5 R canted land barrels.

[ol mike]

What do you guys think of these type barrels?

I read of people getting more velocity and great accuracy out of the canted land barrels.
And does anybody have expierence w/ mike rock barrels?
Thanks Mike

[James Jones]

I have used a couple Rock Creek barrels and have nothing but great things to say about them ,they clean easly shoot fast and seem to last a good while. I also have an Obermeyer barrel and it is the same way , seemingly no fouling great velocity and very accurate.
The Broughton barrels are supposed to follow the same suit but they are button rifled instead of cut rifled. Is their a differance between cut and buttoned? I can't tell , I have never chambered a gun in the same caliber and treated it the same with both to give an honest compairison. Cut rifled barrels are said to last longer.

[Bart B]

Barret (Boots) Obermeyer came up with his 5R rifling design soon after Sierra Bullets introduced their 7mm 168-gr. HPMK bullet my very good friend Tom Treinen used with a borrowed rifle and ammo in 1970 to break the 1000-yard scope sight match record at the highpower Nationals; 42 shots inside 20 inches, prone, windy conditions. Problem with those bullets was their jackets were a bit thin in order for Sierra to get uniform wall thickness for a very long jacket in that caliber. Those thin jackets were engraved a bit too much by conventional rifling and they would occasionally split at a engraved land mark and fly apart. Boots Obermeyer designed the 5R rifling so that less stress was made at the edges of the engraved groove in the bullets. That worked well enough indeed. But Sierra had problems making that bullet as accurate as their 30 caliber ones as jackets just couldn't be made to wall thickness uniformity quite as good as the 30 caliber ones. Those bullets Tom Treinen used were taken out of the final pointing machine as they were tested and found to be very accurate in firing tests.

Meanwhile, Boots Obermeyer made some 30 caliber match barrels with 5R rifing. These shot as good and often better than his conventional rifling. His 5R became quite popular afterwords.

Mike Rock was an apprentice under Boots Obermeyer and there's rumors/facts going around that Mike left Boots' shop under less than aimiable (hostile?) conditions. And Mike Rock took a lot of skills and knowledge with him. Including the 5R rifling design.

I've used both conventional and 5R barrels from Obermeyer; both with the same bore and groove diameters. With the same load for .30-.338 Win. Mag. cartridges, muzzle velocity was within 10 fps of each other. Accuracy was too close between them to say one was better than the other; 15-shot groups at 1000 yards in the 5 to 6 inch range.

[lerch]

there is a good article on 6mmBR about bbl making methods.

pretty interesting to read, covered cut and button pulled bbl's

steve

[Bart B]

[ QUOTE ]
Is their a differance between cut and buttoned?

[/ QUOTE ]Provided each is made with the same tolerances in dimensions and smoothness, I don't think so. In manufacture, button rifled barrels are easier to control groove diameter with; cut rifled barrels are easier to control bore diameter with. Properly made by skilled people using proper tools will show no significant difference in accuracy. Nor in barrel life if both are made with the same steel type.

[bailey1474]

I've got a Broughton chambered in 6-250 that refuses to foul. I would say it's just a tad easier to clean than the 4 groove Lilja on my 300 RUM but way easier to clean than the 3 groove Lilja on my 270 AM. All are superbly accurate though.

I cna't say that I've noticed the increase in velocity. I'm getting about 2970 fps which is right where I thought I should be.

[goodgrouper]

[ QUOTE ]
Barret (Boots) Obermeyer came up with his 5R rifling design soon after Sierra Bullets introduced their 7mm 168-gr. HPMK bullet

[/ QUOTE ]


No offense to Boots but saying he came up with the idea of canted rifling is wrong. To say he was the first American to successfully adapt the idea to solve a thin skinned bullet problem would be more correct. He actually "borrowed" the idea from the Russians (which is what the R stands for in 5R) who were making barrels in this manner as early as WWII and possibly even earlier. Records of production were unfortunately destoyed in the Nazi battles for Russian ground.

I do agree with you that they are good barrels and so are conventional rifled custom barrels if done properly.