Neck sizing with a F/L die

[angus-5024]

Can I neck size with a F/L Die? Do I simply back the die off so it no longer touches the shoulder? Or do I have to put up the extra $80 for a neck sizing die? thanks for the help in advanced, maybe its a stupid question.

 

[Limbic]

First I raise the ram. Then i screw my RCBS FL die down till it touches the ram. Then back it out a 1.5-2 turns. I measure headspace with the RCBS precision mic. FL size the brass. Remeasure. I usually try and bump the shoulder back .002. If the shoulder gets squeezed back too much then I back out the RCBS die and keep trying. It make take a few pieces of fired brass to get it just right.

I don't know how to do it without the precision mic.

This is also not considered neck sizing but partial FL resizing. I don't know how to just size the neck.

Why am I even answering this post.

 

[boomtube]

Maybe. Sometimes anyway. Depends a whole lot on 1) how you do it, 2) the case shape and 3) the actual dimensions of your die. If you die contacts any portion of the case so it changes it, you ain't neck sizing, you are only partial FL sizing.

1) There is no point in neck sizing below the base of a seated bullet.

2) You can easily neck size a steeply tapered case such as a 30-30 or .303 with a FL die. Not nearly so easy with a nearly straight case such as the WSM types.

3) If your chamber is on the small size of tolerance and your die is on the large size you might get away with it. Experiment to see how far down you will need to set the die to reach the bullet base. Then take another case, paint the whole body with a felt tip pin and try sizing, you won't need any body lube if it works. Run the case up the die until it gets tight, pull it out and check the body for ink reemoval. If the ink is scuffed off the body, stop and forget it. If not, figger the resistance is the neck. Repeat, push it further and remove again to check for rubbing again (don't want to stick the case, do we!).

If you can get the neck sized as far down as needed without rubbing the ink off the body, you are home free.

 

[angus-5024]

I guess if I explain what my curcumstances are, someone can probably help me more effectively. I have a .338 RUM, havent shot it yet. But when I was reloading for my .340 Wby I wasnt getting more than 4-5 firings. I think that this was from F/L sizing each time. So my thoughts were, only size the neck and I'll get better life due to less brass streching and I may get more capacity/ accuracy because the brass would be formed to my chamber already. Will a partial F/L size give me what I want or is that not goin to help with the case life issue because I'm still bumping the shoulder back? once again sorry if these are stupid questions.

Jordan

 

[Limbic]

Why were you only getting 4-5 firings? Where was the brass failing? I shoot a 7mm mag mostly. I have to partial full length resize everytime or the brass won't fit in the chamber. It was worse on my factory tube than on my Shilien. I get 10+ firings. I usually pitch them after that. I havent started annealing. Yet.
I spoke with a guy from sinclairs and he uses the brass (300 wsm I think) five times. After that they go to a secondary box for plinking, foil a barrel ect.

 

[D.Camilleri]

I just bought a neck sizing die for my 338 rum and it was only about 30.00 If you shoot full power loads, don't expect a lot of loadings from the rum. Primer pockets usually start to loosen up. there is a tool however to tighten up primer pockets that seems to work well.

 

[angus-5024]

Im not sure why the brass were failing. They were cracking in the neck, on the shoulder, and occasionally right on the body. some of this brass was "once fired", but who knows. I had some new stuff do it too.
As far as die prices go, I'm in Canada so everything is more expensive. I think the Redding neck die is 69.99 + 12.5% tax (mind you I didnt shop around). Not only is it expensive but it usually takes awhile to get in.

 

[Katbird]

There are no dumb questions. They keep us from actually doing dumb things.

You can't neck size with a full length sizing die without also partially resizing the case, but you can size the case less by backing out the die until only about 3/4 of the neck is sized.

Screw your full length sizing die into the press and back it off one and a half turns. Mark a case with a magic marker from the case mouth down past the shoulder and run the case into the die. Look at the case. More than likely, you will see that the shoulder has also been in contact with the die, squeezing the case down a little smaller at the shoulder. This pushes the excess brass up the case where the datum line of the case contacts the corresponding datum line on the chamber. This is where you need to be setting your shoulder back about .0015" to ensure easy chambering. Play around with your die until you only size about 3/4 of the neck. If you can leave a small portion of the neck unsized, the unsized portion of the case centers in the chamber. You also size the case less than you would if you set up your die to size the entire neck.

If this works, you are in great shape. Your best bet is to use a body die and a Lee collet neck sizer.

 

[angus-5024]

Thanks, that was a very helpful response. I will get a neck sizing die when I have $$, but partial F/L resize will work for now.

 

[RUMt]

I partial full resizing my 300, 338 & 375 RUMS. I just back my RCBS full size dies way back, resize and see if the brass easily chambers - I screw it down until it chambers.

3-4 resizes are par for the course with RUMS. This technique will not extend your brass much if any - but it does fit the chamber better.

I read in my sierra manual you can't do with with low taper cartridges like the .243 - so I guess I can't do partial sizing with my .308

 

[MontanaRifleman]

.....3-4 resizes are par for the course with RUMS. This technique will not extend your brass much if any - but it does fit the chamber better.

You are only getting 4-5 firings our of your RUM brass?

 

[Katbird]

I forgot to mention that partial full length resizing can introduce another variable to your load. The further you back the sizing die away from the press, the less the case is supported by the die. You can easily get out-of-concentric loads. You have to start watching more carefully for runout.

 

[LewisH]

Years ago (I mean years ago) I read a very comprehensive article by some respected rifleman enumerating the reasons why it is a bad idea to partial size with a FL die; so I've never tried it.

Naturally, I can't remember the specifics, but I think it had to do with introducing unwanted variables between case/chamber fit, as indicated above by Katbird, RUMt.l

 

[boomtube]

A conventional neck die can help prevent body splits but not neck splits. The neck won't care if it's beng worked in a FL or neck die.

Lee's Collet Neck Dies work the necks least of any and tends to produce straigher necks as well; I love them. I do NOT love bushing type neck dies of any kind for use in factory chambers.