Home Forums Hunting & Shooting Ask The Gunwriters What says the experts about published "barrel time" accuracy nodes....

There seems to be, or at least there was, a quite a following about an internet idea that people should shoot for nodes based on a chart regarding barrel time. The chart had all kinds of different Barrel times based on your barrel length and it was thought to be somewhat of a Golden Goose to get near those times via chronograph and quick load and your accuracy would be wonderful. I haven't been able to shoot as much recently as I did in the past but I look up some of my old loads and thought it had some Merit. I've been getting out a little more lately and I'm starting to think it might have been more hype than realism.
Not that I don't believe Barrel's have some accuracy nodes but I'm not sure the whole Barrel time idea is valid.... what's the experts view based on those who have played with the idea?

I think it's certainly possible. What we're talking about are very high-speed vibrations. If you can make them very consistent from shot to shot, the gun will group consistently.

If you wanted to make it scientific, put some very precise accelerometers at the muzzle, and connect an oscilliscope, so you can measure displacement of the muzzle at extremely high speed, to see if a given change made the vibrations more consistent, or reduced them.

Of course, in lieu of fancy equipment, you could just shoot & measure group size though I guess measuring the vibrations would eliminate effects of bullet consistency, wind, etc.

I think there is some validity to it granted it is a mathematical representation and can never address all the variables.

The old timers from Phil Sharp's era and possibly later would use a tuning fork up and down the barrel to see if it would sing. Sounds like Voodoo or water witching but then I practice both of those too. Voodoo as in having a good single Malt Scotch and a good cigar the night before a hunt and the gods are happy or at least I am.

The proof is in the pudding and sometimes it has panned out with load development. Other times not at all.

I've noticed some rifles tend to "sing" over a much wider range concerning "accuracy nodes". Ussually when a rifle is no where near an accuracy node your going to see a lot of vertical stringing at longer ranges. Tikka's for why I do not know tend to have very little vertical stringing at 500 ish yds where I tend to shoot frequently regardless of powder charge. I've also heard NULA rifles are the same way. On the other hand I've heard pretty frequently that Kimber rifles require planetary alignment but will shoot if your a planetary alignment expert concerning accuracy node's.

Concerning published "accuracy loads" I am of the opinion that there are powder, cartridge, bullet, load combinations that do tend to sing more often than not in a variety of rifles.

Disclaimer....I am not an expert and am only offering my opinion.☺


Trystan

Also heard of others sprinkling talcum powder on the flats of a Sharps barrel and giving it a rap with a rubber hammer. The resulting pattern in the powder due to vibrations supposedly identifies the spot where one should rest his barrel on the shooting sticks.

Haven't tried that yet, but will probably get around to it.

Totally legit!

Just like reading the entrails of a turkey so see where the rest of the flock is hanging out.

I've been pondering the question myself. A while back I ran QL to check on the barrel time of a load that had shot well and to see if it corroborated the OBT theory. Much to my surprise that load fell exactly halfway in between two supposed OBT nodes for my barrel length. I completely don't know what to think.

Another thing I wonder about is the other modes of vibration. I know nothing about calculating or predicting them, or what the factors would be if you possibly COULD calculate or predict...but it seems like you'd need for these different modes of vibration to have points of coincidence in order to get anything to work at all.

I dunno. It seems like a black art to me. I just try different bullets, powders and charges, seating depths, etc. and smile when it all works out.

You fellers go ahead. I'll be taking a nap with the Little Woman.

The modeling is based on an action in a machine rest no other contact so any differences in bedding could completely throw off the tables. But at times it does seem to work out.

It's just one more way of playing with barrel harmonics until you find some combination that works.

It's nothing new or mystical.