Arrow Stabilization Issue?

[Carlos Hathcock]

Dialing in my new bow for the season. Equipment specs below. Here's what is confusing me.

40 yards: approx. 6-7" group
30 yards: approx. 12-14" group
20 yards: approx. 2-3" group

Bow: Diamond SB1
Draw weight: 62 +/-
Arrows: Mossy Oak 400 shaft carbon
Fletching: Bohning helical. (By me)

I seem to have this issue at 30 yards. Is there some chance I'm getting some sort of "destabilization" at that range? I would've though 30 yards would magnify the issue but not so. Any thoughts?

 

[Hillbilly77]

Have you paper tuned the bow to be sure that it is tuned properly?

 

[redtail]

Archerytalk.com

Could be a bunch of things.
You want much better groups from that bow.

 

[Carlos Hathcock]

Have you paper tuned the bow to be sure that it is tuned properly?

Setup and tuned by a verified professional.

 

[Twogunwilly]

check it with your bow square, that should shoot dime sized groups.

 

[Blimey]

I think your grouping is an anomaly. it's difficult to think of a realistic way it's possible unless your arrows are arcing mid filght and 30 yards happens to be the most extreme part of the arc. I'd shoot more groups until you're positive.

As for tuning you can try cutting fletching off an arrow and try bareshaft tuning. I only started fiddling with that recently but I am tentatively of the opinion it has some benefit. I think it's important when doing it to shoot a foam target, which somewhat accurately captures the actual angle of impact (a bag target won't).

Paper tuning is useful if tuning is severely off. Unfortunately the vanes can correct pretty bad flight so it can be difficult to get quite right in terms of how far back from the paper you should be.

Another thing I've done a little with is a lighted nock and film in slow motion on your phone. Get somebody to film directly from behind. iphone tops out at 240 FPS but you can capture some bad wiggling action if the arrow has it. There is a new samsung phone that will do 960 and I'd absolutely love to take that to the range. I think it could masterfully tease out if the arrow is flying properly.

 

[cgrutt]

I think your grouping is an anomaly. it's difficult to think of a realistic way it's possible unless your arrows are arcing mid filght and 30 yards happens to be the most extreme part of the arc. I'd shoot more groups until you're positive.

Would think it's normal trajectory with effect of lift and gravity no?

 

[Hillbilly77]

Setup and tuned by a verified professional.

I would try to check the paper tune with the exact arrow/tip combo in question.
Also it may be a good idea to have somebody knowledgeable watch you shoot to see if there’s something you you may be doing unconsciously that is throwing your shot off.

 

[Blimey]

Would think it's normal trajectory with effect of lift and gravity no?

Normal Arc would indicate an ever increasing grouping size with distance. To have a larger grouping at middle distance is hard to explain and would require some random poor flight but somehow the arrows know they are supposed to track back later.

When I said arc earlier I meant curving like a ball but that doesn’t really make sense either

 

[cgrutt]

Sorry not really following at some point (probably the beginning moment it leaves bow but thats another discussion lol) the arrow has to fall due to effects of gravity. In chart above groups would increase from roughly 4 to about 15 yards then tighten from 15 to about 26 yards. Isn't that same behavior as OP is experiencing (albeit at different yardages)?

 

[Carlos Hathcock]

I can understand the properties shown in the diagram but the groups at 30 are so much a higher verticle only variant as much as they are a general vertical and horizontal spread.

I'm not a professional archer but I guess I was wondering if arrows "stabilize" at a certain distance as I know they flex, unlike a bullet. In that line of thinking my 20 yard groups should be the worst.

I am pretty consistant with my technique so I don't think it's a form issue but I may try the slow mo thing too.

 

[Acer-m14]

Setup and tuned by a verified professional.

but not you shooting it .. i think of it the same as a rifle .. shoots good for me .. not you .,. just saying ..

i also think a bow is per the shooter .. more then rifle .. lots of stuff come into play .. grip .. torq and so on ..

Target Panic .. .. gets the best of me too ..

last weekend just got my bow out for the first time .. my best friend dad says shoot the block not the deer ( bud was using the deer to sight in his new bow) ..
i look at his dad .. WTF .. i was going for the wood pile back stop .. you know i pull the first shot LOL .. ( skeet shooting mussel memory ) and a bit of target panic .. LOL .. first shot i pulled it off to the right just like skeet .. . got settled down and was a 2 inch group at 20 ..

my limit with the bow due to my draw size and poundage ..

 

[Blimey]

Sorry not really following at some point (probably the beginning moment it leaves bow but thats another discussion lol) the arrow has to fall due to effects of gravity. In chart above groups would increase from roughly 4 to about 15 yards then tighten from 15 to about 26 yards. Isn't that same behavior as OP is experiencing (albeit at different yardages)?

He specifically said group size, though--not whether the POI was wrong or not. The arrow behaves the same way as a bullet, so irrespective of where it hits/whether it's zeroed or not/adjusting for distance/etc. the group should always increase as distance does. I'm sure you could identify a distance at which a 40 yard pin on the bow is perfectly zeroed and you're also zeroed much closer, so you'd be consistently high at 30, but your 30 yard group would be still smaller even if the group is above the bullzeye. Same as an AR zeroed at 50 is also zeroed at 200. All the 100 yard groups will be above the bullzeye--but they'll still be tighter than the 200 yard spread.

 

[cgrutt]

@Blimey got ya, thanks.

 

[Blimey]

I can understand the properties shown in the diagram but the groups at 30 are so much a higher verticle only variant as much as they are a general vertical and horizontal spread.

I'm not a professional archer but I guess I was wondering if arrows "stabilize" at a certain distance as I know they flex, unlike a bullet. In that line of thinking my 20 yard groups should be the worst.

I am pretty consistant with my technique so I don't think it's a form issue but I may try the slow mo thing too.

They absolutely do stabilize. If you look at arrows shot from even a properly tuned bow they compress and wiggle coming off the string. If they are coming off the string badly, you could consistently find the nock kicking out to one size or high/low at a closer distance, but the vanes stabilize it so that if you were shooting at a very distance target they would all seem to be parallel to one another when they hit because there is more time to stabilize. So it could certainly seem like the arrows shoot straighter at a further distance than a closer one. But I still think the group would be larger on the far target nonetheless

I'm no expert, but this makes sense to me.

 

[MoMan]

but not you shooting it .. i think of it the same as a rifle .. shoots good for me .. not you .,. just saying ..

i also think a bow is per the shooter .. more then rifle .. lots of stuff come into play .. grip .. torq and so on ..

Target Panic .. .. gets the best of me too ..

last weekend just got my bow out for the first time .. my best friend dad says shoot the block not the deer ( bud was using the deer to sight in his new bow) ..
i look at his dad .. WTF .. i was going for the wood pile back stop .. you know i pull the first shot LOL .. ( skeet shooting mussel memory ) and a bit of target panic .. LOL .. first shot i pulled it off to the right just like skeet .. . got settled down and was a 2 inch group at 20 ..

my limit with the bow due to my draw size and poundage ..

Having shot archery for a long time, including in leagues, I believe @Acer-m14 makes some GREAT points here.
If someone else sets up (paper tunes your bow, etc.), without you doing the actual shooting, there could be a bunch of variations. I have Buddies up there that take their bow into the shop every year, have the guy tune it up, then wonder why they start 'chasing' shots (trying to adjust sights!!) when practicing.

 

[Carlos Hathcock]

Having shot archery for a long time, including in leagues, I believe @Acer-m14 makes some GREAT points here.
If someone else sets up (paper tunes your bow, etc.), without you doing the actual shooting, there could be a bunch of variations. I have Buddies up there that take their bow into the shop every year, have the guy tune it up, then wonder why they start 'chasing' shots (trying to adjust sights!!) when practicing.

I can certainly retest but it was me shooting when the fitting session was going on.

 

[Hillbilly77]

Northern tier archery season opens on Friday. South opens a week from today. This is a dogshit time to develop trouble with your bow. I hope you can get it ironed out ASAP so it doesn't screw up your season.

 

[S&W Fan]

Does the pro shop where you got the bow tuned have an indoor range? It may be worth going back with the arrows you are shooting and see if they can pick up on anything you may or may not be doing