OzFclass

Hi
I am hoping someone can tell me if this is a normal effect or something I need to look into.

The issue I feel I am having is when I seat my 223 Nosler 80grain projectiles I can fell different tension on my arbor press.
I use a Wilson neck die and have neck turned my lapua cases. They have now been fired 5 times.
I seem to be shooting well and holding OK waterline just looking to see if this is normal or not.
Any comment would be great.
Thanks
Pete

pete,
there are several things that affect bullet seating pressure.
for want of a better term we will call this neck tension.
if the inside diameters of your sized necks, which are all of the same thickness, and have the same annealing temper, and have the same coefficient of friction, are the same, your bullets will probably seat similarly, and hopefully release similarly when you put fire in the hole.
the above things are in your control.
a thing not in your control is any actual variance in the metallurgy of the brass.
how much this matters is open to experiment.
keep safe,
bruce moulds.

Pete,
It could be dirty necks. A little unevenness in the remaining carbon residue on the inside of the necks can cause what you are experiencing. Try brushing the necks out with a bristle brush of the right calibre size. If needed you could also get some dry lube to push the neck of the case into to allow smooth seating of the bullets.

Ian

Thanks Bruce and Ian,

Ian I should have mention the cases are cleaned using a ultrasonic cleaner every time I start the re-loading process so my cases are nice and clean inside and outside.
I suspect it might be down to the metallurgy of brass as I have done everything I can control with neck thickness and same re size.

Pete

Pete If you have fired those Lapua cases 5 times the neck tensions will be starting to vary. They will benefit from being annealed to get them all even again. Excessive working of the brass by using too small a sizing bush and then expanding makes the problem show up much sooner. Sizing the necks down just enough to get your required neck tension is the way to go. I like to have the sized case around 222.5 or 223 inside diameter for best results. After three or four firings you will feel differences in the neck tensions which will start to cause groups to open up a little. The neck tension problem is not just with the 223, it happens with most cases, but the 223 needs neck tensions to be all even for best results especially at the longer ranges.
Regards Malcolm.

Hi Malcolm,

My neck tension is probably just a little tighter than yours.
Annealing looks like a black science and you need a special setup to do this.
Is this really worth the effort and money or just get new cases when the problem starts to occur and the group opens up.

Thanks for the comment and reading on case annealing was a bit of a eye opener.

Thanks
Pete

Before we all get carried away with neck tensions, I would suggest that some tests be done. With todays' modern seating dies with interchangeable neck bushing it becomes very simple to vary neck tension from " loose " to very tight.
Try it and document your results - might not be what you think.

Most likely you need to anneal your brass. If your really concerned you can get a force gauge for your press and track changes more accurately.

I'd check for a "donut" before I did anything else, with the 223's short neck and some reamers short throat it's not uncommon with the 80 grain and short neck combo.
Matt P

Hi Dave and Matt,

Thanks for the comments.
Dave I am looking into developing a annealing tool after stacks of research on the net.

Matt i have already checked this as other people in the club where getting this issue.
Mine are all good as I have a long throat to suit the 80 gainers.

Once I get the anneal tool working I will post the update on the neck tension.
May take some time to build and setup but will be interesting doing it.

Pete

hi pete, firstly hope you dont mind a lurker from the 'light' side,but i will have my two bobs worth. i take my shells straight out of the tumbler wipe the outside over and load them up.the small amount of tumbler media that lines the inside of the neck is just enough to provide a smooth entry for the bullet. i dont like having the inside of the necks too clean,benchrest articles confirm this. also try a bigger bushing lighter neck tension will always give you a more consitant feel.

Let's not forget that differential seating pressure does not necessarily equate with neck tension. Therefore measuring seating pressure may not be meaningful. I recall once being directed to a net site showing a rig that a shooter built to test the effort required to remove a projectile seated in a case. That might be a more useful tool.

In any case, I prepare the necks of my .308 & .223 cases with Lee collet dies. I've been convinced that they set the case neck up with minimum runout & with a more uniform tension case to case than can be achieved by arbitrarily selecting a bushing.

I moly nearly all projectiles nowadays, but when I occasionally don't, the unevenness of seating effort is noticeable.

Alan

Hi Budget,
No problems with your comment but I do something similar to you. I have the neck lube from rcbs that has the little balls covered in some dry lubricant. I use then when neck sizing so this would also be in the inside of my neck. So I do not feel the lack of lubricant is causing this issue.

All comments are read and I consider all but try only what I fell is practical.

The annealer is now underway so keen to see if that has any benefit when I get it finished.

Pete