choosing the correct node

[Savageseven]

when you find a flat spot in your velocity as a possable node do you always choose the one with the fastest velocity first to work to see if its going to work ?

 

[JMA]

The widest

 

[Bc'z]

Does it coincide with a flat spot on target?

 

[LVLAaron]

Depends... How long do you want your barrel to last, and how wide is the node?

 

[Savageseven]

i looks like i have 2 nodes one in middle of charge weight and one at the max end of charge weight..
would you choose the one with the faster fps to adjust seating depth and fine tune first ?? or would you stick with the slower fps ?

 

[Savageseven]

this is for a 243 winchester shooting a 70 grain nosler ballistic tip using imr 4350
at 46.0 grains of powder my avaerage over 5 shots was 3481 fps
at 46.5 my average over 5 shots was 3490 fps

 

[Sandstorm]

You usually have more flexibility with the slightly slower node.
Especially if the enviorment changes drasticly...so you wont be over pressure.
Like temperature swings from winter to summer etc.

 

[D-4297]

^^^^^
What he said .

 

[Webster]

when you find a flat spot in your velocity as a possable node do you always choose the one with the fastest velocity first to work to see if its going to work ?

Are you plotting charge vs 1 shot fps? If so there is no flat spot it's just ignoring the fact that there is ES. Most guys look for a small 5 shot group with a small group .3 gr under and over.

 

[Bc'z]

^^^^^
What he said .

Yup

 

[Savageseven]

Are you plotting charge vs 1 shot fps? If so there is no flat spot it's just ignoring the fact that there is ES. Most guys look for a small 5 shot group with a small group .3 gr under and over.

i loaded them up in 5 shot groups then wrote down my average fps on the 5 shots.

 

[INTJ]

I like lower nodes. I tend to find they are wider and thus more forgiving. However, the group on the target is my primary determiner.

 

[CharlieNC]

Does it coincide with a flat spot on target?

Yep. On this forum I would guesstimate 90% use this method based on the flat spot on the target (indicating harmonic compensation) while the remaining 10% want to use velocity.

 

[Savageseven]

Yep. On this forum I would guesstimate 90% use this method based on the flat spot on the target (indicating harmonic compensation) while the remaining 10% want to use velocity.

so is one really better then the other ?

 

[Dub]

whenever you see" 90% on this forum", that is a major clue

 

[Sandstorm]

Yup...90%...say no more Dub

 

[Layne Zuelke]

Since you are talking about pushing a .243 at 3400plus you might try to stick with the lower node and see where it goes with seating depth. IMR is temp sensitive and will speed up in the summer. Also you will burn that barrel out in less than 1500 rounds at those speeds. That’s a given. Another thing to be aware of shooting a fast 6mm is to keep your barrel clean. I developed a carbon ring at 400 rounds in my 6mm because I was listening to too much “don’t clean till accuracy falls off” advice. I was only doing light cleanings every 150 rounds or so and wasn’t doing a full carbon strip around the throat. Result? A carbon ring that caused a wild pressure jump, accuracy loss and blown primers coupled with a 150fps velocity increase. I learned my lesson. Now I clean my barrel. And I check with a bore scope.

 

[Sandstorm]

Since you are talking about pushing a .243 at 3400plus

Now Layne got some good advise....I dint even mention barrel life...or
lack of at those speeds. 6mm rounds are notorious for a short life anyway. My friends Competion barrel
went 900 rounds and he was'nt even close to 3400 fps.

 

[Clancy]

this is for a 243 winchester shooting a 70 grain nosler ballistic tip using imr 4350
at 46.0 grains of powder my avaerage over 5 shots was 3481 fps
at 46.5 my average over 5 shots was 3490 fps

Maybe I’m reading this wrong, but if you only gained 9 FPS over half of grain of powder, that’s not two nodes, that’s one node, it’s wide, and 46.3 sounds like a real fine load to me.

 

[Savageseven]

Ok I will give that powder charge a good look and load a few up