Bartlein barrel 6 mm 4 or 5R?
- Thread starter d1686
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JBT47
Silver $$ Contributor
Probably would not notice a difference. Many of competitive BR guys tend to believe in 4 groove. .236 bore vs .237 is also debated from time to time. I’ve used all of the above in many configurations and cannot tell you I’ve seen a difference...nor have I noticed any trends.
I would go with whichever you can get the quickest if time is of the essence.
I would go with whichever you can get the quickest if time is of the essence.
I've had very good luck in larger calibers than the 6mm with 5R bbls. but have noticed no difference between the 5R and a conventional 4 groove in the 6mm. If you know what bullet you are going to shoot, and know it'd diameter at the pressure, that should tell you what bore size you should get. Personally, I don't thing it matters.
I hope this helps,
Lloyd
I hope this helps,
Lloyd
I feel like, without having any back up of hard numbers, that I get more accurate rounds through a 5R barrel. For the makers that offer it, they don’t really claim any benefits to be had though, maybe a vague ease of cleaning reference here or there.
JBT47
Silver $$ Contributor
I normally order 4 groove 1-8” twist. Mainly because so many good shooters use this specifically. I’be been through over 20 6mm barrels on numerous different rifles.
Started with 5R’s then a couple of years later I began ordering 4 groove. I have not seen a difference in accuracy, ease of tuning, etc. between Krieger 4G’s, Krieger 5R’s, Bartlein 5R’s and Bartlein 4G’s. I’ve been pleased with the accuracy of most all of them.
Started with 5R’s then a couple of years later I began ordering 4 groove. I have not seen a difference in accuracy, ease of tuning, etc. between Krieger 4G’s, Krieger 5R’s, Bartlein 5R’s and Bartlein 4G’s. I’ve been pleased with the accuracy of most all of them.
4 groove all the way. Stellar accuracy for me!
Paul
Paul
You thinking higher round count before the barrel gives out? Or between cleanings?
I’m thinking higher round count before take off. I’m not sure why that would bear out though, which perplexes me.
The theory I might venture, after a 90 round 1,000 yard F-class match this morning, is that Bartlein 5R’s are relatively lower friction / pressure.
I shot 3 rifles today, two Bartlein 5R’s and 1 Brux 4 groove, all 35 plus inches.
The guns can share ammo. The Brux was new and speeding up and it was shot mainly to warm up and put a zero on. When I reracked it, the bullets were at 2,030 FPS at 1,000 and rising. That barrel is crossing identical loads moving towards 100 FPS faster than both 5R’s, which themselves were otherwise the highest V at 1,000. In a sense it’s getting more “result” from the same cartridge, but something is being stressed more inside to arrive there.
I realize that groove shape or number may not account for that kind of pressure difference. Nevertheless, those are all 7mm standard diameter barrels, so... it might.
When I envision a tight fitting jacketed bullet being forced down a hypothetical smooth bore, I’d expect bad galling and a huge pressure spike, (press two panes of glass together while trying to rub them on top of each other) with the lands breaking up the widths of flat metal on metal. In that sense, more lands may have the effect of narrower bands of potentially galling metal on metal.
I believe there may be something to this in that I don’t see any four groove barrels in my larger calibers where quite wide flats would be in contact if only 4 grooves were used. Kreiger uses 6 starting at .338, or 5R, and by the point of 50’s, barrels have 8 grooves.
One of those 5R’s was down only one point per each of two 15 shot, pair fired matches for V2 qualifying purposes, and extremely flat on waterline, which I think was the high on those two matches, so I’m really happy with that accuracy.
The theory I might venture, after a 90 round 1,000 yard F-class match this morning, is that Bartlein 5R’s are relatively lower friction / pressure.
I shot 3 rifles today, two Bartlein 5R’s and 1 Brux 4 groove, all 35 plus inches.
The guns can share ammo. The Brux was new and speeding up and it was shot mainly to warm up and put a zero on. When I reracked it, the bullets were at 2,030 FPS at 1,000 and rising. That barrel is crossing identical loads moving towards 100 FPS faster than both 5R’s, which themselves were otherwise the highest V at 1,000. In a sense it’s getting more “result” from the same cartridge, but something is being stressed more inside to arrive there.
I realize that groove shape or number may not account for that kind of pressure difference. Nevertheless, those are all 7mm standard diameter barrels, so... it might.
When I envision a tight fitting jacketed bullet being forced down a hypothetical smooth bore, I’d expect bad galling and a huge pressure spike, (press two panes of glass together while trying to rub them on top of each other) with the lands breaking up the widths of flat metal on metal. In that sense, more lands may have the effect of narrower bands of potentially galling metal on metal.
I believe there may be something to this in that I don’t see any four groove barrels in my larger calibers where quite wide flats would be in contact if only 4 grooves were used. Kreiger uses 6 starting at .338, or 5R, and by the point of 50’s, barrels have 8 grooves.
One of those 5R’s was down only one point per each of two 15 shot, pair fired matches for V2 qualifying purposes, and extremely flat on waterline, which I think was the high on those two matches, so I’m really happy with that accuracy.
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JBT47
Silver $$ Contributor
Brux barrels are dimensionally tighter than Bartlein 5R’s. Brux typically makes .236 bore 6mm’s and Bartlein’s standard is .237. I’ve been told of several Brux barrels that were even tighter than .236. Your Brux barrels may be operating at a higher pressure than your Bartlein 5R’s. Not sure whether 4 or 5 groove has anything to do with pressure.
Fortunately my blowups seem to have ended but were limited to just one caliber, 7mm, RSAUM. Yes, I do believe that tighter bores contributed to that, when run hot.
I have not blown up a bullet in a Bartlein 5R, although I have put fewer rounds down them, and in later times where I’m more wary. I originally blew up 7’s in Krieger 5R’s that required less powder charge relative to Brux 4 groove barrels, before pressure signs. I surmise they were tight bored, but were very accurate. I have lost only one or two in a Brux.
I haven’t lost any so far in Bartlein 5R even as long as the barrels are, which is very encouraging. I think it’s possible to manage loading to stay below the different thresholds, but I do think that a barrel can here and there come into a condition of temperature or cleanliness where a load that had been fine can lose a bullet.
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For short Range Benchrest, 6PPC stuff with 1-13.5 twist and 65 through 68 grain bullets, I use conventional 4 or 5 groove rifling. In my 6BRA with 105's and a 1-8.0 twist I use 5R rifling.
Same goes with my .22 caliber rifles, the light bullet rifles have 4 groove, the heavy bullet rifles have 5R.
All my hunting, F Class and fun guns have 5R.
I don't have permission to use their names, but research by several large testing and bullet/ammunition makers have found 5R to be superior to conventional rifling at long range and in bore stability.
For the most part, 5R doesn't like light for caliber bullets with a short bearing surface, for that use 4 groove conventional rifling.
For me, everything else will be 5R as it's proven itself to me to be better and cleans easier.
There are some folks that just prefer 4 groove, and they'll shoot, no question about it.
As for .236" vs .237", I'll dig my heels in on this one and say .237" Period, wouldn't bother me to see the .236" go away.
Later, Mark Buettgen
Bartlein Barrels Inc.
Same goes with my .22 caliber rifles, the light bullet rifles have 4 groove, the heavy bullet rifles have 5R.
All my hunting, F Class and fun guns have 5R.
I don't have permission to use their names, but research by several large testing and bullet/ammunition makers have found 5R to be superior to conventional rifling at long range and in bore stability.
For the most part, 5R doesn't like light for caliber bullets with a short bearing surface, for that use 4 groove conventional rifling.
For me, everything else will be 5R as it's proven itself to me to be better and cleans easier.
There are some folks that just prefer 4 groove, and they'll shoot, no question about it.
As for .236" vs .237", I'll dig my heels in on this one and say .237" Period, wouldn't bother me to see the .236" go away.
Later, Mark Buettgen
Bartlein Barrels Inc.
With significantly less testing then most my opinion should be taken lightly, however I have had 11 barrels now in various chamberings, amongst various calibers and have seen minor but still better results from the 5r. With 4, 5r and 6 groove barrels in my Arsenal (6groove is smaller calibers) the 5r has shown so far to be less finicky, easier cleaning. Accuracy though is a tough call as I find slightly wider nodes in the 5r barrels on average, once tuned in they’ve all shot absolutely fantastic and none significantly better then other minus my 1 6 groove 223 rem. That thing is too easy. During load development i shot 3-4 different powders, 4 different bullets, seating depth testing and 2 different primers without a single load shooting larger then 3/4 moa and a ton in 1/4 moa range.
moving forward, if offered I’ll be sticking with 5r for anything medium to large caliber, with the intentions of long target bullets, and 6 groove for small calibers with either target or hunting bullets.
moving forward, if offered I’ll be sticking with 5r for anything medium to large caliber, with the intentions of long target bullets, and 6 groove for small calibers with either target or hunting bullets.
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