Broadheads hitting left (but different)

[SlimTim]

I’ve noticed my broad heads have been slowly drifting left over the last few months. Tried moving my rest right and broadheads are still left of field points.

I appreciate it may be the string stretching, though current string has been on for two years, but wouldn’t this make my arrows stiffer relative to draw weight meaning broad heads hit right of field points?

Could it be cam timing? If so, any advice on how to check without a draw board? I live in the remote Northern Territory of Australia so don’t have access to a shop.

Any other ideas?

Cheers
Tim.

 

[WMag338]

For me, when nothing has changed on my bow (no new strings, stabilziers, arrows, etc) and my broadhead changes impact, it's due to my form. Very sublte changes in my form will make huge changes in my broadhead flight.

I've noticed this if I hit the gym hard for a few weeks or don't hit the gym for a few weeks, get super hot outside and my grip on the bow might been a little sweaty, sleep wrong and a muscle is sore, etc.

Could be something with your bow, but it sounds like if your rest hasn't moved, cams haven't moved, that your form might be a good place to start.

 

[Tony Trietch]

Move your rest in the direction on the BHs.
So if BH point of impact is left of field point, move rest left. Only move rest in small increments, like 1/32" at a time until the two arrows have the same poi.

 

[Decker]

Have someone watch you draw back and watch your cams. See if your cams are touching at same time.

 

[DooleyVT]

Like Tony said moving the rest in the same direction as your broadhead should help. The other thing is maybe your anchor hand positioning is slowly changing and maybe for the better! I know for me shooting a thumb button I had to make sure my anchor hand stayed flatter against my face or my POI would change. If my pinky rotated to 2-3 o’clock from getting relaxed I would hit left. I’ve since adjusted my sight to this more natural hand position after shooting with it for a couple seasons.

 

[Decker]

Also try nock tuning with broadhead.

 

[fishsticks]

To answer your question if you have a draw board you want the cable (or limb) stops to touch at the same time. Maybe the top will barely touch first .

However I’d guess it’s form. Left/rights are often face pressure.

 

[fatlander]

Title says left but different.

Can you expand on the different part?

If individual heads, that are all else equal, are flying better or worse you’ve got at least one problem and likely more.

1.) You’re inconsistent. You can only tune a bow to the point your form allows. If your shot process is not repeatable, you’re going to struggle.

2.) There are inconsistencies in your arrows: broadhead isn’t square with the front end of the shaft and/or the nock isn’t squared with the back end.

3.) Your bow is out of tune. Some folks have mentioned moving the broadhead to the field point. I’ve set up and tuned something like 50 bows in the past decade, and that just doesn’t work for me. I know it works for some, because there are videos on YouTube showing it work that way. Then there are videos showing it the opposite to be true. Moving the rest the way I want the broadhead is the only thing that’s ever worked for me, IF it’s already really close: within a few inches at 60 yards. If the difference is greater than that, shim the cams/yoke tune to get it close then use very fine rest adjustment to get it to tune. If you’ve gotta move it more than 1/16” from manufacturer center shot, you’ve got problems that moving the rest can’t fix.


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[Mighty Mouse]

I’ve noticed my broad heads have been slowly drifting left over the last few months. Tried moving my rest right and broadheads are still left of field points.

The chart below has always worked for me. However, pragmatism is the number one rule in tuning...if moving something in one direction doesn't fix the problem, try moving it the opposite direction (regardless of what anyone says is the "correct" direction).

I appreciate it may be the string stretching, though current string has been on for two years, but wouldn’t this make my arrows stiffer relative to draw weight meaning broad heads hit right of field points?

String/cable stretch can affect a bow in various ways. Stretching of the shooting string causes draw weight to increase. Stretching of the buss and/or control cable causes draw weight to decrease. It's possible that string/cable stretch could affect the horizontal tune of your bow, but it wouldn't be my first guess as to the root cause of your broadheads hitting left.

Also, the old "broadhead left = arrow is too stiff, broadhead right = arrow is too weak" (for a right-handed shooter) advice doesn't apply to a modern compound bow shot with a mechanical release. Today's compounds are cut well past center with the rest mounted in line with the string path, so the arrow doesn't have to bend around the riser during the shot (like it does on most recurves/longbows). And a mechanical release eliminates the left/right effects of shooting with fingers. Arrow spine can affect how a bow tunes, but the effect doesn't necessarily manifest as broadhead left if too stiff/broadhead right if too weak. Modern compounds can typically tolerate a fairly wide range of arrow spines.

Could it be cam timing? If so, any advice on how to check without a draw board? I live in the remote Northern Territory of Australia so don’t have access to a shop.

Cam timing primarily affects vertical point of impact. If your broadheads are vertically aligned with field points, I wouldn't suspect a cam timing issue. It never hurts to check though.

Without a draw board, you could try taking a slow motion video or having someone else watch as you draw to see if the top and bottom draw stops are hitting at the same time. A draw board is fairly cheap and easy to build; however, you would (likely) need a bow press to actually make an adjustment if you were to find that the timing is off. APA bows and Mathews' V3X/Phase4 are notable exceptions that can be timed without a press.

Any other ideas?

Check for vane contact. Put a tattletale substance (e.g., lip stick, chalk, spray foot powder) on the edges of the vanes then look for marks on the rest, cables, etc. after shooting.

Confirm the trend with multiple arrows to make sure that what you're seeing is not just an artifact of one particular broadhead or shaft.

Put the arrows on a spinner to visually check for misalignment.

Try moving the rest the opposite way.

Try adjusting cam lean/lateral position per the chart above. This will likely require a bow press.

Try bareshaft tuning. If you can get bareshafts to hit alongside fletched shafts (both tipped with field points), broadheads (on fletched shafts) should follow suit. If they don't and a tiny rest adjustment can't get them there, you may not have enough fletching to adequately steer/stabilize your broadhead.

 

[Billy Goat]

Does one or both of your cables make a Y at the cam?

It could be one side of your yoke has crept, it would actually be a bundle in your cable, buy if one side had more pressure it could have crept changing your cam lean.

 

[Inthebloodhunts]

I’ve noticed my broad heads have been slowly drifting left over the last few months. Tried moving my rest right and broadheads are still left of field points.

I appreciate it may be the string stretching, though current string has been on for two years, but wouldn’t this make my arrows stiffer relative to draw weight meaning broad heads hit right of field points?

Could it be cam timing? If so, any advice on how to check without a draw board? I live in the remote Northern Territory of Australia so don’t have access to a shop.

Any other ideas?

Cheers
Tim.

Elkshape on YouTube has a bunch of great videos on this and everything you could want to learn about tuning. MFJJ on there really knows his stuff.

 

[mod-it]

Lots of good info above.
I would suspect, if it was tuned before and nothing has been changed, that either the rest has moved (unlikely), it has yokes and one side has changed more than the other, your grip position has slightly changed, or face pressure has changed.
If it is consistent, then no biggie really, just tune to adjust for it.
Like said above, you probably moved the rest the wrong way for what has caused the issue.
I'd bet every single one of us has done that when new to tuning. In our mind the broadhead (BH) hitting left of field points makes us think the arrow is sitting at an angle like this \ between the string and rest, so it "makes sense" to move the rest right. And sometimes that may be the case, but it is much more rare (it's really not that hard to align the rest with the string with a square or measuring to the riser) than the cause actually being cam lean. Cam lean means the string is not traveling in a straight line from full draw to brace. In your case of BH hitting left, it would mean the string is moving from right to left a bit as it drops, so moving the rest left to align it with the powerstroke of the string will bring your BH's and field points back together.

 

[MattB]

You can check your cam timing in a bathroom mirror by drawing, letting down slightly, and drawing back against the stops. You can visually see and/or feel if the stops are not hitting together.

My bet would be hand position or cam lean. Trying moving your rest in the opposite direction and past where you started and see if that changes anything.

Lest it become confusing, string “creep” is what some people are inaccurately referring to as “stretch”. They are separate and distinct concepts, with creep being permanent elongation (which is what causes bows to come out of time/tune) and stretch being a temporary elastic elongation that occurs during each shot cycle. Stretch has ceased to be a relevant concept with modern modern string materials so we only have to deal with creep - but for some reason most everyone (especially those under 40) seems to now use the term “stretch” to describe “creep”.

 

[fatlander]

One other thing to consider is your fletchings.

I’m not a professional archer, so take this for what it’s worth. I’m a just guy that shoots a lot, tunes a lot of bows, tests a lot of stuff, doesn’t make any money in competitive archery, and doesn’t have business endeavors with fletching companies.

High profile fletchings steer broadheads better than lower profile fletchings.

Fletchings with more offset (helical) steer broadheads better than those with less.

All else equal, 3 blazers with a decent amount of offest are going to steer your broadheads better than 3 heats, x vanes, or max stealth’s. Blazers are so prevalent because they work.


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[NYSKIER]

Haven't see it above, maybe try to bare shaft tune and see how it looks? Or if form is the culprit you can shoot the same arrow only for a few days and see how it looks (maybe if knock tune will help?). I always look to form first and then I start to tinker

 

[Trial153]

Put two turns in your limb bolts or 6 twists in your cables. If that brings them together you know your over spinned. Drift left over a period time is almost always cable stretch

 

[Meshnasty]

I’d highly reccomend making a draw board. You used to be able to do it for $25-35. You should be able to find plans for one on AT. This will at least tell you if your cams are timed because if they aren’t you can spend as long as you want trying to tune and work on form but you likely won’t get anywhere with it.

I’ve only had a continual shift in BH impact due to a poorly built string and cable creeping. I was loosing my timing by over a couple of the timing dots on the Elite Energy cam every week or so. It was a few weeks of misery chasing my form and re-timing my cams right before I left for a hunt. I thought I had it fixed as my bow stayed timed for more then a couple days and went on a 9 day hunt and my POI had changed 4-6” by the end of it. Only time I’ve been happy to not get a shot.

Any other change in impacts for me have been form or tuning issues, but none of those are a slow continual change.

Also, before I bought a real press I used a bow master portable press for tuning. It was a major PITA, but if you are far from a shop getting one might be worth your money and time.

 

[Bump79]

Move your rest in the direction on the BHs.
So if BH point of impact is left of field point, move rest left. Only move rest in small increments, like 1/32" at a time until the two arrows have the same poi.

You're right this is the problem. Correct for left/right but however it's opposite for up/down.

Broadhead down move rest up. To make it easy the best way for people to visualize it is the adjustments are the same as a paper tear. Meaning your broadhead is catching air and planing in the same direction as the tip in a paper tear.

 

[SlimTim]

For me, when nothing has changed on my bow (no new strings, stabilziers, arrows, etc) and my broadhead changes impact, it's due to my form. Very sublte changes in my form will make huge changes in my broadhead flight.

I've noticed this if I hit the gym hard for a few weeks or don't hit the gym for a few weeks, get super hot outside and my grip on the bow might been a little sweaty, sleep wrong and a muscle is sore, etc.

Could be something with your bow, but it sounds like if your rest hasn't moved, cams haven't moved, that your form might be a good place to start.

Interesting. I've definitely started a different gym routine that involves lifting way more.

 

[SlimTim]

Have someone watch you draw back and watch your cams. See if your cams are touching at same time.

I'll get the missus to check it out.