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I'm stumped...bolt won't close

patriot07

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Minuteman
Oct 17, 2017
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Dallas
Defiance action with Bartlein barrel. 175-ish rounds on it. I bought it used (safe queen bought 10 years ago from customer maker and hardly used) and I have only put 15 rounds on it. Original buyer had 160 rounds on it.

All of a sudden the bolt won't close on factory 140 ELD-M ammo. If I really force it, it will barely go, but it takes an insane amount of force. When I extract the round, there are marks all over the bullet (see pic at end).

My handloads are all 140-ELD-M. I made one just for grins with the same results. It will chamber and extract new or fired brass no issue, so the binding is definitely at the bullet. Remainder of the action is smooth. It runs fine with nothing in it obviously, and it ran factory ammo last week no issue. But this week not so much. Can't see anything obvious with the bore camera.

This is a new box of ammo...maybe these bullets are slightly larger? It will cycle factory federal 6.5CM ammo and leave only a light mark...

Is the solution to have a gunsmith just run the reamer in on a clean-up pass?

Pic of new bullet (right) and chambered/extracted bullet (left).

bullets.jpg
 
Defiance action with Bartlein barrel. 175-ish rounds on it. I bought it used (safe queen bought 10 years ago from customer maker and hardly used) and I have only put 15 rounds on it. Original buyer had 160 rounds on it.

All of a sudden the bolt won't close on factory 140 ELD-M ammo. If I really force it, it will barely go, but it takes an insane amount of force. When I extract the round, there are marks all over the bullet (see pic at end).

My handloads are all 140-ELD-M. I made one just for grins with the same results. It will chamber and extract new or fired brass no issue, so the binding is definitely at the bullet. Remainder of the action is smooth. It runs fine with nothing in it obviously, and it ran factory ammo last week no issue. But this week not so much. Can't see anything obvious with the bore camera.

This is a new box of ammo...maybe these bullets are slightly larger? It will cycle factory federal 6.5CM ammo and leave only a light mark...

Is the solution to have a gunsmith just run the reamer in on a clean-up pass?

Pic of new bullet (right) and chambered/extracted bullet (left).

View attachment 8744516
Have you measured the new round vs the extracted round? That is some serious engraving on the extracted round.
 
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Do you have a modified case that you can drop a bullet in and just see where the lands engage at?

It’s nuts that it literally started from nowhere after shooting fine recently but I’d be interested to see where it touches the lands and what the CBTO measurement it compared to the factory loaded rounds.
 
Pull the bullet on a known "hard to close round" and try to chamber that empty case w/o a bullet. That would isolate the possibility of over size cases, which are not uncommon.

You could have more than one thing going on.....

Usually, jamming a bullet into a tight leader or throat that hard would result in a bullet staying stuck in the bore and powder all in the action when extracting the case. Rub marks on the bullet may only be a secondary issue. Maybe, maybe not...

Isolate and remove one thing at a time from the equation.
 
Do you have a modified case that you can drop a bullet in and just see where the lands engage at?

It’s nuts that it literally started from nowhere after shooting fine recently but I’d be interested to see where it touches the lands and what the CBTO measurement it compared to the factory loaded rounds.
Yes I used my hornady oal length gauge and it was crazy short. Like 145 thousandths short of the factory round
 
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The Creedmoor chamber freebore diameter is spec'd at 0.2435". So, if the new bullet is 0.2435" or greater you could have interference fit.

Another possibility is the carbon ring buildup is aggravating the small-ish freebore diameter.
Do you mean .2635?

That may be it - the new bullets (before chambering) are around .2638-.2639 in the section where the marks are showing up
 
Looking at the end of case picture, that seems like where the copper is catching. You can see flakes of it on that edge.

This was a new box of ammo last night. Maybe the bullets were just slightly larger in this box enough to catch? I looked up 6.5CM spec and the .2645 is correct diameter for the space past that lip, and if the bullets are .2638-.2639, they shouldn't be scraping around the entire diameter like that....wonder if it was a slightly worn reamer and we are paying the price a decade later?

ETA - I cleaned and cleaned and cleaned it and it appears maybe there was a light carbon ring. I took a few more new rounds and now the marks are still there, but lighter. The force to close is still there, but lighter. In the bore scope, the black by the end of the case is significantly lighter. Maybe @Terry Cross was correct that it's a couple things - a slightly tight freebore combined with a light carbon ring...

Of course I don't recall other rifles making any mark at all when I chamber a round so maybe there is still something else going on?
 
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Is the profile the same on the two bullets, or is there more taper on the one that chambers easily without the engraving marks? Perhaps it's an optical illusion in the photo, but the bullets look slightly different. to my old eyes. What is the diameter of the bullet just ahead of the case mouths on each bullet in the photo where the problem is occurring?
 
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The Creedmoor chamber freebore diameter is spec'd at 0.2435". So, if the new bullet is 0.2435" or greater you could have interference fit.

Another possibility is the carbon ring buildup is aggravating the small-ish freebore diameter.
That's my vote ... a nasty carbon ring. Maybe there were a few more than 160 rounds through when you bought it.
 
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Looking at the end of case picture, that seems like where the copper is catching. You can see flakes of it on that edge.

This was a new box of ammo last night. Maybe the bullets were just slightly larger in this box enough to catch? I looked up 6.5CM spec and the .2645 is correct diameter for the space past that lip, and if the bullets are .2638-.2639, they shouldn't be scraping around the entire diameter like that....wonder if it was a slightly worn reamer and we are paying the price a decade later?

ETA - I cleaned and cleaned and cleaned it and it appears maybe there was a light carbon ring. I took a few more new rounds and now the marks are still there, but lighter. The force to close is still there, but lighter. In the bore scope, the black by the end of the case is significantly lighter. Maybe @Terry Cross was correct that it's a couple things - a slightly tight freebore combined with a light carbon ring...

Of course I don't recall other rifles making any mark at all when I chamber a round so maybe there is still something else going on?
I've never had this particular issue. Problem is you have no idea if a custom tight reamer was used ect. In you pictures and from your description it seems the problem is the throat/freebore. I see no marks from the lands & no marks on the shoulder datum of the case.
I'd still pick up a go gauge & check but that doesn't look like the problem.

I have had a short reamed 6.5C that wouldn't close on go gauge. It was short enough that factory 130 prime ammo wouldn't close (AR barrel was Larue). My solution for that is the same I'd due in your shoes.

Clymer finish reamer off the shelf at Brownells with a few bushings cost about $200. I just turned by hand with a tap wrench & some tap magic cutting oil. Worked like a champ, gun hammers.
Just stop when you hit the shoulder and should be good to go.
If you don't have a barrel vise then pick up one of the PTG extensions from Midway & you wouldn't even need to remove the barrel.

1754837477421.jpeg



1754836416958.png
 
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Just started happening with a new box of ammo? Did I read that correctly? Hornady? Compare bullet measurements, ogive location, and loaded round measurements. The rifle didn’t magically contract suddenly.
Bullet measurements are identical between this new box of loaded ammo and my box of individual bullets for reloading.

I think it just so happened to occur when I went to a new box of ammo. Minor carbon ring combined with slightly tight freebore.
 
I've never had this particular issue. Problem is you have no idea if a custom tight reamer was used ect. In you pictures and from your description it seems the problem is the throat/freebore. I see no marks from the lands & no marks on the shoulder datum of the case.
I'd still pick up a go gauge & check but that doesn't look like the problem.

I have had a short reamed 6.5C that wouldn't close on go gauge. It was short enough that factory 130 prime ammo wouldn't close (AR barrel was Larue). My solution for that is the same I'd due in your shoes.

Clymer finish reamer off the shelf at Brownells with a few bushings cost about $200. I just turned by hand with a tap wrench & some tap magic cutting oil. Worked like a champ, gun hammers.
Just stop when you hit the shoulder and should be good to go.
If you don't have a barrel vise then pick up one of the PTG extensions from Midway & you wouldn't even need to remove the barrel.

View attachment 8744714


View attachment 8744709
I have a barrel vise but no action wrench for the Defiant and I have no idea how much it was tightened and would rather not mar up the gun-kote finish. Do you have any interest renting out the tools?
 
That's my vote ... a nasty carbon ring. Maybe there were a few more than 160 rounds through when you bought it.
Perhaps, but he is a guy with a good reputation on the local forum and like 20k posts with nothing but positive reviews, and he had a log book showing the rounds. So I don't suspect that to be the case, but obviously I have no way of knowing for certain.

I do know he was reloading for it and can't remember the powder, so it's possible he was using a powder more prone to carbon deposits? I don't know specifically what causes the carbon ring honestly, although I did have a carbon ring show up on my Tikka around the 500 round mark if I recall. No bullet interference or bolt issues - just crap accuracy
 
Is the profile the same on the two bullets, or is there more taper on the one that chambers easily without the engraving marks? Perhaps it's an optical illusion in the photo, but the bullets look slightly different. to my old eyes. What is the diameter of the bullet just ahead of the case mouths on each bullet in the photo where the problem is occurring?
Same profile
 
The new bullets are just slightly larger Im guessing. The reamer was probably tight in the throat to start with. I have sent back a few reamers with undersized throats. A good smith can tell you the actual diameter for free and fix it for pretty cheap. Guage pin on a magnet works, I use an aluminum rod with bore and set screw to hold pins to check that.
 
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I am going to take a shot in the dark on this one. If you are shooting with a suppressor, check to see if there are any carbon deposits on the bolt face. I had a similar incident a couple of years ago. If you have loose carbon in the suppressor and set the gun down on the butt the loose carbon lands on the bolt face and effectively decreases the headspace. A small speck of hard carbon prevented me from closing the bolt no matter how hard I tried. This has happened to me at least three times. I full lenght size my ammo with about .002" shoulder setback. I now clean my suppressor regularly.
 
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I had exactly the same marks on a new 6mm barrel - 6mm GT. Turns out the barrel was reamed not with a SAMMI 6GT spec reamer but more like an older .243 reamer. My guess is that they didn't have the newer SAMMI reamer for the 6 GT. Get a new reamer (SAMMI spec) and have it redone on the same barrel. Make sure your gunsmith is aware of the issue.

Image below:

IMG_3467-Edit.jpg
 
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I had exactly the same marks on a new 6mm barrel - 6mm GT. Turns out the barrel was reamed not with a SAMMI 6GT spec reamer but more like an older .243 reamer. My guess is that they didn't have the newer SAMMI reamer for the 6 GT. Get a new reamer (SAMMI spec) and have it redone on the same barrel. Make sure your gunsmith is aware of the issue.

Image below:

View attachment 8745234
Looks very similar to the issue I'm having. Thanks for the info
 
I don't know if you have a bronze brush. If you do, see if you can brush out the transition (end of case area). If not, you are going to need a lot of Boretech Cu2+ applications to remove that ammount of copper.

Doesn’t look like much of a carbon ring, if any, but you can see a lot of copper at the edge that will just get worse the more you try to chamber a cartridge.

If you can get ahold of the reamer drawing from the previous owner, I think that you will find that the freebore is very close to bullet diameter. I suspect that any secant ogive bullet with a long bearing surface, loaded long, will be scratched by that transition.
 
I don't know if you have a bronze brush. If you do, see if you can brush out the transition (end of case area). If not, you are going to need a lot of Boretech Cu2+ applications to remove that ammount of copper.

Doesn’t look like much of a carbon ring, if any, but you can see a lot of copper at the edge that will just get worse the more you try to chamber a cartridge.

If you can get ahold of the reamer drawing from the previous owner, I think that you will find that the freebore is very close to bullet diameter. I suspect that any secant ogive bullet with a long bearing surface, loaded long, will be scratched by that transition.
When I saw that my thought was the copper from the bullet jacket is getting scraped off by the carbon.
 
I don't know if you have a bronze brush. If you do, see if you can brush out the transition (end of case area). If not, you are going to need a lot of Boretech Cu2+ applications to remove that ammount of copper.

Doesn’t look like much of a carbon ring, if any, but you can see a lot of copper at the edge that will just get worse the more you try to chamber a cartridge.

If you can get ahold of the reamer drawing from the previous owner, I think that you will find that the freebore is very close to bullet diameter. I suspect that any secant ogive bullet with a long bearing surface, loaded long, will be scratched by that transition.
That's pretty much what's going on. I think I need to just run a reamer in there to open it up to saami spec, and I think the issue will go away.
 
Looks very similar to the issue I'm having. Thanks for the info
You're welcome. I did research on this issue and I'm probably let my barrel wear out. A 6 GT is a barrel burner anyways and after 200 rounds it has gotten a lot better because the first point of wear is in the throat area. My bolt is already closing almost perfectly and extracting well. Once in a while I get a had close but it's gotten minimal now. I have a Defiance action as well.
 
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You're welcome. I did research on this issue and I'm probably let my barrel wear out. A 6 GT is a barrel burner anyways and after 200 rounds it has gotten a lot better because the first point of wear is in the throat area. My bolt is already closing almost perfectly and extracting well. Once in a while I get a had close but it's gotten minimal now. I have a Defiance action as well.
Does it shoot well?
 
Tough call! The more you magnify you see stuff that might not be an issue.

The other hard part about looking at your pic's is.... "what did it look like before the gun had any rounds fired thru it?"

How many rounds are on it?

Is it shooting good?

My one guess is the carbon ring is not causing the issue of leaving marks on the bullet. The throat is undersize on how the reamer cut.
 
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Looking at the end of case picture, that seems like where the copper is catching. You can see flakes of it on that edge.

This was a new box of ammo last night. Maybe the bullets were just slightly larger in this box enough to catch? I looked up 6.5CM spec and the .2645 is correct diameter for the space past that lip, and if the bullets are .2638-.2639, they shouldn't be scraping around the entire diameter like that....wonder if it was a slightly worn reamer and we are paying the price a decade later?

ETA - I cleaned and cleaned and cleaned it and it appears maybe there was a light carbon ring. I took a few more new rounds and now the marks are still there, but lighter. The force to close is still there, but lighter. In the bore scope, the black by the end of the case is significantly lighter. Maybe @Terry Cross was correct that it's a couple things - a slightly tight freebore combined with a light carbon ring...

Of course I don't recall other rifles making any mark at all when I chamber a round so maybe there is still something else going on?
To the question of the throat diameter being .2645" and your bullet diameter of .2638"/.2639".

How many chambers has that reamer cut? The first thing that goes on a reamer is the throat. Even if you use a roughing tool when you go to finish chamber that finish reamer the throat area of the reamer is always cutting.

I've seen brand new reamers where they were not ground correctly or should I say not to the correct dimensions. Or it can be ground to the correct dimensions but will not cut to spec.

We have multiple caliber reamers where the throat area is a tight spec. In some cases we will or have to ball gage this area for inspection for ammunition test barrels. There is a range on the depth that the ball gage has to be in. Also we will take live rounds (box ammo) and drop it into the chamber by hand and check for it sticking and or leaving any marks on the bullet. If the ball gage is out of spec and or leaving marks on the bullet... either the reamer is going or if it's a brand new tool it wasn't ground properly. Pretty easy check to do. We've even taken reamers and had them checked/measured on a CMM machine to figure out what the heck is going on.

This is another reason why we don't use reamers from a rental place. No one has ever been able to tell me... how many barrels has it been used in? How has it been treated? Was it used in a c.m. steel barrel or a s.s. steel barrel? When was the last time it was resharpened?

How many times it was used? Yes it can make a difference. There can be a build up on the tool and it can cause it to cut differently.

Later, Frank
Bartlein Barrels
 
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To the question of the throat diameter being .2645" and your bullet diameter of .2638"/.2639".

How many chambers has that reamer cut? The first thing that goes on a reamer is the throat. Even if you use a roughing tool when you go to finish chamber that finish reamer the throat area of the reamer is always cutting.

I've seen brand new reamers where they were not ground correctly or should I say not to the correct dimensions. Or it can be ground to the correct dimensions but will not cut to spec.

We have multiple caliber reamers where the throat area is a tight spec. In some cases we will or have to ball gage this area for inspection for ammunition test barrels. There is a range on the depth that the ball gage has to be in. Also we will take live rounds (box ammo) and drop it into the chamber by hand and check for it sticking and or leaving any marks on the bullet. If the ball gage is out of spec and or leaving marks on the bullet... either the reamer is going or if it's a brand new tool it wasn't ground properly. Pretty easy check to do. We've even taken reamers and had them checked/measured on a CMM machine to figure out what the heck is going on.

This another reason why we don't use reamers from a rental place. No one has ever been able to tell me... how many barrels has it been used in? How has it been treated? Was it used in a c.m. steel barrel or a s.s. steel barrel? Yes it can make a difference/leave a build up on the tool and it can cause it to cut differently.

Later, Frank
Bartlein Barrels
Frank
How many barrels can a typical reamer cut before they need to be replaced?
 
Are you sure the bullets measure .2638"/.2639".

Are you sure your mic or measuring tool is properly calibrated and reading correctly?

I ask not to be offensive at all but more often than not what you measure and what you use vs what tools the manufacturer has and uses the measurements are not even close.

Think of this for a minute... let's say your reamer actually cut undersize by a couple/few tenths. Let's say the reamer actually cut the throat at .2642". Then let's say your bullets are actually measuring .2642". Your size on size. Bullets could be in spec but the throat is undersize and causing your issue.

I don't recall or know offhand the actual spec. Hornady makes the 140 ELDM's to. Usually a bullet maker has a standard spec for a given bullet. I'm guessing here so bear with me and don't call Hornady and say... Frank said So!

Let's assume Hornady makes those bullets to a min spec. of .2640" with a tolerance of +.0002". That could give you bullets in the same lot measuring from .2640" to .2642".

Even if the reamer is spec'd at .2645". Now let's say the bullets measure .2642". That doesn't leave a whole lot for clearance per side. Total it leaves you only .0003" total clearance on the diameter. Your numbers start to stack and presto... you have issues.

I've seen it with 300AAC as well. The clown that spec'd the chamber spec'd the throat at .309" diameter. Well guess what they did.... they spec'd the bullet could be as large as .309" diameter and I've actually measured reference ammo where the bullets measured .309" diameter. Then a brand new reamer we had cut the throat at .3088" to .3089". Guess what? The rounds wouldn't go into the chamber. The rim thickness of the case actually stuck out of the chamber around .050"! Pressure jumped 6k psi on a pressure test barrel and velocity jumped like 75fps. on the spec reference ammo.
 
Frank
How many barrels can a typical reamer cut before they need to be replaced?
That can vary quite a bit!

Type and quality of steel can play a part, your set up and type of coolant being used for lubrication etc... as well as how the tool is cared for.

Is it a carbide tool or a HSS tool? Carbide will last longer typically.

I've seen 5.56 reamers and 7.62 spec. reamers and even 50BMG reamers when we make ammunition test barrels and using carbide reamers get say 40 barrels out of a tool and I've seen as much as up to 80 out of a tool. Even have seen HSS go that long also but it's not the norm. Yes we have to ball gauge / measure 10 different areas of the chamber and two of those dimensions we check have to be in the throat area of the chamber and they've all been in spec.
 
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That can vary quite a bit!

Type and quality of steel can play a part, your set up and type of coolant being used for lubrication etc... as well as how the tool is cared for.

Is it a carbide tool or a HSS tool? Carbide will last longer typically.

I've seen 5.56 reamers and 7.62 spec. reamers and even 50BMG reamers when we make ammunition test barrels and using carbide reamers get say 40 barrels out of a tool and I've seen as much as up to 80 out of a tool. Even have seen HSS go that long also but it's not the norm. Yes we have to ball gauge / measure 10 different areas of the chamber and two of those dimensions we check have to be in the throat area of the chamber and they've all been in spec.
Thank you! I knew that was a loaded question with multiple variables, but you did a good job answering it anyway.

A friend has a semi-custom reamer that has been getting passed around a lot. The same gunsmith is doing the chambers but several barrels have been cut and I doubt anyone knows how many it has done. I haven't heard of any issues with it but it seems like it might be time to order my own reamer.
 
Thank you! I knew that was a loaded question with multiple variables, but you did a good job answering it anyway.

A friend has a semi-custom reamer that has been getting passed around a lot. The same gunsmith is doing the chambers but several barrels have been cut and I doubt anyone knows how many it has done. I haven't heard of any issues with it but it seems like it might be time to order my own reamer.
If you for see yourself putting multiple barrels on your gun / or guns and for the cost of say $250 for a reamer and add gauges in there as well... it's not that expensive in the long run. Also when it's time to get resharpened it's about half the cost to resharpen it. If I recall correctly we are getting two resharps on a tool.

So even if you are only getting say 10 barrels out of a tool it works out to say $25 a barrel. That being said... for the amount of barrels we get out of a tool... let's say 40...that works out to a cost per barrel of only $6 or so.

Then you have your own tool and know what's being done with it etc...

JGS Precision Tools or Manson is who we use. Get a reamer with interchangeable pilots. For example if it's a 308win. reamer and your using our barrels. I'd get a .2996" pilot bushing put on it.

If your going to use it in other brands of barrels you have to watch the bore size. If the bore is tighter or looser then just order a couple of extra bushings for it.
 
Just to chime in, this barrel WAS NOT chambered by Bartlein. This was done by a gunsmith nearly a decade ago.

I think the real culprit was a carbon ring and a tight chamber. I cleaned the carbon out again just for good measure and did some load development this morning. Looks like a Bartlein doing Bartlein things...thanks @Frank Green for your excellent work

View attachment Bartlein groups.jpg
 
I had exactly the same marks on a new 6mm barrel - 6mm GT. Turns out the barrel was reamed not with a SAMMI 6GT spec reamer but more like an older .243 reamer. My guess is that they didn't have the newer SAMMI reamer for the 6 GT. Get a new reamer (SAMMI spec) and have it redone on the same barrel. Make sure your gunsmith is aware of the issue.

Image below:

View attachment 8745234
Please name the shop that cut a 6GT with a .243 reamer. Please!
 
I had exactly the same marks on a new 6mm barrel - 6mm GT. Turns out the barrel was reamed not with a SAMMI 6GT spec reamer but more like an older .243 reamer. My guess is that they didn't have the newer SAMMI reamer for the 6 GT. Get a new reamer (SAMMI spec) and have it redone on the same barrel. Make sure your gunsmith is aware of the issue.

Image below:

View attachment 8745234
This was probably about the time the 6GT got SAAMI approval. I heard there were some discrepancies between the SAAMI approved GT and the original .120 FB GT drawings and the two didn't necessarily play nice for everyone.