The Accurate Reloading Forums
Finding Optimum Bullet Seating Depth

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/822107203

18 July 2005, 20:27
First Shot
Finding 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
-------------------------------
Make your first shot count!
18 July 2005, 21:00
hvy barrel
I 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.


------------------------------------
The trouble with the Internet is that it's replacing masturbation as a leisure activity. ~Patrick Murray


"Why shouldn`t truth be stranger then fiction?
Fiction after all has to make sense." (Samual Clemens)

"Saepe errans, numquam dubitans --Frequently in error, never in doubt".



18 July 2005, 22:55
First Shot
Thanks 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
worriedman
Maybe 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 Brumbelow
quote:
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 Sibley
I'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
charger
I'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
dustoffer
In 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"
22 July 2005, 00:14
kraky
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
dustoffer
I 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"