243 wssm fired case neck diameter?

I have looked through this thread, and perhaps I am missing it, but I don't see where you posted what the neck diameter was on your new brass with a bullet seated.

As 204 AR posted that his extracted cases measured .290"-.291" at the neck, those cases were extracted from a chamber with a neck diameter of .287". As I said earlier, the diameter of the neck of a case extracted from a WSSM AR chamber is not relevant. Each bullet/powder combination, each stick of brass, depending on how work-hardened it is, and even shot-to-shot variances in pressure are all going to give you a different spent-case neck diameter.

There are several things I would like to know:

1) What is the neck-diameter of the case with a seated bullet?

2) What brand of brass are you using?

3) What method are you using to determine that you are setting the shoulder back?

As I have said before: The WSSM fired from an AR is nothing short of magic, but you can't treat it like you do a .223. There are virtually countless things that can give you problems where you won't notice them while loading for a .223.

What is somewhat odd is that it seems that having a fair amount of hand-loading experience and mechanical ability just doesn't seem to be make the user immune to loading issues, in fact, to the contrary. It seems, including in my own case many years ago, I though I knew better and chased my tail around for some time. The customers with little experience that closely follow advise seem to do quite well.

Bear mentioned small-base dies. I have never found them to be needed. However, I have seen dies crack and give folks fits. The cracked sizing die will sometimes allow a sized case to fit, while leaving others that will stick in the chamber. For a while, Redding was having quite a bit of failures, and actually contacted me regarding chamber dimensions. They were taking measurements of extracted brass and though the chamber I was producing was over-sized. When I gave them the chamber dimensions, they moved on and found that it was an issue in heat-treating. In all my years, I have never seen a cracked sizing die.... Other than several WSSM's.
 
I was just about to post these findings after test firing the gun which did not go well.
The first attempt of 3 fired the first one after I chambered it by hand with quite a bit of force, but the bolt would not close on the second one. So I put the third one in by hand and put the second one in the mag and then it cycle and functioned.

I loaded three more and set the coal back to 2.200 with the 85 grain Sierra hollow point boat tail and 40 and 1/2 grains of Varget. I force the chamber closed on the first one it went Bang but the extractor rip past the case which was stuck in the chamber. Once again I had to hammer the bolt open with a plastic punch and a small hammer.

I am shooting the Winchester brass that Midway was blowing out a few months ago.

New brass and resize brass will drop in the chamber and fall back out of the chamber under its own weight. It would not do this before I sent it in.

New and resized brass measures .280 at neck

Loaded brass measures .2825" ish

Fired brass measures maybe .0005" bigger.

I'm taking measurements with my $15 caliper so my it is tough the measure that last .0005". I will try to remember to bring a good micrometer home from the shop tonight but as I measure a little bit lower on the neck it seems that the loaded cases are are the same .284" as the fired cases as opposed to measuring higher on the neck.

As a machinist who measures in .0001" on a daily basis I think I can say that the average neck diameter depending on the location you measure it is basically identical to a fired case at least when measured with a $15 calipers.

 
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I am measuring shoulder bump with the Hornady headspace gauge with the 350 bushing.

New brass measures 1.320
Resized with huge cam over 1.330
Fired brass 1.340
Of course those measurements can vary .001" depending on case.

After realizing new brass was .010 short at shoulder than new I reloaded three more new unsized with a 2.230 coal and once again the round chambered extremely hard and after it fired the extractor ripped past the case and tried to feed the next one into the back of it. Again I had to hammer the bolt open with my plastic punch which I am getting very efficient at now.

All of these cases even at the 1.330 shoulder measurement chamber with ease until you stick a bullet in the neck.

I don't have a single doubt in my mind that the hang-up at the neck.

I load for at least 40 rifles and I can't say that I measure this on every one but I've never seen one that doesn't expand somewhere around an additional ten thousandths at the neck upon firing.

 
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Without having it in my hands, I would say that the 40.5 grains of Varget is probably too hot for that twist and that bore. That load is what we have used for testing 1:10 twist barrels for years, and it is, in our chamber, a stout load. If your bore is tighter than others, coupled with the 1:8 twist, I would say you are over-pressure.

Try backing down that charge and see what happens.

The .243 WSSM really should have always been a rifle-plus 2 gas-system. When the chamber pressure is high while the bolt is trying to unlock, something is going to give. In your case, it is your case-rim.

Case-necks measured from a case extracted from your chamber when the bolt doesn't extract the brass will run real close to the chamber dimensions. It is when the bolt jerks the case out of the chamber while under pressure that the case neck and body can and will be larger than the chamber that it was fired in.
 
Originally Posted By: varminter .223

After realizing new brass was .010 short at shoulder than new I reloaded three more with a 2.230 coal and once again the round chambered extremely hard and after it fired the extractor ripped past the case and tried to feed the next one into the back of it. Again I had to hammer the bolt open with my plastic punch which I am getting very efficient at now LOL.



I believe you will find that seating that bullet to 2.23 is too long. That is a VERY blunt bullet and you have probably driven it into the lands. I believe, from memory, that you are safe at 2.2"
 
I already tried that and I testing them at 2.200" this morning with the same results and if I recall I shot some other bullets that did the same thing.

This still doesn't explain why brand new Winchester brass will not chamber after you put a bullet in the neck.

What diameter is your reamer supposed to cut the neck portion of the chamber too?
.284? I would guess the chamber should be cut closer to .290?

The CCI 200 primers are flat with a slight round edge yet. No case head marks to speak of and ejection is somewhere around 2:30.

I will try to back to charge down but I don't know if I'll have time today. That still isn't going to fix the fact that my rounds chamber terribly hard though.

I need to check with my buddy and see if he ever got any factory ammo coming.

 
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On the two cartridges that I polished the neck until they chambered after they chambered you could still see shiny marks where it was making contact with the sides of the neck portion of the chamber.

If you're telling me a stuck cartridge will be very close to the same chamber size then your chamber has to be cut to .284 at the neck. I'm going to guess that is not the case.
 
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As I said in an earlier post, the chamber neck is cut to .287".

Not being able to chamber a round with that bullet seated to 2.23 would be explained by the bullet hitting the lands. That bullet seated to 2.2" not chambering with ease would have to be case distortion. That is all that is left.

We have seen lots of different problems with brass. Some brass is so soft that it gets distorted while the expander-ball is being pulled back though the neck. Sometimes folks have their seating die set so that the crimp-band in the die is distorting the case at the end of the seating cycle. We have also had problems with brass that is too hard.

If your sized brass drops in the chamber and falls out, and your loaded round won't chamber, it should be easy troubleshooting to find out what is going on. My guess would be that you are distorting the brass near the base of the neck.

Blacken the case with a marker and find out where it is binding. Make sure your seating die does not attempt to crimp any of the case. (make sure it is backed off enough so even a longer case doesn't get crimped)
 
I always back my seating dies off one round from touching the top of the neck so I know I'm not crimping. I would say I have about .001 to .0015 slip fit when sliding a bullet in the neck of a fired case and .001 is about the neck growth I'm getting at most. I wondered if maybe the issue was at the very base of the neck where it radius's to the should but as I stated I'm working on this for another individual and he is supposed to be coming up with factory ammo. I already bought another set of dies to try.

One would think Factory brass should chamber after loaded though.

I'm not going to do another thing or consume another minute of anyone's time until I have different brass in my hand.
 
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Nothing would surprise me anymore. I would say there is a high likelihood that the brass is the issue. You should be able to take the tips of your caliper and measure along the neck with a bullet seated. My chambers are .287", so anything real close to that is going to give you problems.

I'm not trying to throw Winchester under the bus, but they have certainly had their share of issues since they moved their ammunition manufacturing. The last batch of factory .243 WSSM loads that we received had huge issues with the crimp. You could look through one box of ammo and find crimps that were so light you could barley detect it, all the way to ones that were so deep it squirted the tip of the bullet forward!

Bottom line is that the upper you have has run like a sewing machine for everyone but you. It sounds like you have a good grasp on hand-loading, so you are probably going to find that the brass is what it causing you all the problems.
 
Well we have over a thousand rounds of that brass so it would only make sense that it is not good LOL. I might have an individual I know who used to do a lot of neck turning spin a few necks down just to test if nothing else not to necessarily reduce the diameter but take any bulges or irregularities out of it. I also have a dial bore gauge that would work perfectly for reaching down into the throat and measuring the diameter of it.
 
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Originally Posted By: varminter .223 I also have a dial bore gauge that would work perfectly for reaching down into the throat and measuring the diameter of it.


You can go ahead and measure it you wish, but quite frankly, it's impossible for the same reamer to cut one chamber tighter than another. It is the same reamer dimensions that have cut all of my chambers for probably more than 12 years.

Logically, if it were a chamber that somehow got cut with a smaller neck than all of my others, then it would not have worked for others, and it has.

The diameter of the neck is only relevant in knowing whether the neck of a loaded round will fit or not.
 
Well I don't know how many chambers you can cut with the reamer before they dull and you lose a thou or even a couple but my only concern is those necks not growing to reamer neck diameter. I thought maybe my brass was a little thick along with the combination of a neck that could be just a hair tight that maybe doesn't show up with thinner brass. Tollerance stack so to speak. I size, ream, clearance and fit things in holes everday and I have a good acquaintance with Murphy and I understand the things that can go wrong no matter how much money is spent on equipment or how much attention is paid to the job. Sometimes peace of mind is worth the effort to get it.

As they say in the engine building world if it's a hair loose only the guy putting it together knows and if it's a hair tight everyone knows.
 
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Our chamber reamers have a solid carbide body, with a removable bushing pilot with oil groves ground into them. The pilot wears and is replaced as needed.

The chamber is roughed with a solid carbide roughing reamer, so the finish reamer really does very little work. If the reamer gets dull or is chipped, it is replace with another cut to the same dimensions, and the old one is sent in (one time) to be resharpened. When they are resharpened, everything gets moved back, keeping all of the neck and body dimensions the exact same as new.

The reamers actually will cut a huge amount of chambers, and I wouldn't doubt that the one that cut your chamber is still the same exact reamer that we are using today, and it's still not cutting tight chambers.

Edited to add: Come to think of it, in all the tens of thousands of barrels that I have chambered, I've never seen a chamber reamer actually cut a smaller chamber due to wear. I have measured necks on reamers that have done more than their share of work, and have never been able to measure any wear on a solid carbide reamer. And when I say any, I mean down to the 1/10th of a thousandth of an inch, much less a "thousandth or two."
 
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Originally Posted By: BigdwebsterWhen I had this upper I loaded with rcbs rockchucker and rcbs and Redding dies without any jams. Regular rcbs shellholder and firm cam over. I have factory ammo and some reloads your welcome to try. If you still have my number shoot me a txt or if not pm me and I will get them to you.

so what has changed?
 
Lots: different brass, different dies, different press and different hand-loader.


My best guess is the brass is the culprit. The truth is that the sooner we can put suspicion that the neck is tight behind us, the sooner the problem will be resolved.
 
The Press is basically new and it is a rock chucker 2. The dies are also brand new RCBS. I generally won't mess with used dies. I have seen brass cause problems before and I'm hoping that is the problem.
 
Mine did the same thing. Make sure when your resizing that the press cams over and the shell holder hits the bottom of the die. I went to Pam cooking spray on them cases and they all chambered. Make sure the shell holder bottoms out.
 
I use RCBS Case Lube with huge press cam over LOL. The new unsized rounds with an additional .010 shoulder setback do the same thing. As stated before new and resize cases chamber like a champ. Issue arises when you expand the case neck when seating a bullet. I'm not sure if I ever tried any one shot Lube before seating though. I don't know if that would have any effect on distortion of the brass or not.
 
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Something that has helped me as much as anything was to get a case length, headspace gauge, if it fits, it shoots in the ar.

Don't be afraid to mortar the ar if you get a stuck round, I also carry a military 223 cleaning kit so I can drive out a stuck round from the chamber as well.

The ar 243 wssm is worth the BS when you get it worked out. 60-69 grain bullets and the coyotes just give up out of respect. LOL.
 
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