Thread: Barrel Accuracy Nodes - How wide are yours ?

I've got a No.2 profile on the .280 IMP. I've found two nodes for the 168gr VLDs at useable velocities. They look tight, maybe +/- 0.2gr before the POI goes tracking off again (and quite fast per grain too! ). I was hoping to be able to throw the powder for the .280 rather than check-weigh each, and not have to be so particular about the brass prep, but with these narrow nodes I'll have to stick at it.

On the other hand I've heard of short, large diameter barrels that move so little it is impossible to locate nodes or otherwise, always shooting the same small group size for any charge weight up to maximum.

Any chance of some members who hand-load replying with the details on rifles they've done load development for?
- in terms of the amount of powder to stay within the node, number of nodes identified for that barrel & chambering, and the contour of the barrel. I'm trying to get a feel for what is typical for a given contour.

Recent range example of the narrow nodes with the POIs copied over onto the same target. Each colour in 1 grain steps.

Looking back through my load development the accuracy nodes seem to be of a similar "width" to what your finding

I think you might be chasing rainbows if you can see that much variation from a 0.2g powder variation. That's gotta be less than 0.5% of your total charge. You'd want extremely temp insensitive powder if that is the case.

Thanks for the feedback. Typical of a light barrel then. This was with 1 grain steps from which I estimated the two nodes were maybe +/-0.2grain wide - the barrel seems to be tracking something along the lines of the scribble on the left I added. Probably should have left more meat on the barrel and would have ended up with something like on the right - wider nodes and less shift overall. As always a price to every compromise....

Barrel profile will mean nothing regarding your "node". It will only heat up faster and push shots as it distorts under heat. Heavier barrels will do the same but the extra weight will offer a buffer in the speed it heats.

I have aways found heavy barrels are easier to find a load for, but have also found light barrels shoot just the same once you find that node witch can vairy barrel to barrel as well some smaller profiles still have big nodes like a axel barrel would. Its one of those things you never really know untill you shoot it

Next step for me would be load up more of that crimson load. Quick double check that wasnt a one off group then go hunting

What powder are you using

Re-25.

The blue might be OK too and was 140 ft/sec faster, but very few shots so agreed - indicative only. Max is 2-3 grains off the top of the chart.

Something that interested me was how the the shots between the nodes had spread out along the trend line. The barrel is shooting consistently enough in combination with quite a bit of movement with changes in shot-to-shot variables to see this (if that makes sense). It will be this movement in POI with changes in velocity & barrel time that are reduced by loading at a node giving the tighter groups, allowing reloading tolerances (and powder temp stability etc.) to be relaxed with a reduced impact on accuracy - at least that's my understanding of the theory. And wide nodes allow for the greatest flexibility so are good to have. Anyone got an alternative take on this ?

All the truck axle barrels I've had shot very well with little development. The skinny ones were all very fussy, and in smaller cals like .223 I found that 0.2 of a grain could be the difference between 1.5'' and 0.5'' groups. Even my 7mmWSM halves its groups with a 0.5 grain powder change (26'' No5 fluted Trueflite barrel).

The 7mmSTW that Abe built me has a 26'' fluted Sendero profiled Trueflite barrel and the 5 shots I used for load development (5 loads - 1grain apart) all shot inside 0.5''...so once again showing that how a heavy barrel can make load development a breeze.

I've gone away from spending too much time on seating death. I mainly use powder to fine tune my loads now and just seat to mag.
kj

I hunt and have the occasional blat at steel.
I just find max and back off a bit then play with seating depth.
But Im not real fussy , under 3/4 will do me but its nice when things shoot 1/4 or half.
If it won't shoot that at book velocity or a bit more i look to another projectile.

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Originally Posted by veitnamcam

I hunt and have the occasional blat at steel.
I just find max and back off a bit then play with seating depth.
But Im not real fussy , under 3/4 will do me but its nice when things shoot 1/4 or half.
If it won't shoot that at book velocity or a bit more i look to another projectile.

Sent from my GT-S5360T using Tapatalk 2

Imbwith u.. if it dont shoot around max or just under its probably not gonna

Originally Posted by baldbob

Imbwith u.. if it dont shoot around max or just under its probably not gonna

+1 A barrel will either shoot or it wont, generally. I have encountered fussy ones in heavy or light.

Originally Posted by R93

+1 A barrel will either shoot or it wont, generally. I have encountered fussy ones in heavy or light.

While my 6.506 is crazy accyrate its fussy..
Its gotta be on the lands or else.. that reminds me its not shootin to well.. must chase some lands!!!