# Seating depth or velocity



## jk3hunter (Dec 29, 2010)

So I have seen and heard conflicting stories on what is more crucial to accuracy. Some argue that seating depth is more important, yet others say that velocity is more important. The latter say by performing a ladder test to find your magic velocity, seating depth will no longer be as crucial. What do you guys think? Should a reloader pick a charge then mess with the seating depth or pick a seating depth then pick a charge? Or should both be messed with?


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## People (Jan 17, 2005)

Both are equally important. As you do your ladder test will show there will be a few rds that are close to each other. This is roughly the speed your rifle likes with that combo you are shooting. Then you play with seating length.

Lets say you started 5 thousandths off the lands and fired a ladder test then you did the same test with your bullets 3 thousandths off the lands. Your nodes might be better at 5 or 3. Then you have to play with length closer to the one that gave you the best accuracy.

With that testing you will get the best accuracy in your rifle. Granted there is no guarantee that you can be close to the lands if you need to use a mag. Then you load to get what you can get. I have been surprised how well a rifle can shoot even with a very long jump.

In an average living room there are 1,242 objects Chuck Norris could use to kill you, including the room itself.


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## jk3hunter (Dec 29, 2010)

Thank you for the reply. My AR shoots half inch at 20 thousandths off the lands. I asked this question in regards to loads I plan on doing in the future. with this ladder test do I use 3 of the same charge weights or is two of the same charge enough to detect a node.


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## noylj (Nov 10, 2010)

The "funny" thing about a "ladder test" is you do it at 300 yards and look for the range of charge weights that put the bullets into the "same" location. After proving this, the "typical" reloader then starts to worry about charge weight and wants to weigh the powder to +/- 0.01gn.
They have "proven" to themselves that there is a charge weight range where the exact charge doesn't matter, out to at least 300 yards, yet they still worry about it.
Once you have the charge range (and you load to the middle of that range, let us say), then you can play with COL to see if there is a COL range that is best for your rifle.


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## Plainsman (Jul 30, 2003)

I think your off a decimal place on your weight noylj. Unless your willing to pay $1000 for a laboratory scale. I don't know anyone who goes to 1/100 th grain. I only go to 1/10 (0.1) grain.

I also work with both. I really can't say which is the most important to start with. I guess I normally start with a reasonable distance from the lands and load three weights. For example I would start about .005 off the lands for Berger VLD bullets, and about .010 for most other bullets. Barnes X bullets I often start back .015 off the lands. I will start closer to the lands with bullets that have a very long ogive. I start further from the lands with round nose for example. Also, I stay back further with harder bullets like the Barnes X or the Bonded core. Just me though.

I guess I just start off the lands where years of experience have taught me to start. Nothing wrong with working on distance from lands first though. Just make sure you work on both for maximum accuracy.


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## Sasha and Abby (May 11, 2004)

Thanks People and Plainsman! I always love reading your posts and always gain some knowledge that I had never thought of. :beer: :beer: :beer:


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## CoyoteBlitz (Apr 11, 2007)

okay so maybe this is a dumb question, but im thinking about reloading for my 22-250(55grn vmax to start with). but how do you know where your lands start on a particular load? like how do you figure out the depth at which your bullet touches the lands?


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## Plainsman (Jul 30, 2003)

I use a Stoney Point tool that measures off the ogive. When I got my 6.5 Creedmoor they didn't have the correct cartridge insert to work with the tool yet. So I used the poor man's measure devise. Normally I use a jewelers saw, but at my age I spend more time looking for my tools than using them. I lost my patience and grabbed a hacksaw. Hence the crude work on the photo you will see. Size one of your brass and cut (down both sides) to the point you will see in the photo. Then just start a bullet into the case. Put that in your rifle and close the bolt. When you extract you should have the bullet at exactly where it meets the lands. Make sure your chamber is clean and dry when you do this. The neck split like this acts like a spring holding the bullet in place, but lets the bolt of your rifle seat it to the lands.

Please excuse the poor photo. I just run downstairs and took it hand held, without flash, on macro, at 1/10 sec.


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## KurtR (May 3, 2008)

you running moly on those?


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## Plainsman (Jul 30, 2003)

No. I tried some with the 120 Ballistic Tip, just because I had them. Yesterday I put the bullets in the tumbler and took the moly off. I just have a few hundred 6.5 to shoot up. Some Ballistic tip, and some 140 Seirra Game King. Otherwise I am sticking to the 140 Berger VLD.


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## KurtR (May 3, 2008)

i see looked pretty black in the pick. i have been stocking up on the 6.5 140's in amax and bergers in anticipation of geting the creed done. Cant wait.


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## xdeano (Jan 14, 2005)

Doing a ladder test is critical to find velocity node for accuracy. Once you have the velocity node then you can play with seating dept. Id start of doing a standard. .015 off the lands and work it from there. Another thing that can be changed once you get your velocity is neck tension. Suprisingly neck tension plays a lot in accuracy. Get your velocity node first.

Deano


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## huntin1 (Nov 14, 2003)

Like xdeano, I start with velocity and then fine tune with the seating depth. For me 2 or 3 rounds isn't enough, I use a 5 round minimum, and sometimes more on my ladder tests.

I cheated on my 308 175 VLD's though. I knew they liked being close to the lands and I wanted to be able to magazine load them, so I used the stoney point tool and then backed them off until they would just fit the mag. Then played with the velocity. I'm too lazy to go look this morning, but I think they ended up at .004 off the lands. I have only shot to 300 for group size, but I'm getting .5 MOA out to 300 so I guess they are okay.

Huntin1


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