Where do you start your seating depth for OCW load Dev

champ198

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Minuteman
Aug 5, 2010
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I have a couple rifles I am trying to work up loads for.
The range is about 45 min away so I try and get multiple rifles set up to go shoot.

Right now I am working on a 6.5 CM in a Savage. 143 ELD-X H4350
Also a 243 Win in a Rem 700 Sierra TMK 90 Gr H4831SC
And the next on the list is a Model 70 in 300 WSM. 180 Gr Nosler Accubonds H4350

My question is where to start seating depths at?
Right now the 6.5 and 243 are at .050 off the lands. The 243 even at .050 is about as close as I can get as its an old Blind Box mag and they wouldnt fit with them at .040.
The 6.5 I have lots of room and still unsure on the 300 WSM as I havent loaded any for it yet, thats tonights project.

From my understanding.....And Im still new and trying to learn....Is to run an OCW to find a stable charge node. Both the 6.5 and 243 i went from Book Max down .2 grains until I had 12-13 3 shot loads made for each powder charge.
The 300 WSM with the larger case capacity I plan to do .3 increments.

Once I find a stable charge then I would play with seating depths...Correct?
But the only way I can do anything with the 243 is go shorter in seating depth, not longer due to the mag size.

Am I thinking right and on the right track?
 
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bullets would help a lot. the manufacturers will often put out information about where the bullets shoot best. Berger VLDs shoot best jammed while the hybirds shoot best with a lot of jump.
 
Thanks for that info. First time I have seen that on the Nosler site and I have been on there a bunch.

Now for the others will .050 also be a good starting point?
If I switched to another Bullet Co. Say Berger. Is it best to just email them to get an idea of a starting point?
Again. Still trying to learn as much as I can.
 
lol...I load max mag length with 6.5 CM in a SAAMI chamber with Berger 140 HT....and with a new barrel that still put me 70-80 thousand off of the lands...and of course that will just grow with round count and throat erosion.

I have a barrel in the safe that I had chambered with a .150" free bore which should let me get closer to the lands but as I shoot Berger 140 HT I'll prob find myself backing up a bit but this should give me a bit of room to extend seating as barrel erodes. Or so I tell myself. lol