New barrel problems with free bore

[Zero333]

With a borescope you should be able to see if it has short or long or non-existent freebore length.
Then you'll know if the freebore diameter is the problem or the freebore length.

No matter what..., you have to call whoever made the barrel and tell them the problem and give them a chance to correct it.

I've had some pre-fit barrels that had very little freebore in the area of 0.075" - 0.090". I just lived with them.

What Dusty said is also a good option.. Buy or rent a 6mm throater and hand cut the freebore length to your needs. PTG makes hand throating tools.

 

[varget204]

Measure distance to lands and grooves,some 6 creeds have .104 freebore,.183 is standard freebore,compare BTO to factory roud,a lot of Rugers the 108 ELD factory round,winds up jammed .100-.125 ; way to much

 

[Joel Dubose]

Measure distance to lands and grooves,some 6 creeds have .104 freebore,.183 is standard freebore,compare BTO to factory roud,a lot of Rugers the 108 ELD factory round,winds up jammed .100-.125 ; way to much

Thats exactly what I'm experiencing. With the 108 its probably that number plus. I dropped a bullet in the barrel from chamber side and looked do wn inside. What I saw was about what im seeing when I load the bullet to just touch the lands.

 

[243winxb]

If the bullets ogive is not below the case mouth, it should be ok. Just work up the powder charge from starting loads.

 

[Joel Dubose]

If the bullets ogive is not below the case mouth, it should be ok. Just work up the powder charge from starting loads.

The pressure ring is out of the neck and in the powder chamber. These bullts are long. In the case of the 110 SMK the ogive is below the mouth.

 

[Highpower-FClass]

Joel, when you say 'will not close on a factory round' do you mean that it does not close on a factory loaded 6mm Creedmoor round that you purchased in a store? Or that it does not close on a round that you yourself loaded for your old (factory) barrel?

Factory barrels are not always to SAAMI specs. For example Savage barrels can come with very long freebores compared to the SAAMI specified freebore.

So if you are using the old (factory) barrel and the ammo you yourself loaded for that as the benchmark, it could be the old barrel is out of spec and the new one is the 'correct' freebore (as per SAAMI)

However if you are unable to close the bolt on a factory round that you purchased off the shelf, that would definitely seem like a problem with the new barrel, as off the shelf ammo should be within SAAMI specs.

 

[jim_k]

I've measured the CBTO of factory ammo, and compared it to both the "standard" PT&G reamer throat and the SAAMI spec, and the factory ammo is about 0.200" too long for the throat. BTW, 6 CM is listed in the SAAMI download under "New Cartridges". The ammo I measured was Hornady factory ammo, and if I remember correctly, the factory CBTO was 0.183" longer than the chamber/reamer freebore length. This can happen with new cartridge development, and that's why I like the 6.5 CM, because the FB is pretty much standard. Savage 6.5 CM chambers are either 0.200" or 0.225" in my experience. Neither is too short or too long. I'm taking 0.200 (technically, 0.199") as the favored standard 6.5 CM FB, and I think the 6 CM drawing on the SAAMI site is also 0.200".

 

[Joel Dubose]

Joel, when you say 'will not close on a factory round' do you mean that it does not close on a factory loaded 6mm Creedmoor round that you purchased in a store? Or that it does not close on a round that you yourself loaded for your old (factory) barrel?

Factory barrels are not always to SAAMI specs. For example Savage barrels can come with very long freebores compared to the SAAMI specified freebore.

So if you are using the old (factory) barrel and the ammo you yourself loaded for that as the benchmark, it could be the old barrel is out of spec and the new one is the 'correct' freebore (as per SAAMI)

However if you are unable to close the bolt on a factory round that you purchased off the shelf, that would definitely seem like a problem with the new barrel, as off the shelf ammo should be within SAAMI specs.

Factory Horandy round. Its actually a 108 ELD match round so its possible that its long compared to a factory low weight round. Not sure what that would be, I've only ran the 103 ELD x hunting round.

 

[Joel Dubose]

I've measured the CBTO of factory ammo, and compared it to both the "standard" PT&G reamer throat and the SAAMI spec, and the factory ammo is about 0.200" too long for the throat. BTW, 6 CM is listed in the SAAMI download under "New Cartridges". The ammo I measured was Hornady factory ammo, and if I remember correctly, the factory CBTO was 0.183" longer than the chamber/reamer freebore length. This can happen with new cartridge development, and that's why I like the 6.5 CM, because the FB is pretty much standard. Savage 6.5 CM chambers are either 0.200" or 0.225" in my experience. Neither is too short or too long. I'm taking 0.200 (technically, 0.199") as the favored standard 6.5 CM FB, and I think the 6 CM drawing on the SAAMI site is also 0.200".

Bingo, this is exactly the type of info that I was hoping for.

 

[L.Sherm]

I think saami freebore for the 6 CM is around .075.

 

[jim_k]

I think saami freebore for the 6 CM is around .075.

I just rechecked, and it's 0.200". But either of these would cause the problem the OP is having.

 

[dolek]

https://saami.org/wp-content/uploads/2018/04/6mm-Creedmoor.pdf

 

[Deleted old_dood]

Joel, read this thread http://forum.accurateshooter.com/threads/rpr-6mm-creedmoor-freebore.3930200/

I had a RPR in 6 CM. I tried a box of the Hornady 108s and traded for something else because they'd have to be loaded too far into the case. I think the factory ELD-M rounds are just too long for your freebore. It sounds like the reamer used on your barrel is the same as the one Ruger uses. I didn't have that problem with Sierra 107 or 110, DTACs, or Nosler 105 RDFs.

 

[varget204]

Thats exactly what I'm experiencing. With the 108 its probably that number plus. I dropped a bullet in the barrel from chamber side and looked do wn inside. What I saw was about what im seeing when I load the bullet to just touch the lands.

A couple of months ago,a guy on 6 creedmoor forum[facebook] posted pic's of a blown High $ rifle,he never measured CBTO,was shooting factory 108 ELD,they were Jammed .150+. A Warning to Everybody,ALWAYS Measure CBTO before shooting Factory or Reloaded ammo and Compare

 

[L.Sherm]

I just rechecked, and it's 0.200". But either of these would cause the problem the OP is having.

Yeah, I forgot to drop down the 1 when I did the math off the print yesterday

 

[jim_k]

If not for the valuable information shared on this forum by you guys, there would be a lot of problems out there, causing endless consternation, and more than a little damage.

 

[Ringostar]

Both SAAMI charts posted show it at .1829 freebore.

 

[Texas10]

I took two dummy cartridges like what you have to the gunsmith and had him throat the barrel to fit. Or as Dusty advised, throat it yourself by renting a tool. I don't have a good borescope so I took mine to the professional.

YMMV.