Seating depth

CDSG Shooting Sports


Well-Known Member
HI all,

New to reloading and literally shot my first loads today at Bisley. I found the process fun and interesting. however, what got me is the correct seating depth. Is there an ideal depth or does it very on calibre, bullet weight, etc.

If it helps im shooting a 7x57 with 140 or 150gr bullets. My current load is 45gr H4831sc in the 140 (Hornady) and 47gr with the 150gr nosler. accuracy wasnt bad but needed some work.



Distinguished Member
spark not an expert but try backing off the lands 5 thou at a time on a batch of bullets your rifle will tell you by the way the pattern tightens up no experience on your calibre but worked well on a couple of rifles i own one shoots well 5 thou back the other 25 thou just experiment .


Well-Known Member
Excellent 145 grain 7x57 load! My pet 145 grain load for my own 7x57! I have used it for 27 years with nothing but success.

If you have the typical 7x57, the lands are a good ways off. Try magazine length minus .050" to start. It will be a compressed charge but you already knew that I'm sure. Good shooting! ~Muir


Well-Known Member

Some literature suggests that the minimum seating depth should be the same as the calibre of the rifle eg seat a .308 win .308 inches into the case, (not counting any boat-tail) the idea is that less than that can lead to the bullet not being true in the case neck. I have found this works very well with accuracy and personally believe that moving a thou here and there has less benifit than most people believe, pressure is varied considerably however. In bench rest shooting where people shoot for the tightest groups possible they normally seat the bullet into the lands, but doing this in a stalking situation where you may need to extract a live round can pull the bullet head off and spill powder into your mechanism. The factory load used as a standard to compare reloads on gun reviews in many US shooting journals is the Federal Gold Match, which consistantly gets very accurate results in many rifles in spite that the seating depth is not a variable, I believe consistancy is more important.
All the best
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