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Case neck clearance

bobcat93

I'm having a tight neck (.265") 6mm. BR built. I hear some guys run as little as .002" of neck clearance.
What do you guys suggest?
I would like to start my case prep, and get some loaded rounds made up.. I use redding dies. I have a regular redding 6mm BR full length die, and I'm going to purchase the competition bushing neck die set.
What I need to know is how much neck clearance do I need, and what size neck bushings should I order.
Thank you
 
Bobcat,

Based upon my own testing, after consulting with experienced reloaders who also compete or have competed in the past, my Savage Benchrest 6mmbr shoots the best with the .002 brass clearance. My testing (6-5 shot groups) was done at 100 yds using Bart's 68 gr FB bullet being pushed by 29.1 gr of VVN133. I also tested using this same load/ Lapua brass with a .003 and .004 clearance, however the results weren't quite as good as the .002 neck clearance. I also use a Redding Bushing Die and seat using a Wilson In-Line die. My suggestion is you try these clearances in your own particular rifle and record the differences and variations to determine which makes a difference. As for determining which Bushings to use, I'd start with a .267 Bushing and if you can, go up by one and see what your brass measures after resizing and see how they shoot. Not knowing anything about the brass you are using (virgin or turned necks) neck tension becomes important to also keep in mind. .002 there also works great for me, although some guys I know prefer .001 Neck Tension.

Alex
 
I also use .002`s expansion on my tight necks. I would use zero, but any thing would keep the round form chambering, and I have had no trouble with .002 in the field.
 
Catfish said:
I also use .002`s expansion on my tight necks. I would use zero, but any thing would keep the round form chambering, and I have had no trouble with .002 in the field.
Click to expand...
bobcat93 said:
I'm having a tight neck (.265") 6mm. BR built. I hear some guys run as little as .002" of neck clearance.
What do you guys suggest?
I would like to start my case prep, and get some loaded rounds made up.. I use redding dies. I have a regular redding 6mm BR full length die, and I'm going to purchase the competition bushing neck die set.
What I need to know is how much neck clearance do I need, and what size neck bushings should I order.
Thank you
Click to expand...
The size bushing you use has nothing to do with neck clearance. For a tight neck you will need to turn the brass to get the clearance you want on a loaded round. You will use the proper bushing to set the neck tension to your specs. A starting point would be to turn your brass to .010 for a .263 loaded round and a .261 bushing for .002 neck tension.
 
I have tested clearance on a Dasher at 1000 yards and didn't see any difference between .004 and .001. I use .003 just to add a little safety factor in. To get a loaded round of .262 you will need to turn to .0095 wall thickness. I would start with a .260 bushing to load. Don't be afraid to try a .259 or .258 bushing. Some guns like a little more tension. Matt
 
dkhunt14 said:
I have tested clearance on a Dasher at 1000 yards and didn't see any difference between .004 and .001. I use .003 just to add a little safety factor in. To get a loaded round of .262 you will need to turn to .0095 wall thickness. I would start with a .260 bushing to load. Don't be afraid to try a .259 or .258 bushing. Some guns like a little more tension. Matt
Click to expand...
I think Matt is on to this with trying "tighter or more" neck tension. I used to shoot, a long time ago, with the "short range" (100 and 200) yards Benchrest people. I shot "factory class" but they all had 6 PPC's. They turned their neck walls down pretty "thin" and ran "about" 4 thousandths neck tension. With a tight chamber and thinner neck walls, tighter or more neck tension may be the key here..
 
dkhunt14 said:
I have tested clearance on a Dasher at 1000 yards and didn't see any difference between .004 and .001. I use .003 just to add a little safety factor in. To get a loaded round of .262 you will need to turn to .0095 wall thickness. I would start with a .260 bushing to load. Don't be afraid to try a .259 or .258 bushing. Some guns like a little more tension. Matt
Click to expand...
DK hunt14, thank you for your comment ..clear and to the point..that's what I need right now..
 
I set myself up to run .002, but i found myself feeling better about running .003, just gives it that little extra "Fudge Factor".;)

Phil.
 
Another question..when you guys turn your case necks..do you just kiss the neck shoulder juncture.. I seen some guys online who stop just above the shoulder..I would think if you don't turn down all the way that would cause the donut..can some one post a pic that shows the proper stoping point when neck turning..thank you
 
Yes,

Turn to the neck / shoulder junction.

The guy`s that stop up the neck are probably creating a false shoulder for fire forming dasher brass.........


Phil.
 
bobcat93 said:
Another question..when you guys turn your case necks..do you just kiss the neck shoulder juncture.. I seen some guys online who stop just above the shoulder..I would think if you don't turn down all the way that would cause the donut..can some one post a pic that shows the proper stoping point when neck turning..thank you
Click to expand...
Here is a good example of how far down to turn..
IMG_0414.jpg
 
You probably already know this but you said you have issues. Make sure your cutter angle matches the shoulder angle (in case that's one of your issues).
 
Im not a fan of matching cutter angles to shoulder angles. If you do you cut way too far down the shoulder to cut the junction. You want it to just kiss the junction like the one preacher man posted. You cant do that with a matched angle
 
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