F/L size case to bump shoulder .001 or just resize neck?

[BaconFat]

For my Cooper M38 in 20VT, I'm getting ready to reload some Nosler brass after its initial firing. I chambered a random selection of empty cases and they all chambered easily with a fairly light bolt closure. Using my Hornady headspace gauge, these once fired cases are .001" longer than another group of unfired, loaded cases. Since the only way to bump the shoulder back is to use my Redding F/L die, should I bump the shoulder back or use my neck sizing die and just resize the neck? If I should bump the shoulders back, is .001" enough?

Most of my reloading experience is from reloading my .308. In that situation I always bump the shoulder back .002", but I also use a Forster neck bushing, shoulder bump die. I never F/L size my brass after the initial sizing.

 

[varmintshooter]

I would neck size only as they already fit your chamber. I fl size because I have 2 vartargs and I don't keep rounds separate.

 

[Preacher]

FL sizing is always your best bet for consistent accuracy....
Set the FL die up so you have that same feel your getting with the once fired cases in the chamber...
No need to go more than that..

 

[artbosco]

Always, always, always F/L size with a F/L Bushing Die.

 

[BaconFat]

Always, always, always F/L size with a F/L Bushing Die.

Why? All the information I have read and the advice I've been given for my .308 was to not F/L size every time. The thought process was that the case body was being overworked and would harden the brass which would lead to premature failure. I just want to develop good, sound skills when it comes to reloading.

 

[TAJ45]

^^^^^^^ +1. But will listen to correct any misinformation I have accumulated.

 

[pacificman]

Always, always, always F/L size with a F/L Bushing Die.

Why? All the information I have read and the advice I've been given for my .308 was to not F/L size every time. The thought process was that the case body was being overworked and would harden the brass which would lead to premature failure. I just want to develop good, sound skills when it comes to reloading.

That's why I "partial full length size" ...I set my Full length dies up so that the neck and most of the case is sized to fit chamber every time. This way your brass is not overworked. I have found that by neck sizing only...you will eventually have to full length size and set the shoulder back anyway so by setting my dies up to partial size I always have the brass fit in the chamber just right.

 

[BoydAllen]

The key to understanding the issues involved is the fit between the die and the chamber. Bolt action match rifles generally have custom chambers and well matched FL dies, that do not work fired brass any more than is necessary to create minimum clearance. In those situations, FL sizing every time does not over work brass. On the other hand, if your die reduces the diameter of the body of fired cases quite a bit, then you may have issues that result from sizing every time.

On the bumping thing, I never bump back shoulders of once fired brass, when I FL size it. This is because bumping should be from the shoulder to head (actually datum to head) dimension of a deprimed case that has reached its largest dimension from several firings, neck sizing only. It takes several firings for this dimension to reach its maximum. Once you have a case that has reached that dimension (for your particular rifle) you can use its datum to head dimension as a reference to come up with what a .001 or .002 bump should measure. I always have had good luck setting fl dies to give me the exact dimension of a fired case, if the brass is once fired. The bolt closes easily, because there is clearance at the sholder, and the diameter of the body has been reduced. If you bump more than needed, for cases that have factory style shoulders, you are likely to get a bright ring that indicates an incipient separation quite early in the life of your brass. Bumping is to create a little clearance, and if you already have some, it can be counterproductive to increase it.

 

[222 rem]

FL sizing with the should set back .001 to ,002.
If you are overworking the brass you most likely have a factory chamber.

 

[bheadboy]

as Boyd has indicated, I do the following,

with a fl die, I adjust it for the fired case to just touch the shoulder, moving at most .002, and not a complete full length body size.

this way the case chambers as a fired case with a very very slight "feel" on bolt close.

Bob

 

[BaconFat]

Well, because I processed the first 100 cases before I read Boyd's reply, I bumped the shoulders .0015". Thank you Boyd for taking your time to explain what I needed to know. I also appreciate the suggestions made by the others. Now if I can just get my gray matter to assimilate what everyone has said.

Learning never stops but it sure takes longer to absorb it when you get older. ???

 

[LHSmith]

Don't get hung up on the idea that setting back shoulders .001" is necessary for optimum accuracy. Some accomplished BR competitors set them back .002" because it offers less resistance operating the bolt. Unless you anneal often, or use light loads, you will find that individual cases will spring-back at different rates even though they see the same number of firings with the same loads. Setting back a tad more will help minimize disturbing the bags.

 

[BoydAllen]

In benchrest, the match between dies and chambers can sometimes be too close, such that not enough sizing is done to the body of the case, reducing its diameter, to create the needed clearance. Because of the taper of the case body and die, slightly increasing shoulder bump increases the sizing of the diameter of the case body. Also, there can be issues with variation in shoulder bump at the same die setting. In that situation, one needs to set the die to produce the minimum bump on the hardest case in the set. I have not found this to be a problem with my PPC cases, but I have seen it working with magnum brass that has thicker shoulders. We annealed to deal with the problem, and it worked very well, but we found that in order to keep our results, that we needed to anneal fairly often.

 

[bow shot]

+1 on Boyd's and LH's posts. Learned that the looong, sloooow, painful way, LOL!!