243 wssm fired case neck diameter?

varminter .223

Active member
I've been fighting a 243 wssm upper. New brass won't chamber, resize brass won't chamber, and fired brass doesn't like to extract. My fired case necks measure basically the same as reloaded case necks. Curious if someone could measure a piece of fired brass at the neck and get give me that dimension. Thanks!
 
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I measured a few, .290 to .291".

It sounds like your chamber is tight if new brass won't chamber. Who made the upper?
 
It's a Dtech. I sent it back to them and they claim they shot it and it functions perfect for them. I tried new Winchester brass and two different dies. I'm setting shoulder back enough and I've tried seating bullet deeper etc. If I do get one chambered it won't extract. The extractor rips past the case head and case remains stuck. My fired necks measure .283 to .284 ish. My loaded case measure the same.
Before sending it back to Mike I lightly polished the chamber since I kept seeing a scratch in the same location on a case gently placed in the chamber and tapped out with a cleaning rod. It worked for five or six rounds and went right back to the same thing. We are going to try some factory ammo next but fired cases measure like they should everywhere except at the necks. It seems like the neck portion of the chamber is tight in my opinion. The only other thing that makes sense to me is if the chamber is not concentric. Once the stuck brass is removed and you try to rechamber it it sticks again.
 
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I would send it back with some of your brass. Tell him to send you some of the brass or ammo he used if he says there is nothing wrong with it. That just isn't right. Mine will shoot new but the reloaded needs the sizing die set to cam over under pressure.

On another note, try a different shell holder, maybe even grind the top down on the one you have now, not all shell holders are the same and an extra thick one on the top can really cause issues. I would bet this would solve your problem. A good flat file will shave it down pretty quick and won't hurt the shell holder as long as you don't ruin the temper by getting it too hot by using a grinder.
 
That's weird. I take it you're measuring shoulder set back so you know it's ok for sure. I set these back more than other cases, I can't remember right now but considerably more than 3 or 4 thousandths for normal cases.

I wonder if Hornady brass has thinner necks? Maybe try turning one of yours?

My Dtech 243 wssm runs like a top, but I know the chamber is pretty big. Years ago I had a 25 wssm upper from Mike, and it did a lot of the stuff you're seeing. Very frustrating for sure. Nothing I tried would make it extract reliably. I have quite bit more knowledge now and wonder sometimes if I could make it work if I still had it. I was even turning necks and reaming donuts from fc brass I'd converted from 223 wssm. I finally gave up.
 
The Dtech 243WSSM I just sold had 250-300 rounds through it and it never had a single malfunction w/factory or handloads (using some WW brass but mostly Fed.).

Regards,
hm
 
If I recall I was setting shoulders back as much as .010". That was as much Cam over as I could really do sensibly. The odd part is after you get a case in it and fire it it's just stuck in there period and the bolt has to be driven back with a small hammer and a plastic punch. This Winchester brass is the only brass I have here at the moment. The gun actually belongs to my hunting partner so I'm going to wait for him to get some factory rounds just to test it. I don't have a means of turning the neck but I had considered that last night just to see if it would chamber. I took all kinds of measurements last night but the problem is I don't have anything to compare it to. We have over a thousand rounds of this brass and it hasn't done as much good so far LOL. Bear in mind the factory cases before we resize them don't function either.
 
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Originally Posted By: varminter .223I've been fighting a 243 wssm upper. New brass won't chamber, resize brass won't chamber, and fired brass doesn't like to extract. My fired case necks measure basically the same as reloaded case necks. Curious if someone could measure a piece of fired brass at the neck and get give me that dimension. Thanks!

I do not have any fired brass left to measure but a new, unfired FC neck measures .2815 and a dummy round w/bullet seated made from a fired FC case measures .282 (both chambered in my rifle easily).

Have you tried painting a case with sight black or a black marker then break the rifle open and chamber round by hand until it begins to feel snug; remove and see where the friction is just for kicks?

Regards,
hm
 
I'm not sure what I all did last winter when I was messing with it but I messed with it until I had had enough and we sent it back to him. It took him a few months to look at it and he said all he did was cleaned it and shot it and then sent it back. I asked him if he tried to chamber a round before he cleaned it and I never got a straight answer. When I got it back from him I never even took it out of the box for a couple months. We got it out last night and it's the same thing so I said screw it let's get some Factory ammo.
 
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Not sure what the problem is but if you want to send me two cases that you have prepped and ready to load that won't work in your Dtech mail them to me and I will try them in my Detech to see if they will hand cycle in my Dtech. PM me if you are interested in going that route. I have not had a problem with my 243 Dtech cycling.
 
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If new brass won't chamber and brass you sized won't chamber, what have you fired that will not eject or extract? If it is factory rounds you fired( probably what dtech tried) you have everything you need to find the fit problem(factory, factory once fired and all your other brass).
 
What we have fired were rounds that we had loaded. On occasion I could get the bolt jammed closed on one. After I lightly polished the chamber the rifle functioned for six or seven rounds. Then it went right back to how it was before I polished the chamber. Only thing that can come and go that quick is carbon.
 
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I'd call Mike and discuss the problem with him. Did you send him any fired, and resized cases that would not chamber with the upper? Maybe some of the new cases that won't chamber, too.

Regards,
hm
 
Originally Posted By: 204 ARI measured a few, .290 to .291".

It sounds like your chamber is tight if new brass won't chamber. Who made the upper?

Not a tight chamber. Our chamber dimensions on that round has not changed in over 12 years.
 
Originally Posted By: hm1996

I do not have any fired brass left to measure but a new, unfired FC neck measures .2815 and a dummy case made from a fired FC case measures .282 (both chambered in my rifle easily).

Have you tried painting a case with sight black or a black marker then break the rifle open and chamber round by hand until it begins to feel snug; remove and see where the friction is just for kicks?

Regards,
hm

For the most part, measuring brass extracted from a gas-operated weapon is an unsure science at best. The neck diameter especially can and does get to be larger in diameter than the chamber from which it was extracted.

I had been hand-loading literally my entire life when the WSSM came along. It just about killed me! I ended up making a device much like the RCBS precision case micrometer, and that allowed me to troubleshoot, and fix my reloading problems.

The problem is that folks get by with making small mistakes on the .223 for the AR and everything still runs fine. On a .223 case if the shoulder is not set back far enough, and the brass is 1/2 a thousandth of an inch longer than the chamber, the heavy BCG will "smash" the case into the chamber, the bolt will close, and no one will be the wiser. Not so on a WSSM. If that case, as thick and as large in diameter as it is, is 1/2 of a thousandth of an inch longer than the chamber, the bolt just STOPS!

After licking my wounds 15-18 years ago, I wrote a two-page letter that we make available to WSSM users to help them troubleshoot their loading techniques.

This particular upper we actually have a fair amount of history on: We built it for a guy that wanted to shoot long, heavy bullets, so it started life as a 1:8 twist, 24" barrel. The original customer had no problems with accuracy or feed/function. He ended up selling the upper to another person that wanted to shoot light bullets, and thought he was getting the correct twist. The new owner sent it to us to have it cut back to 22" and fluted. We did so, tested it and returned it to him. It fed and functioned flawlessly, but he just wasn't able get the light bullets to shoot the way he wanted, so he ordered a 1:12 twist from us and sold the 1:8.

When Varminter .223 spoke with me about it, he mentioned that it had something in the chamber that was scratch the brass. I talked him through what I thought he should do, but he thought there was still a problem, so he sent it to us.

I borescoped it, and wasn't able to see anything that might scratch brass, but I lightly lapped it with a fine ball-hone, then tested it with factory and handloaded ammunition. We even took it to the range and shot groups with it. The upper not only fed and functioned as it should, it had good accuracy.

We have not received a call, message or email about any problems with it since we returned it. My partner just happened to see this thread and bring it to my attention.
 
Mike I just pulled it put of the box Sunday evening. I am trying to get the upper functioning for my hunting partner who knows little about reloading etc. I told him to get some factory ammo before we proceed any farther. We have since ordered AR10 uppers and then decided we can't do without sidecharging uppers which we have many of so our concern to get this wssm up and running is not great at the moment however I'm sure we will. They only thing I haven't tried is grinding the shellholder to get additional shoulder set back. (More than .010") and turning the necks. I also would like to verify that I never load any cartridge without measuring this dimension and I am already at max press cam over. When I measure a fired case everything measures to my knowledge as it should except at the neck. It measures .283 to .284 and that is basically within a half thou of what my loaded cases measure. New brass will not chamber and one does cram in and we fired it the bolt has to be beat open with a small hammer and plastic punch. This brass is that stuff Midway was blowing out recently and I'm trying to imagine how thick or hard brass can cause this. I have no other brass for this cartridge on hand hence why I came here asking for dimensions. When a fired case is the chambeedthe bolt has to be beat open again bit I'm assuming that is from the case growing beyond chamber length during high pressure after the bolt unlocks.
 
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When 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.
 
I'm going to load a few rounds in the morning as we were very pushed for time sat. evening. After some scope mounting issues it was already about to dark to shoot and when it wouldn't chamber we said screw it for the moment. Being stubborn I gave it one more attempt and it chambered, fired and was locked up like Fort Knox so that was it for Saturday after we got the case out. However I just got it out and new unsized brass as well as fired resized is fitting in and out of the chamber under it's own weight and a few rounds that I had loaded Saturday would chamber. The ones that would not chamber did finally go in after I polished the neck and the bodies down with 400 grit which tells me it isn't too little shoulder bump. The fact that it didnt extract a fired round still worries me but since I have time I'm gonna function test it in the morning to see what we I have going for sure. I will be in touch. Thanks!
 
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Get a small base die. I have a 30-06 that does that and a small base die cured it. My 06 would rip the rim right off the case but not now.
 
no small base dies available for wssm, file the shell holder top down. Cam the press over center under pressure. These are tough cases and will spring back. Take the firing pin out of the bolt, use only thumb pressure to test whether a case or found will chamber and lock up on closing.

Another way is to take some metal off the bottom of the sizing die, I don't like to do it this way myself. Much better to file the top of the shell holder.
 
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