Has anyone worked with a Bartlein 5r barrel with 38 or 40cal cast bullets?Pros or cons?Thanks,Bob

ARe you talking about Krieger Barrels?
Or whom?
beltfed/arnie

Duh, how did I miss the Bartlein in  "Bartlein 5r barrel..."
Their barrels are top drawer, and Wisconsin made.

Indeed, I am interested in how the 5r would work on 35-40cal lead bullets. Have been trying to get one last Obermeyer barrel from  Boots, probably in 0.375"x10-12 twist. No success at this point.
In the meanwhile, I have got a Ruger No 1, rebarrelled with 
an Obermeyer 5r, 8 twist, chambered for 30USA (30-40K) and am trying to get started working with it for up to 247 gr cast bullets.
ONe thing,tho-- I wonder if the 5r would decently cut the paper on PP bullets which I am currently enjoying in a couple of 40s I have. I plan first to find out on the 30USA rifle.
beltfed/arnie

Sorry for the confused post earlier. I got my Rs and 4&5's mixed up and thought you were inquiring about Fred Federson's barrels at R4 one of the names his company advertises with . Comes with aging.

If anyone is interested they are here:
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Part of their process involves honing the bored blank before rifling with some very specialized Sunnen machines. 

speaking in terms of black powder.
a most interesting question re 5r barrels and lead alloy bullets.
do canted lands allow the bullet to strip more than square lands?
probably not, because metford's segmental rifling with rounded contours did and does work extremely well with alloy bullets.
but were the bullets used in those guns bore or groove diameter?
metford's rifling is believed to allow powder fouling to flow forward and not accumulate in the barrel, and canted lands would possibly offer this to some degree as well.
metford's rifling require a gaintwist to cause patches to turn into confetti, whereas canted lands with sharp corners would probably cut the paper more like conventional rifling.
having shot bartlein canted land barrels in 6.5 and 7mm smokeless leaves no doubt as to their accuracy. no better than square rifling, but at least as good in match grade examples.
bore diameter bullets might well bump up into canted lands, filling them more easily than the square profile.
this same bumpup would hold the bullet in the rifling with pressure.
5 grooves and lands has always been considered a good idea for alloy bullets, as lead pushed in from one side by a land is pushed into a groove opposite.
one thing to be aware of with canted lands is a potential for brushes and patches on jags not to follow the rifling twist, but to just jump the rifling.
the rod might need a little help to follow the twist.
it has been reported that canted land barrels have worn in an irregular manner due to this to such an extent that flames have been allowed past the bullet, flame cutting the rifling parallel to the axis of the bore across the lands. this with smokeless.
for those who wipe a lot this could be worthy of consideration.
keep safe,
bruce.

All barrels, that I've seen anyway, have angled lands. Most of the diagrams you see comparing conventional to 5R are incorrect, in that there's no way for a rifling cutter with straight sides to cut a groove that angles outward to form parallel sided lands. Same goes for a button.

A 4 groove barrel therefore has a 90° included angle between the sides of each land.

Like this nonsense:

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The angled lands of a 5R are simply exaggerated a bit over what comes out naturally from the process of cut rifling.

The only thing I see different about them is they're harder to indicate in in the lathe.

The only way possible to create parallel sides on the lands would be by broaching. Never made one, but I 'think' it might be more trouble to grind one that way than with parallel sides to the cutting teeth. I have a couple 4 groove .30 cal broaches, and IIRC they have parallel sides.