hard bolt lift after rifle starts to get warm

[Avigerman]

I have a Christensen arms ridgeline in 300 prc. i have about 150 rounds down the barrel with 225 eldm factory Hornady ammo. just recently when zeroing the rifle for hunting, I am getting a hard bolt lift after about 5 or so rounds. I fired the gun 2 more times after the hard bolt loft and the bolt got to the point to where I couldn't pull it back at all without tapping it with a mallet. i tired cleaning the barrel and chamber very thoroughly and I still go the same problem again after 4-5 rounds. I also tried shooting some hand loads i recently made and i get the same exact result. I'm just looking for any input on what to try next.

 

[spife7980]

So is it heavy after 5 rounds? Or is it heavy after being fouled?

If you don’t clean it and just let it cool, are they easy to extract again?

 

[Avigerman]

It only gets heavy after about 4-5 shots. I let the barrel cool and went back the next day without cleaning and it did the same thing. I fired 4 shots and noticed the bolt starting to get heavy again. Then after that I cleaned it and re tested

 

[spife7980]

If you chamber a round and extract it, are there scuff marks on/going around the bullet?
If so it could be a carbon ring spiking pressure

 

[isofahunter]

Had similar issue with a 270 WBY by Ultra Light Arms, basically a single shot due to second round sticking in chamber post shot. It was determined the chamber was to tight probably due to an end of life reamer. Had the chamber touched up with in spec reamer and problem went away and has not come back. First clean it to eliminate carbon ring/dirty chamber and try again, if problem remains I would suggest having the chamber specs reviewed.

 

[Avigerman]

If you chamber a round and extract it, are there scuff marks on/going around the bullet?
If so it could be a carbon ring spiking pressure

I don't see any marks any where in the case when I extract around. Did this with about 10 rounds and didn't see any marks

 

[spife7980]

I’d try another ammo to make sure that’s not the problem and then get in contact with Christensen

 

[Bradu]

Have you tried letting it cool down at the range and shooting to see if it opens like it’s supposed to? I’ve seen one rifle get signs of pressure when shooting a string of 5 rounds quickly on a hot day. If you changed the magazine and kept shooting, the bolt would get stiffer with each shot. Let it sit for 15-20 minutes and it was fine.

 

[Diablo]

Am with Bradu on this, sounds like a pressure problem.

Same effect as leaving cartridges sitting in hot sun (temperature increases and pressure increases).

 

[whatsupdoc]

You shot 150 rounds previously without issue and now you are having this problem correct?
Is it the same ammo? If it is is it the same lot? Do you have different ammo you could try?

 

[db2000]

Call Christensen. They will email an RMA and shipping label on their dime and have it back to you in about 2 weeks was my experience with a different issue.

 

[Forrest]

Check the headspace. Then touch it up with a good known reamer.