Rounds not chambering

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UndFrm

Sergeant of the Hide
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Minuteman
Dec 13, 2022
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CA
#1
Using 6 Dasher in Zermatt Origin

After 3x firing, I verified that the brass won't chamber in so I bumped the shoulder.

After bumping the shoulder and without seating a projectile, I verified that the brass was chambering without too much (or any) resistance on the bolt. So, I proceeded to load the rounds (primer, charge and seat).
Now that a projectile has been seated, I took the firing pin out to verify, and it won't chamber. I also verified that none of the rounds that I loaded can be chambered, which without the projectile they were. The bolt simply wouldn't close, even with significant pressure.

First thing I thought, the projectile is seated too long. I compared the case to a dummy round I keep on the bench, it's slightly less than the dummy round's datum and cartridge base length, which chambers with just a hint of pressure.

Any idea what's wrong that I am doing and how do I fix this?

Edit:
Took a fresh round (unseated) that chambers with 0 pressure on bolt. Charged it and seated. It does chamber in but there is a little resistance. Also, there's some stuff mark on the projectile.

 
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#2
Judging by the scuffmarks on the body/shoulder junction, the shoulders have expanded. I suspect that your cases have lengthend and the seating die is making contact with the case mouth when seating the bullets. This then expands the shoulder

Trim your cases or screw your seating die body out one full turn and try again.

Also, if you have a Redding nody die you can size the shoulders back safely on a loaded round.
 
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#3
1735440182506.png


The case lips may cause an odd feeling while chambering, but what's happening at the shoulder might cause a failure to chamber.

img_3384-jpeg.8492164


Any chance the brass was excessively annealed (subjected to waaay too much heat)?

The second picture is the reason I ask.

That's what happened after excessive annealing, when the necks were to be dilated with a mandrel - similar forces to seating a bullet. Mandrel didn't even get past the case lips, and crushed the shoulders.
 
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#5
Edsel has magnified two problem areas. I'd bet it's the very weird lip on the shoulder (What in your resizing and seating is doing this???). The lip on the neck, while it shouldn't be there, should be OK unless you have a very tight necked chambering (you need to deburr/chamfer your case mouths). I'd suggest taking a few rounds and "painting" them black with magic marker and then chambering and removing them. This should clearly ID the problem area. I doubt it is the scuff marks on the bullet as while you might feel this deep "into the lands" seating, you should still be able to chamber a round.
 
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#6
JerkyFreak said:
Judging by the scuffmarks on the body/shoulder junction, the shoulders have expanded. I suspect that your cases have lengthend and the seating die is making contact with the case mouth when seating the bullets. This then expands the shoulder

Trim your cases or screw your seating die body out one full turn and try again.

Also, if you have a Redding nody die you can size the shoulders back safely on a loaded round.
Click to expand...
The flair on the neck and ring on shoulder and the fact it didnt start until the bras was 3x fired makes me think this is probably the correct answer.
 
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#7
JerkyFreak said:
Judging by the scuffmarks on the body/shoulder junction, the shoulders have expanded. I suspect that your cases have lengthend and the seating die is making contact with the case mouth when seating the bullets. This then expands the shoulder

Trim your cases or screw your seating die body out one full turn and try again.

Also, if you have a Redding nody die you can size the shoulders back safely on a loaded round.
Click to expand...

Edsel said:


The case lips may cause an odd feeling while chambering, but what's happening a the shoulder might cause a failure to chamber.

Any chance the brass was excessively annealed?
Click to expand...
THIS
 
#8
The scuffs on the bullet say carbon ring to me, as does the observation that brass with no projectile chambers just fine. I'd go ahead and put an outside chamfer on the case mouth as well in case there's a lip there that's big enough to snag in the chamber once a bullet is seated...but I think it's a carbon issue.
 
#9
Still couldn't figure out what the issue is. I once again ran the unseated rounds to see they are all chambering without pressure. I tried finding the jam or "touch" point just to ensure that my bullets aren't seated far too long. Went with this point and a few measurements down just to be on the safe side.
I also cleaned the barrel and chamber out, making sure there isn't an obstruction there (I did spill powder when the projectile got stuck).
Since the unseated brass is chambering without any pressure, I can rule out that I didn't shoulder bump enough/correctly, right? This was the first time I had to size the brass, so I am new to this.


JerkyFreak said:
Judging by the scuffmarks on the body/shoulder junction, the shoulders have expanded. I suspect that your cases have lengthend and the seating die is making contact with the case mouth when seating the bullets. This then expands the shoulder

Trim your cases or screw your seating die body out one full turn and try again.

Also, if you have a Redding nody die you can size the shoulders back safely on a loaded round.
Click to expand...
Interesting, didn't even think about that. Adjusted the seating die with 1 full turn out.

Edsel said:


The case lips may cause an odd feeling while chambering, but what's happening at the shoulder might cause a failure to chamber.

Any chance the brass was excessively annealed (subjected to waaay too much heat)?
Click to expand...
I just chamfered and deburred all of the not seated cases. For annealing, I wouldn't think so? I did read quite a bit about it before I started doing it.

37L1 said:
I'm guessing carbon ring.
Click to expand...
Used C4 to clean the barrel out. Unfortunately, I don't have a borescope on hand to verify if there was a ring or not, but I did scrub through with the C4 and then some dry patches.

Rider47 said:
Edsel has magnified two problem areas. I'd bet it's the very weird lip on the shoulder (What in your resizing and seating is doing this???). The lip on the neck, while it shouldn't be there, should be OK unless you have a very tight necked chambering (you need to deburr/chamfer your case mouths). I'd suggest taking a few rounds and "painting" them black with magic marker and then chambering and removing them. This should clearly ID the problem area. I doubt it is the scuff marks on the bullet as while you might feel this deep "into the lands" seating, you should still be able to chamber a round.
Click to expand...
I am not sure about the sizing/seating die. I know that the FL sizing die (Forster) was too tight so sometimes I had to put excessive force. While the lip is weird, I don't suppose that would be the cause since the shoulder bumped brass does chamber without any pressure? Unless it's the seating die that somehow causing it, but I did screw it out 1 full turn.
 
#10
Wait, you say the bullet got stuck? That narrows it down, I'd say. This is either a carbon problem, you're seating the bullets out too far, or there's some other restriction where the bullet lives. Because the scuffing on your bullet in the photo above appears to be symmetrical and all the way around (correct?), I don't think it's a huge runout issue, which would've been my other guess.

You probably want a borescope; I highly recommend one just to facilitate your cleaning process (especially removing carbon rings), but half the Hide disagrees lol.
 
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#12
Edsel said:


The case lips may cause an odd feeling while chambering, but what's happening at the shoulder might cause a failure to chamber.

Any chance the brass was excessively annealed (subjected to waaay too much heat)?
Click to expand...
This picture is key . Measure the diameter with a caliper of the areas circled on an empty case that chambers. Then measure the same areas on one that won't chamber. Somehow in the seating operation you are collapsing the shoulder like you would if you over-crimped with a seatng die.
 
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#13
KnowNothing256 said:
Wait, you say the bullet got stuck? That narrows it down, I'd say. This is either a carbon problem, you're seating the bullets out too far, or there's some other restriction where the bullet lives. Because the scuffing on your bullet in the photo above appears to be symmetrical and all the way around (correct?), I don't think it's a huge runout issue, which would've been my other guess.

You probably want a borescope; I highly recommend one just to facilitate your cleaning process (especially removing carbon rings), but half the Hide disagrees lol.
Click to expand...

I mean that does sound like after reading all this, but...
Ogive to cartridge base of the round that chambers is 1.906 and the one that wouldn't chamber is 1.905 using the same comparator/bushing.

supercorndogs said:
Run one into the seater die all the way with no bullet. See if that empty case chambers.
Click to expand...
Yes, it does chamber after running through seater die without a bullet.
 
#14
mtrmn said:
This picture is key . Measure the diameter with a caliper of the areas circled on an empty case that chambers. Then measure the same areas on one that won't chamber. Somehow in the seating operation you are collapsing the shoulder like you would if you over-crimped with a seatng die.
Click to expand...
Can someone please reupload the image. Says "image not found or removed for me".
Edit: Nvm, image showing up now.

Thank you
 
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#17
mtrmn said:
See post #3
Click to expand...
Same, image not found. Weird that you can see it and I cannot.
Edit: Nvm, image showing up now.

Here's something else I tested:
Took a chambering unseated case and measured the shoulder using comparator. Took another seated case that wouldn't chamber and pulled the bullet out using an impact hammer. The shoulder is the same as the one that chambers and now this one chambers as well.
 
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#18
One area that I'm wondering about is the edge/mouth of the case neck looking expanded. If it is actually a larger diameter than the case neck then it would be possible to chamber the case without the bullet and then have difficulty chambering with the bullet.
 
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#19
ShtrRdy said:
One area that I'm wondering about is the edge/mouth of the case neck looking expanded. If it is actually a larger diameter than the case neck then it would be possible to chamber the case without the bullet and then have difficulty chambering with the bullet.
Click to expand...
That makes sense. Because the case chambers without projectile, but with the projectile the neck is expanded possibly over the size. My question would be, I have fired these cases 3, would it be possible that the "neck thickness" has increased and now I need to neck turn?
While on this train, I don't suppose the case length would be an issue as it's chambering fine without bullet, correct?
 
#20
Neck thickness should not have changed much, if any. I wonder what is causing the neck opening to get expanded. What is the length of the cases you haven't loaded, but have been resized?

If the case length is longer than the chamber I would suspect that you could chamber an empty case. The reason why this is possible is because there is usually a 45° Slope from the neck portion of the chamber to the freebore portion. This slope would guide the case neck to a smaller diameter.
 
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#21
UndFrm said:
I am not sure about the sizing/seating die. I know that the FL sizing die (Forster) was too tight so sometimes I had to put excessive force. While the lip is weird, I don't suppose that would be the cause since the shoulder bumped brass does chamber without any pressure? Unless it's the seating die that somehow causing it, but I did screw it out 1 full turn.
Click to expand...
Shouldn't need excessive force. What lube are you using?

What is the brass length? Have these been trimmed at all?

How are you finding your seating depth?
If you do not have the Hornady Tool for such a thing.
I would do this.


Another method if you do not want to play with loctite.
 
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#22
loveha said:
Shouldn't need excessive force. What lube are you using?

What is the brass length? Have these been trimmed at all?

How are you finding your seating depth?
If you do not have the Hornady Tool for such a thing.
I would do this.


Another method if you do not want to play with loctite.
Click to expand...

Imperial die wax, the one that comes in a little flat tub.

Brass length is 1.541 average. Some brass are +/- 0.001
Haven't trimmed at all.

For seating depth, I found the jam point but letting the projectile seat itself with a little pressure on bolt and then went down from there to -0.030
Although, I might try a different method as suggested.
 
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#23
Your reamer probably doesn't match your dies and brass. You really need some comparators and good calipers if you don't have them. You'll have exact measurement rather than turning does and guessing. You probably have a couple things happening at once. 3 firings on the brass is why you're seeing it. I didn't see anybody ask which brand of brass, this is important. Dasher isn't saami, it's all custom, no standard for reamers/dies/brass.

Find out if your chamber is no-turn or tight neck from your smith if possible.

Keep a fired piece of with your dies for reference. Measure the fired neck circumference. That's your chamber. Measure the neck thickness in a few spots (turn/no-turn). Measure the 200 line on the brass. Write it all down and keep it handy.

It's likely you have thick necks and your not sizing the base enough. Full length size everytime (2-3 thousands). Trim a little short of 6br saami length.

Same yourself the headache. Send a 3 times fired piece to Harrell's and they will send a die that matches your chamber. Their dies will bump and size the base down. You can have forster whack 100/1000 from the base of your die and open the neck up, but a Harrell's is better option.

If you have to turn the necks, turn them. If you can run Lapua brass, switch.
 
#24
Once again, paint a few of the loaded rounds with a black magic marker. This includes the bullet. Then attempt to chamber, and then remove. Where the issue is should be clearly visible and the people attempting to help you will have the proper info. Photograph and post the results.

What did you do differently to get the result shown on the "Edit:" in your initial post?
The "scuff marks" on the bullet do not really look like they were made by engraving the lands, which would likely show discreet land marks, not a full circumference of scuff, unless you chambered this round more than once.
 
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#27
Rider47 said:
Once again, paint a few of the loaded rounds with a black magic marker. This includes the bullet. Then attempt to chamber, and then remove. Where the issue is should be clearly visible and the people attempting to help you will have the proper info. Photograph and post the results.

What did you do differently to get the result shown on the "Edit:" in your initial post?
The "scuff marks" on the bullet do not really look like they were made by engraving the lands, which would likely show discreet land marks, not a full circumference of scuff, unless you chambered this round more than once.
Click to expand...

The only signs that I can notice aren't obvious to me but I have highlighted in the images.
For th edit portion, I just grabbed a different brass from another batch, I probably should have measure that before popping it in.



 
#28
Thanks for your latest post with images.
Did this round chamber properly? Has your chambering problem gone away?
- No sign of the previously observed "scuff band" on the bullet.
- The circled scratch close to the bullet tip is from when the round is chambered from the magazine or feed ramp? Should not be from deep in the chamber.
- The circled deep scratch on the case neck is concerning, unless this too is from some contact before the case neck is in the neck portion of your chamber. If it is from when the neck of the case slides into the neck portion of the chamber, there is an issue, as this should not happen. Is there a burr or some kind of obstruction here? (Your .243" borescope should allow you to see into your chamber?)
- Also visible is magic marker missing from the outside rim of the case neck, end even some missing from the shoulder, suggesting too close contact at both locations.
 
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#30
If you can’t force the bolt closed if you run it hard (think something like the cortina find jam method, but harder), then it’s not the bullet contacting carbon and such. If it were, you’d be able to slam the bolt shut and the bullet would just seat deeper into the case. You’d have to have some pretty crazy interference fit and friction in the neck for the bullet not to just seat deeper and possibly get stuck in the lands.

If I’m reading correctly, sized brass fits and bolt closed. Seated with a bullet it wont. But if you pull a seated bullet, it will chamber again.

If I have that assumption correct, then it’s going to be a neck issue. When there’s no bullet in the neck to prevent the brass from moving, you can’t chamber it. Once you remove the bullet, the neck can now bend/flex/move when it’s contacting the chamber.


If you really want to test that theory, take a piece of sized brass that fits in the chamber without a bullet. Then put a bullet in upside down and tap it into the neck with a small hammer until only the boat tail is above the top of the neck. This will enable you to have full bearing surface in the neck for resistance in the chamber, but no bullet protruding to touch anything at all. You could also seat a bullet normally with full bearing surface in neck and then just cut the bullet off above the neck, but tapping one upside down is easier. Can also use a tight fitting pin gauge, but then you might have to cut the case to get your pin gauge out.

If it doesn’t chamber after the sized brass without the bullet chambers, your problem is with the neck.


If you know what reamer was used, you can look at the print and see what the diameter of the neck is, then take a micrometer and see what the diameter is of a loaded round. Calipers can suffice, but problems like this tend to come down to .001 - .002 and you have that much margin of error in calipers or more.

Same with all dimensions. You can check the base, body, shoulders, and neck of your loaded rounds vs the reamer print.
 
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#33
I'm under the impression that in a bolt gun, the following do not prevent chambering as the cartridge can be "cam - squished" in:

1) ...an oversized bullet (by as much as 0.002" to 0.003”)
2) ...a bullet "seated far out"
3) Carbon Rings
4) flower vase flared case lips

It usually has something to do with the brass dimensions...

1) errant measurements (headspacing, need for small base dies when with fat bottoms, etc.)
2) necks that need to be trimmed to length (most of the time, the bullet ends up with a weird - looking crimp)

That being said, in an AR - even the bolt slamming the loaded cartridge home can “headspace” it in the process.
 
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#34
Look at the 'skyline profile" of the cases in these pictures. Right at the junction of the case body and the shoulder there is a visible bulge circled in the first picture. In the same area on the second picture that's marked up with a sharpie there is no such bulge. This bulge in the first pic looks identical to the bulge I got years ago when I was crimping my rounds with the built-in roll crimp feature in my seating die. I can guarantee that bulge will cause that round to be hard if not impossible to chamber.
Even if the crimp portion of the die is not making contact during the seating operation, ANY downward force while seating that is too great will cause this same bulge. This is why it's been asked before how hard you have to push to seat the bullets. If you happened to get some out-of-spec bullets that had too large a diameter, that would possibly explain the bulge AND the neck being too large to chamber.
 

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#36
Edsel said:
I'm under the impression that in a bolt gun, the following do not prevent chambering and the cartridge can be "cam - squished" in:

1) ...an oversized bullet (by as much as 0.002" to 0.003”)
2) ...a bullet "seated far out"
3) Carbon Rings
4) flower vase flared case lips
Click to expand...
1) if your bullets are that far out from one another you need to throw them in the trash. I’ve never encountered anything like that ever when using proper components.

2) it can prevent but when forming dashers I jam them like .1 out and they jam u til they seat back into the case, shouldn’t prevent chambering.

3) makes it tough but the bullet should seat back into the case with a hefty bolt close

4) totally can prevent it. A guy at the local match got one chambered and fired, the second jammed and that was it for the day, had to go home, pull bullets, trim brass to get the flare out. Ruined his match.
It’s what’s being pointed out repeatedly here. His die is messed up (shoulder lip) or his seater is too low (flared mouth)
 
#38
O/P, are you 100% sure you have the seating die screwed out enough not to be putting ANY crimp on the case neck? That WILL cause the case shoulder to buckle some and cause the case not to chamber. Are your case lengths are at or below recommended max length?
 
#39
Rider47 said:
Thanks for your latest post with images.
Did this round chamber properly? Has your chambering problem gone away?
- No sign of the previously observed "scuff band" on the bullet.
- The circled scratch close to the bullet tip is from when the round is chambered from the magazine or feed ramp? Should not be from deep in the chamber.
- The circled deep scratch on the case neck is concerning, unless this too is from some contact before the case neck is in the neck portion of your chamber. If it is from when the neck of the case slides into the neck portion of the chamber, there is an issue, as this should not happen. Is there a burr or some kind of obstruction here? (Your .243" borescope should allow you to see into your chamber?)
- Also visible is magic marker missing from the outside rim of the case neck, end even some missing from the shoulder, suggesting too close contact at both locations.
Click to expand...

The images are for the one that couldn't be chambered. I put this round by hand, without a magazine or sled.
Scuff on th neck, I am not sure what can I cause this? Wasn't there prior to trying to chamber and again no magazine used.
When you say too close contact, should I be sizing it further down and then try again?

For the crimp, the die I am using is a Forster Ultra seating die. I am not sure if this die crimps? I am played with the seating die setup, unscrewing it more out.

I am not sure about the "recommended max length", but the case overall length is under the max overall length.
 
#41
UndFrm said:
The images are for the one that couldn't be chambered. I put this round by hand, without a magazine or sled.
Scuff on th neck, I am not sure what can I cause this? Wasn't there prior to trying to chamber and again no magazine used.
When you say too close contact, should I be sizing it further down and then try again?

For the crimp, the die I am using is a Forster Ultra seating die. I am not sure if this die crimps? I am played with the seating die setup, unscrewing it more out.

I am not sure about the "recommended max length", but the case overall length is under the max overall length.
Click to expand...

I’ve you have the body of the die screwed down too far, you can get rolled necks. If this turned out to be the issue, back the body of the die up and screw the seating micrometer further down to achieve your target seating depth.
 
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#42
Adjusting your seating die is probably the simplest thing in the equation. Put a round of sized brass (no bullet) in the shell holder and run it to the top of the press stroke. Leave it there. Back the seating stem out of the seating die a LOT to insure it will never reach the brass. Screw the seating die body down until it touches the empty brass. Now UNSCREW the die upward at least 1 round, 3 or 4 rounds won't hurt. Lock it down in that position. NOW you can adjust the seating stem through trial and error to reach your desired seating depth for the bullet. After this, you KNOW the seating die is not contacting the brass and cannot be the problem.

If you do not own a micrometer or at least a dial or digital caliper and know how to use them, get some. Measurements have been requested here several times and all I've seen is crickets rubbing their legs together. Something is happening to your brass that should not be happening, most likely during the seating process. It's very hard for any of us to help you without some meaningful feedback. I'm not being mean, just trying to get you to help us help you.
 
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#44
CK1.0 said:
What dies are you using?
Click to expand...
Forster Ultra seating and FL sizing die ( no bushing)

I think at this point I'll start from scratch with the sizing of brass. I'll get another press as well as there's significant flex in the Lee torrent that I am using, that might perhaps me affecting the die setup. Also, I have mixed a lot of brass trying to figure this out and I'm not sure what's what now. My bad on the organization of the batches.

Thank you for the suggestion on setting up the seating die, it's way more than what's mentioned in the basic instructions.

Thank you
 
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#45
img_3384-jpeg.8492164


Edsel said:
That's what happened after excessive annealing, when the necks were to be dilated with a mandrel - similar forces to seating a bullet. Mandrel didn't even get past the case lips, and crushed the shoulders.
Click to expand...

Edited Post #3...
 
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