Question on seating depth?

flying pig

flying pig

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Wondering what you guys do to determine your seating depth? I switched bullets in my 223 yesterday. I read my Lee manual for my start load and checked the min OAL. Thought I would try to figure out how far out the bullet has to be to touch the lands so I stuck a new bullet in a spent/non neck sized case and chambered it. Manual said min oal was 2.25" and my test cartridge came out at 2.5". Is this a safe way to determine Seating depth? These particular bullets have enough straight section that they still contact the neck full depth at this oal.
 
As long as you have enough bullet stuck in the case that it doesn't fall out or seat cockeyed, you are good to go. If feeding from the mag isn't an issue and your not jamming the bullets into the lands, carry on. Now, not all bullet/barrel combinations will like the same seating depth. Some bullets will shoot better with a little jump, some with a lot of jump and some do like to be jammed.
Start about .020" off the lands and find the load that works best for that bullet/powder/barrel combination. Then play with the seating depth so see if you can fine tune the load.
 
I do the loose bullet in a spent cartridge. I also marker the bullet to see if it's touching. Then use that as a dummy round ONLY for those lot of bullets.

I do find they change, and measureing full on OAL does change quite a bit, even with match grade bullets. (mine in particular are AMAX's)

So to eleviate that deviation, use a bullet from the lot of bullets you are using, marker the bullet and when the land lines dissapear, measure OAL. Subtract from there how far you want off the lands, set-up seating die and run your rounds.

A bit of work, but pretty easy and quick. Prevents the need for special tools. Just make sure the bullet moves relatively freely in the case. Keep the round handy for further reloads / testing. The bullet can be shot if you switch rounds and you just implement a new one into your dummy case.

It may not be perfect, but seems to work.

My next outting will involve testing varying distance off lands. I know it changes the location of my gouping beacuse my mag length rounds (very short on my 700 .308 - 2.8**) shoot high and left compared to my .015 rounds which are bang on zeroed..

So much witchcraft..
 
I guess I am old fashioned. I seat the first bullet deliberately long. I chamber it and note how much rifling mark is on the bullet. I then seat the next bullet deeper and check it. I keep doing this, seating bullets a half or quarter turn deeper until there is no rifling marks. Then I check to make sure they will fit the mag. My log book shows the max mag length for each gun.

Once I have a length that clears the rifling, I then re-seat the longer test rounds.
 
I like the Sinclair system myself as you don't need to buy their cases, you use your own resized case ht tp://www.brownells.com/reloading/measuring-tools/bullet-seating-depth-accessories/sinclair-bullet-seating-depth-tool-prod35491.aspx
Kim
 
maynard said:
As long as you have enough bullet stuck in the case that it doesn't fall out or seat cockeyed, you are good to go. If feeding from the mag isn't an issue and your not jamming the bullets into the lands, carry on. Now, not all bullet/barrel combinations will like the same seating depth. Some bullets will shoot better with a little jump, some with a lot of jump and some do like to be jammed.
Start about .020" off the lands and find the load that works best for that bullet/powder/barrel combination. Then play with the seating depth so see if you can fine tune the load.
Click to expand...

x 1 I agree
 
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