New arrows, new points?

[SlimTim]

I've recently bought some new arrows to try something different. I went from the nexxus 250 spine (11.1 GPI) to the easton axis 260 spine (11.5 GPI), cut pretty much the exact same length.

I've noticed the POI on the eastern is much higher (maybe 3 inches at 30+ yards) than the nexxus. Why is this? Is that slightly weaker spine make that much difference?

I've also been thinking about going up from 125gn to 150gn points before I get my sight tape sorted. What actual difference will this make? Am I slightly over spined and does this really matter? Will this make my groups better or tuning easier? Do I actually need to re-tune my bow (which for me seems like some mystical art that I'm never sure if I'm actually doing it correctly)

Thanks in advance.

 

[Billy Goat]

Aren't you comparing a micro (.166 id) to a small diameter (.204 id) that difference translated to od will put the center of the arrow higher at your rest. Which elevates impact, also will change the nock height (tune).

 

[SlimTim]

Aren't you comparing a micro (.166 id) to a small diameter (.204 id) that difference translated to od will put the center of the arrow higher at your rest. Which elevates impact, also will change the nock height (tune).

Yes. That makes sense. I hadn't thought about that.

 

[Billy Goat]

You won't see much of any real world difference between 150 or 125 heads, except selection.


Hard to know where you are weak or stiff spine. No information.

 

[mfllood3800]

If you told us the Bow, the bow DW , your DL and total arrow weight we can better help you. There's more info needed but not as critical for a base est of guidance.

 

[SlimTim]

If you told us the Bow, the bow DW , your DL and total arrow weight we can better help you. There's more info needed but not as critical for a base est of guidance.

PSE EVL 32. DW 70#, DL 29 inches, arrow length 28.5 inches. Total arrow weight about 510gn.

 

[Mighty Mouse]

Are total weights of both arrows the same? Even though the Axis gpi is higher, its total weight could be lower depending on the weights of other components. If the Axis TAW is lighter, that would help explain the higher POI. Or it could just be due to the larger diameter changing the launch angle as Billy Goat pointed out.

I had to make some assumptions on missing info, but qSpine indicates that you're probably on the stiff side. Spine software/charts just give a recommended starting point though, not a hard-and-fast requirement for good arrow flight. You can quite likely get those arrows to fly just fine even though they are on the stiff side of calculated "optimal" spine.

Bow inputs: 345 fps IBO, 70# DW, 29" DL, 32" ATA, 6.25" BH, 80% LO
Arrow inputs: 28.5" C2C, 125 gr point, 25 gr insert, 9 gr nock, 3 vanes at 7 gr each

 

[Swampcruiser]

Yes, you need to recheck your tune, probably lower the rest. As stated above the axis is a slightly larger diameter. Probably have a tail low tear now if it was in tune before the change.

 

[Kholt456]

Aren't you comparing a micro (.166 id) to a small diameter (.204 id) that difference translated to od will put the center of the arrow higher at your rest. Which elevates impact, also will change the nock height (tune).

Agreed

 

[Cs36]

I just switched recurve bows, and added 3lbs roughly in draw weight . I was shooting 500 spines in my old bow w #49lbs draw @ 28 . 450s are shooting weak in new bow that’s #52 @ 28. I’ve got a 26” draw. Should I jump down to 300, 350, for my arrow selection? Thanks fellas