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Cams horizontally equal, cocked and uncocked. But, cam lean backwards when you look from side, only when cocked. Uncocked, paralel, horizontal. When cocked they dive towards back.
 

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Discussion Starter · #162 ·
Cams horizontally equal, cocked and uncocked. But, cam lean backwards when you look from side, only when cocked. Uncocked, paralel, horizontal. When cocked they dive towards back.
you have thick raiser shims?
 

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Discussion Starter · #165 ·
2mm shims, 3mm wide..
i have just bit wider than 1mm, maybe 1,15mm wide gap with ~2mm rubber shims, this was enough to reduce pressure on string but it did not lift it

i dont know if its shims or not, and if its not from shims then i have no idea
 

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Here is a link to a discussion about cam lean on Amped, that is Kraken. Interesting, with photos and how he measured... Checking cam lean

on my bow, BOTH cams, cocked are like in the photo of the left cam of this guy, also on a centerpoint/mankung.
 

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Discussion Starter · #167 ·
these are no good for this crossbow

SKYLON X-BOW BOLTS 3K CARBON dia 8.7mm 20" MOONNOCK + INSERT + POINT 6/pk | SSA Archery (ssa-archery.com)

they were all over the place on longer distance. not sure if its that they are too light or thin or the fieldpoints i changed on em to get em 390gn
could be wear too, they are still good practice arrows for shorter distance as they dont whack target too bad and have vanes that dosnt mind getting buried

reflecthed stiff poelang arrow shot exactly where i pulled the shot at 50yards :rolleyes:

didnt shoot the 480grain but drop did appear significally lower now with new front end

cant but wonder what goes on with wild life here, last time it was deer that came to check me while zeroing, now it was young rabbit, was just about to shoot 50 when he came sitting in front of me at 5yards, didnt even move when i put safety back on
 

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Discussion Starter · #168 ·
what i learned this morning:

allways clear the target before shooting another arrow when paper tuning

205724


and have another cup of coffee before taking an shot

im just glad this was the arrow that swinged upwards
 

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This is the good case when arrow go the same hole...
Today I took the little courage left and I used the improvised bow press (photo) from a pipe-clamp and tried to replace washers on cam axles and do some tuning to cables and yokes.
Total disaster, the clamp screw is too short and barely presses enough to give the cables some slack, and after I too axles from cams out, neat and careful, the bow JUMPED out of the press, sliding against its margins.
I barely put everything back together, immense effort and patience, but I am almost certain I totally messed up the number of twists and turns, maybe even which cable goes above the other...
Beginner's bad luck. I will play with it until I will have some money to get a DECENT bowpress...
 

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Discussion Starter · #170 ·
This is the good case when arrow go the same hole...
Today I took the little courage left and I used the improvised bow press (photo) from a pipe-clamp and tried to replace washers on cam axles and do some tuning to cables and yokes.
Total disaster, the clamp screw is too short and barely presses enough to give the cables some slack, and after I too axles from cams out, neat and careful, the bow JUMPED out of the press, sliding against its margins.
I barely put everything back together, immense effort and patience, but I am almost certain I totally messed up the number of twists and turns, maybe even which cable goes above the other...
Beginner's bad luck. I will play with it until I will have some money to get a DECENT bowpress...
be carefull with it please, i heard someone lost they neck with bow press, and that was from store
 

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Yeah, this improvisation is totally NOT what needs to be used for these bows.
I was careful, but lucky to be able to put all together after everything flew FAST throughout all the balcony... Missed my head, fortunately.
 

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Discussion Starter · #172 ·
Yeah, this improvisation is totally NOT what needs to be used for these bows.
I was careful, but lucky to be able to put all together after everything flew FAST throughout all the balcony... Missed my head, fortunately.
mods ive seen from pipe clamps had very sturdy wooden support pieces screwd in place tightly
 

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Sturdiness is ok, those are hard stainless steel plates, but they are slippery, and screw is weak and too short, not pressing enough, barely.
 

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Discussion Starter · #174 ·
did some more paper tuning, looks like arrows dosnt mind much if spine is top or bottom through paper

impact is bit lower when spine is on top, presumably arrow impacts more rail when spine is on bottom

from right to left:
1. reference to get level of poa with fletched
2. spine on bottom
3. spine on top
205846


spine on top looks cleanest




some "out of tune" shots

205847


looks like arrow dosnt tear em but its actually pressure from impact that makes paper tear it self
 

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Look up to my photos when paper tuning. Even MORE diagonal. It is the bow, the string un-evenness, I think, need exact leveling, cam lean, and tuneup.
I put the courage at work today, again, pressing just enough to be able to slack the yokes, enough to take them out and twist.
First changed shims to raise string just under a business card thickness (which worked), then cocked and checked levels (again left three time more leaned than right, applied twists), and the result pleases me, for the time being (that is, next measurement, today I am out of allowed quota).
String just under a business card thickness in height, string level, string perpendicular on rail, distance to shock absorbers a little greater than zero.
Until next (final) cocking to check for cam lean feedback, I am happy.
 

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Discussion Starter · #176 ·
Look up to my photos when paper tuning. Even MORE diagonal. It is the bow, the string un-evenness, I think, need exact leveling, cam lean, and tuneup.
I put the courage at work today, again, pressing just enough to be able to slack the yokes, enough to take them out and twist.
First changed shims to raise string just under a business car thickness (which worked), then cocked and checked levels (again left three time more leaned than right, applied twists), and the result pleases me, for the time being (that is, next measurement, today I am out of allowed quota).
String just under a business card thickness in height, string level, string perpendicular on rail, distance to shock absorbers a little greater than zero.
Until next (final) cocking to check for cam lean feedback, I am happy.
what i came to understand and concluded in past few days, that arrows can hit low when there is much drag from vanes, i.e full size vanes, also ackward spine location can make rear jump, if arrows turns to left or right its about timings and ata. you can get arrow hit straight even if there is cam lean, if its correctly spined and stiff enough to withstand the speed and if timings are right. what cam lean does mostly with too much pressure on rail, it ruins the serving
i assume that lifting string from rail would also minimize drag from full sized vanes
 

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Discussion Starter · #177 ·
Congratulations, now letțs have some FUN.
Today I spend two hours in the sun in the little backyard of my mother-in-law, me being an apartment guy...

My first bareshaft papertune.
Distance 16 meters

Bow – mankung XB58 Kraken, advertised 405 fps, actual 385 fps.
Poor quality kit arrows from mankung from package, approximately 425 grains with 100 gr field tips, bent vanes, BUT perfectly spot on. See photo 1.

BARESHAFTS
Chinese good quality, +/- 0.001 straightness, pure carbon 20 inch long, spine 240, spine matched, 198.8 grains, Lok-n-Load 92 grains inserts, 100 grain field tip, aluminum half moon nocks 36 grains with fixed with teflon band for easy indexing. Total 324 grains plus 100 grain field tip = 425 grain, approx, plus minus few tenths of grain.

The shafts were spine indexed, static spine determined on stand, dynamic spine determined on stand with laser and permanently marked the plane where obtained FLO (flatline oscillation).

Initially shafts were shot with spine plan DOWN at 6 o’clock like with the cock vane down…

Judging from the fletched arrows results, tac-like, spot-on at 16 meters (tiny backyard), I expected SOME performance, hoping to fine-tune and finally index the nock so to obtain perfect paper holes, before fletching the shafts…

From my observations and measurements the bow, riser and cams are square, except a little cam lean front-back, when cocked… without bad consequences so far.

I repeat, the bow is EXTREMELY precise with fletched arrows, se photo 1, with fletched arrows.

RESULT – total disaster, see photo 2, with total results, including last hit of a fletched arrow, VERY GOOD, on my noob opinion...

Bareshafts hit almost at 45%, making long tears.
First shaft, numer 2, broke from half on impact with the target bag behind.
Rest of them consistently hit long, LONG tears.

Now my questions for the knowledgeable colleagues on this esteemed forum is WHAT THE … happened? Suggestions for this noob here?
Thanks in advance, respectfully, and Cheers from Bucharest, Romania. View attachment 204507 View attachment 204508

View attachment 204509
just turn the nock small amount and shoot again, you should eventually have it shoot straight
ones i had tears with was spined about 15 degrees off, i can get about 35 degrees approximation with my improvised tester
 

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Discussion Starter · #178 ·
forgot to mention that drag from vanes also effect poi on sideways, if cockvane is bend or not pefectly aligned it will drag arrow left or right
 

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Discussion Starter · #179 ·
Look up to my photos when paper tuning. Even MORE diagonal. It is the bow, the string un-evenness, I think, need exact leveling, cam lean, and tuneup.
I put the courage at work today, again, pressing just enough to be able to slack the yokes, enough to take them out and twist.
First changed shims to raise string just under a business card thickness (which worked), then cocked and checked levels (again left three time more leaned than right, applied twists), and the result pleases me, for the time being (that is, next measurement, today I am out of allowed quota).
String just under a business card thickness in height, string level, string perpendicular on rail, distance to shock absorbers a little greater than zero.
Until next (final) cocking to check for cam lean feedback, I am happy.
not sure if you seen this, good threat for adjusting

Pics to help folks with putting strings and cables on bows and tuning | Crossbow Nation

Thank You @Riflenut
 

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Discussion Starter · #180 ·
just went and measured about 100meters with rope and placed apple size object on top of branch
gonna be feat to hit that even with one arrow
might even need magnification
maybe one day i will put few through deck of cards, not sure if it happens with this scope or not
but now i have measure of how small i need to aim
 
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