experimented. All I can tell you is that my bolts with 20% FOC (and Slicks) are very accurate and consistent.
I mention Slicks (smallish, 4 bladed heads) because I've found larger, 3 bladed broadheads I tried less accurate by lacking consistency from one bolt to the next.
BTW: I found brass inserts in 90 and 110 gr weights; there may be others.

KLS

I havent used them but have checked them out, if you could get them locally they'd probably be something to try, howeverif you had to buy them plus pay the shipping costs then IMO a guy could probably find something just as goodina small screw at any local hardware store that would work just as good andbe cheaper

I've came up with several ideasas far as inserts/insert weights that would work good, some are pretty simple ideas and someare so elaboratethat they would require my making them completely by hand(I have access to a machine shop), but the easiest I've came up with so far to add weight to thefront of the arrowis to simply switch to 125gr tips

I'm going to be trying some different things myself in the near future to see how they work, I'm happy with the weight of my arrows but even though my FOC is decent its not as good as I'd like it to be

sproulman

boy did i have hard time getting those 2020 shafts into a 2216 alum arrow.

i had to sand the 2020 down.
funny,they slid right into a 2213/2215.

real hard to even find a 2020 arrow.
i was over on the archery forum and some use the PDP system.

gent from italy suggested i use a 3 inch 2020 arrow inside my 2216 or if i wanted, buy his inserts which brings arrow up to 570 grs.

those PDPinsert/weights really dont cost a lot to try.

they go in increaments of 10/20/30/40/50 grs.

sproulman

a lot of guys at club are using BULLETS to bring the FOC up.

they glue them in behind the insert.

cant tell you what caliber or dia. they used on 2213/2216/2219but on my 2020 arrow i am cutting 3 inchs for inside 2216, the .25 caliber bullet which is 87 grs/100 grs and dia of .257 fits in perfect.

tonight i may melt out the insert from my 2216 and see if i have bullet that will fit perfect .


well, i did not wait,i found that a 30cal bullet fit in nice in a 2216.
it is .308 on box.

wow, its 150 grs and i have some that are 180 grs.they make them in 100/110/130/150/180 grs.

270 cal also fit in but a little tighter,it is .277 dia.
they also go down to 100 grs.

you could most likey make bullet lighter like below 100 grsby cutting some off of it.that i could not offer how to do that.

you know, i think you could glue the bullet right on the insert on back and make it work..

by doing this you could use ANY caliber bullet below a .308 and also go down to weights of like 45 grs on up.
they would have to be tested to see if they would stay on the insert with glue but just a guess, i think they will stay on with strong glue.only thing is, you would be glueing that hole shot on bottom of insert that i assume lets air out of insert when screwing in the point.

but the PDP system seals the insert with no hole in bottom ,so it may not be necessary to have that hole.

this way you could really play around on your FOC.

KLS

thats not a bad idea, I've thought about doing that actually and even experimented a little with it,alumin arrow's ID varies with wall thickness(which is more than likely why you had trouble geting those 20/64 arrows inside those 2216's), and from what I've foundalumin. arrow'sIDalso varies from carbon arrows
I have looked in my books before and found that there are a number of bullets that should theoritically work in a number of different arrows, I cant remember any of them now but all ittakes is a dial caliper to measure the arrows ID and a bulletreference guide to figure out what dia bullet would fit the arrow best...
anidea I had along the same line was making my own plugs to fit behind the insert, however theres a few things that didnt really appeal to me with going that route, or the bullet route, or even with the screw-in weights


one is the fact that with that approach the weight is behind the insert and the fartherinward from the tip of the arrow the weight is the less effect it has on FOC, too far in and all it becomes is dead weight, the inserts in my thunderbolts are already an 1-1/4" long, which would put the plug at around 1-1/4" to probably 2" in from the end of the arrow, which in my case would be around 4" in from the tip of the arrowspoint(broadhead), which with a 22" total length arrowwith an 11" centeritsclosing in fast on what the actual balance point would be in calculating FOC...
my arrow weight is good enough, I dont reallywant toadd any unnecessary weight, so all the weight I add or moveI'd like to be as far forward as possible to be as efficient as possible in improving FOC, making brass washers to put between the tip and insert is one idea I had which would put the weight in front of the insert, however with the size limitation of doing that your kind of limited as to how much weight thewasher can be, your also increasing the total length of the arrow(not that that little bit would really matter)

I run inserts for nocksbecause I need them for my fletching jig(I made an adapter for my fletching jig that screws into the insert and then locks into my jig),the insertsweigh 43gr but Ifound that I can cut them down without any effect on my adapter, from the little bit I've experimented I cancut well over 20gr off of them, which would drop the inserts weight to around 20gr,probably less,that will have an fairly big impact on shifting weight without adding any I think, sothats on my list of things to try(and probablyre-do)...



another thing that doesnt appeal to me is the fact that I dont really like or trustthe idea of a plug being just glued inside the shaft, even with epoxy I just wouldnt trust that it would hold in place and would have to have it screwed into the back of the insert somehow anyway, which would require a fair ammount of fab work to get everything the same and equal in a dozen arrows, besides the fact of getting it back out if I decided I didnt like it in there...


which brings me to the next reason it doesnt really appeal to me(or alot of the other ideas)... and that is the fact thatI like to tinker with the best of them, but I'm notdumb, andI see it as kind of pointless to go through all the elaborate work and messing around to make something custom work to add or move weightto the front of the arrowwhen I can just buy the more effecient brass inserts and be done with it...

which is also on the list...

sproulman

well, so much for the bullet idea.
i forgot to mention that all that used the bullet idea,were all compound bow shooters who do shoot a longer arrow.

question, do they make a brass inserts for aluminum arrows?

KLS

well, the idea is good, its just that doing it that way youd have to add quite a bit more weight to get the same effect and in my case I just dont want to do that...

I also want to add that IMO that FOC calculator isnt as accurate as itwould seem, or I should say I think its kind of deceiving... when calculating FOC it asks for overall arrow length, my 125gr thunderheads are a touch over 2" long but my 125gr field points areonly about an inch,and that one inchmakes a pretty drastic differencein its calculation,and I dontbelievethe broadheads weight is concentratedenough out at the tip to justify adding its extra length,which IMO gives a somewhat false calculation...



not having any brass inserts to work with at the moment I've been doing some rough figuring and number crunching and came up with some kind of surprising results...
my arrows as is weigh 438gr with 43gr inserts front and rear, feathers, and 125gr pointsand has a FOC with field points at a little over 12%, with broadheads its actually only a little over 10%(I dont know why but I never did checkitafter I got my broadheads, I've only calculated FOC with the field points)

with feathers and 20gr cut down inserts for nocks I have the back end of my arrows about as light as I can make them, which leaves adding weight to the front as the only option to increasing FOC... I've done some figuring and found that with the weight of the thunderbolt shaftsthemselves, thata 110gr brass insert and 125gr broadhead would only get meto about 18% FOC, and thats adding the weight directly to the broadhead, at the tip of the arrow and not 4" behind the tip of the broadhead,having to add all that weight to getto that FOC would up my overall arrow weight to around 485gr(if my calculations are correct... ), which is alot heavier than I want to go to begin with...were I to add the weight behind the insert I'd more than likely have to add quite a bitmore weight still to equal the difference in weight placement,which is where mycomment of not wanting to add unnecessary weight comes from, I'm going to have to add enough as it is...


I'd like to stick to around 440gr,but I would also like to up my FOC, and do it without adding a ton of weight, soI have somethinking to do to try to figure out how...I've said before that I didnt likeshooting 2213's, but I'm starting to wonder now ifgoing that route may be an answer...



I'm probably getting way too involved with this(like I usually do...)but I want to be completely happy with my arrow setup, and when I'm done putting them together I want to know that they're the best they're going to get, and I dont want to be left thinking I should have done something different...


but for me this is half the fun, and I have all summer...

Stan00

I use this to measure my foc. Gold tip also makes weights that screw into the back of the inserts. I also used a 8-32 socket head cap screw screwed into the insert.

Good luck, Stan


http://www.lmariana.com/foc.htm

Wyvern Crossbow

"question, do they make a brass inserts for aluminum arrows?"

Not specifically...the 110gr brass inserts are about .005 too small (they are designed for carbon). The collar is fine, but they are abit loose in the shaft. Epoxy would work to hold them, but you may have to play arround to get them straight...

Wyvern