SEATING DEPTHS AND THEIR ROLE

[joshruger]

I have been reloading for two years and have just now started to adjust bullet seating depth in my ruger 22-250. I have been using hornadys bullet seating depth guage and comparator. If my standard load calls for 39 gr. of win760 and a c.o.l. of 2.350 inches, what difference would it make if I seated the bullet at .020" off the lands and still use this same powder charge. pressure? velocity? I'm just trying to get a little more accuracy. thanks/.

 

[M-61]

My suggestions:
First determine the throat (freebore) of YOUR rifle. Where does a length of 2.350 put you? Find that out thru various methods and tools ( Hornady OAL gauge is one). Some throats are so long you will never reach the lands with the bullet seated in the case securely. Every move of the bullet will change the pressures (and of course vel.) Into the lands may raise the pressures as well as 'jumping'. A jump may require to seat the bullet deeper into the case thus reducing volume hense raising pressures. Careful watching for signs of pressure changes is important. How is the accuracy now? I've reloaded a 22-250 (Colt Sauer) for many years and found that H-380 was the winner by far.
I load it on the hot side and jump in my particular rifle. It will shoot really impressive THREE shot groups. I really have always liked this cartridge even though it somewhat hard on barrels. I have found that my best loads always have cratering around the firing pin indentation, which does show a hotter load but also various with the hardness of the primer.
PMC made small rifle primer brass years ago which I have and the groups with this are the best ever. Sorry I got off the track but 22-250 is a favorite of mine.

 

[LorenC]

I'd like to recommend arranging your setup to where you can do some loading at a range. As you do start with what you think is a slightly short OAL than what measurements say you should be at, and shoot some groups so you have things settled and a base to work from. Raise the seater stem in increments as you shoot more groups. Watch the usual pressure signs and such for any safety issues. As you lengthen OAL there will be a length your gun likes the best, unless you started longer than it prefers.