Thinking about a new barrel

[Kevin Stenberg]

I was looking at Bear Creek Arsenal barrels. They list a 1 in 8 5R ROT. What does the 5R stand for?
This will be going on a PSA upper 16" carbine barrel with a standard cheep hand guard. And changing it to an 18" midlength gas system and free float handguard.

 

[RBHarter]

5 land&groove . R is a Ratchet land . It's a wedge shaped land , square on the push side tapered on the off side .

I have one it shoots cast fine .

 

[Kevin Stenberg]

Thank you.
I assume they also have no problem with jacketed.

 

[358156 hp]

Ratchet rifling was designed with the intention of minimizing bullet distortion as is seen in conventional rifling. I don't feel it's a cure-all, but I sure some out there may believe that it possibly is.

 

[RBHarter]

I have it in a 6.8 . I haven't shot any jacketed in it , I am pleased it otherwise .

 

[CWLONGSHOT]

Id choose 5R is avalible.

Much written on some boards. Sounds plausible and enough big names are now utalizing there must be something to it.

I have a few barrels and they do shoot well I was also explained that rifling dosnet directly oppose rifling. (Minimizing Bullet distortion as mentioned above.)

CW

 

[popper]

Why the midlength gas? My 24" 308 has it, not too popular. I use carbine gas in my 18" BO, works fine. You look at KAK barrels? My 1:8 pistol is KAK, works great and cheap.

 

[fiver]

I have a 5-R on my 7ackley, you do need to pay attention to the land and groove heights if you plan on shooting lead in one.
they seem to have a bit less land height so will allow [or need as the case may be] a bit more nose diameter.

 

[RBHarter]

Kind of a Micro Groove situation with them . The 6.8 loadings were already .280 , basically the scuffed dia on the .279-124 NOE . Mine is .2795 , .271ish on the nose .
.278- groove I don't have .0000 tools so .00025/5/75 is eye ball on the thimble or dial .

 

[Ian]

Why the midlength gas? My 24" 308 has it, not too popular. I use carbine gas in my 18" BO, works fine. You look at KAK barrels? My 1:8 pistol is KAK, works great and cheap.

Chasing dwell time. 18" should have midlength. 20+ should have rifle. Under 14 should have pistol gas length. Ar-10/15 all the same rules.

 

[Kevin Stenberg]

Thank you Ian. I have always wondered when which gas system should be used.