How many grains to see a difference?

[razorsharptokill]

I was looking at another post about arrow weight with a light draw weight bow. So how much weight would I have to drop or add to see a difference in trajectory and speed? i.e. 50 grain gold tip weights.

I'm shooting a 630 ish gr. arrow out of a 55 lb longbow for deer hogs turkey. I'm thinking I could drop 100 grains, improve my trajectory and speed a little and still be in the power factor for those game animals? Any thoughts? Would iut even matter at 15-20 yards? Arrow flight is great. I'd hate to have to re-tune everything for a few more FPS or a SLIGHTLY flatter trajectory.

[Jason R. Wesbrock]

How much weight you'd have to add or drop to see a difference in trajectory is really a personal thing. An archer who groups extremely well would notice a change in impact from relatively little weight change compared to someone who shoots with less consistency.

For example: I know a guy who tells me he can’t see an impact difference between arrows ranging 30# in spine and 100 grains in weight. Conversely, I had a fellow at my house the other day who I know for a fact can detect very minor differences in arrow spine and weight. The former admittedly has a 12-yard effective range on deer-sized targets. The latter I’ve watched empty his quiver into the kill zone of a 3D pig target at 40 yards without a problem.

Realistically, a 530-grain arrow out of a 55# longbow should be able to easily bring down an elk or moose, so whitetails and turkeys would be no problem. But if you drop 100 grains in arrow weight, as with any such arrow change, you should definitely recheck your tuning and adjust as needed.

[30coupe]

You won't notice much at 15 yard, but at 20 you will start to notice a difference in trajectory. Beyond that, there will be a significant difference.

As Jason said, nothing is free. If you change weight, you will change spine, so you will have to either use a longer arrow or one with a weaker spine. Depending on your bow, you may also notice more noise with the lighter arrow.

On the positive side, I dropped about the same amount of arrow weight you are contemplating, and  I shoot more consistent groups out to 25 yards (that's about as far as I can get in my driveway). You won't have any trouble killing deer with either setup.

[Jesse Peltan]

If you want faster you should use a faster string (8125, d97etc). That will also make you use a slightly lighter point when you retune.

[Rob DiStefano]

imho, all that matters to me is employing an arrow that's 10gpp or higher.  

lower weight arrows just don't feel right on release, and my bow hand can feel it.  

heavier arrows absorb more of the limb's energy and make for a smoother release and follow through, and are kinder to the bow's longevity.  

my 55# holding weight longbow uses a 590 grain arrow very effectively out to 25-30 yards.  don't need or want more than that for hunting.

use whatever works best for you.

[Guru]

Originally posted by Jason R. Wesbrock:
Realistically, a 530-grain arrow out of a 55# longbow should be able to easily bring down an elk or moose, so whitetails and turkeys would be no problem. But if you drop 100 grains in arrow weight, as with any such arrow change, you should definitely recheck your tuning and adjust as needed.

[Paul Mattson]

a light draw weight bow...I'm shooting a 630 ish gr. arrow out of a 55 lb longbow        

WOW, What do you consider an average wt.?

[James Wrenn]

Dropping 100gns can make you have to adjust your sights some at 20.    

However there will be a lot less adjustments when you shoot that 25+yd shot you think is 20 one day as well.  

[James Wrenn]

quote:
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a light draw weight bow...I'm shooting a 630 ish gr. arrow out of a 55 lb longbow
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WOW, What wt are your average wt bows?

 

Hey I caught that too.  :D

[KVTA TANK]

I shoot 58# with a 2213 with 125 up front for deer and 2117 with 145 up front for big stuff..

[razorsharptokill]

I saw about 8" drop at 27-30 yards with the 100 grain left in the shaft. Little to no difference at 15-20.

[Dick in Seattle]

The original question regarded light draw weight... guess i qualify.  I can't shoot much more than 30#.   Try shooting this light if you really want to learn about arrow tuning. With a light bow, every change becomes very noticeable.

Yesterday I was tuning for my newest Hill style 32# ( my "heavy" bow).  I started getting good flight out of 1717's with 80gr. tips, but they were consistent left.  I changed to 100 gr. and they were right on line.

As to trajectory, again, at light weight things show up fast.  I tune at 30 yards and I can tell right away when they're dropping from weight. (As opposed to when I'm not getting to full draw :^)  

Even at this light a draw, with the Hill style bow I'm still shooting 10.5 gr. per pound.  I can flatten the trajectory at 8.5 to 9 gr. per pound, but the arrows get "goosey"... I think too sensitive to variations in release.

[Rob DiStefano]

Originally posted by Dick in Seattle:
... Even at this light a draw, with the Hill style bow I'm still shooting 10.5 gr. per pound.  I can flatten the trajectory at 8.5 to 9 gr. per pound, but the arrows get "goosey"... I think too sensitive to variations in release.

indeed, sir - my findings, too.  heavy arras are just easier to control and seem to find the center of the target more often.

[wtpops]

With my set up i can visualy see a trajectory change at 20yards with a 75 grain change.

[razorsharptokill]

I think I'll keep the 100 grains in.