Load Development - Ladder testing question

[Drewski2324]

When doing load development specifically using a ladder test, does the test need to be performed for every bullet choice? Or if the weights are similar can these be generalized by choosing one bullet to test with?

Example: I am in the beginning stages of load development for my 7mm Rem Mag and these are the 3 bullets I am considering Barnes TTSX 150gn, Barnes TSX 175gn & Hammer Hunter 177gn.

 

[JakeSCH]

Disclosure: I'm new into reloading (started in march) and don't anything.

I have been employing a modified ladder test and it has been working well (search 65 guys for more info on it). The key is having a good chronograph and looking for velocity flat spots. To me this method makes sense as long as your are able to be "precise" with your powder charge.

Basically I will start a 3 gr's or so below max and work up every 0.5 or 0.3 (depending on max charge)...you can do this simultaneously on a "work up" to find max pressure. Once you get those flat spots, you can then load up 3 or 5 at a charge in the middle and look at group, tweaking seating depth to tighten up the groups.

So far this has worked well for me in my 308, 6.5 PRC, my dad's 30-06, and just starting the 300 WM now. But to this point my skill is the limiting factor, not the ammo.

Eventually I will get a lead sled to see how good it actually is or if I am full of sh!t.

 

[punkur67]

Disclosure: I'm new into reloading (started in march) and don't anything.

I have been employing a modified ladder test and it has been working well (search 65 guys for more info on it). The key is having a good chronograph and looking for velocity flat spots. To me this method makes sense as long as your are able to be "precise" with your powder charge.

Basically I will start a 3 gr's or so below max and work up every 0.5 or 0.3 (depending on max charge)...you can do this simultaneously on a "work up" to find max pressure. Once you get those flat spots, you can then load up 3 or 5 at a charge in the middle and look at group, tweaking seating depth to tighten up the groups.

So far this has worked well for me in my 308, 6.5 PRC, my dad's 30-06, and just starting the 300 WM now. But to this point my skill is the limiting factor, not the ammo.

Eventually I will get a led sled to see how good it actually is or if I am full of sh!t.

I have a lead sled for sale if your interested

 

[punkur67]

When doing load development specifically using a ladder test, does the test need to be performed for every bullet choice? Or if the weights are similar can these be generalized by choosing one bullet to test with?

Example: I am in the beginning stages of load development for my 7mm Rem Mag and these are the 3 bullets I am considering Barnes TTSX 150gn, Barnes TSX 175gn & Hammer Hunter 177gn.

You need to do load development for each of those bullets. Each bullet weight will change your results

 

[JakeSCH]

You need to do load development for each of those bullets. Each bullet weight will change your results

Hahaha I did my entire response and left out the answer to his questions. I derailed myself and sound like Larry now . Agree that each bullet by itself, however the hammers may have a node "close" to the 175 tsx.

 

[Aeon]

yup for each bullet...
The ladder test is looking for the sweet spot in the harmonics of the barrel as much as its looking for the sweet spot in charge weight. Both in a perfect world would not mean much but in real life with powder brass and bullet variations you need as big a window to hit as possible. Think of it this way... if your harmonic is mid swing then slight speed changes will have a big affect on the bullet leaving the barrel. If you hit the harmonic at the top or bottom of its swing then you have broad window where the bullet leaves the tube the same way. Hard to see or prove what matters more speed or harmonics and even more difficult to prove its one or the other. If it shoots small groups at 500 yards run with it! If it shoots small groups at 500 yards in cold and warm weather then its more then good.....

read this article. its a mile more info then i can give here and covers it pretty damn good. Ladders are one of the more misunderstood things in long range shooting.
READ THIS


Do not get to lost in all this testing BS. if it shoots it shoots. If you shoot a lot its a moving target as you erode the lands away your node erodes with it. A hot round like the 6.5rsaum can be half wore out before you figure out the perfect load and by that time its changed find a speed that works and modify your loads to keep that speed as you wear out your tube and nine times out of ten you will be good to go!

 

[Aeon]

oh and if you are really worried about ladders then get off the sled! The sled changes the harmonics of the stock and in turn the barrel. Shoot her like you will be in the real world.

 

[Drewski2324]

No sled for me. I just use a gamechanger bag and badger bone bag.

 

[White Smoke]

You need to do a ladder for each bullet. I have found that even identical weights of similar bullets fly differently. I was doing a ladder once for my 308. The 150 grain Barnes TSX flew like a dream, but the 150 TTSX would not pattern. Go figure!