help with arrow grain

[ikillsdeer]

im getting a vectrix with a 30 inch draw, my local bow shop says to get 350 grain arrows, im getting the fmj arrows. does this sound right, and is there any beniefit to going heavier or would it slow me down to much?

[ikillsdeer]

oh yeah, im pulling 70 pounds and getting the xl

[Arthur P]

I guess it depends on your point of view and what you intend to do with those arrows. For 3D or targets, yeah. 350 is okay.For hunting, my personal opinion is anything under 400 grains is too light for a hunting arrow, and even 400 is pushing it.

I've learned through my own testing that the difference in trajectory out to 30 yards - reasonable hunting distance for most of us - is practically nil between a 350 gn arrow at 300 fps and a 500 gn arrow at 250 fps. For hunting, the heavy arrow hasmany benefits when compared to the miniscule trajectory benefit of the faster 350 gn arrow:

Less bow noise (no matter how quiet the bow is with light arrows, it's quieter with a heavy one).

Less wear and tear on the bow and accessories.

Less need for expensivevibration damping rubber doohickies.

Easier tuning.

Slightly more energy.

Slightly better retained energy downrange, where it really counts (a couple of ft lbs of extra energy absorbed from the bow + a couple of extra ft lbs of retained energy at the deer's ribcage... You wind up with about the same effect you'd get if you shot an extra five pounds of draw weight, just by using the heavier arrow.)

MUCH higher momentum... No matter whether you come down on the side of energy or momentum as the prime indicator of penetration potential, the heavier arrow wins.

This is an old argument and it likely won't be resolved. The speed cult loves their light little arrows too much to surrender to reason.[8D]The sensible approach is to pick something right in the middle. Not too light, not too heavy. But I prefer to err to the heavy side.

[bigbulls]

I agree with Arthur 100%

I have a hard time finding a carbon arrow heavy enough for me. I prefer to have one that weighs at least 450 grains and I find that a 500 grain is about ideal for me.

[ikillsdeer]

not sure i understand, the bow shop told me that 350 was the spline and referred to the sturdyness of the arrow and had nothing to do with weight. come arrows had another number like 9.9 or 10.8 and they said theese were the weight ???????

[Kanga]

arrows had another number like 9.9 or 10.8 and they said theese were the weight ???????

That would grains per inch.

I with Arthur I shot a 60lb bow and use 410gr arrowsit is better to er on the heavy side than the light side.

[mobow]

I'm confused actually....Did he say 350 GRAIN arrows or 350 SPINE?? In your DL and weight you should shoot a 340 spine, or 350, pert near the same....

If he is referring to 350 grains, that's 5 grains per pound, the lowest ANY manufacturer recommends. Personally, I've found the "sweet spot" to be around 5.8 gpp.....But that's just me.

[Arthur P]

Lordy, ikillsdeer, you really are confused...

First off, there is no such thing as arrow spline. Spline is what you find on gears. When you're talking about arrows, it's arrow SPINE. As most archers use the word, spine refers to the stiffness of the shaft and hasnothing to do with arrow weight or durability, at least not directly.

Spine is generally measured by hanging a weight on the shaft and measuring how much bend, or deflection, the weight causes, in thousandths of an inch. Some shaft manufacturers use the deflection number as the shaft size. Like some Easton shafts, a 340 has a .340" deflection and a 400 has a .400" deflection. The 340 doesn't bend/deflect as much so it's stiffer. The lower the number, the stiffer the shaft.

Not all manufacturers use that system, and even the ones who do use it usually don't apply it across their entire product line. So it can be awfully confusing even for experienced archers when switching from one manufacturer to another, or even switching to different models from the same manufacturer. It sux, basically. [&:]

Most manufacturers list the grains per inch weight of their shafts. That's where the 9.9 or 10.0 typenumbers come from. A shaft that's 10.0 grains per inch is 300 grainswhen cut to 30". Then you add the insert weight, fletching weight, tip weight and nock weight to get your total arrow weight. Anyway, those numbers are simply weight and have no bearing on spine or durability. Again, not directly.

In fact, there isnothing in an arrow size that will tell you how durable it will be, at least when talking about carbon arrows. You can get a good idea about arrow durability when looking at the sizes of aluminum arrows, but, since you're confused enough as is, let's not worry about THAT for now. Generally, the heavier the shaft, the more durable it will be. But not always.

Now, about the 350 grains... Nearly all bows these days are designed to be used with arrows as light as 5 grains per pound of draw weight. So, a 70 pound bow would be in warranty as long as you never shoot an arrow less than 350 grains in total weight. While some dingalings seem to think 5 grains per pound is the recommended arrow weight, it most definitely is NOT! 5 grains per pound is simply the minimum arrow weightthat will keep the bow in warranty.

So, if someone at a bow shop tells you that you need arrows that weigh 350 grains for a 70 pound bow, I'd really suggest you turn around and go to the next shop down the road. As you leave, running out the door and screaming in sheer terror is optional.

If, on the other hand, he was suggesting you get the SIZE 350 shafts as the proper spine for your bow, then that would be something entirely different. Since I don't know your draw length, arrow length, performance level of your bow, release type, tip weight, etc. there's no way I could advise you on that. They all play a part in determining the proper spine arrow for your bow.

Unfortunately though, Easton doesn't offer the FMJ arrows in size 350, so I don't know whether the guy at the shop was selling you a bill of goods or you just misunderstood what he was telling you.

Hope I haven't really muddied the waters for you.

[willyd5]

You want to stay around 6 grains per pound of pull.

[ikillsdeer]

thanks for all the help guys, so at 6 gpp. and a 70 lb bow, im looking for an arrow with a 340 spine, and 420 grain which for a 30 inch arrow would be 14 grains per inch right??? you guys are grats for taking the time to help people