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Proper necking up procedure.

wpafh1

Private
Minuteman
Oct 8, 2009
12
0
49
Maine, United States
I am going to neck up Win. 243 brass to .260. I have read that you need to expand the neck and then cut it to remove donut. I am sure this is in another post but I am having a hard time to find it. I would apreciate any help.

NM
 
Re: Proper necking up procedure.

I think you'll find it easier and less work to neck down 7-08
 
Re: Proper necking up procedure.

for me I would just lube them up in/out and run them through a full length die.then remove the lube and load them up and shoot.after shooting them for the first time the necks will fire form to your chamber.then they will be straight.its not like you are resizeing a 243 to a 308.your just opening up the neck .5mm more.but there is one thing to keep in mind.do not forget to alter the head stamp.would hate to shoot one in a 243 after loaded for a 260.that is if they will chamber.would think it wouldn't.but might if the chamber is a loose chamber.but hey this is just what I would do.
 
Re: Proper necking up procedure.

I go from .2240" to .2430" (22-250 brass necked up to 6mm) with a dry Redding tapered expander button on a new dry case. Just adjust the die so that only the expander button touches the case not any other part of the die. Prime and shoot after that.

I go up 19 thou, you up 21 thou, I think you will be just fine. If it makes you feel better drag every 5th case mouth across your lube pad to keep the expander lubed then tumble them before loading.
 
Re: Proper necking up procedure.

saint clairs international has a neck sizer from 243 to 260 then fl resize and your done did it two years ago on some lapua brass slick as snake sh--!the resizer has different mandrels that go in the die.
 
Re: Proper necking up procedure.

5r mil yes it will go!243 in a 260 and it will go bang!but nothing like dropping a 308 in a 300rsaum that makes one hell of a mess of the but plate and trigger guard. Did it not paying attention at the firing range,got disstracted by someone talking to me and didnt remove my 08 ammo from the bench,sure as hell woke me up!!
 
Re: Proper necking up procedure.

I was under the impression that I would need to do some neck turning. Is that not necessary for my intentions? Thanks for the input guys.
 
Re: Proper necking up procedure.

When going from the smaller caliber up it will thin the neck some. Yes different brass will have different neck thickness but you shouldn't have to turn. You might if you go down from 7mm but still shouldn't be enough to make you turn them in order for them to chamber. But does depend on how tight the chamber is in the first place. Neck turning will of course help some but if you not looking for extreme accuracy don worry about it. If you are close then i would just use a inside neck reamer to take a small amount out.
 
Re: Proper necking up procedure.

Thanks NotAGuru. I think I will just neck up and see if they chamber ok then I'll prep and load up to fire form. Thanks again.
 
Re: Proper necking up procedure.

If you neck down the donut will be on the inside the neck, if you expand up it will be on the outside the neck. In either case a K&M tool with carbide pilot will handle both.
 
Re: Proper necking up procedure.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: B y r o n</div><div class="ubbcode-body">If you neck down the donut will be on the inside the neck, if you expand up it will be on the outside the neck. In either case a K&M tool with carbide pilot will handle both. </div></div>

Yes you have a better chance of getting donuts when you neck down. Its not something that happens all the time there is alot of variables that can make them happen. After the first firing if you use a inside neck reamer like i said in my earlier post after resizing there is no chance that you will get donuts in the necks of the case. Sometimes it takes a couple of tries after they are formed and run through the die but they will go away. If you want to avoid them then what you do is turn 7mm-08 brass down just past where the new shoulder intersection is and then neck down. I have never had and donuts when i do it this way. Also a false shoulder is a great way of firing forming over pushing bullets into the lands or using that crap corn meal....