6 BR bushing size question?

[in2deep]

My twice fired lapua brass measures .271 at the neck and .267 when reloaded with a SMK 107 grain bullet after resizing with the .266 Forster bushing. this is the largest bushing that came with the die and the numbers appear to be spot on from what others have posted with .001 neck tension BUT there appears to be too much tension as I am unable to remove a bullet with pliers. Is this because the brass is fairly new and springy and gripping the bullet tight and will loosen up as the brass get's worked more?

 

[RonAKA]

Based on my experience your numbers don't seem to add up. If you use a .266 bushing your brass should be close to 0.267" as it comes out of the bushing. If it is still measuring 0.267 loaded that would suggest it has zero tension. A couple of possibilities. The bushing is not really 0.266, or your micrometer has an error. What do you measure the Sierra bullet body at?

And one other thought. Can you slide a bullet easily into the neck of a fired case? I can up to the point of the shoulder. However, there is a donut on the inside of the case and it will not go past that point. I don't worry about it much as I don't seat the bullets any where that deep. Are you seating them down to the shoulder junction?

 

[dantiff2]

I think his numbers are spot on. I also run a .266 bushing and my neck measures .266 after resize. That measurement was taken with two different calipers. So I assume there is little to no spring back or the bushing is slightly under .266. I don't have a bore mic to precisely measure it.

I'm using Redding equipment

Dan

 

[in2deep]

yes the bullets slide easily all the way into a fired case. I did tumble the brass clean after firing and have heard that if all the carbon is removed from inside the neck then the bullet will tend to stick tight so maybe everything is normal.

 

[RonAKA]

I think his numbers are spot on. I also run a .266 bushing and my neck measures .266 after resize. That measurement was taken with two different calipers. So I assume there is little to no spring back or the bushing is slightly under .266. I don't have a bore mic to precisely measure it.

I'm using Redding equipment

Dan

Dan, I've seen a number of posts from those who have the Redding bushing die that suggest Redding is possibly dumbing down the bushing idea. Instead of stamping the actual bushing inside diameter on the bushing, they stamp it with what they estimate it will spring back to. From what I can see with Forster they do not do that. If you follow their bushing selection instructions you have to allow for spring back. It unfortunately causes confusion when users of the two brands try to compare experience.

To the OP, I suggest you measure fired case OD's and then again after sizing. Measure about 10, and average them. It should give you a good idea how much tension you have. I'm sure I'm seating mine with very close to 0.001" tension. With the bullet seated around 0.080" into the neck I can pull the bullets with my fingers. I use graphite lube and a bore brush to clean and lube to neck size and there will be some remaining.

 

[500x]

Ron is correct, a Redding bushing will usually allways measure smaller than marked, where as a Forster bushing will usuall allways measure exactly what it is marked, just as when you order, or send in a die to Forster to have the neck honed, it come's back to you with the exact dimension you ordered to the .0005". That is why Redding recommends .001 smaller than a loaded round and Forster recommends .002 smaller than loaded.

OP- I'm not sure if you are using the old or the new brass, but all of my older 6BR brass is .269" loaded with Bergers or SMK's, I have not seen any of the newer stuff, but reports state that it runs a little thinner. Your statement make sense that your brass is .271 after firing in a .272 neck, that adds up, the other not so much. I run .002 tension in my 6BR, and the bullet does not come out easy if I have to pull one for some reason, I use the old green hammer looking thing, and it takes several good solid hits to get it out.