Home Forums Hunting & Shooting Bowhunting I need a spine...

I recently indulged in a entry level long bow since my efforts at building one may take a lifetime... It pulls 55# @28, I have a 30 inch draw. I started out with Beman 340 carbons with 100 grain points (450 grains total weight) as the spine charts state. I can occasionally shoot a decent flight with them. Today while shooting with my 4H archery kids (traditional night) I shot some of my Genesis arrows thru the bow (Easton 1820's at basically the same length, plastic vanes, 400 grains) and they shot fantastic. How do I find the spine on an 1820 and make a hunting arrow substitution over these fairly weak arrows. I have been playing with nocking points and brace heights already and seem to have found nirvana. Would a heavier point on the Bemans weaken them enough (I have tried 125's already but not really any great improvement). Thanks...

It would help to know the name, that is who made it, of the longbow, it's lenght and shape, is it straight or do the limb curve back and then forward again, whether it has a quiver attached and if you know whether it has a Dacron or more modern "fast flight" string.

In the most general terms, you need a arrow with an effective spine of at least 70#, but potentially as high as 85#. But more importantly, you should consider arrows of at least 500 grains.

Are you sure the 1820s are 400 grains total?

Yes, folks have reported great success with point weights of up to 300 grains on carbon arrows. One way to get heavily weighted points is to get a 5/16 steel tapered adapter, 100 grains, and glue on a 125 grain steel point for a total weight of 225.
It's a non-standard solution though, and you'll get nine yards of grief from folks who probably have never tried them but claim the FOC is too high to be practical. But within the limits of longbow shooting, as the world knows it inside of 30 yards, most folks don't find the FOC diff particularly noticable.

I personally don't care for very heavily weigthed carbons and shoot wood mostly, sometimes aluminum or Arrow Dynamics tapered carbons. I never could find a carbon setup that worked well from my bow and wasn't fragile as hell, splitting out the shafting with point inserts and nocks. My hunting recurve is 56# @ 30#, very similar to your bow, depending upon how you answer the questions raised above. I shoot 80# effective spine, total weight from 600 to 700 grains.

I don't recall whether 340 is the deflection on the carbons, or if it's just a name. If deflection, I'm guessing it's spine is 85# or more.

I can't find the spine quoted specfically but the 1820s probably spine between 50# and 55#, closer to 50# probably. The 1818 is 50#, and 1918 to 1920 on the 19xx diameter shafts add 5#.

http://www.arrowsbykelly.com/Spine_Charts.html

just as an fyi, I've had best success with heavier and heavier spined arrows than any chart would indicate.

I have a 50 & 55 @28 and shoot a hair over 29 and use 70-75# cedar.

I have some western larch but have not tried it -- those buggers are really dense!

I've also done well with AL arrows (fletched) in similar spine.

I admit to having no love of carbon......

The longbow is a PSE Sequoia, dacron 50, slight reflex. I weighed an 1820 at 402 grains so I called it 400 for clarity.

According to Beman's info the 340 indicates deflection (.340). In other internet research the 1820's are .600. I would assume that to achieve a .600 spine on this relatively stiff carbon arrow I will have to hang an anchor on the front. While carbons may not be authentic, the thing I like is they are either good or broken, not much in between. They will also shoot in my compound if I need to change arrows, so nothing lost.

I will shoot a comparison grouping and take a photo of it and show the obvious results... It seems contrary to what common knowledge is. It was night and day for me the moment I had used them...

Don't get me wrong, I have no doubt the 50# arrows shoot fine. But I bet 70# would shoot as well, and would make a great hunting arrow. A 2018 is about that spine I think. But it would be an investment to make. It's sometimes a challenge to get the just right setup, but most bows will shoot a fairly wide range of spine.

Using the link above it seems that the 2018 is the approximate in aluminum. I shot some more today and at 30 yards put out a 6 inch group with the 1820's. I even tried 40 but my shooting leaves something to be desired, only hit the antelope once, but the arrows flew well. My misses grouped in the hay bale though.

The title of this thread made me think of my Brother-in-law dealing with his wife...........

http://home.att.net/~sajackson/archery.html

There are lots of resources for spine selection and tuning, and as you are already aware, google is yer fren.

90% of trad shooters practice and shoot inside of 30 yards and a 6" group at that range is very good shooting. If the 1820s are a little weak, which we both suspect, they may occasionally wag their little tail at you. But with good form, confirmed by you good groups, you can get away with a little extra paradox evidently.

http://www.rosecityarchery.com/AMOspine.html

Actually .340 spine may not be that far off. This shows 76# spine. I would not give up on the carbons, particularly if you can get a hold of some heavy points, as suggested above for example. I think there are other options with carbons to weight the point in the inside, behind the insert perhaps. I haven't looked into that lately. I've heard they can be tuned by lenght very effectively too. Perhaps an extra 1" or so, and the 225 points which have the advantage of adding 1" to the overall lenght by virtue of their design will tame them enough. Trial and error is sometimes 1/2 the fun.

Have fun.

I picked up some 2117's today which have a .400 spine and screwed a 125 grain tip on and they seem to fly pretty well. They were the only option at our local store and fairly cheap (I hate when that happens). It will take a little experimenting to see if this is the magic combo but results look good so far. I will play with my brace height a tad and see what that does as well as trying different tip weights...

Thanks for the info...

If 2117s deflect .400 then .340 run well North of 85#. I recall now that carbon deflection is measured differently, perhaps on different span (wood is measured on 26" span). There may be other differences but suffice to say the .340 are a good bit stiffer than the 2117s and 2117s run nearly 80-85#. Not to mention carbons will "shoot" stiffer for a lot of reasons. Just a little follow up for folks who might transition to traditional and stumble upon our notes here.

Remember also that a FastFlight (or other premium material) string will often let you shoot 5# more spine so if you replace the string at some point your 2117s may be just right. Not sure the PSE bows are made for FastFligth but I'd be surprised if not. Most modern (post 1990) bows are.

I think they caution against Fast Flight. I am pleased that it only took one substitution to find a decent arrow. The carbons will work with my compound so nothing lost... Thanks for the help...

I was gonna do that joke . . . . .

BMT

Now that I have found my spine, what do you traditional shooters recommend on practice? In shooting my compound the good group is a very small one, what is a good group for a long bow and what ranges should I practice at? I have been following the practice thread but there should be a progression of practice as with anything... Paper plate at 20 yards? 30 yards? What constitutes good and what goals should I work toward? Thanks.

As you have found out it is always better to over-spine than to under-spine. Most guys who use a long bow for hunting always caution to NOT shoot past 20 yds, and i would have to agree.

I started bow hunting shooting my Bear whitetail legend(compound), instinctively, (without sights) killed three bucks that way, but once past 20 yds things got a little dicey. I would shoot to 25yds max range.