Can any of you guy tell me about the pros and cons of 5R rifling?

I have seen that Border Barrels offers 5R rifling, but am not very familiar with this.

Any info would be appreciated.

ErikD,

To make a long story short... 5R & 7R rifling drops from the land at an angle into the groove rather than the 90 degrees which standard to most rifling.

Standard rifling lands and groves --> | |_| |_| |

R5/R7 rifling lands and grooves --> / \_/ \_/ \

From what I have been told some of the benefits are as follows....

- increase in velocity 50 to 100 fps. +
- ease in cleaning
- less deformity of bullet jacket
- better gas seal
- longer barrel life

I have a couple barrels on order using R5 & R7 type of rifling from Mike Rock at Rock Creek Barrels.

Regards,
Dave

Hey Davidc ! Please give full address for Rock Creek Barrels or web Site if there is one Thanks

concho,

Rock Creek Barrels is owned by Mike Rock who learned the 5R/7R cut rifle barrel making trade from Boots Obermeyer.

Mike has a PhD. in metalurgy and was the Chief Ballistics Engineer for the US Army at the Aberdeen proving grounds in the 1970s. Mike has incorporated what he learned at Aberdeen into his barrel making process. For example he does NOT want one to use a break in cleaning process for his barrels! I was told just shoot 20 rounds and then begin a regular cleaning regime. This is to create the proper burnish in the barrel and avoid a metal(barrel) to metal(bullet) contact.

Rock Creek Barrels

His barrels have a reputation for being extremely accurate and are used by many high power competators as well as the US Armys for their sniper rifles.

Regards,
Dave

Thanks for the info guys!

But this has brought up a new question: what is the differance between 5R and 7R rifling?

ErikD,

5 & 7 simply stands for the number of grooves in the barrel.

Check out the Rock Creek website under their cut rifled section to see how caliber size affects this number.

Regards,
Dave

Thanks David.

(I should have figured that out myself... )

I just bought a barrel from PacNor with 5R Polygonal rifling. I havent had a chance to shoot it yet but, ill post some results once i get it up an running (before Oct 23 i hope)

Make sure you talk to Mike's assistant, and place your order with the assistant. Mike is a bit forgetful, writes things down on paper, and stuffs them under his hat during the day. Also, do not take it personally if it takes a long time for the barrel to come.

Broughton does a 5C barrel that is basically the same deal.

That said, I built an LTR (Light Tactical Rifle) with a Mike Rock 5R barrel. It makes tiny little groups out to 750 meters (then the bullets run out of steam from the short barrel.

This thread is 4 years old. But, now you can get the canted land or "Russian" style rifling from Krieger, Bartlein, Broughton, Obermeyer, Rock, and probably a few more. I don't know if Hart is doing it or not.