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Case Length Gage Issue

2K views 26 replies 10 participants last post by  shootbrownelk 
#1 ·
Tonight I spent a little time cleaning up some brass from last week's shooting with the .243. Since the last time I loaded some up, I bought a Wilson case gage on the high recommendations in this forum, and I was looking forward to optimizing my resizing die adjustment using this simple, but brilliant tool. After sizing and decapping the cases, I carefully wiped off the lubricant and dropped a random sample of cases into the gage.

For those not familiar with these gages, the bore is machined to a precise profile to match the case dimensions, especially the shoulder for bottle-necked rifle cases. On the Head end, two flats are machined, one low and the other high, which precisely match the SAAMI minimum and maximum headspace lengths. On the Neck end, the flats are machined to correspond with the minimum and maximum case length. The tolerance for the head is 0.005", and for the neck, it's 0.010". Ideally, the properly sized case should fall midway between the limits for each end.

After sizing using an RCBS Full Length Resizing die adjusted to contact the shell holder with no gap between them when the ram is fully raised, I tested a sample of the cases and found that every one of them extended very slightly above the maximum head space flat. I haven't tried measuring the excess, but as an eyeball estimate I'd be surprised if it was more than 0.003". I tried lowering the die a bit, to the point that the turret on my press deflects a little at the top of the ram's travel, and this did not change the results. I really didn't expect it to, but I tried it anyway, just because someone here would probably suggest it.

Flipping the gage over, I also measured the neck length using a metal straight edge across the upper flat and found that each of the sample cases had a neck length which fell between the upper and lower limits. That's a pleasant surprise!:)

So, my question/issue is, does the excessive height of the head of the finished cases require correction, or is it just the way my gun likes things, and perfectly safe? I guess that leads to a second question, in that the necks after resizing are still within specs, is there a good reason to trim them? I do use the Lee FCD for crimping, and that tool seems to eliminate a lot of problems with inconsistent neck lengths.

What are your thoughts?
 
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#5 ·
I haven't trimmed them yet,since this is the first time I've used the gage and I wanted to follow the instructions as closely as possible. The gage instructions said to check the base first, then flip the whole thing over to check for neck length. Trimming shouldn't make a difference, since the gage is designed to work off a point on the shoulder, but if the shoulder isn't pressed back enough by resizing, that will certainly give a bad measurement on the neck!
 
#3 ·
What press are you using. Doesn't RCBS instruct you to lower the ram and turn the die in an additional 1/8 of a turn? This could be causing the shoulder to not be bumped back thus creating the protruding case head.
 
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#6 ·
I've got the RCBS turret press, and normal setup calls for turning the die in to contact the shellholder, back off the ram, then add 1/8 turn. I added a little extra, just in case, thinking that when an actual case is in the rig, some additional force might be required to get that last 0.001" pushback on the shoulder. I think tonight when I have more time I'll try running a couple back through the die and see if I can get a 0.001" feeler gauge between the shellholder and the die base. If not, there's no point in adjusting it any further, as nothing is going to make it closer short of grinding a bit off the top of the shellholder. I don't plan to go there.:)
 
#4 ·
I have one of those Wilson case gauges in the mail now and anxiously waiting. It is for .223 so will see what it tells about my sized and trimmed cases. Can't load any now till I find a supply of bullets, most people are out of stock.
 
#7 ·
The way I do it is to measure headspace of a case after firing but before resizing. I then adjust the sizing die to make the headspace .001" less than the fired measurement. For total case length I lock my calipers down at the maximum case length then use it as a trim - no trim gauge.

As a side note I load .223 for two different rifles and the chamber headspace measurement of both is below the SAAMI minimum. The SAAMI minimum is 1.4636" my Remington is 1.461" and the MVP is 1.460".
 
#8 ·
I use the Horandy case gauge and for my bolt guns I use fired cases like Stev34K and set my press to resize .001" under the fired size.
However for general shooting in my semi auto ARs I go 3-4 thousandths under the smallest fired case of all of my ARs to ensure they will cycle well in all of my guns.
 
#9 ·
But Rawrights problem is that even when the die is pressing on the shell holder, his brass is still to long.

I'd use the rifle chamber for a gage and use that Wilson crap for a paper weight.

Rawright,
Does the brass fit your chamber after sizing?
 
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#20 ·
But Rawrights problem is that even when the die is pressing on the shell holder, his brass is still to long.

I'd use the rifle chamber for a gage and use that Wilson crap for a paper weight.

Rawright,
Does the brass fit your chamber after sizing?
Yep, the brass fits great after sizing. And I think I've solved the issue.

I checked the gap between the shellholder and die with the ram fully raised and found that it's significant. The die and shellholder are designed to work together with their surfaces touching, so this is clearly not right. What I see is that, when the case is in the assembly and the ram fully raised, the turret is deflected upward quite a bit. That makes sense, since a cantilevered platform is always going to give a little. In this case it's too much. I readjusted the die to a position somewhat lower than the instructions called for - about 3/8 turn vs the 1/8 recommended - then resized a few cases. The turret still deflects, of course, but not the gap between shellholder and die is much smaller, and every case gages within spec. In fact, there's no visible difference among all of them I did tonight, with the heads sitting in the gage about 0.001" below the top of the upper ledge of the gage.

I think this is about ideal. All of this batch came from two guns - my BLR and my shooting partner's Remington, and both chambers are so close that I couldn't tell which brass came from which gun when I gaged the fired cases before resizing. If I'm only moving the shoulders back a couple of thousandths, that's going to extend the useful life of the brass a bunch! As a bonus, after resizing this time, none of the cases had necks that extended above the upper neck level of the gage, so there's not yet any need to trim them. I think this is going to work out very nicely.:)

The issue of the turret deflecting isn't going to go away, and it's to be expected; that's the way it's designed. It's not a design flaw, just something that needs to be remembered and taken into consideration when setting up the press. I can still recall, as a small boy, poring over Dad's Herter's catalog, drooling over the rifle parts and designing my dream rifle that I'd build one day. Unfortunately, I've outlived Herter's by quite a span, so that's never going to happen. But I can remember reading the ads touting their O-frame press, and especially their claims about the superior stability of their design compared to turrets and C-frame presses. As an engineer, I know that they were entirely correct, but back then I thought they were just bragging. I think one day after I retire, I'll devote some time to designing a press that combines the dimensional stability of an O-frame with the convenience of a C-frame or turret design. It can be done, and I have some ideas about that already. I also think it should be an option to operate the ram from a foot pedal that controls a hydraulic or pneumatic cylinder so that as we get older and have trouble with levers, we won't have to give up our hobby. But it's going to be a while before I have the time or money for the tools to build it, so you'll all have to wait.

In the meantime, I think I've got this one solved - Thanks, everyone!:D
 
#12 ·
Yep, 55gr. boat tail is what I am looking for. Midway, Natches, and others have them listed but there is just one problem and that is in the fine print, "out of stock, no back order" but thanks for the info.
 
#14 ·
Right on Dale. I am still swimming in the shallow end when it comes to loading the .223. They will be fired in friends ARs so will need a crimp or so the book says. My first attempts I didn't have the crimp die properly adjusted and was collapsing the shoulder just a wee bit not allowing for chambering. Think I have that solved but still going slowly thus the case gauge. My last loads were with a Win. 55gr SPBT and 25grs. of Win. 748, case length of 1.75 and a COL of 2.250 at least that is what my log book says. They worked fine if I didn't let a crushed shoulder slip by me.
 
#21 ·
Glad that you got it figured out.

You're stealing my idea with the pneumatic press :). I've got the cylinder and spare press, just need a coupling to connect them. Not sure whether to cut a hole in the bench or put it on an above bench mount.
 
#22 ·
I'd put it on a L-shaped plate arrangement that extends off to the side of the bench, since my bench is more of a roll-away tool cabinet. Cutting a hole isn't an option, and mounting it above will put the whole thing out of convenient reach. Offering your rig in multiple mounting configurations would be even better, as you could accommodate more buyers.:)
 
#24 ·
I just ordered some more from Nathches Shooter's so when these two orders come in I will have enough to keep me busy. My case gauge arrived today and I was able to confirm my trimming was spot on. When the Lee FCD arrives i will have to learn how to adjust it but it seems pretty straight forward as long as I don't over do it.
 
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