Factory ammo won’t chamber

[NJRaised]

Proof 223 (gunsmith chambered) on origin action.

Been feeding it nothing but hornady match ammo. Have had zero issues. All of the sudden , it won’t chamber approx 1 out of every 10 rounds. Barrel and chamber have been cleaned and borescoped. Barrel has about 7-800 rounds through it. Clean every 100 rounds or so.

I measured the “bad” rounds in comparison with some rounds that chambered (that I did not fire). The “bad” rounds were measuring about 2 thousandths longer (using hornady lock and load headspace gauge).

Has anyone else seen this? I figured factory ammo would have no issues chambering .

 

[straightshooter1]

Proof 223 (gunsmith chambered) on origin action.

Been feeding it nothing but hornady match ammo. Have had zero issues. All of the sudden , it won’t chamber approx 1 out of every 10 rounds. Barrel and chamber have been cleaned and borescoped. Barrel has about 7-800 rounds through it. Clean every 100 rounds or so.

I measured the “bad” rounds in comparison with some rounds that chambered (that I did not fire). The “bad” rounds were measuring about 2 thousandths longer (using hornady lock and load headspace gauge).

Has anyone else seen this? I figured factory ammo would have no issues chambering .

When you borescoped it, you saw that you got the carbon ring removed?

 

[NJRaised]

When you borescoped it, you saw that you got the carbon ring removed?

Yes, copper ring removed or at least very very faint.

 

[ma smith]

I measured the “bad” rounds in comparison with some rounds that chambered (that I did not fire). The “bad” rounds were measuring about 2 thousandths longer (using hornady lock and load headspace gauge).

min spec chamber? try 'tape trick' on a good round... (remove firing pin of course)

 

[NJRaised]

min spec chamber? try 'tape trick' on a good round... (remove firing pin of course)

I’m gotta imagine min spec chamber. Strange that some rounds chamber and some don’t.

Haven’t “forced” it into battery, but hoping I haven’t accidentally galled any lugs by having ammo that’s slightly too large for chamber. Bolt lugs look fine, but need to run a borescope and check lugs in receiver.

 

[bax]

Proof 223 (gunsmith chambered) on origin action.

Been feeding it nothing but hornady match ammo. Have had zero issues. All of the sudden , it won’t chamber approx 1 out of every 10 rounds. Barrel and chamber have been cleaned and borescoped. Barrel has about 7-800 rounds through it. Clean every 100 rounds or so.

I measured the “bad” rounds in comparison with some rounds that chambered (that I did not fire). The “bad” rounds were measuring about 2 thousandths longer (using hornady lock and load headspace gauge).

Has anyone else seen this? I figured factory ammo would have no issues chambering .

It won't chamber because the factory ammo is too big in some dimension.

• could be overall length - the bullet hits the lands before the bolt closes. You have to force the bullet deeper into the case.
• could be the "headspace length" the case-shoulder-to-base is longer than your chamber.
• could be that the cartridge base or shoulder diameter is too large
• wrong bolt, bolt face is too small for brass

Find a fired case that has not been resized. Measure it. Compare dimensions with the factory ammo. See which Factory dimension is too big.

Cover a piece of factory ammo with magic marker, try to chamber it. The marker will run off on the place where it is tight.

Magic-marker the bullet try to chamber. If the COL is too long, the marker on the bullet will be rubbed off.

Keeping in mind that sometimes we just lose our mind,

• make sure that the extractor pops over the rim and
• you are using ammo that matches your chamber - so for a .308 chamber you want to use .308 ammo - ought six ammo is not the same, 30-caliber ammo in a 7mm chamber is not the same I try hard to check stuff like that before I stand up in public - avoids embarrassment

I am that guy whose primary reason for living is to be a bad example for others.

 

[Missalot]

Do you have a case gauge? They are handy to gauge length and case mouth.

 

[NJRaised]

Ammo fits case gauge, meets spec.

Barrel is cleaned, no carbon ring, correct bolt head.

I ran another box of match ammo through it, only 1 out of 20 rounds wound chamber. Bolt is getting extremely heavy and gritty, even dry firing.

I called up zermatt and they are helping me out. They are good people, excellent CS. Hopefully they can get this squared away if it’s an action issue.

I’m Totally out of ideas.

 

[spife7980]

Throw the gauge away: what are your actual measurements?
Diameters of the base, shoulder, neck and then the length of the base to shoulder datum via comparator. Do this on fired vs sized. Your answer is in the numbers.

 

[918v]

Ammo fits case gauge, meets spec.

Barrel is cleaned, no carbon ring, correct bolt head.

I ran another box of match ammo through it, only 1 out of 20 rounds wound chamber. Bolt is getting extremely heavy and gritty, even dry firing.

I called up zermatt and they are helping me out. They are good people, excellent CS. Hopefully they can get this squared away if it’s an action issue.

I’m Totally out of ideas.

The bad ones were .002” longer than the good ones. That’s the problem.

 

[Mordamer]

This is why I don't chamber barrels to minimum headspace. So many videos of rookie gunsmiths online have them showing how they can barely close the bolt on a go gauge and they think this has some correlation to better precision.

My guess is that a go gauge will not allow the bolt to close or it will be tight. If so, make the gunsmith fix it. Maybe he'll learn something.

 

[NJRaised]

Update…. Issue is getting worse. Bolt won’t close on 15 out 20 factory hornady match rounds (I’ve shot hundred prior to this with no issue).

I cleaned the barrel well, hit any type of carbon ring there. Still will not chamber.

Could a galled action lug change headspace on me?

 

[Cascade Hemi]

Debris in the firing pin channel?

 

[ma smith]

Update…. Issue is getting worse. Bolt won’t close on 15 out 20 factory hornady match rounds (I’ve shot hundred prior to this with no issue).

I cleaned the barrel well, hit any type of carbon ring there. Still will not chamber.

Could a galled action lug change headspace on me?

check out this way of measuring headspace...


This is one possible way forward...try to measure the ammo that will chamber. Set one asied. Put a piece of masking tape on the base. Try to close the bolt (NB: with firing pin removed). What happens? If it chambers, put another piece of tape. Try again. Once you get the "good" ammo to not chamber, measure the heaspace again, with the tape layer still on it. What is it? Write it down. Compare this to the factory ammo still in the boxes, the good ones and the ones that won't chamber. Write it down into a table

Good:

xxx

Bad:

xxx+ 2 piece of tape (≈ .004 thous ... or whatever)

etc

Box of Ammo

{list : measurements of ±10 random samples}

Compare this data with the sammi reamer drawing for your cartridge.

Spec is for headspace is

YYY - .0070 (or whatever)...btw...This means ther is 7 thou of variation in the acceptable range.

If either the ammo is out of spec or the chamber is out of spec, this will table tell you. If you need to contact the OEM of either your rifle/action or the ammo OEM, you will want to have the data laid out. Send them an e-mail, and ask them to work with you for a fix.

If none of that is the problem, its also possible you have a messed up bolt-lug surface or bolt raceway.But eliminate the other causes first to narrow down your problem solving.

Good luck and keep us posted.

 

[spife7980]

Update…. Issue is getting worse. Bolt won’t close on 15 out 20 factory hornady match rounds (I’ve shot hundred prior to this with no issue).

I cleaned the barrel well, hit any type of carbon ring there. Still will not chamber.

Could a galled action lug change headspace on me?

And yet you still refuse to either take or share measurements that would show you exactly where your problem is.

 

[RTH1800]

Magic marker the entire cartridge. Try to chamber. It will show you the tight spot or spots.
Alter chamber, ammo or change ammo.
If just bullet issue. Seat to uniform depth that works.
If neck too tight going to need to change ammo or chamber. If shoulder …

 

[NJRaised]

And yet you still refuse to either take or share measurements that would show you exactly where your problem is.

fireformed case 1.4600” (headspace measurement)

Rounds that will not chamber 1.459”

 

[NJRaised]

Have sharpied entire round and chambered. No marks .

 

[spife7980]

fireformed case 1.4600” (headspace measurement)

Rounds that will not chamber 1.459”

Well you got one number thats really close to the fired.
Possible source right there.
Its also not consistent with the relative .002 longer figure you provided initially. So what changed, the ammo or your measuring technique?

Now do the entire rest of the case. We cant tell you what dimension it is that wont fit without being provided your dimensions.

Diameters of the base, shoulder, neck and then the length of the base to shoulder datum via comparator. Do this on fired vs sized. Your answer is in the numbers.

 

[OREGUN]

Debris trapped in your extractor or ejector which is preventing their normal spring action….effectively holding the cartridge off the bolt face by .250”?

Strip the bolt completely and clean all the bits?

 

[918v]

I measured the “bad” rounds in comparison with some rounds that chambered (that I did not fire). The “bad” rounds were measuring about 2 thousandths longer (using hornady lock and load headspace gauge). The

So the good ones measure 1.457”?

 

[RTH1800]

Have sharpied entire round and chambered. No marks .

If you cannot chamber you will get a mark with a bit of pressure. It’s got to be hanging up somewhere.

 

[NJRaised]

So the good ones measure 1.457”?

Yes, the ones that will chamber measure at 1.457” or 1.458”.

 

[NJRaised]

Im getting a ring around the neck/shoulder junction and a ring around the shoulder/body junction.

Ammo all passes the case gauge.

May be a tight chamber. But what I don’t understand is, I’ve been shooting this exact same ammo for hundreds of rounds, not a single hiccup. Different lot number, different boxes, all functioned fine. Now most of it will not chamber.

I have thoroughly cleaned the barrel, chamber, neck region. Bronze and nylon brushes (including slightly oversized). Boretech eliminator soaked for hours.

The only thing crossing my mind right now is some type of galling on the receiver lugs or some type of damage to the chamber that’s causing a Hang up.

Zermatt sent me a new bolt and firing pin assembly , same issues.

 

[RTH1800]

It’s not lugs. It’s nothing a case gauge will fix. Not a cleaning issue.

Ammo is on long side of spec, chamber on short side of spec.

Three ways to deal with it.

 

[OREGUN]

Do you have the tools/skills to take the barrel off. Might be worth doing for cleaning and inspection of the chamber and front end of the receiver. Interesting that they thought it was bolt related. I would guess your chamber is min length and your ammo is a little long. All within the stated +/- tolerances for the reamer and the ammo but not great in combo. Maybe have your smith give you a little more chamber. Or, to repeat SH dogma, you simply must start reloading.

 

[NJRaised]

It’s not lugs. It’s nothing a case gauge will fix. Not a cleaning issue.

Ammo is on long side of spec, chamber on short side of spec.

Three ways to deal with it.

If that’s the case, then why would the same exact factory ammo chamber without issue for 7-800 rounds prior to this ? All different lot numbers, etc, worked fine. Not a single issue.

I even had a half box of the same factory ammo I shot at a prs match (leftover ammo) all of which functioned fine, but now the leftover stuff won’t chamber .

 

[RTH1800]

Production specs change. Don’t over complicate it. Fix it.

 

[OREGUN]

Bolt is getting extremely heavy and gritty, even dry firing.

Can you tell us what this means? Closing or opening? Before or after trigger press or both?

 

[Mike Casselton]

OP
Do you use any lube on the bolt lugs and cooking ramp?
If it's hard to cycle dry firing, it sounds like you have a galling issue

 

[RTH1800]

I thought he said lugs were not galled?
If bolt is gritty something is galled.

 

[918v]

Yes, the ones that will chamber measure at 1.457” or 1.458”.

Get a Reading body die, and bump the shoulders to 1.457 inch. You won’t even need to lube the case.

 

[NJRaised]

OP
Do you use any lube on the bolt lugs and cooking ramp?
If it's hard to cycle dry firing, it sounds like you have a galling issue

Always lubed with slip 2000 ewg.

 

[Mike Casselton]

Sounds like the issue you have with a gritty bolt lift on dry firing is a galled cocking ramp.
It also sounds like your lugs or the abutments on the receiver are galled. Combined it would be pretty stiff

How about some pics?

 

[NJRaised]

Sounds like the issue you have with a gritty bolt lift on dry firing is a galled cocking ramp.
It also sounds like your lugs or the abutments on the receiver are galled. Combined it would be pretty stiff

How about some pics?

I’ll try to get some pics, between a recent move and Covid, a lot of my reloading equipment is packed up currently

 

[Mike Casselton]

We need pics of the bolt lugs and the cocking ramp...

 

[NJRaised]

Long story short, I sent the barreled action out to zermatt to inspect. Zermatt was awesome to work with. The action is perfectly in spec, no damage, all good.

Zermatt inspected the barrel and said it was chambered to absolute minimum headspace. Ray said the bolt would barely close on a go gauge. He also said the extractor is ever so slightly rubbing on the breech face when the bolt is closed.


So my question now is….. I tend to enjoy shooting factory ammo (I have a newborn and time/space is extremely limited). Does anyone know any good 223 factory ammo that’s going to be ok with a minimum spec chamber? The hornady 223 match 75gr bthp is too borderline (only about half the rounds will chamber).

Thanks in advance

 

[RegionRat]

Long story short, I sent the barreled action out to zermatt to inspect. Zermatt was awesome to work with. The action is perfectly in spec, no damage, all good.

Zermatt inspected the barrel and said it was chambered to absolute minimum headspace. Ray said the bolt would barely close on a go gauge. He also said the extractor is ever so slightly rubbing on the breech face when the bolt is closed.


So my question now is….. I tend to enjoy shooting factory ammo (I have a newborn and time/space is extremely limited). Does anyone know any good 223 factory ammo that’s going to be ok with a minimum spec chamber? The hornady 223 match 75gr bthp is too borderline (only about half the rounds will chamber).

Thanks in advance

Did the gunsmith or whoever inspected your rig mention any remedies?
With the right reamer, getting your chamber corrected to allow factory ammo is not difficult for a qualified gunsmith.
In a way, the smith who cut that chamber in the first place should be the one to help you out.
If this is marginal, he may be able to clean it up without a fuss.

 

[Doom]

You have a headspace issue and will likely fight this as long as you own the rifle. You have two options in my opinion:

Correct the headspace by having the chamber recut.
Reset the barrel to correct the headspace if this is a REMAGE barrel
Hand Load your ammunition.

 

[tomme boy]

Your GS needs to fix this on his dime. Or do what I would do and rent a reamer and give it a turn or two and set the HS to what I want. I used to do this with short chambered barrels all the time years ago. Just get a reamer with no throat so that is not changed.