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Post by jwiatrek on Oct 3, 2012 15:33:14 GMT -8
I saw a post on another thread that got me thinking about what I saw when I looked in my new barrel. It sure seems to have a groove in the barrel that looks surprisingly like a thin rifling groove. I have never owned a poly barrel before and was wondering that is normal or possibly a defect?? I was expecting it to be perfectly smooth with just a hint of the 3 sides polygonal shape... thoughts? Ideas?
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Deleted
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Post by Deleted on Oct 3, 2012 15:41:30 GMT -8
You should be able to 3 groves. Those are where the full diameter of the barrel is. The high or raised part of the polygon is not visible only the grove or lowest point.
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cb4017
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Post by cb4017 on Oct 3, 2012 21:03:42 GMT -8
Now you got me wondering. My new barrel seems to have 3 distinct sharp edged rifling lands. Thought it was normal for this barrel. Guess I better call.
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Post by SwampFox JR on Oct 4, 2012 3:20:41 GMT -8
Now you got me wondering. My new barrel seems to have 3 distinct sharp edged rifling lands. Thought it was normal for this barrel. Guess I better call. I would bet that it is fine. The tool they use to cut the rifling probably has a small radius where the "edges" meet. Between my dad and myself, there are 3 BHW barrels we have. They look just as you described, but I wasn't concerned and went straight to the break-in process before I cared about looking at how grouping would look. In doing so and having been around firearms my whole life, I've noticed that the effort to clean and amount of solvent and patches are far less than a typical rifling of other firearms.
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Deleted
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Post by Deleted on Oct 4, 2012 10:56:03 GMT -8
I think it's probably one of the biggest misconceptions about poly-rifling is that it'll be perfectly smooth. You will see 3 small lines that twist around the bore of the barrel. It differs from traditional rifling in that it's small arcs and not the dramatic, deep, squared notches one will find in traditional rifled barrels. For example, here is what traditional rifling looks like with hard-square edges: in comparison to some poly rifled barrels (This one is not one of our barrels but it's a similar idea) where the smoother curvature and lack of deep crevices won't cause the build up and added difficulty to cleaning that the traditional rifled barrel will.
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Post by GLSHOOTER on Oct 4, 2012 11:44:34 GMT -8
That is a great illustration Kiz. I always think of looking at a Pepsi bottle with the twist/flutes.
I must say that my first look down a BHW barrel was educational. I had already shot it and it did well and since I am the guy that likes results I wouldn't have cared if the Purple People Eater had been staring back at me!!
Greg
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Post by jwiatrek on Oct 4, 2012 12:53:24 GMT -8
So I got home and took a good hard look at the barrel again. And to amend/clarify my first poset, there are 3 distinct "lines' that follow the rifle pattern in the barrel. I guess I was not expecting to so clearly see that in the barrel. But it does look like the intersection point between the 3 raised areas.
I guess this is all good; I had a different idea in mind as to what it would look like. Chalk it up to newbieness with polygonal barrels.
I will see the accuracy this weekend so that should be the definitive proof.
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Post by GLSHOOTER on Oct 4, 2012 12:58:03 GMT -8
So I got home and took a good hard look at the barrel again. And to amend/clarify my first poset, there are 3 distinct "lines' that follow the rifle pattern in the barrel. I guess I was not expecting to so clearly see that in the barrel. But it does look like the intersection point between the 3 raised areas. I guess this is all good; I had a different idea in mind as to what it would look like. Chalk it up to newbieness with polygonal barrels. I will see the accuracy this weekend so that should be the definitive proof. Nothing wrong with expecting something different. Had I not seen HK poly barrels years ago I would have been caught off guard myself. You will find the unique rifling pays off big time in accuracy, velocity and cleaning. Greg
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Post by The Wolverine on Oct 5, 2012 6:10:44 GMT -8
I tried to get on, and post this from my phone yesterday when I saw this post, but for some reason could not get on. Here is a pic down a BHW p3 barrel, it is not the clearest, I took it with my cell phone, but it gives you a idea what it looks like. I posted this on the Armory when someone had this same question last year.
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Post by jwiatrek on Oct 7, 2012 18:18:34 GMT -8
got out and shot my new 6x45 this weekend. I tried a few different loads to begin my testing
70gr Hornady HP using H335 and getting about 2800 ft/sec. Accuracy was pretty marginal - about 2 1/2 inch groups.
After those rounds I tried some 87gr Vmax pushed to 2700ft/sec (load was consistent, I had a standard deviation at 13) and accuracy was non-existant. I olny loaded a few to get velocity data and had rounds hitting 15 or 16 inches high low left lterally it was like a 2 foot group.
I have been shooting for years and just to check that I had not had too much coffee that morning I tried my 6.8 SPC and shot a 1 1/4 inch group.
Unfortunately the 5 VMAX were the last 6x45 so I could not shoot the other load again to see if maybe my scope's internals broke loose or something.
I have since checked the extrernal scope mounts, looked at the barrel with a bore light and checked the bolt carrier group and see nothing out of whack...
Has anyone had such drastically terrible accuracy with 87gr Vmax?
Thoughts? ideas??
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cb4017
Junior Member
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Post by cb4017 on Oct 7, 2012 19:22:47 GMT -8
I coincidentally tried some 87 grain Vmax today in front of IMR 8208. Not good results. My groups were not as bad as yours but did run 2-3 inches. Worst part was multiple Failures to Eject with these loads. These were loaded to mag length, 2.260".
I can understand the poor accuracy but can't figure out why the heavy bullets would cause FTEs.
I went back to my break-in load of 70 grain Sierra HPBT match bullets with 8208. I was rewarded with a 5 round .786" group and perfect functioning.
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Post by GLSHOOTER on Oct 7, 2012 20:50:20 GMT -8
I've shot a small ton of the 87 Hornady HPBT bullets but none of the VMAX in the 6X45. I have shot them in the 6X68 a bunch and now the 243 LBC.
COL can enter in to how they shoot, as you know, and as to function are you all using any adjustable gas blocks or just the regular style?
Greg
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