Arrow build question: 340 spine or 300 spine?

[cpalm9]

I'm setting up some new arrows for elk this season. Planning on using Easton Axis 5mm. My draw length is 27.5" so I think I'll do 28" arrows as that is what seems to fit best with how my rest is setup. Last time I checked, the shop said my draw weight was around 67lbs.

I want to build an arrow that's around 450 grains. My question is because I am adding more to the front of the arrow such as a 100 grain broadhead and the 75 grain insert, would I be better off on a 300 spine vs a 340 spine? Easton recommends both spines so I'm just not sure which would be ideal. A 300 spine would get me closer to 475 while the 340 spine would be more around 450

 

[Keith Stone]

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This arrow chart has worked really well for me and it is showing a 300 spine being ideal. But the arrow weight will be closer to 520 by my calculations.

 

[Marble]

Your arrow can be quite a bit shorter than your draw length. My hunting bow is 29" and the arrow is 28" plus the nock. I could easily take a full inch off the overall length. Not saying you should buy it's an option.

I had a bow set up similar to yours, only it was 28.5 draw length. 75 grain insert and 125 grain head. Field points flew great but broadheads not so great. Actually horrible. I dropped to 300 spine and all was well.

You should also consider the bow, meaning how aggressive the cam is. The bow I referenced above had a fairly aggressive cam. I shot that same arrow in another bow that had a much less aggressive cam and broadheads shot great.

288.9 grain Axis 300 cut@27"
16 grain HIT insert
100 grain point weight
7 grain nock
24 grain four fletch

Total weight of 435.9 plus a tiny bit for epoxy and glue. If you added a 50 grain insert you would be at 470. Or use a 125 point and your at 460. Shoot 3 fletch, take away a little weight.

If you chose a 340 spine, bare arrow would be 256 grains.

If it were me and I wanted decent point weight, but not a super heavy arrow, I would use the 50 grain insert, 100 grain head and go shoot. That set up will kill anything in North America.

The biggest factor for success will be you...

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[Mighty Mouse]

A 340 spine 5mm Axis cut to 26.5" with 100 gr head, 75 gr brass HIT, three 7 gr vanes, and a 9 gr nock adds up to 457 gr. Assuming typical modern flagship bow specs (340 fps IBO/30" ATA/6" BH/85% LO) at 67# DW/27.5" DL, qSpine says this arrow would be "optimally" spined.

 

[nphunter]

I would do 340's if it were me, 300's will be on the stiff side and like you mentioned heavier. I'm shooting 73lbs, 28" Draw with 300's and have 100gr inserts, 25gr collars and 100gr heads, I also have lightweight fletchings. I agree with the above about using a shorter arrow. I'm shooting a 26.25" arrow with an inch long collar at 28" draw.

 

[cpalm9]

A 340 spine 5mm Axis cut to 26.5" with 100 gr head, 75 gr brass HIT, three 7 gr vanes, and a 9 gr nock adds up to 457 gr. Assuming typical modern flagship bow specs (340 fps IBO/30" ATA/6" BH/85% LO) at 67# DW/27.5" DL, qSpine says this arrow would be "optimally" spined.
View attachment 424055

I'm not opposed to cutting the arrows shorter. I'll probably have my shop help me out there. I was shooting arrows that were much too long before as I didn't have my draw length honed in. I don't have a flagship bow (Mission Ballistic). I'd love to get one in the next few years.

 

[cpalm9]

I would do 340's if it were me, 300's will be on the stiff side and like you mentioned heavier. I'm shooting 73lbs, 28" Draw with 300's and have 100gr inserts, 25gr collars and 100gr heads, I also have lightweight fletchings. I agree with the above about using a shorter arrow. I'm shooting a 26.25" arrow with an inch long collar at 28" draw.

Definitely leaning in the 340 direction, especially if I do a shorter arrow.

 

[Mighty Mouse]

I'm not opposed to cutting the arrows shorter. I'll probably have my shop help me out there. I was shooting arrows that were much too long before as I didn't have my draw length honed in. I don't have a flagship bow (Mission Ballistic). I'd love to get one in the next few years.

Nothing wrong with a Mission. It will be a little gentler on the arrows than what I put into qSpine above (stiffen the dynamic spine and move the needle a bit to the right). I think 340 would be the best choice for you.

 

[Super 91]

I'd opt for the 300 if it were me. I have found that 340's with enough up front can act like a weak spine, but you are well within the correct tolerances. I just prefer to err on the side of too stiff as I can always get them to tune. Once you go to weak on spine, there is nothing else you can do but change arrows.

 

[socoalt]

I shoot 27.5" dl @ 70# I have Easton axis 340's and 300's both with 175 gr. up front. The 340's weigh in around 452 and the 300's are right at 480. Although mine are cut at 26.5 both fly great. I think you will be fine with 340's if that's how you want to go.

 

[ncavi8tor]

I have similar specs as you at 67lbs and 28" draw length. I just finalized my hunting arrows after testing several options over the past few months I ended up with a .300 spine RIP TKO at 27" ctc, 3 x AAE Max Stealth vanes, Bohning A Nocks, and a Goldtip Traditional 600 insert (72 grains). TAW = 467 grains. Bareshafts fly like lasers. Every broadhead I have tested flies exactly like my field points. Shooting 125 grain points. Couldn't be happier with this setup and very excited for the coming season!

Mathews V3X29

I believe the .300 spine will broadhead tune easier if you're shooting fixed blade heads, but I'm sure you could get the .340 spine to work with some experimenting.

Also, the .300 will be a more robust shaft due to thicker walls.

Good luck! I enjoy the process!

NC

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[homebru.trout]

Should have made this thread a poll LOL. I have no reason to believe that a 300 will tune easier and at least one real life example that it won't. I had a 70# Athens that would not tune 300s with 50gr HITs up front at 28.5. Dropped to stock 400s to get bullet holes and finally settled on spartan 340s with that big old stainless insert up front plus added weight when all was said and done.

On that Mission I would start with 340s and not give it another thought. You'll shoot a little flatter and the animal will never know the difference anyway. As has been said, the man holding the machine makes the difference.

 

[Pgidley]

I shoot 28" draw with 27" Hexx 330s, 75 grain insert and 150 grain points. Usually 3 fletch. Last I had my 70lb Synergy on the scale it was topping out at 67lbs. It tunes great. I'd probably go with the 340s and play with point weight or your draw weight until it tunes.

 

[S.Clancy]

340 for sure. I shoot 300 Axis @27", 150gr total upfront, total arrow weight ~500 gr. My bow is 82lbs and 28" draw.

 

[fatcats]

I have a very similar setup. 27.5" draw at 70 lbs dw. Last year I ran axis 5mm 300 spine with a 50 grain half outsert and I thought it was too heavy. My speed was 262 fps but there was quite a bit of curvature to the trajectory that I didnt like. This year I've been practicing with 340's and a 50 grain brass hit insert and they fly in much straighter at longer distances (269 fps). Overall I've been pretty satisfied. As others mentioned, the arrow can be shorter. Mine is set up 27.25 carbon to carbon

 

[cpalm9]

Ended up going with Easton Axis 5mm in 340 cut so the point/broadhead is right around the riser. Ended up around 27” with a weight of 460 grains with the 75 grain insert. The shop recommended that length and is now tuning things up.

I’m pretty happy with them overall though.

 

[mortskee]

sounds like a sweet setup

 

[Marble]

Ended up going with Easton Axis 5mm in 340 cut so the point/broadhead is right around the riser. Ended up around 27” with a weight of 460 grains with the 75 grain insert. The shop recommended that length and is now tuning things up.

I’m pretty happy with them overall though.

Those sound like a winner! If you do have any weird issues a d want to stiffen that arrow up a tad, you can quite a bit off that arrow. But at your DL, poundage, tip weight and total arrow length, you should be just fine. Let's us know!!!

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[cpalm9]

Those sound like a winner! If you do have any weird issues a d want to stiffen that arrow up a tad, you can quite a bit off that arrow. But at your DL, poundage, tip weight and total arrow length, you should be just fine. Let's us know!!!

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So far, they’ve been shooting great. I’m feeling much more confident with them than previous arrow builds. I’m swapping out for broadheads this week so we’ll see how that goes

 

[ncavi8tor]

I'm glad you ended up cutting them at 27" rather than 28". That increases the dynamic spine and should broadhead tune really well. Like I said previously I would always error on the stiff side with broadheads! Good shooting!

NC

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