how to determine the proper bullet seating depth

[centerfire]

Hey guys I have a question for you all on how you determine your seating depth. I am reloading 100 grain bullets for a .243. I have used a fired cartridge, dented the neck, started the bullet in the neck, coloured the bullet with a black marker, and determined the rifle seating depth. Then reducing the length by .020" . my cartridge looks too long and is about 1/8 of an inch away from the crimping ring.I am using Hornady 100 gr interlocks with a crimping ring and speer 100gr btsp. What do you guys do? Do you subtract .015 " to .030 " from your rifle seating depth or go by manufactures spec.?

Thanks for the input!

 

[kawicrash]

Depends on the throat length. Sometimes the COAL will be too long for the magazine.
I go by the throat length, not specs.
I also use an RCBS Precision Mic. It has the dual use of measuring seating length and headspace.

 

[dusticles]

If you're playing with a factory barrel you're going to find they have very long throats... what you have done so far is near exactly what I would have done. I like to start my loads .015 off the lands and play back and forth from there once I find my powder weight.

Bullets with cannelures really restrict playing with seating depth though.

 

[bigedp51]

Hey guys I have a question for you all on how you determine your seating depth. I am reloading 100 grain bullets for a .243. I have used a fired cartridge, dented the neck, started the bullet in the neck, coloured the bullet with a black marker, and determined the rifle seating depth. Then reducing the length by .020" . my cartridge looks too long and is about 1/8 of an inch away from the crimping ring.I am using Hornady 100 gr interlocks with a crimping ring and speer 100gr btsp. What do you guys do? Do you subtract .015 " to .030 " from your rifle seating depth or go by manufactures spec.?

Thanks for the input!

centerfire

I'm going to let you in on a little secret, for over 25 years I used my .243 for deer hunting where most shots are taken standing up on your hind legs. I kept things simple and seated my 100 grain Hornady interlocks to the cannelure. The longest shot at a deer for me was 125 yards sitting in a tree stand using a rest.

Bottom line, I would work up loads with different powders trying for small groups and the "last" thing I would do is work on the OAL or how far off the lands. I will assume your not shooting ground hogs with your 100 grain bullets and deer size game and larger game do not require shooting bug hole groups. Hunting accuracy standing is being able to keep 5 shots inside a six inch circle at 100 yards.

KISS = Keep it simple stupid......................use the cannelure, non of my hunting rifles are used in benchrest competition.

 

[centerfire]

For deer hunting yes

 

[elkhuntr]

You have covered off the first step, finding the maximum length to touch the lands. I have found many times that 60 thou jump in a hunting rifle with hunting bullets will be very satisfactory. Be sure to play with one variable at a time. First find a load using the length you choose and then play with seating depth if you wish. The limiting factor is your magazine length. So try to not go too long or you will find the bullets get marred up a bit when shots are taken.

For normal hunting ranges up to 300m hitting a 6" pie plate is all that's necessary. But if you wish to play further then you need to hone the tools and skills to make those shots. Finding a sub 1" load in a 243 should be attainable.