Question about Neck Sizing only and trimming

[radmacks]

So I have a Lee Collet Neck sizing die for .308. I plan to once fire in my rifle and then neck size only. Range brass would be full re sized trimmed and then fired. My question is, should I trim my fired only in my rifle neck sized only brass to sami oal spec? Or once its fired and sized to my chamber is it good to neck size de-prime tumble/clean, prime, powder and bullet seat?

I'm still fairly new to rifle reloading. I have read all the books and watched every video I can and the majority of info deals with full length re sizing. I understand to fire in another chamber the full length re-size and trim is necessary.

 

[thump_rrr]

After you size you must ensure that it is not longer than SAAMI spec regardless if it is neck sized or full length sized

If the brass is too long it can "pinch" the bullet leading to an over pressure situation.

 

[TargetAcquired]

Lots of variables. I went through all this extensively with .303b. I was getting separations and other nasty problems. I eventually started marrying brass to rifle and the ship righted itself. I was still measuring and trimming on neck sized brass, but after I honed in on a few loads I like I was finding there was nothing to trim. If I get my hands on a new pill or experiment with a different power or feel like hurting myself with a hotter recipe, I will still only neck size, but get back into measuring and trimming, as I do find that the differences in load treats the brass differently.

All in, just develop good habits and the rest should fall in place.

 

[Canadian_Zuk]

I would trim all the 1F brass the first time just to have a uniform batch to start with. wheter or not it's required kinda depends on if your crimping and what your crimping with. You most likely will never need to trim your brass again if you keep neck sizing only. Brass grows longer with fewer firings if you full length size every time.

 

[bsand]

Lots of variables. I went through all this extensively with .303b. I was getting separations and other nasty problems. I eventually started marrying brass to rifle and the ship righted itself. I was still measuring and trimming on neck sized brass, but after I honed in on a few loads I like I was finding there was nothing to trim. If I get my hands on a new pill or experiment with a different power or feel like hurting myself with a hotter recipe, I will still only neck size, but get back into measuring and trimming, as I do find that the differences in load treats the brass differently.

All in, just develop good habits and the rest should fall in place.

That's what I was doing, I finally FL sized and measured cases. They were about 5-10 thou over max OAL neck sizing 308 win lapua brass. This was over 2 annealing and maybe 10 reloads? I'm going to start checking every 2-3 loadings and trim sooner, cause going from 2.022 to 2.005 takes a lot of time!

 

[supernova]

Neck sized brass, especially in a die that works the brass very little, will hardly stretch at all. I keep an eye on them and only bother trimming when necessary. FL sized brass will stretch alot more.