I have three bows that I'd like to try various arrow combos with so I can have them all shooting the same speed.

What I'm trying to attain is the same trajectory between all 3 bows, which should help my shooting when switching back and forth between my bows.

Soooooo, my question is, how small of a range in feet per seconds will I need to keep the bows between to have them all shooting the same trajectory?

20 yards would be my goal.

 

Morning Star,  I try to work my bows to a certain point-on.  Although I shoot without consciously seeing the arrow, I do know where my point-on is....about 55 yards.  Keep in mind that I anchor with index finger corner of mouth, and back of hand/thumb in my cheek bone and use a dynamic release...not static.  If you shoot three under, or use static release, you will probably have a much shorter point-on.  

Some bows are a little faster than others...some slower,  but much adjustment can be made through brace height, string type, etc.  If your bows are close to the same weight, it shouldn't be too difficult.  

What you need is a constant....that's why I use point-on to judge my bows. You could also use a cronograph if that is available.

At 20 yards, you shouldn't be able to tell a difference in trajectory as long as all three bows are shooting the same GPP unless your bows are drastically different in speed.

I do have access to a chrono, that's how I planned on working.


 

QuoteAt 20 yards, you shouldn't be able to tell a difference in trajectory as long as all three bows are shooting the same GPP unless your bows are drastically different in speed.

That's something I need to find out.  Two of the three bows are 56@28, but one of those 56ers takes a much stiffer shaft than the other.   This has thrown off the GPP, because the stiffer arrow I'm using now is a bit heavier than the other arrows.  I don't think it's a shelf issue, as I tried building out the shelf on one to get them to both shooting same spine and weight shaft.  One 56er takes a MFX 400 and the other will only shoot a 340.....go figure, pretty big difference in those two shafts IMO.

Anyhow, just wondering how close in speed I'll need to be.  I'll eventually get to testing with the chrono.....maybe even a hooter shooter.  I'll put some numbers up when I get time to test.

I shoot 5 different bows that are w/in +or- 3 lbs and have noticed very little point of impact at 20yrds and really don't see alot of difference til 27+ yrds.
I shoot bows in the 60 to 65 lbs range and from straight limb longbow to triple carbon hybrid.

This isn't somthing most archers can tell, you have to be a great shooter to see a 2-3 in. Point of impact change at 25 yards. But this is why most great shooters get one bow and shoot it, then you can see the slight difference another bow makes.

I would like to see the POI change with 5 and 10 fps slower arrow starting with 190 fps at 20 yards. Anyone know the formula for that equation? Or someone with a slow compound to shoot tight groups and measure the difference.

My first step would be to match GPP on each bow setup. i like 9.5 to 10 gpp

Scientifically and mathematically you will need to be shooting the same speed and arrow weight to keep the same trajectory.

I like the flattest trajectory I can get at 175 to 180 fps for hunting  :D  

Steve

I think if you did like Geaorge said and have a constant - plus the same arrow set up - 20 yards wouldn't be nuthin to worry about trajectory?

J

be aware there are other important factors to consider, such as nock point and brace height.  i've been down that road of having more than a few bows that i'd like to have the same instinctive aiming 'feel' at 20 yards, +/- 5 yards, and in the end i just set each bow up for a good arrow match up/flight and make 'gray matter' aiming/shooting adjustments.  

I use to do the same thing you are talking about.Faster bows got heavier arrows and sloer ones got lighter ones.Now I feel at the distances I normally hunt it makes no difference at all in the long run.If I am carring a wood bows with heavy arrows I just don't take as long of shot as I might with a carbon limbed bow spitting out light weight slivers.For the common 20 and under stuff it matters very little on hitting an 8 ring on a whitetail or poping a hog in the ditch beside you.

Others have pretty much summed up my thoughts for those 20 yard and under shots in that the difference is hardly worth considering

Most of us in the West have the added challenge of more open terrain in our pursuits.  Knowing your setup is critical for those 20-40 yard shots at mule deer we are commonly presented.