OzFclass

Does anybody know if benchmark make 5 groove non 5R barrels? Saw one today that was apparently not 5R but still had 5 grooves/5 lands. I thought the lands looked canted, but wasnt really able to tell. The owner would probably like to know as well.

Why don't you contact the Australian agent, Grenfell Armouring Services in Bendigo?

I believe they are all conventional style rifling regardless of the number of grooves and not the 5R style. You should talk to the guys at Benchmark to find out for sure. I haven't talked to them in a while now.

Later, Frank
Bartlein Barrels

When I ordered my first Benchmark, I was told a regular 5 and a 5R were available in 7mm 9" twist.

Can someone put up the specs for 5r or conventional rifling ,or photos , ? for those that dont know what we are looking at, Frank ? then we know what we are looking at , Chop

Chopper wrote:Can someone put up the specs for 5r or conventional rifling ,or photos , ? for those that dont know what we are looking at, Frank ? then we know what we are looking at , Chop

Chop, All I got for now. First picture isn't the greatest. A little out of focus and the marks are not marks. It's just the light rings/reflection from the bore scope etc....this is my .284win. barrel. You can see though the angles on both sides of the lands. This is the 5R rifling. It's a 5 groove barrel with basically a 45 degree angle on both sides of the lands.



Next picture is a old factory Winchester 52C .22rf barrel but it's a pretty good picture. This is what we call Whitworth/English/standard type rifling regardless of the number of grooves. It's where the land basically meets the groove at a 90 degree corner.



I'll try and take some better pictures next week and post them. I won't be here the rest of the week and my camera is at home.

Later, Frank
Bartlein Barrels

Frank I've had krieger, Broughton and bartlein 5c barrels and the Bartlein's seem to have the narrowest lands and the most cant on the sides. Very pronounced compared to the other makers!

This is a photo of an untouched Bartlein 7mm blank that is a 1 in 9" twist.It went Berry - McEwan - Fairbairn - ......to.probably shot out by now !
The semi-circle of bright light on the left is the Groove, with the sloping "canted" side of the land leading up to the flat top of the land more or less being "in the shade". The flat "top surface" of the land is then back in the bright light of the borescope.
You just have to remember that the Borescope is 25 x Magnification, and then all of my photos have to be on the full 10 x Digital zoom to get them to focus, so this view is effectively 250 x Magnification.
Because everything photographed like this is nearly an optical illusion, the Right side of the land where it runs down to the next groove is probably a lot truer photo of the actual angles involved.

Chop,
This is a short 20 sec video of the borescope being held in the one position, but just rotating the lens around 360 degrees
This is the same brand new Bartlein blank that i just posted the jpeg of, which Mark Fairbairn had..

Hopefully it might help to understand what the "canted lands" looks like

I understand 5r , but was also intersested in the specs . Thanks

Chopper wrote:I understand 5r , but was also intersested in the specs . Thanks

Chopper, Specs. as far as what? Width of the lands etc.....? Width of the lands and grooves unless the barrel is made to a SAAMI/CIP spec. is left up to the individual barrel maker.

The angles on the sides of the lands of a 5R are at a 45 degrees.

Broughton makes a 5C not a 5R. They only put the angle on the driving side of the land. They took a 6.5mm Obermeyer 5R barrel and had a button maker make they're buttons based off of that barrel but only put the one angle on.

Later, Frank
Bartlein Barrels