Bolt won't close on new rifle

[the_marshall]

I purchased a new rifle in 6.5CM on a LPA Fuzion action. The rifle shoots great (a bit over 0.5MOA, but I'm pretty sure that's my fault), but I have the following issue:

Factory Hornady ammo (140gr black and 140gr match) won't chamber. When I apply pressure, then extract the ammo, I can see a ring around the bullet where the lands (I assume) scratch it. See photo. I'm unsure on this as the scratch is essentially symmetrical and doesn't show rifling.

I followed the barrel break-in procedure from Hawk-Hill ((shoot then clean) 5 times, followed by (shoot 3 then clean) 3 times). After that I shot regularly for a total of 70 rds (counting break in). The last few rounds of the 70 were a bit hard to feed. Then I switched to a new box and the bolt won't close (at least not with reasonable force. I haven't tried anything extreme.

I've measured the rounds and they all seem to be in spec. I'm wondering what could cause this. My best guess is something got scraped into the chamber and is stuck before the lands. I'm unsure on this because it seems very symmetrical for scraped debris / copper / whatever. I would assume debris would mostly occur at the bottom of the chamber, while the marking is almost perfectly symetrical. Is there a good way to test this without buying a bore scope? If this is the case, do I just apply solvent and scrub vigorously? Will this damage the barrel?

(Image shows handloaded 140gr berger, 140gr Hornady match and 140gr Hornady black. The handload is adjusted so it chambers without issue.)

 

[NWnewguy]

Do you have another box of ammo to try?

Seems odd that it would chamber fine for the first few boxes then have issues. Seems light on round count to be a carbon ring issue. Not reloaded brass so it can't be a neck donut.

Assuming that it headspaces correctly, I would have to point, at least initially with the limited info that I have, that you got a box of ammo that could be out of spec, or at least your chamber doesn't like it.

I would buy a borescope either way though. The new digital ones are amazing for the money and have really removed the cost of entry prohibiting purchase.

 

[Wheres-Waldo]

Brush & swab out chamber/neck/throat
Bore snake or similar through bore
Remove FP ASSY from body
Try chambering

 

[Mike_in_FL]

I would try copper remover in the throat. These are pretty popular for 50 bucks: https://smile.amazon.com/Teslong-Bo...ong+borescope+2mm&qid=1583282386&sr=8-2-fkmr2

Or you can buy the Hornady OAL tool and measure how far to the lands.

 

[Rob01]

140 ELDs are .070" off the lands with a SAAMI spec chamber. Who chambered the rifle and what reamer did they use? What ammo did you use with the 70 rounds?

It's obvious the handload is set back farther. I would try and give it a good cleaning and see what happens. If factory rounds chambered and then didn;t there must be something going on in the chamber.

 

[Lowlight]

You broke it breaking it in ... should have just shot it vs doing that silly shoot one, clean, shoot 3, clean, etc,

Chamber looks short, the Berger handload is working because the Ogive is back farther even though the OAL appears the same.

It could be a carbon ring in there, but if you were cleaning it, it should not be right?
Check for a ring then check the chamber I bet it's short,

 

[jwood1284]

Looks like a short chamber to me.

 

[Namekagon]

I also suspect short chamber. I bet you would see lands if you pushed the bolt forward until it stopped, then extracted the round without fully closing the bolt. Forcing the bolt to close could be rotating the round in the chamber, causing the lands to circumscribe the scratch around the bullet.

The reason the problem was worse when you switched boxes is either a different seating depth for that lot of ammo, or slightly different bullet geometry for that lot of bullets. I've seem some very big swings in location of the ogive on a bullet from lot to lot.

 

[KAIFS]

OAL and Ojive are two different things. as posted above, you might have a short chamber (my guess) or a carbon ring (however, does not sound as you shot it enough to develop that already). Easiest thing to do is make a quick chamber cast and just measure it - could be as simple as gunsmith (or you if you are competent enough) taking a bit off with a finishing reamer...
one way or another, sucks arse you are dealing with this on a new rifle...
as far as break in - everyone has an opinion... I break in ALL of mine new Krieger barrels with my way of breaking in a barrel. Never had I f.cked up a chamber by my break in... I guess I am just lucky.

 

[4066.5]

You can color the bullet with a sharpie on a factory load and then do this

If you want to compare different rounds or use the Hornady OAL tool, measure the base to datum and keep that consistent or at least keep track of it. The Hornady modified case may be different then the case your using.

 

[the_marshall]

Thanks for all the advice. I should have mentioned that the issue came up half-way through boxes of ammo (I shot 10 shots from each box a week ago and was shooting again yesterday to get chronograph data at different temps). So I'm skeptical that the ammo is the issue. Unfortunately I didn't measure any of the other bullets before shooting. I've ordered a bore scope and will update when it arrives.

 

[Boatninja]

I just had a similar thing happen with rifle with around 500 rounds on it, took it to gun shop with bore scope that revealed s copper deposit. Anybody explain this to me or is this to be expected? I have been soaking with Wipe O## and scrubbing, for a week and still have a smudge of copper. I don’t want to hijack thread or do anything unethical, will move or cease if needed.

 

[the_marshall]

Here are two sets of 3 pictures from the bore scope at 0 and 180 degrees rotation about the bore axis. Sequences show lands, then free bore then something at the end of the cartridge. Maybe a carbon ring? Seems very odd at this round count though.

 

[Mike_in_FL]

I just had a similar thing happen with rifle with around 500 rounds on it, took it to gun shop with bore scope that revealed s copper deposit. Anybody explain this to me or is this to be expected? I have been soaking with Wipe O## and scrubbing, for a week and still have a smudge of copper. I don’t want to hijack thread or do anything unethical, will move or cease if needed.

I've always had better luck with ammonia based copper removers like Barnes or Sweets 762. I don't really ever follow a break in, my break is is sighting in and trying out different loads. I've only had one barrel give me grief and after cleaning it with Sweets it will do 1/2 moa. Just be aware that once you strip out all the copper you're going to be putting some back in the barrel so don't be surprised if it takes some rounds to settle down.

 

[Terry Cross]

The rub marks are all the way around your bullets.
If the lead was too short, the only marks would be where the lands/throat are engaging the ogive.
Yours do not look like clean throat engraving.

If this rifle is new, my money is that whoever chambered the barrel could have had a reamer with considerable wear in the lead/freebore section leading to the throat.
As mentioned in a separate thread a week or so ago, this is fairly common and rarely caught especially if using HSS reamers.

If this is the case with your barrel, the lead/freebore is rough and under-size.
If the very first rounds didn't exhibit this conflict, the condition would produce such an interference after just a few rounds.

This should be an easy fix.

I would suggest that you contact the builder of the rifle regarding your issue rather than spending energy and time on internet forums.

./

 

[lennyo3034]

The rub marks are all the way around your bullets.
If the lead was too short, the only marks would be where the lands/throat are engaging the ogive.
Yours do not look like clean throat engraving.

If this rifle is new, my money is that whoever chambered the barrel could have had a reamer with considerable wear in the lead/freebore section leading to the throat.
As mentioned in a separate thread a week or so ago, this is fairly common and rarely caught especially if using HSS reamers.

If this is the case with your barrel, the lead/freebore is rough and under-size.
If the very first rounds didn't exhibit this conflict, the condition would produce such an interference after just a few rounds.

This should be an easy fix.

I would suggest that you contact the builder of the rifle regarding your issue rather than spending energy and time on internet forums.

./

Damn. All my projectiles in all my guns look like this if I unchamber them.

 

[Mike_in_FL]

The rub marks are all the way around your bullets.
If the lead was too short, the only marks would be where the lands/throat are engaging the ogive.
Yours do not look like clean throat engraving.

If this rifle is new, my money is that whoever chambered the barrel could have had a reamer with considerable wear in the lead/freebore section leading to the throat.
As mentioned in a separate thread a week or so ago, this is fairly common and rarely caught especially if using HSS reamers.

If this is the case with your barrel, the lead/freebore is rough and under-size.
If the very first rounds didn't exhibit this conflict, the condition would produce such an interference after just a few rounds.

This should be an easy fix.

I would suggest that you contact the builder of the rifle regarding your issue rather than spending energy and time on internet forums.

./

This always makes me wonder if gunsmiths still buy roughing and finishing reamers or if you can even get reamers sharpened these days.

 

[2aBaC̶a̶]

Here are two sets of 3 pictures from the bore scope at 0 and 180 degrees rotation about the bore axis. Sequences show lands, then free bore then something at the end of the cartridge. Maybe a carbon ring? Seems very odd at this round count though.

Can you focus your borescope a little better? Maybe screwing the tip in or out?

Kinda looks like a carbon ring in a couple of those but hard to tell.

 

[Terry Cross]

Am I tracking that this rifle has 70'ish rounds down a new barrel?

If so, why would anyone think a carbon ring is causing an issue?


./

 

[Dthomas3523]

Am I tracking that this rifle has 70'ish rounds down a new barrel?

If so, why would anyone think a carbon ring is causing an issue?


./

My thoughts exactly. I’d have pulled the eject and firing pin, confirmed the bold didn’t drop free, and then sent it back to builder for fixing.

 

[the_marshall]

Here are better-focused pictures. I'll ask the gunsmith if I have to, but I don't want to make extra work for him if it's something I did wrong. The rifle ran fine at first, so I suspect the problem is on my end. That being said, I've never had this issue before and I've shot thousands of rounds through other guns. This is my first "custom" rifle, so maybe the tighter tolerances exacerbate something I do wrong?

 

[Dthomas3523]

Take the ejector and firing pin out. Pull a bullet from the factory ammo. Make sure the bolt falls free with the bass.

Then take loaded round and see if the bolt falls free. If it doesn’t, the bullet is jammed in the lands and either way, your Smith is gonna have to deal with it.

 

[Terry Cross]

I'll ask the gunsmith if I have to, but I don't want to make extra work for him if it's something I did wrong. The rifle ran fine at first, so I suspect the problem is on my end. That being said, I've never had this issue before and I've shot thousands of rounds through other guns. This is my first "custom" rifle, so maybe the tighter tolerances exacerbate something I do wrong?

In my opinion, there is nothing you could have done even on purpose to cause this problem.

....AND even if you did cause it, you cannot fix this without correct tools and expertise.

This is not a "carbon ring".
This will not go away with lapping or chemicals.
This will not get better with more shots down the bore (it will get worse and quickly)
This cannot be resolved by changing ammo specs.

The radial direction of the scoring and blemishes are something that happened between the time the Hawk Hill was put in the lathe and the time it was removed.

As outlined above, it is possible for the rifle to run ok with this condition at first. I believe even your first rounds were rubbing and creating resistance but the first few shots started to build the interference between the bullets and the flaws where the (smooth) freebore and throat should have been. Even a couple ten thousandths matter greatly in the lead area.

This could happen to anybody building guns/chambering barrels but if the shop inspects the work with a borescope prior to shipping (most don't) and/or they at least shoot some control groups and do a complete function test on the gun with live ammo the work would never leave their shop before being corrected.

I would encourage you to contact the maker for a resolution.
I have seen a shit ton of fucked up barrels due to the users being idiots and creating their own issues. I do not believe this is the case here.


./

 

[fdkay]

Terry has given you the answer.
Follow his advice.

 

[Terry Cross]

The first image in your post #21 shows that your chamber has no throat at all as best I can tell.
There is no transition from freebore to the lands.

Maybe someone smarter than me can give an alternative argument.

Still waiting on some of the previous posters above to expand on why you think he had a carbon ring issue at 70 rounds. Is that really a thing?


./

 

[mudpig]

I agree with Terry on this. You can see the VERY short taper the lands, but this even looks too short for a typical 1'30" degree cut and there is NO freebore section at all.

 

[Snuby642]

Strait back to the manufacturers, asap.

Forgot finishing reamer?

 

[Lowlight]

LOL

I have a feeling he took me seriously when I said he broke it breaking it in ...

 

[the_marshall]

LOL

I have a feeling he took me seriously when I said he broke it breaking it in ...

No, just my wishful thinking, hoping it was something I could fix in time for a match next weekend.


Thanks for all the help guys! I'll contact the gunsmith.

 

[Dthomas3523]

The first image in your post #21 shows that your chamber has no throat at all as best I can tell.
There is no transition from freebore to the lands.

Maybe someone smarter than me can give an alternative argument.

Still waiting on some of the previous posters above to expand on why you think he had a carbon ring issue at 70 rounds. Is that really a thing?


./

Because everyone always gives generic answers without reading the actual scenario.

Happens every time someone puts up an issue.