arrow spine. 400 too weak?

fatcats

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My draw weight is 70 lbs and draw length is 27.5". I'm hunting elk this year and was running low on 340 spine arrows, so I went to my bow shop to get more. They talked me into using my 400 spine arrows instead of my 340's since I have more of those already on hand. According to several of them, I'm at the very edge of where 400 spine is usable as long as I don't add any more weight to them. At least 3 of them claimed that they also run 400's at 70 lbs and it works fine. However that contradicts every spine chart I've seen. Per their recommendation I went ahead and shot my 400 spine arrows for a bit and they appeared to fly just fine. Very straight and fast at 288 fps based on their chrono. The carbon to carbon length is between 27 1/8" to 27 1/4" . Im calculating that they weigh ~386 grains with the blazer vanes and 100 grain point as opposed to the 340's with 50 grain insert weighing 350 grains. Just curious if other people have ran 400 spine at this poundage and draw length successfully or had spine issues?
 

GilG

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You czn probably make it work with a little more tuning. If you are not heavyhead user, it will work. Borderline but can be made to work.
 
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fatcats

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That's basically what they told me. They took my bow and showed me the center shot was slightly off so I left it with them to fix that and broadhead tune. I use 100 grain heads and standard 16 grain hit inserts on my 400 spine arrows.

Sidenote, my 340 spine arrows are 450* grain not 350.
 

Lowg08

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I personally wouldn’t do it. If it’s borderline. I wouldn’t want to be digging carbon out of my face. One arrow slapped off another already already on the line. If I was to make any spine changes it would be lower. 300 rather than 400
 
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Yes. I've used 400 spine arrows on elk with good success, 70 lb draw weight at 28" draw length. 100 gr broadhead with a standard weight aluminum insert, total arrow weight is 445 gr.

They were FMJ's though.
 
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fatcats

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I'm very skeptical about this working too @Lowg08. I'll probably go back to my 340's just so I don't have the thought of an arrow splitting on release bugging me. I guess the question now is will a broadhead tune translate between a 400 to a 340? I left a 400 spine arrow with them
 

Agross

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I pull 70 lbs with a 28” draw and have shot 400 spine arrows with 100 grain heads as long as I can remember Without issue.
 

Lowg08

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I'm very skeptical about this working too @Lowg08. I'll probably go back to my 340's just so I don't have the thought of an arrow splitting on release bugging me. I guess the question now is will a broadhead tune translate between a 400 to a 340? I left a 400 spine arrow with them
Easton doesn’t even give this spine at those specs as an option. I’m not an expert but I do shoot bows competitively around the southeast and hang out with reputable bow techs and I have never heard of going borderline. It’s always been I’d rather be over spined that’s under. To much can go wrong. Grab the wrong weight head and it could explode in your face
 

4rcgoat

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I would use that for deer,but not elk. Not saying it won't work,but I'd bump up to 300 spine and have the option of adding more head weight.
 

Rob5589

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On the weak end but should work. Why'd you let them talk you into .400's if the .340 was working? I'm guessing they claim to use .400's because they like the speed from a lighter set up.
 

cnelk

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Toss some weed trimmer line inside the shaft and that will add about 40grs.

I’ve killed a pile of elk with this using 400 arrows.
I now use 340s with trimmer line


 
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fatcats

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I brought the 400's in to see if they would buy them off me and help me shorten my 340's. They saw how many 400's I had for when i was shooting 60lbs and suggested I use those instead of spending money on more arrows. And yeah they said it would give me a lot more speed which they thought was good. I'm not experienced to know if it is or not. I'll just call them and have them hold off on broadhead tuning..
 

Lowg08

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I’m not even shooting 400 at 60# and 30.5 draw. I was shooting 400 at 55# and 30.5 draw. I’m shooting the recommended spine for my set up now. 340 spine at 60# at 30.5 draw. 31” arrows. Easton sonic 6.0. If you want speed. Just select a different arrow at a lighter GPI with the correct spine. I will strongly recommend the Easton sonic 6.0. I have shot anything but foam with them yet but man they fly.
 

Sapcut

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I could go on and on about what I would recommend and why, but in short…. I would go with 340s, add a 3-4” aluminum footing, heavier broadhead and tuned perfectly resulting in a heavier stronger arrow.
 

Wellsdw

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Toss some weed trimmer line inside the shaft and that will add about 40grs.

I’ve killed a pile of elk with this using 400 arrows.
I now use 340s with trimmer line


I’m trying to figure out if this is crazy and only an idiot Would do it…..( before I try it ) or if it’s genius.

2 questions though

1) will my broadheads still hit with field points at 120 yards?

2) what kind of weed eater line is Aron using?
 

cnelk

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I’m trying to figure out if this is crazy and only an idiot Would do it…..( before I try it ) or if it’s genius.

2 questions though

1) will my broadheads still hit with field points at 120 yards?

2) what kind of weed eater line is Aron using?

How many pics of dead elk do you want with arrows that have been used this way? ;)
 
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