Chambering issue

[D-Money97]

First time poster here looking for some input,
Recently picked up a prefit for an American rifle company Nucleus. Chambered in 6.5 creedmoor. I bought it second hand with low round count. Spun it onto my action and torqued it down. Doesn’t close on a no go, closed on go gauge, little tight, but good to go. Trying to run a 140 EldM. Sat at 2.800 COAL and 2.180 +- .02 BTO I get a really stiff bolt close and when removing a complete round, I get pretty heavy marks on the bullet between the case and the ogive. I have to seat that particular bullet clear down around 2.700 in order to get lighter(not completely gone) marks on the bullet. I have some 153 a tips on hand, sat at 2.800 and a BTO of 2.135 they close no problem, no marking on brass. I had a box of factory 143 eldx on hand that also received scuffs attempting to chamber too. First prefit experience(more than fine saying that and if I did something wrong on my end I’m okay with that) and pretty sure I’m doing everything correctly. Previous owner was running 140 RDFs at 2.830 COAL and 2.096 BTO. Borrowed a scope from a friend and did some inspecting and found a pretty decent carbon ring built up(I suspect, from what I’ve gather reading some other forums). Got what I would believe to be pretty well cleaned up(hard to tell with the focus ability of the camera I had) enough that I can now insert and chamber with a much better feeling and no super tight bolt closure, only issue when extracting a loaded round I still get scuff marks/ contact on the ogive region of the projectile. I’m at a little bit of a loss and just want to know if anyone has some input on which direction to head. Hopefully I’ve input enough info to get a little help, Thanks!
1st picture should be before cleaning, 2nd is after at the end of the chamber and 3rd being where the chamber transitions to the throat

 

[D-Money97]

 

[dmuffman80]

is this chamber misalignment?

 

[D-Money97]

I would like to not think so. Reputable company and previous owner spoke positively on the barrel, just made a switch to CF for a light rig.

 

[dmuffman80]

Nothing but praises here for the company! It has been prior owned. I hope to order a short and long action Coup de grace. I wonder if the OP can measure the runout before and after chambering a hand load.

 

[AllenOne1]

Sounds like you are not getting your case shoulder pushed back far enough to fit this chamber. Push it back .002-.003 further and see if that helps. I would also check the case length to make sure it is spec, you can even check this with a borescope to make sure you have clearance in the chamber.

The bullet scuffing could be coming from pushing the bullet into the chamber and not really from hitting the lands. just scraping on the edge of the chamber opening.

 

[D-Money97]

I’ll try to get a way to measure that in the next day hopefully. I’ve been just using some steel wool to clean up the marks after and then proceed with cleaning and then come back after a awhile of cleaning and seeing if my marks stay and they have been returning

 

[D-Money97]

Sounds like you are not getting your case shoulder pushed back far enough to fit this chamber. Push it back .002-.003 further and see if that helps. I would also check the case length to make sure it is spec, you can even check this with a borescope to make sure you have clearance in the chamber.

The bullet scuffing could be coming from pushing the bullet into the chamber and not really from hitting the lands. just scraping on the edge of the chamber opening.

 

[D-Money97]

I’ve had identical results with brass pushed way further back than I normally would 8-9 thou and brass pushed back about 4-5 thou(pushed back a bunch of once fired to have on hand for this barrel) all trimmed back to book length. With a scope coming out of the case mouth I can still see a clear gal between the end of the brass and the chamber end. But I can try going back further.

 

[FisherT&C]

It could be an undersized freebore diameter.
6.5 Creedmoor usually has only .0005" clearance in the freebore diameter so if the reamer was worn it could have cut an undersized freebore diameter.

 

[spife7980]

Maybe next time focus the camera. Looks like a teslong with the floating mirror, you screw it in and out to adjust focus.

Keep cleaning, stick a patch wet with clr in the throat and let it soak a couple minutes, spin it and let it sit a little longer. Then push it out the end of the barrel. Do it again for a few more minutes. Then dry patch it out and try again.