Neck sizing... Quick question...

[oneshot onekill]

I'm neck sizing some FGMM brass that has been fired once in my HS Precision RDR. I made the length of the brass 2.015" after neck sizing it. When I close the bolt on the brass it's a little tight. Is that normal? Thanks in advance!

John

 

[ChrisGarrett]

Re: Neck sizing... Quick question...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">I'm neck sizing some FGMM brass that has been fired once in my HS Precision RDR. I made the length of the brass 2.015" after neck sizing it. When I close the bolt on the brass it's a little tight. Is that normal? Thanks in advance!

John </div></div>

2.015" is at the MAX recommended case length, so without knowing your chamber length, I'd cut them back to 2.005"-2.010" to be safe.

You probably need to bump your shoulders back a bit more, if they chamber tightly with the cases trimmed to <2.015".

Chris

 

[oneshot onekill]

Re: Neck sizing... Quick question...

Ok... I cut one back to 2.010" and no difference. Since the rounds were fired in this rifle I was under the impression they were "fire-formed" to that chamber and all I would need to do is trim them a little if they were stretched a little long by firing and/or neck sizing. I shouldn't need to, nor is there any way to, bump the shoulders... Right?

 

[ChrisGarrett]

Re: Neck sizing... Quick question...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">Ok... I cut one back to 2.010" and no difference. Since the rounds were fired in this rifle I was under the impression they were "fire-formed" to that chamber and all I would need to do is trim them a little if they were stretched a little long by firing and/or neck sizing. I shouldn't need to, nor is there any way to, bump the shoulders... Right? </div></div>

Generally, one might be able to get away with two or three cycles without having to bump the shoulders back, but eventually brass will not spring back after it expands and you'll need to FL size the shoulders back down, or use a body die which does the same thing relative to the shoulder, but leaves the neck untouched. You can then bushing size the neck for proper neck tension.

If you can chamber the round with just a little effort, meaning the case is snug in the chamber when the bolt is closed, this is fine. You might want to test all of those trimmed cases, out, just to be sure.

It's when you have to use a good deal of effort to close the bolt, or can't close the bolt at all, that you need a shoulder bump.

Snug fitting cartridges in a chamber are a good thing, as Martha would say! Not being able to close your bolt, isn't.

Good luck, Chris

 

[mdmp5]

Re: Neck sizing... Quick question...

sticky bolt is mostly due to the body and shoulder, not the brass length. My factory chamber can accommodate brass as long as 2.04" or so. Most factory chambers will do the same.

 

[sst04]

Re: Neck sizing... Quick question...

Sorry to hijack the thread,, but could someone explane 'bumping' the sholder for me.. Using a Redding neck die I had a few rounds that I neck sized and the bolt would not close on them.

 

[ChrisGarrett]

Re: Neck sizing... Quick question...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sst04</div><div class="ubbcode-body">Sorry to hijack the thread,, but could someone explane 'bumping' the sholder for me.. Using a Redding neck die I had a few rounds that I neck sized and the bolt would not close on them. </div></div>

Neck dies, whether they be bushing dies (little donuts at specific diameters) or standard neck sizers, don't touch the shoulder, or body area of a cartridge case. They ONLY squeeze the necks down enough to grip the bullet.

If you're only neck sizing, brass will after a number of firings, not shrink back down to normal size, which it will do when it's new and fresh. The more brass is physically moved, the harder it gets. This will cause chambering issues.

These issues might manifest themselves in a) resistance when closing the bolt, b) a lot of resistance when closing the bolt, or c) NOT being able to close the bolt on a loaded round.

In gas guns, you might have 'out of battery' issues, which will ruin your whole day.

Bumping the shoulder back is what a Full Length Sizing die does (along with squeezing the neck back down) and you kill two birds with one stone.

For those of us who don't want to bump the shoulder back after every cycle, we'll opt for NECK sizing only, but eventually, we'll want to bump that shoulder and we can either use the FL sizing die, or a body die, which only touches the shoulder.

In this regard, we're wanting to size the necks in certain amounts (bushings), to create neck tension of a specific amount. You...we, can measure this. A softer grip on the bullet is thought to be more accurate down the road and typical FL sizing dies err on the side of caution and place more grip/neck tension on the bullet, as is necessary. Liability issues, of course.

Chris

 

[oneshot onekill]

Re: Neck sizing... Quick question...

I think the issue is the brass itself. I've only recently started reloading and until now I've only used Lake City Match brass. It's thick... really thick, and I think the FGMM brass just expands more and maybe becomes more snug than the LC brass. It appears, after I extract the brass I just neck sized, that the marks on the shiney, tumbled brass are, in fact on the shoulders and main body of the brass.

 

[mdmp5]

Re: Neck sizing... Quick question...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">Ok... I cut one back to 2.010" and no difference. Since the rounds were fired in this rifle I was under the impression they were "fire-formed" to that chamber and all I would need to do is trim them a little if they were stretched a little long by firing and/or neck sizing. I shouldn't need to, nor is there any way to, bump the shoulders... Right?</div></div>

Neck sizing doesn't stretch the brass length bro, only FL sizing does that. Fire forming doesn't lengthen the case either, it pushes the shoulder forward. The cases can only lengthen when you FL size them. Kind of like squishing toothpaste upwards. You don't need to trim your brass as often as you may think. Let it grow a bit. To be certain of your chamber dimensions, sinclair sells a wad that you stick in a trimmed case. As I said earlier, my SPR chamber (308) will accommodate brass up to 2.04" in length, so I am never in any hurry to trim. If I do trim, I only trim the longer cases down to about 2.015" so that I get uniformity in the entire batch of brass. My current batch of 200 lapua cases varies from about 2.005" to 2.020".

 

[mdmp5]

Re: Neck sizing... Quick question...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">I think the issue is the brass itself. I've only recently started reloading and until now I've only used Lake City Match brass. It's thick... really thick, and I think the FGMM brass just expands more and maybe becomes more snug than the LC brass. It appears, after I extract the brass I just neck sized, that the marks on the shiney, tumbled brass are, in fact on the shoulders and main body of the brass. </div></div>

Federal brass is a bit on the malleable side, so your observation may be correct. But you need to get yourself a FL bushing die, or a body die if that is your preference. I FL size my brass every time bumping the shoulder minimally, after passing it thru a neck die with a larger bushing first. With this method of sizing, I get about 0.001" of runout on avg.

 

[Nessal]

Re: Neck sizing... Quick question...

Generally chamber length is pretty big. I borrowed a case length gage from another member here and my krieger barrel measured at 2.038". That means that the book length of 2.015 is pretty conservative. I don't have to trim until it approaches around 2.025" which gives me ample room still. A factory barrel may even be longer. My brass never gets anywhere near that length anyways as I fire form them and only neck size. Actually my Win brass came new at 2.005-2.010" so I just trimmed them all down to 2.005 for consistency.

When I get rounds that are hard to chamber, I just full length size them and they should chamber fine.

 

[Fuzzball]

Re: Neck sizing... Quick question...

"Ok... I cut one back to 2.010" and no difference."

That's becasue case length is rarely the cause of such problems, mostly it just indicates a need to set the shoulder back 3-4 thou. Either a body or FL die properly adjusted will do it nicely. (Neck sizing is not the cure-all for anything that many say it is.)

 

[oneshot onekill]

Re: Neck sizing... Quick question...

Great info from all! Thanks guys! I think my brass is OK the way it is for this next firing. Then I'll probably bump the shoulders back a little with a FL sizer. The main reason I even had a concern is because the rifle is an HS Precision RDR and they claim a "tight" chamber which left me wondering what that means. I assumed it meant the diameter only but you know what happens when we assume... I didn't want to make my brass 2.015" only to find that the term "tight" means it's 2.010" (which is what the Factory loaded FGMM brass measured). I'm not familiar enough with the physics involved to know the neck will not stretch much when fired.