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seating depth increments?

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24 February 2004, 16:14
rufous
seating depth increments?
My gunsmith suggested that my 6-284 would most likely shoot best with the Sierra 107 matchking bullet seated 0.010� to 0.015� into the lands. I plan to go out and try several different seating depths and wonder what increment to use? Should I try just touching the lands, 0.005�, 0.010� and 0.015� into the lands or should I try in 0.001� or 0.002� increments or what? Thanks, Rufous.
25 February 2004, 02:24
knobmtn


rufous:

Increments of .005 have always worked for me. Into the lands is probably best with most 6mm rifles but once the cases are formed don't be afraid to come back out of the lands if you need to. All rifles are different.

knobmtn
25 February 2004, 07:01
packrat
ditto what knobmtn said...
26 February 2004, 19:44
dodiejig
I prefer staying away from the lands. Touching them will create more chamber pressure and aid in early throat erossion. You will be able to work up a load that will give you great accuracy and keep you off the lands. Just be patient and try many.
26 February 2004, 23:07
BLR7 (Texas Cactus Shooter)
Iwould start about 0.035" AWAY from the lands and seat test
rounds of 3 each increased by 0.010" closer until I was just
0.005" off the lands and watch for pressure signs and group
tightening at any of the intervals. You may find the best
barrel harmonics (sweet spot) needs a running start to avoid
undue pressure buildups. Good luck...BLR7
27 February 2004, 01:56
Hot Core
Quote:

... Increments of .005 have always worked for me. ...All rifles are different...





Hey rufous, I also agree with knobmtn.



When it comes to Benchmarking the rifle using MatchKings I agree with your Gunsmiths recommendation of Seating them "0.010" to 0.015" into the lands" to start with. Sometimes if you begin at 0.015" Into-the-Lands, you may have difficulty closing the Bolt though. Occasionally they shoot better with a bit of distance Off-the-Lands, but you only know which is more accurate by trying.



But first I look for the best harmonic by varying the amount of Powder using the never improved upon Creighton Audette Method. Once I find it, then I fine tune the Load by varying the Seating Depth.



If you are intending to stick with MatchKings for all your shooting, I've often found their most accurate Loads to be closer to the "Starting Loads" than the "SAFE MAX Loads".