I'm completely stumped on this one.

[mattp8893]

I'll do my best to explain but I may not get my point across very well in text so anything y'all don't understand just ask and I'll try to clarify.

I'm running a tikka t3x in 6.5 creedmoor. The action is the only thing stock on this it's not a ctr or anything. First off my brass is full length sized back .001-.002 every time it's annealed and trimmed every firing as well. I've had this happen a few times but recently it has been happening ALOT. So loaded rounds will hardly load. They go in the chamber fine but when it gets to that last hair and closing the bolt it's very hard to get it to close and you have to beat the bolt back open on an unfired case. But once fired there's no problem taking it out. No heavy bolt lift no pressure signs nothing the problem is solely with unfired rounds. I was running h4350 and had this problem some but not much. I recently ran out and decided to swap to reloader 16 and that's when it started happening a lot. I doubt the powder has anything to do with it but just covering all bases. I can put the sized case in the chamber and it closes perfectly fine. I can load it and the problem begins. I have even taken some that wouldn't close and pulled the bullet dumped the powder and chambered it and it chambers perfect again. I've checked headspace with it loaded and it's the same as freshly sized. I covered a case in sharpie this morning and chambered it a couple times and couldn't find any wear marks on the case. Any help would be greatly appreciated to what this could be


Sent from my iPhone using Tapatalk

 

[Sheldon N]

Carbon ring in the throat would be my first thought.

 

[spife7980]

You say getting to the last bit and closing, do you mean the last bit of the bolt still moving forward to get the lugs to clear and then still has the whole rest of the trip down or are you experiencing it after the lugs are twisting and at the end of the knobs downward trip? The first sounds like it's something being too long or a carbon ring cutting the effective distances down as sheldon said and the second idk galling maybe?

Everything lubed up and clean?

 

[mattp8893]

Carbon ring in the throat would be my first thought.

Cleaned it very heavily lastnight including the chamber because I thought I might have build up in the chamber and it didn't help


Sent from my iPhone using Tapatalk

 

[mattp8893]

You say getting to the last bit and closing, do you mean the last bit of the bolt still moving forward to get the lugs to clear and then still has the whole rest of the trip down or are you experiencing it after the lugs are twisting and at the end of the knobs downward trip? The first sounds like it's something being too long or a carbon ring cutting the effective distances down as sheldon said and the second idk galling maybe?

Everything lubed up and clean?

Yeah the last bit to get the lugs to clear before I start the bolt down at all. I don't know how or if it's possible but it's almost like the case itself expanded and chamfering it squeezes it back down because after chambering that one with sharpie a couple times then it went right in like nothing was wrong when I actually fired it a couple hours ago. My chamber was cut with Sami spec reamer and I think my smith went alittle too deep when I checked my chamber length for what to cut it was so much longer than my brass that with them on the 6th firing I don't think they would even be to full length if I hadn't trimmed at all.


Sent from my iPhone using Tapatalk

 

[Pakratt99]

What's your process for annealing? Also any chance after you had one load stiff, before forcing it you pulled the case and knocked the head out to take measurements? I've seen something similar with a friend who was annealing by eye with a MAP torch and made the necks WAY too soft so they turned into mush when being chambered and produced issues.....

 

[maggitas]

Have you checked the seating depth of the rifle. try decreasing you COAL and see what happens

 

[Milo 2.5]

Chamber a loaded rd and see if the bullet is scuffed up. I just built a 6 creed, was going to run Norma MRP as the powder, had 40rds down it, ended up buying factory ammo to shoot cause I was too lazy to load, it put a carbon ring in throat from hell. I was lucky enough to have my press at the range next outing, and when it did not chamber, seated bullet 40 thou deeper and blew it out.
When you clean your throat for a carbon ring, need to get a 7mm brush and jack it off the throat, with a decent solvent.

 

[mattp8893]

What's your process for annealing? Also any chance after you had one load stiff, before forcing it you pulled the case and knocked the head out to take measurements? I've seen something similar with a friend who was annealing by eye with a MAP torch and made the necks WAY too soft so they turned into mush when being chambered and produced issues.....

I use an annealeze but I'm very careful if anything I don't anneal enough instead of roasting them


Sent from my iPhone using Tapatalk

 

[mattp8893]

Chamber a loaded rd and see if the bullet is scuffed up. I just built a 6 creed, was going to run Norma MRP as the powder, had 40rds down it, ended up buying factory ammo to shoot cause I was too lazy to load, it put a carbon ring in throat from hell. I was lucky enough to have my press at the range next outing, and when it did not chamber, seated bullet 40 thou deeper and blew it out.
When you clean your throat for a carbon ring, need to get a 7mm brush and jack it off the throat, with a decent solvent.

I marked an entire case and bullet with sharpie and it showed no scuffs anywhere on the case or the bullet. Right above the collar it was debatable if there might be a small bit of wear there but not enough to be definitive I'll try decreasing the seating depth and see if that will make them chamber easier but I should be .025 off the lands atleast. Maybe a little more. I saw enough people say that you could seat into the lands easily with the hornady seating depth gauge enough that I took .005 off what it showed and used that for my to the lands number and went from there


Sent from my iPhone using Tapatalk

 

[Gohring65]

Did you try to screw your die down until one chambered?
Take the firing pin out of the bolt and screw the die down very little at a time until it chambers then measure compared to a case that's been fired more than once.

 

[mattp8893]

Just seated some 40 thousands deeper than my normal seating depth like suggested and the bolt closes fine on them. For what that's worth


Sent from my iPhone using Tapatalk

 

[maggitas]

carbon ring is looking like a good call.

 

[jfields]

Carbon ring. It can be a real bitch to get out, too. I have a Lyman bore scope and it has really been an asset with issues like this.

-J

 

[culater]

I would go to 6mmbr.com and ask the question thier

 

[mattp8893]

I'm running mine at .025 off the lands but yes I believe it was a carbon ring. I have a buddy that's friends with josh at pva and he said injector cleaner worked best for removing them so I bought some sea foam soaked an oversized mop and let it set for about 20 minutes and it seems to have fixed it.

I'm still confused on how a carbon ring even builds up. It just doesn't seem possible since a bullet is flying down the barrel every shot seems like it wouldn't be able to build up. Anyone know what causes it?


Sent from my iPhone using Tapatalk

 

[Gohring65]

You can buy a Sinclair chamber length gauge, measure and trim you brass to match your chamber, ( I trim .005" under my chamber length). And it will help in eliminating a carbon ring.

 

[shoot4fun]

I use an annealeze but I'm very careful if anything I don't anneal enough instead of roasting them


Sent from my iPhone using Tapatalk

Under-annealed is like not doing it at all, only you are wasting your time. You say in the initial post that you move the shoulder back .001 to .002. I know most calipers will have close to that in error margin but you, if annealed properly, should not have any variance in that number. You can still get a lot of life from brass if you take the shoulder back .003 and reliability will be better.
Now, as one who has shot a fair amount of RL16, I had to agree with what the guys who pointed to carbon ring said. RL16 is very sooty and it takes a lot of cleaning to get that carbon ring out once it gets ensconced. I use a battery powered drill, short coated cleaning rod piece & nylon bore brush to clean it out. Put some Iosso or JB Bore Paste on the patch and put it over the end of the brush. go just up into the area of the leade/throat and clean the crap out of it. Don't hit the body of the chamber because you don't want that polished. What will happen is your carbon ring will vanish and the throat will be nicely polished. DO NOT be too aggressive with this process and keep that rod from scratching chamber walls. i do it all the time and it will improve your accuracy.

 

[mattp8893]

Under-annealed is like not doing it at all, only you are wasting your time. You say in the initial post that you move the shoulder back .001 to .002. I know most calipers will have close to that in error margin but you, if annealed properly, should not have any variance in that number. You can still get a lot of life from brass if you take the shoulder back .003 and reliability will be better.
Now, as one who has shot a fair amount of RL16, I had to agree with what the guys who pointed to carbon ring said. RL16 is very sooty and it takes a lot of cleaning to get that carbon ring out once it gets ensconced. I use a battery powered drill, short coated cleaning rod piece & nylon bore brush to clean it out. Put some Iosso or JB Bore Paste on the patch and put it over the end of the brush. go just up into the area of the leade/throat and clean the crap out of it. Don't hit the body of the chamber because you don't want that polished. What will happen is your carbon ring will vanish and the throat will be nicely polished. DO NOT be too aggressive with this process and keep that rod from scratching chamber walls. i do it all the time and it will improve your accuracy.

This actually began with the 16 I have run exclusively h4350 until this past week. I ran out of the 4350 and we all know how hard it is to get. So I decided to swap to 16 I think the carbon ring was present but some of it was also my brass spring back. As far as under annealing I don't believe I go too low but I'd say I'm closer to that side than I am seeing all crazy colors in the flame and ruining my brass. I started getting lazy during brass sizing as I was in a hurry and had a lot to do. And may have been shorting them trying to keep them closer to .001 back. I actually went over to my small time smiths to get his help on the carbon ring and he was having the same problem with his 7br he said that it was his brass not being sized enough. We smashed a couple of mine back alittle more than I would have probably .006 but it completely fixed the little bit of problem that was left after the carbon ring removal and I've gone back and sized most of mine again trying to stay in the .003-.004 area and it's running flawlessly and still keeping the accuracy and sd but my speed has dropped about 20 fps which is understandable given it's having to expand the case more


Sent from my iPhone using Tapatalk