Wanting to know if I need 400 or 500 spine. The bow is a Pronghorn longbow, 56# at 28". My draw is 27" and I'd like to have my arrows around 29". Which would y'all recommend?


Sent from my iPhone using Tapatalk

That is a hard question to answer with the limited info provided.

Is your bow cut to center? What point weight you looking to run?

It is cut to center and I'd like to use 125-150 grain points.


Sent from my iPhone using Tapatalk

"Probably"500 spine if you go with 125/150g head and standard aluminum insert.

You need to decide on a maker and model.  Not all .400 spine arrows are the same in weight, true sline, or diameter.   All of which affect flight.
Once you decide on what artow you want to shoot, order 2 of each spine from LAS.   Then you will only have 2 arrows that don't work.  You can then order mire of the ones that do.
I recommend two of each as you can fletch one and shoot one bare shaft.

Get a spine tester kit from 3 rivers. Carbons at best are funny, read posts by Big Jim and others with more experience.  You may get away with a lot more point weight. Also are you considering footings, arrow wraps and what is the fletch type?

I agree with Tuffhead.  If you want them 29 inches BOP for your 27-inch draw and 125 to 150 grains up front, .500s will be good regardless of their diameter and variances from one manufacturer to another. Can accommodate small differences in diameter and spine with side plate adjustments or point weight.  Also with arrow length, unless your preferred 29-inch BOP length is firm. 

Just starting carbons myself> Finding out they sure do like heavy heads! I'm using Gold Tip 400's with 50gr insert and 180 grain field points (175 gr point with 5gr washer) out of 51# Martin Hatfield Take Down.

My guess you could go either way. All depends on point weight.

I shoot 52 lbs. 27.5 " draw with 150 grain heads and 400s fly perfect and I can use a lot of variances with them like a slightly heavier heads or 125 gr. field tips . I have tried 500s and they dont fly as well they are not stiff enough  . I shoot gold tips and Bemans .

I shoot 400s mostly from my 52#@27-1/2" longbow that I draw to 30-1/2". They normally have 200 grain points on them and they do fine with standard inserts. These are Gold Tip 5575 shafts. I can shoot 3555s (500 spine) from the same bow with lighter points and do OK as well.

However, these are full length shafts. I have no experience with cut shafts at all.

Your setup is similar to mine.  .500 with normal points, .400 with heavy points.

500 spine and cut to length to tune bareshaft

All I recommend is not picking your arrow length or anything with an idea that it will work. Carbons just are very different.  I'd go 500 with a 125 gr point and pick start full length, tune with your broad heads, and work your way down inch by inch until they are good to go.