Polygonal rifling??/

[cowhtr]

Hi msinc,
I need to re-barrel my Kimber 84L Mtn Ascent in 280 Ack Imp. I have been in contact with PAC-NOR about a 24",#1 Sporter, 1-10", polygonal via email about the new barrel. Your thread somewhat answered my question about some bullets (as I was told by a good gunsmith) simple don't like polygonal rifling. I know, that statement applies to most barrels, but I'm specifically interested in .284 solids like the Nosler E-tip or Barnes TTXP. I assume the keeper you built for your nephew was a hunting rig and was wondering what bullets he uses? I also have the 7mm bullets in polygonal barrels question emailed to Nosler and Barnes. Now for the ballbusting reason for re-barreling after 469 rounds (the 1st 50 was lightly cleaned after each round) . I bought a borescope to check out a friend's 223 MVP that he couldn't get to shoot; he obviously didn't do much cleaning. Now I check my Kimber and see some dark grey fouling. I run a couple Lead Away patches though it and now see severe black carbon fouling, especially in the area where the land meets the groove. The Lead Away did such a good job on the 223, I figured no sweat with the 280 AI. It took about 1/2 the amount as the 223 to get the barrel somewhat carbon free. During the entire process, I don't remember checking the barrel's throat, and only the end of the barrel. Only when the rod didn't rotate at all did the bell go off! Anyway, there is now no lands for about the 1st 12" of the barrel. I emailed Kimber about getting a replacement and they quoted a relatively cheap price, so I asked what grade of SS they use for their barrels. After 2 email inquires, I called and was told that information was not available. I can only assume they don't know (barrel made by other), it is poor quality SS (which I now understand you have to beware of), or they just don't care.
Thanks in advance for any info anyone can provide.

 

[msinc]

Hi msinc,
I need to re-barrel my Kimber 84L Mtn Ascent in 280 Ack Imp. I have been in contact with PAC-NOR about a 24",#1 Sporter, 1-10", polygonal via email about the new barrel. Your thread somewhat answered my question about some bullets (as I was told by a good gunsmith) simple don't like polygonal rifling. I know, that statement applies to most barrels, but I'm specifically interested in .284 solids like the Nosler E-tip or Barnes TTXP. I assume the keeper you built for your nephew was a hunting rig and was wondering what bullets he uses? I also have the 7mm bullets in polygonal barrels question emailed to Nosler and Barnes. Now for the ballbusting reason for re-barreling after 469 rounds (the 1st 50 was lightly cleaned after each round) . I bought a borescope to check out a friend's 223 MVP that he couldn't get to shoot; he obviously didn't do much cleaning. Now I check my Kimber and see some dark grey fouling. I run a couple Lead Away patches though it and now see severe black carbon fouling, especially in the area where the land meets the groove. The Lead Away did such a good job on the 223, I figured no sweat with the 280 AI. It took about 1/2 the amount as the 223 to get the barrel somewhat carbon free. During the entire process, I don't remember checking the barrel's throat, and only the end of the barrel. Only when the rod didn't rotate at all did the bell go off! Anyway, there is now no lands for about the 1st 12" of the barrel. I emailed Kimber about getting a replacement and they quoted a relatively cheap price, so I asked what grade of SS they use for their barrels. After 2 email inquires, I called and was told that information was not available. I can only assume they don't know (barrel made by other), it is poor quality SS (which I now understand you have to beware of), or they just don't care.
Thanks in advance for any info anyone can provide.

Sorry for the delay, I just got around to looking at this post....What weight bullets do you intend to shoot in this 280AI??? I ask because I am shooting 175 grain Nosler Partitions and 168 grain Accu-Bond Long Range bullets and I have a 1-in-9" twist in one rifle and 1-in-8 3/4" in the other. Cant tell any difference, both rifles stabilize these bullets just fine. I would suggest if you are going to possibly shoot heavier bullets like these in your 280AI that you consider going with at least a 1-in-9" twist. I have 4 different 7mm rifles and they all shoot lighter bullets with these twists just fine.
As I understand it, Kimber is making their own barrels now. At one time they used Douglas, but now they are making their own and using cut rifling. They also have invested in a Sunnen hone. My Mountain Ascent {also a 280AI} has one of these barrels and it don't shoot bad at all. I will say that the lands are very smooth {because they are honed} but the grooves are way rougher than I would like to see. However, it don't foul and honestly never really did. I rechambered my mountain ascent and based on how it machined I would say it is probably 416 stainless alloy like most barrels and not the harder stuff that some makers use.
I don't know what you intend to hunt with this rifle, but I have also have very good luck with the 140 grain Berger Hunting VLD's. I have also gotten excellent performance with 139 and 154 grain Hornady Inter Bonds. The good old Nosler Ballistic Tip is a great bullet too. I have not used any of the solid copper or alloy bullets so I am sorry but I cant really say how they work. I mostly use these rifles for black bear and so I prefer a heavier premium hunting bullet like the Partition. I was unable to find any bullets that did not shoot well out of my Pac-Nor polygonal barrels. None stood out as not grouping good and also none seemed to foul any more or less.
I really believe you will be very happy with that rifle after it is rebarreled with a Pac-Nor polygonal barrel.

Edit; I want to say that the one I built for my nephew shot the new Hornady ELF bullets the best. He shoots long range but uses that same rifle for deer and has said those bullets work fine and drop 'em dead. The solid bullets can be picky about the rifle and the load, I am sure they perform fine on game but we just don't use them, in part because of the expense.

 

[Clark]

6mmBR
Rem 700 BDL short action
Stainless Super Match. 1-8" Twist. 6mm. Polygonal rifling. 28" long. Factory Remington Mountain Rifle Contour. 40 oz threaded, chambered, and crowned 27.125" long

This super lightweight rifle shoot the lights out. I build a lot of rifles, and this Polygonal is one of my favorites.

 

[cowhtr]

Sorry for the delay, I just got around to looking at this post....What weight bullets do you intend to shoot in this 280AI??? I ask because I am shooting 175 grain Nosler Partitions and 168 grain Accu-Bond Long Range bullets and I have a 1-in-9" twist in one rifle and 1-in-8 3/4" in the other. Cant tell any difference, both rifles stabilize these bullets just fine. I would suggest if you are going to possibly shoot heavier bullets like these in your 280AI that you consider going with at least a 1-in-9" twist. I have 4 different 7mm rifles and they all shoot lighter bullets with these twists just fine.
As I understand it, Kimber is making their own barrels now. At one time they used Douglas, but now they are making their own and using cut rifling. They also have invested in a Sunnen hone. My Mountain Ascent {also a 280AI} has one of these barrels and it don't shoot bad at all. I will say that the lands are very smooth {because they are honed} but the grooves are way rougher than I would like to see. However, it don't foul and honestly never really did. I rechambered my mountain ascent and based on how it machined I would say it is probably 416 stainless alloy like most barrels and not the harder stuff that some makers use.
I don't know what you intend to hunt with this rifle, but I have also have very good luck with the 140 grain Berger Hunting VLD's. I have also gotten excellent performance with 139 and 154 grain Hornady Inter Bonds. The good old Nosler Ballistic Tip is a great bullet too. I have not used any of the solid copper or alloy bullets so I am sorry but I cant really say how they work. I mostly use these rifles for black bear and so I prefer a heavier premium hunting bullet like the Partition. I was unable to find any bullets that did not shoot well out of my Pac-Nor polygonal barrels. None stood out as not grouping good and also none seemed to foul any more or less.
I really believe you will be very happy with that rifle after it is rebarreled with a Pac-Nor polygonal barrel.

Edit; I want to say that the one I built for my nephew shot the new Hornady ELF bullets the best. He shoots long range but uses that same rifle for deer and has said those bullets work fine and drop 'em dead. The solid bullets can be picky about the rifle and the load, I am sure they perform fine on game but we just don't use them, in part because of the expense.

 

[cowhtr]

Sorry for the delay, I just got around to looking at this post....What weight bullets do you intend to shoot in this 280AI??? I ask because I am shooting 175 grain Nosler Partitions and 168 grain Accu-Bond Long Range bullets and I have a 1-in-9" twist in one rifle and 1-in-8 3/4" in the other. Cant tell any difference, both rifles stabilize these bullets just fine. I would suggest if you are going to possibly shoot heavier bullets like these in your 280AI that you consider going with at least a 1-in-9" twist. I have 4 different 7mm rifles and they all shoot lighter bullets with these twists just fine.
As I understand it, Kimber is making their own barrels now. At one time they used Douglas, but now they are making their own and using cut rifling. They also have invested in a Sunnen hone. My Mountain Ascent {also a 280AI} has one of these barrels and it don't shoot bad at all. I will say that the lands are very smooth {because they are honed} but the grooves are way rougher than I would like to see. However, it don't foul and honestly never really did. I rechambered my mountain ascent and based on how it machined I would say it is probably 416 stainless alloy like most barrels and not the harder stuff that some makers use.
I don't know what you intend to hunt with this rifle, but I have also have very good luck with the 140 grain Berger Hunting VLD's. I have also gotten excellent performance with 139 and 154 grain Hornady Inter Bonds. The good old Nosler Ballistic Tip is a great bullet too. I have not used any of the solid copper or alloy bullets so I am sorry but I cant really say how they work. I mostly use these rifles for black bear and so I prefer a heavier premium hunting bullet like the Partition. I was unable to find any bullets that did not shoot well out of my Pac-Nor polygonal barrels. None stood out as not grouping good and also none seemed to foul any more or less.
I really believe you will be very happy with that rifle after it is rebarreled with a Pac-Nor polygonal barrel.

Edit; I want to say that the one I built for my nephew shot the new Hornady ELF bullets the best. He shoots long range but uses that same rifle for deer and has said those bullets work fine and drop 'em dead. The solid bullets can be picky about the rifle and the load, I am sure they perform fine on game but we just don't use them, in part because of the expense.

WOW! Thanks for all the info. This is my 1st try at blogging so bare with me. I hunt deer, antelope, cow elk and a bull once in a blue moon and use 120-140 grain E-tip or Barnes TTSX/TSX. My 7mm Whby Mag 1-10" twist shoots 120 LazerHead bullets very well. I found that the solid copper bullets need less weight to make a good one shot kill and I have no qualms about heart shooting a bull out to 300 yds through the front leg to the heart. My go to shot for cows out to 400 yds.
Anyway, back to the barrel. I think I will get the PAC-NOR barrel in chrome moly instead of stainless steel and have them put that Cerakote on it. I was thinking of putting another inch of length on it, but not sure there'll be any benefit.
Again, thanks so much for responding. I'll keep you informed on my progress if interested.

 

[msinc]

WOW! Thanks for all the info. This is my 1st try at blogging so bare with me. I hunt deer, antelope, cow elk and a bull once in a blue moon and use 120-140 grain E-tip or Barnes TTSX/TSX. My 7mm Whby Mag 1-10" twist shoots 120 LazerHead bullets very well. I found that the solid copper bullets need less weight to make a good one shot kill and I have no qualms about heart shooting a bull out to 300 yds through the front leg to the heart. My go to shot for cows out to 400 yds.
Anyway, back to the barrel. I think I will get the PAC-NOR barrel in chrome moly instead of stainless steel and have them put that Cerakote on it. I was thinking of putting another inch of length on it, but not sure there'll be any benefit.
Again, thanks so much for responding. I'll keep you informed on my progress if interested.

Yeah, keep me posted...I guess I didn't comment on barrel length and I should have...the first 280AI that I got was a Mountain Ascent, so I was limited to the 24" barrel. I have since built another one and it has a 27" barrel. It works real good with Reloder 26 powder and heavier bullets. I would suggest you go with a longer barrel too if you like free velocity. Good luck with your rifle and definitely keep us posted. Always interested in a new build.

 

[Rakkasan]

Good day Gentleman!

I am a brand new member this morning. Please be critical...

I'm shopping for a replacement barrel for my 7x57 "walking around gun" I have some experience with true polygonal rifling, but only in handguns, 98% of which is with my personal H&K P7's.

I have read this thread with interest. Then re-read it. My question is:

Is anyone making true polygonal 7mm rifle barrels available to me? I have had no success searching the net. Until this morning I had not found a forum which seemed to understand the question. You all get high marks from me.

Thanks in advance!

 

[Macropod]

How is the BC of the bullet effected by a polygonal barrel as opposed to say a 5R barrel I wonder?

 

[cmillard]

Check pac nor barrels and Schneider barrels

 

[Rakkasan]

How is the BC of the bullet effected by a polygonal barrel as opposed to say a 5R barrel I wonder?

How is the BC of the bullet effected by a polygonal barrel as opposed to say a 5R barrel I wonder?

Macropod,

That is a fine question! I would love to learn the answer!

Doug

 

[Rakkasan]

Check pac nor barrels and Schneider barrels

cmillard,

I have checked. Pac-nor "calls" theirs poly, but they are not in the true sense of the word. Schneider says straight up that they do not make polygonal barrels.

Of course, even the H&K poly barrels are not "true" polygons. From a high school geometry book: "a plane figure with at least three straight sides and angles, and typically five or more". No radii in the corners. But that would defeat our purpose, wouldn't it?

The search continues...