Home Forums Reloading Big Game Rifles got the Lee Neck sizer nd a question

I just the Lee Neck sizer dies and am going to follow mathman's instructions.
First off all of my cases have been sized with the RCBS dies and yeah the mandrels have ben pulled through from the RCBS concentrity gauge. The case neck appear to have runout of .002 - .003.
I will be trimmimg them and testing the run out of the cases.
My question is if I use the Lee neck sizers and since the neck is pressed against the mandrel the necks will get a little longer. Do I need to trim to the minimum length again?
Second question is if my case has run out of .002 or less I can use the Lee neck sizer to get straighter cases. What about cases that have more run outs? Do I just discard these cases?

The obvious question here I am asking is this is what I have so I am on the journey to see if I can get straighter neck but throwing away cases that are bad...no way to fix this right?
I will be trying first the 308 or 243 and see how it goes but I also got a few others. Its too bad all of my cases were run through the rcbs sizer dies where the mandrel is pulled through the necks!

Thanks.

You likely won’t have to trim your brass, but it’s up to you. Personally, I’d measure length of several after sizing to see how much variation you have and make a decision based on that.

Before chunking them, I’d want to fire them in my rifle, resize using your new method, then check runout before deciding.

Just my preferences. YMMV.

Its pretty rare for me to see case runout over 0.002” using Lee neck dies or Forster/Redding bushing dies.

.002 RO ain’t bad. Generally, in a factory chamber or even a custom bbl for hunting, there is a threshold where less RO doesn’t make the ammo more accurate. As a general rule, in a factory bbl, .001 neck runout won’t be more accurate than .002 RO for most hunting bullets.

If the seater induces more bullet RO, than striving for lower neck RO may be worth it.

What cartridge and brass are you playing with?

Also, I would check case length of your brass if you FL sized or PFL sized.

Pull your expander out of your sizer and run the brass through the FL sizer. That will eliminate the runout. Then put the expander back in the die and run the brass in just until you expand the neck but no more. That should give you straight brass and you can use the LCD next time.

^^This^^

Yep, don't use the Lee collet die after the necks have been processed by other means.

Thanks Mathman. I will just shoot what I already processed and see how it goes.

I found some FC brass for a 243 and also a 223 Win so these will get worked on with this neck sizer. I am going to do what Blacktailer says, pull the expander out of your sizer and run the brass through the FL sizer for these two. The rest were done with the expander in the sizer so these will get shot up and then on to the neck sizer.

These rifles are my son's rifle and he's in college now but will come home in a couple months so I will play with them to see how the neck sizer does. And by the way I last went to the range a couple weeks ago and it was hot as hell so I was not able to shoot up all of the loaded ammo I have, thus some left.

One thing I noted that I did the 243 with Sierra 85gr HPBK with H4831 (I used this because I do not have anything besides the 270 to us this with) and the accuracy was not that good. Tried the IMR4350 and accuracy seems to be a little better but I see some reference using W760 so may try that and see with these new FC cases and Neck sizing.

Previously someone mention the Norma 308Win ammo box with 150SP bullets. These did not do too good too but at least I got some brass lol.

Again working these rifles trying to find a load for this but primarily learning the neck sizers with these.

Thanks for contributing folks.

BTW Mathman has said sometimes Lee QC is not that great and that the mandel gets out that is not sized right? How small should a neck be for say a 308 bullet or a 243 bullet? Do you guys even check the Lee mandrel for proper size before commencing? Obviously this has to be size just right to hold a bullet...

The mandrel size on the LCD is only one of the determining factors. Spring back comes into play so how many times the brass has been resized or to put it another way, how many times it has been resized since annealing makes some difference. I don't know if there is a rule of thumb for how undersized the necks need to be but IME .002-.004 inch seems to give adequate neck tension. Maybe some of the target shooters can give a more precise answer.

I just want to update what happened with my neck sizer for the 243's.
For the 85g HPBT Sierra loads I used FC brass and Fed 210M, H4831 (43.0 - 46.0) and the 43.0/44.0 loads shot the best. However in this case when I lift the bolt...the initial life was easy but going to the top it appears to get harder or its binding. This is the M700 SPS newer version with SN RR...this looks to be a brass to me but the first time I did the Lee neck sizer and was annealed and OAL = 2.650

Second load was85g HPBT Sierra with Brass = RP, 9 1/2 primers, IMR4350 (41.5 - 43.5) and all gave good accuracies but the 42.5 gave me .900". This is with OAL at 2.650 It appears this load did not give hard bolt lift but I will have to try again by adjusting the OAL and see how it does.

I did the same thing with the FC brass, Fed210M and Sierra 85g with W760 (42.0 - 45.0), OAL = 2.650 and I experience the same bolt life issue. At first it felt ok but getting near the top it was harder.

To me it is either the FC brass...unknown how many times I shot this brass but it was annealed and fill size and then Lee neck size. I am not sure if I am doing the neck sizing correctly but will try again but this time with the RP brass.

BTW I used the H4831 and IMR4350 because these are usually used with the LA cases but have not shot this since the pandemic begun so I decided to use these and see how they did.

As you can tell I am still learning how to do these neck sizing. It looks easy enough but the neck OD is very very hard to see...but I think the worse case the neck has to help some.
And no I do not have a before neck sizer and after neck sizer done to verify...

Blacktailer...at lease the mandrel for the Lee neck sizer 243 is a little smaller such that the bullet does not move if I have a full diameter in the neck so this appears to be ok.

I have some now loaded up with the same components, IMR4350 and the 85g adjust for a little less/more and see if it helps. (also trying the NBT 95gr as well)...now for this rain to stop so I can go to the range lol.

Sounds to me like the brass was fired in a looser chamber at some point, and the base of the cases is a little over-diameter. A small-base die should fix the issue. Or you could try some other cases.

This^^
Or the shoulder hasn’t been bumped back enough.