Intresting POI shift

[nchunterkw]

Was doing some shooting/playing around this weekend and saw this.

Shooting from a bench, with bags front and back.
Vortex, FFF string, 503gr arrow

Sighted in some new arrows at 40yds and had about a 1 1/2" group across all 5 arrows. Feeling pretty good, I decided to try to quiet the bow down a bit, so I wrapped the stirrup with some rubberized tape I had lying around. Of course I did not have exactly enough, and rather than trying to unwrap and re-wrap I just finished it off with electrical tape. From the shooters perspective, I started wrapping the stirrup from the right side and ran out of material with about 1" to go on the left side. I was not paying much attention to how tight I wrapped it or anything like that.

My next shot was about 2" to the right. Tried a few more arrows and all were pulling to the right. Since I did not hear much difference, I took the tape off and everything was right back where it was before.

My conclusion is that by changing the way the bow vibrated, I changed the way it effected the arrow as it was leaving the bow. Something to keep in mind I think.

[Galgo]

Interesting...is there any chance that you put enough material on the stirrup that the fletching was touching it after being fired? I wrapped mine this year and have not fired it yet but the clearance is really close....were you still getting the same group jut different POI?

F

[nchunterkw]

It was a really stretchy kind of rubberized tape - I think it's called Magic Tape or something. You can use it to fix a puncture hole in PVC in a non-pressure line like a drain or something, and it works great for that. So it did not add much to the thickness of the stirrup, but I did not check that. Good point.

Since it did not help too much I doubt I will go back to it. But I did think of putting a rubber gasket between the stirrup and the riser. Anyone try that?

[Kegbelly]

Interesting...is there any chance that you put enough material on the stirrup that the fletching was touching it after being fired? I wrapped mine this year and have not fired it yet but the clearance is really close....were you still getting the same group jut different POI?

F

That's what I was thinking... slight contact with the vane. I wrapped mine with a layer of rubber splicing tape and went over that with a layer of cloth camo tape, no clearance issues, but it's close. I guess it could happen depending on which vanes you are using.

As for the stirrup wrap changing the vibration and thus changing your POI, I don't think that would have any effect... the vibration takes place after the shot, and the arrow is long gone by then. JMO of course, I've been wrong before

[Kegbelly]

It was a really stretchy kind of rubberized tape - I think it's called Magic Tape or something. You can use it to fix a puncture hole in PVC in a non-pressure line like a drain or something, and it works great for that. So it did not add much to the thickness of the stirrup, but I did not check that. Good point.

Since it did not help too much I doubt I will go back to it. But I did think of putting a rubber gasket between the stirrup and the riser. Anyone try that?

I tried a gasket from some reinforced rubber material I had on hand, turned out to be too soft and the gasket squished out when I tightened the stirrup bolts down. Ended up using some 00 plumbing washers, but you'll have to drill or punch the center hole out so the bolts will go through. It seems to help a tiny bit, or at least I think it does Since you can't really torque the bolts down real tight with the rubber washers, use blue Loctite on them or they will work loose eventually.

[paulaboutform]

It was a really stretchy kind of rubberized tape - I think it's called Magic Tape or something. You can use it to fix a puncture hole in PVC in a non-pressure line like a drain or something, and it works great for that. So it did not add much to the thickness of the stirrup, but I did not check that. Good point.

Since it did not help too much I doubt I will go back to it. But I did think of putting a rubber gasket between the stirrup and the riser. Anyone try that?

I bought some rubber work mat material from princess auto and cut and drilled it to put between the stirrup and the bow. I also had my stirrup sprayed with rhino liner and it seems to work well. If you want to check for fletching contact, buy some Dr. Sholls foot powder, the powdery spray type, and spray the top of your stirrup after you've cocked the bow. It will show if anything is contacting it.

[newbie]

It was a really stretchy kind of rubberized tape - I think it's called Magic Tape or something. You can use it to fix a puncture hole in PVC in a non-pressure line like a drain or something, and it works great for that. So it did not add much to the thickness of the stirrup, but I did not check that. Good point.

Since it did not help too much I doubt I will go back to it. But I did think of putting a rubber gasket between the stirrup and the riser. Anyone try that?

I bought some rubber work mat material from princess auto and cut and drilled it to put between the stirrup and the bow. I also had my stirrup sprayed with rhino liner and it seems to work well. If you want to check for fletching contact, buy some Dr. Sholls foot powder, the powdery spray type, and spray the top of your stirrup after you've cocked the bow. It will show if anything is contacting it.

Magic markrer on the edge of the vane will also show contact with the stirrup. It will leave colour on the stirrup.

[flightattendant100]

It was a really stretchy kind of rubberized tape - I think it's called Magic Tape or something. You can use it to fix a puncture hole in PVC in a non-pressure line like a drain or something, and it works great for that. So it did not add much to the thickness of the stirrup, but I did not check that. Good point.

Since it did not help too much I doubt I will go back to it. But I did think of putting a rubber gasket between the stirrup and the riser. Anyone try that?

I bought some rubber work mat material from princess auto and cut and drilled it to put between the stirrup and the bow. I also had my stirrup sprayed with rhino liner and it seems to work well. If you want to check for fletching contact, buy some Dr. Sholls foot powder, the powdery spray type, and spray the top of your stirrup after you've cocked the bow. It will show if anything is contacting it.

OR.....just turn the arrow around and SEE if the fletching touches.

[greybuff]

I took a plastic milk carton and cut a gasket for under the stirrup, seems to quieten it down some and doesn't compress when you torque it down. Also wrapped the stirrup on the PHX/VIXEN w/para chord and the Exocet with hockey tape, which also helped some. Of course the three Texas hogs we took couldn't hear much difference.

[nchunterkw]

How about something like giant sized cat whiskers tied onto the sides of the stirrup? I am thinking they would absorb vibration pretty well.