The Accurate Reloading Forums
Finding Optimum Bullet Seating Depth
18 July 2005, 20:27
First ShotFinding Optimum Bullet Seating Depth
I'm currently working up loads for a 7MM-08 and, when the magazine will allow it, seating the bullets .01 off the lands.
I've found a couple of prety good loads but now want to adjust seating depth to see if I can get any improvement.
If starting .01 off the lands, at what increments should I adjust the seating depth and how far off the lands should I stop?
Thanks
First Shot
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Make your first shot count!
18 July 2005, 21:00
hvy barrelI have been seating the bullets .005 off of the lands in my 7mm08.
18 July 2005, 21:12
Ol` Joe.005" increments is a fairly std amount to move the bullet. I stop at the most accurate distance I find, usually not more then ~.030" or so off the lands, but I have went to .10" off or more in my 6.5 Swede depending on the bullet shape & wgt. The Swede has a lot of free bore though and is not the norm.
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18 July 2005, 22:55
First ShotThanks guys. I appreciate the info. I'll start at .010 off the lands and seat deeper at .005 increments and see what happens.
Thanks
First Shot
-----------------------------
Make your first shot count!
19 July 2005, 22:12
worriedmanMaybe I am reading the decimals wrong, but I have found most of my loads to be most accurate .003-.005 off the lands. I change the depth .001 per trial, starting at the lands and working back. Seems that .005 is a fairly large increment.
"It could probably be shown by facts and figures that there is no distinctly native American criminal class except Congress." Mark Twain
21 July 2005, 05:35
Russ Brumbelowquote:
Originally posted by worriedman:
I have found most of my loads to be most accurate .003-.005 off the lands. I change the depth .001 per trial, starting at the lands and working back. Seems that .005 is a fairly large increment.
My favorite rifle likes em .004 off the lands.
21 July 2005, 09:10
Cal SibleyI'd load the rounds in groups of 5, each group being an additional .005" further back off the lands. Do this for 4 groups or 20 rounds, a total of .020". That should pretty well tell you which OAL the round prefers. Just one mans opinion. Best wishes.
Cal - Montreal
Cal Sibley
21 July 2005, 14:51
chargerI've got one of the old sako av deluxe 300 weath,that isnt content unless you jam the proj. right up to the rifling. I got to seat em .010 long and let the bolt cam them down. If I do that she's a one holer
21 July 2005, 23:17
dustofferIn my accuracy workup business, I start at .005 off, then .015, 025, .035 off. By this point you most likely have identified the "sweet spot" for the bullet/barrel combo. I then go +/- .005 on either side of that depth as a final check. I've found too little change to make it worth the effort in doing the +/- .001 or .002, but if it was a high end gun with tight throat, etc., etc., I would do it. But, there is a point of diminishing returns in this game, and customers don't like to pay for non-productive efforts by me. Also, the practical aspect of what is "good enough" enters in.
An old pilot, not a bold pilot, aka "the pig murdering fool"
Those bigger imcrements make more sense to me. It would take along time to work groups at .005 change. Also you might just take a factory round and check it and set for that depth as an experiment. There is alot of accurate factory ammo that's probably sitting .050-.080" off the lands and can be dynamite accurate.
22 July 2005, 06:25
dustofferI have a 7mm mag that absolutely loved Federal Premium ammo with 160 gr Nosler Partitions--shot under .75" for 5 shot groups off the bench all day long. Never found another bullet that it would shoot though. When that barrel gave it up and I rebarreled with an unfired factory takeoff barrel ($45 plus $75 install and headspace) I found out it likes 150 gr Ballistic Tips. And, if I wasn't in it for the money, maybe I'd use the smaller increments, but just not worth my time.
An old pilot, not a bold pilot, aka "the pig murdering fool"