barrel nodes.

this chrony gizmo is revealing all kinds of interesting factoids. the object of my experimentation is my savage 10 pc in .308. 20" heavy barrel. it was touted by several people i talked to as being super accurate. well, now that i'm rolling my own ammo, it is showing serious potential, BUT, with light loads, and at low velocities. with 168 gr match bthp from sierra or speer, it is sub .5 moa if i keep the velocity right around 2400 fps. the groups open significantly as soon as i get over that velocity. i suspect that the "sweet spot" velocity will change with bullet weight, and that there may be another sweet spot up higher (i did shoot some good groups in hot weather with maximum loads, but i didn't have the chrony then). is this correct?

Sometimes.....

WIL TERRY said:

Sometimes.....

Click to expand...

Hi,

Yup... that's the "quick start" version!

Long version: every gun and ammo combo is a law unto itself, discoverable only thru extensive testing.

Rick C

Rick Courtright said:

WIL TERRY said:

Sometimes.....

Click to expand...

Hi,

Yup... that's the "quick start" version!

Long version: every gun and ammo combo is a law unto itself, discoverable only thru extensive testing.

Rick C

Click to expand...

yep. i've only been doing this a few months, but i should have known the answer to this one. i have a LOT of experiments pending. what a fascinating pursuit! thanks for your patience, all.

It could be barrel nodes but it could be any number of other things. If the maximum loads you shot were with a different powder having a different burn rate it could be that the velocity wasn't far off that 2400fps of your current load. It could be that the powder you're currently using is accelerating the bullet fast enough to "smash" it into the rifling at higher loads, causing deteriorating accuracy because of slight bullet deformations. Now, subsitute catridge OAL in place of powder differences and that's another whole set of variables. Likewise case capacity (not just brand but also trim length)...and so on, ad infinitum.

Chronographs are great fun...but if you're not careful they can drive you crazy. My advice is that for any given gun/bullet/powder/primer combination you work up a "maximum good" load that is at the point where either pressure signs begin to appear or accuracy begins to fall off...then chrono it just to find out your muzzle energy, what you can expect from different zero ranges based on the bullet BC, etc.

If you switch anything in the mix (gun, powder, bullet, case length, OAL, etc.) - scrap it all and start over without trying to build to the same velocity but again looking to maximize velocity and accuracy without going to overpressure.

Do this and you may or may not determine that the barrel (and bedding) has "nodes" - at that point it's kind of moot because you will have found the best load for the components being used.

I often work up the most accurate load,powder and bullet combination and THEN check it over the chrono to see what it is doing.

44.0 gr Varget under a 165 gr. hpbt is a favorite of mine and shoots well in every .308 I have fired it in. That load is in the velocity range you found to be accurate.

Rick Courtright said:

WIL TERRY said:

Sometimes.....

Click to expand...

Hi,

Yup... that's the "quick start" version!

Long version: every gun and ammo combo is a law unto itself, discoverable only thru extensive testing.

Rick C

Click to expand...

Both are much better than my stock answer.

I feel your pain. I have a Winchester Stealth in .308 that is driving me crazy. I have been working with loads for it off and on for a few months now. The best I have gotten so far is a few groups in the .650 neighborhood.
I have a Winchester Heavy Varmint in .223 that I hit on a one hole load on the third or forth one I tried. I have shot that load for years, never tried to change it.
I guess it spoiled me a little with the .223 being so easy to come up with a good load for it.

Cleardatum...I'm curious as to what kind of glass and reticle is on this BR Savage?

barrel nodes. Sounds like something you should see a doctor about.

:lol: :lol: :lol: Do you file them nodes off or pound them down with a ball peen hammer? :? :? :?

Bucks Owin said:

Cleardatum...I'm curious as to what kind of glass and reticle is on this BR Savage?

Click to expand...

leupold vx-2 6-18x40 target with a fine duplex reticle.