Neck Tension/Bullet Pull

[antelopedundee]

Being a fan of the 6.5 caliber, I was somewhat curious about the 6.5-270WSM cartridge so I did a bit of internet searching. I came across a discussion of it, the 6.5-06 and the 270WSM. This was on the savageshooters.com website message boards. A poster was looking to build a 270WSM or 6.5-06.

As a recommendation for the 6.5-06 one poster made the following statement since cases for the 6.5-06 are easiest to make from .25-06 cases. The post is about 6 years old.

"It would be nearly the same for the 6.5-06. I would choose to neck up 25-06 brass instead of necking down other brass. Just run it into the 6.5-06 die and your done forming. Necking up brass is an easier step than necking down. Check the length and you're good to go."

So how on earth do you neck up a smaller case by running it up into a larger die? The proper way to expand the neck would be to use a carbide mandrel and you'd probably want that in a .270 size die.

Why not simply seat the 6.5 bullet in the .25-06 case without doing anything else. If a boattail bullet is used there should be little chance of squishing the neck or collapsing the shoulder. So would seating a bullet like that result in too much neck tension? Is it possible to have such a thing as too much neck tension? I've never had any issues with seating 6.5 bullets in .25-06 cases.

Another approach would be to use once-fired .25-06 cases since the neck on those would be a bit larger than on new brass, but likely not require any additional tinkering. If one used .270 cases, they'd need to be trimmed about .050 and sized in the 6.5-06 FL die.

 

[jackie schmidt]

Being a fan of the 6.5 caliber, I was somewhat curious about the 6.5-270WSM cartridge so I did a bit of internet searching. I came across a discussion of it, the 6.5-06 and the 270WSM. This was on the savageshooters.com website message boards. A poster was looking to build a 270WSM or 6.5-06.

As a recommendation for the 6.5-06 one poster made the following statement since cases for the 6.5-06 are easiest to make from .25-06 cases. The post is about 6 years old.

"It would be nearly the same for the 6.5-06. I would choose to neck up 25-06 brass instead of necking down other brass. Just run it into the 6.5-06 die and your done forming. Necking up brass is an easier step than necking down. Check the length and you're good to go."

So how on earth do you neck up a smaller case by running it up into a larger die? The proper way to expand the neck would be to use a carbide mandrel and you'd probably want that in a .270 size die.

Why not simply seat the 6.5 bullet in the .25-06 case without doing anything else. If a boattail bullet is used there should be little chance of squishing the neck or collapsing the shoulder. So would seating a bullet like that result in too much neck tension? Is it possible to have such a thing as too much neck tension? I've never had any issues with seating 6.5 bullets in .25-06 cases.

Another approach would be to use once-fired .25-06 cases since the neck on those would be a bit larger than on new brass, but likely not require any additional tinkering. If one used .270 cases, they'd need to be trimmed about .050 and sized in the 6.5-06 FL die.

Perhaps he was thinking of a die with an expander ball.

As for just cramming a 6.5 boat ail into a 26-06, If you can get it to chamber and fire, what will come out is a good straight 6.5 '06 case.

 

[antelopedundee]

Perhaps he was thinking of a die with an expander ball.

As for just cramming a 6.5 boat ail into a 26-06, If you can get it to chamber and fire, what will come out is a good straight 6.5 '06 case.

You'd first see if the .25-06 case will chamber as is with no issues. New brass should be of minimum size I'd think. One can also get tapered or football shaped expander balls so you just want to run it up into the die enough to expand the neck and no further. No point to running an expanded neck back into the sizing die since it will just size it back down and you'll have to re-expand the neck on the downstroke.

 

[243winxb]

http://benchrest.com/showthread.php?98706-Neck-Tension

See chart Post 6

 

[antelopedundee]

http://benchrest.com/showthread.php?98706-Neck-Tension

See chart Post 6

I would think that as far as powder burning it would be desirable to hold the bullet as long as possible before it starts on its way down the barrel. Also this would be a factory neck/chamber situation unless there was some sort of special order chamber in which case the necks would likely need turning at some point before loading. The final loaded round would have the same neck diameter regardless if you did one step or two steps to get there. I suppose if one was worried about it, one could put a LIGHT coating of resizing wax on the bullet before seating it. The good thing is that he'll only need to do it just the one time.

I've got a 6.5-06 on the way, but I've already made my cases for it from .270 Win brass; a simple matter to trim the cases 0.050. I just necked it down in a 6.5-06 sizing die with no expander. I might run a couple cases up into a .25-06 die with no expander just to see what happens.

For chits n giggles, I had some once-fired .270 cases already trimmed and sized and ready to load. I ran a couple up into a .25-06 die sans expander. Using my Redding seat die I proceeded to try to seat 2 bullets. One was from a box of 120 grain Sierra Pro Hunter with a flat base. It seated ok, but the bullet ended up stuck in the seater plug. For the other I used a Sierra 140 grain match bullet which seated ok too. It only took a couple of light taps with a RCBS kinetic puller to pull the match bullet so the neck tension wasn't all that great.

In the pics, the match bullet is on the bottom or right.