Seating depth adjustment

the big greasy · Mar 19, 2024

I took everyone's advice on here a while ago, and have narrowed down 3 potential loads. My lands coal ogive is 3.005. I did all my testing with a coal ogive at 2.975. I have tested some loads with 5 shot groups 2 seperate loads that are good groups but loads on either sides start to open up again. These are loaded and shot in .1 grain increments. The 3rd load is good with decent groups on either side. Wanting to test seating depths on these 3 loads what seating depth increments should I move in? I was thinking 10-15 thousandths. Just wanting to conserve some ammo. Thanks

Koda_ · Mar 19, 2024

the big greasy said:
Wanting to test seating depths on these 3 loads what seating depth increments should I move in? I was thinking 10-15 thousandths. Just wanting to conserve some ammo. Thanks

I have read that seating depth nodes are in .006" increments.

cued up to the explanation....

lancetkenyon · Mar 19, 2024

I usually start at .010"-.015" increments. Find a good node, and then try .005"+/- from there.

Pdyson · Mar 19, 2024

i like to jump bullets because a bullet stuck in the bore will ruin my hunt. Start at least 20 thou from jam and go .006 increments. You won't have to go very far before you hit a node. If you make huge jumps you'll skip good nodes and risk getting into the neck donut.

MagnumManiac · Mar 19, 2024

I have always started at touching, then course adjustment is .010" increments, then fine tuning is .005" either side of whatever shoots best.
I have to add that I do not tune powder first, this is backwards to me.
If you find .010"-.020" is the sweet spot for that bullet and you have already tuned powder, the resultant fine tuning may disappear because it will be lost in the noise…

Cheers.

Phil Rizzo · Mar 19, 2024

Being the complicator I usually am, I start at 15-20 off, adjust in .003 increments and try to find a spot where 2 adjustments are the same or very similar, then get in the middle.
I shoot 3 shot groups at every depth change and watch the trends.

Dont know if it's the best way but I normally use a medium powder charge, try to get depth set close, then go up on powder. Normally there is a little more depth tweaking in the end according to group shape but not much.
Seems like I normally end up .030-.045 off with hybrids.

FEENIX · Mar 20, 2024

the big greasy said:
I took everyone's advice on here a while ago, and have narrowed down 3 potential loads. My lands coal ogive is 3.005. I did all my testing with a coal ogive at 2.975. I have tested some loads with 5 shot groups 2 seperate loads that are good groups but loads on either sides start to open up again. These are loaded and shot in .1 grain increments. The 3rd load is good with decent groups on either side. Wanting to test seating depths on these 3 loads what seating depth increments should I move in? I was thinking 10-15 thousandths. Just wanting to conserve some ammo. Thanks

As with anything else, YMMV. It depends on the bullet and what your rifle wants to shoot, but as others noted, I, too, typically end up at the .010" to .020" off the lands. On my .300 WSM, I had to find the best compromise between COAL and CBTO due to mag clearance for 215 Berger and ended up with .080" off the lands.

Seating depth adjustment

the big greasy

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Koda_

Well-Known Member

lancetkenyon

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Pdyson

Well-Known Member

MagnumManiac

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Phil Rizzo

Well-Known Member

FEENIX

Well-Known Member

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