.308 Upper/Bolt Group?

[Glockslap]

I'm still going back and forth between and ADCO recontour to an already great shooter (1 moa with match), or just buying a barrel (est 1.5 lbs), and upper, and a bolt.

What is the going rate and turn around for an upper reciever in .308 with bolt these days?

[Robocop1051]

I don't like the idea of recontouring anything... Well I actually like the idea, but I don't quite trust it. I believe that every barrel manufacturer flutes and contours their barrels PRIOR to rifling for a reason...

16" DPMS Lightweight $249.95

16" DPMS AP4 $229.99

16" SI Defense M4 $199.00

You can get a forged DPMS upper for $184.95 and a BCG for about $210-$250 (when they are in stock).

[Jgun]

I think your mistaken here Robo, as far as I know, all barrels are manufactured from rifled blanks that are contoured/fluted, ported, threaded, chambered,crowned  afterwards,(not in that order)

[Robocop1051]

I may very well have been misinformed. Wouldn't be the first time.

[MaDuce]

I'm no expert on the process of carving bores, but contouring should be done PRIOR to heat treat.

Contouring an already drilled barrel is doable without any harm to the bore of the gun, but in many cases, it will be wise to re-treat the barrel.

  However, doing it SAFELY after the barrel has already been heat treated is going to be a nightmare. I'm guessing that's the main reason manufactures do it as early on as they do. You've got a huge jump in time and a dramatic amount of wear on your milling bits that is going to hike up the price. Doesn't make much sense when you can save hundreds per barrel by doing the exact same thing in a different order.

[Tripledeuce]

    Recontouring barrels is one thing that I'v seen a lot of in my  general gunsmithing days.

    The only "safe" way is to make "small" cuts .030-.040 total at a time, and the lathe run in its slowest back gear( 60-80 rpm)

    Yes, I know a lot have done it with bigger cuts, and faster feeds, I'v also seen a lot of bent bbls, and "un-screwed"  bbls. unscrewed meaning you could look down the bore and actually SEE the variation of the rifling.

    Flame me if you will,,but that's been my experience, especially the lighter the contour.  The lighter the contour, the easier it is to screw up.

  And, yes!  The bbl defiantly should be reheat treated after re-profiling.

    Respectfully

    Terry

[Matt.Cross]

    Flame me if you will,,but that's been my experience, especially the lighter the contour.  The lighter the contour, the easier it is to screw up.

  And, yes!  The bbl defiantly should be reheat treated after re-profiling.

    Respectfully

    Terry

I do not disagree with your post, but as a moderator I merely want to point out that flaming isn't an occurrence here, nor should it be invited/suggested. I wouldn't even mention this if it hadn't been an issue in recent weeks. Nobody has license to flame anyone else here EVER. Anything that is derogative apart from good-natured joking will be promptly dealt with by the Mods/Admins.

Now having said that, I don't see any indication whatsoever that you are any less than a fine upstanding member of our community. So please don't take this as chastisement, I'm just clarifying our position on troublemakers. Enjoy the forums!  <thumbsup>

[Tripledeuce]

  My apologies

  Terry

[Matt.Cross]

  My apologies

  Terry

Not necessary, you did nothing wrong, I do appreciate the spirit of cooperation though. Carry on! <thumbsup>

[98Z5V]

        The only "safe" way is to make "small" cuts .030-.040 total at a time, and the lathe run in its slowest back gear( 60-80 rpm)

   

Even 30 or 40-thou seems like a hell of alot to me - I have no, read: zero, experience recontouring a barrel, too.  I bore motorcycle cylinders.  On those, even if I was immediately going to a large overbore, I only make cuts somewhere between 0.002~0.005" at a time.  It's never over 2-thou once the sleeve starts getting thin, too... 

Just a difference in applications, and an observance on my part.  I'd suck at recontouring barrels, because it would take me forever, trying to do what I do with cylinder boring...  <lmao>

[Tripledeuce]

    Actually, taking to small a cut on 4140 steel can  actually work harden the steel, and make it harder to  make additional cuts.

    A .030 total cut = .015 per side, small by machinest standards.  Think 3 sheets of printer paper held together.

  Fluting is the Last step befor heat treating,,,,,unless you have your gunsmith turn or flute the bbl.

  respectfully

  Terry

[Jgun]

This isn't something I've got prior experience doing it the wrong way or training of doing it the right way to draw from, but it would seem to me that a good way to contour an AR barrel and minimize the chances of damaging or bending it would be to support the barrel in the center (at the gas block location?) in a steady rest to effectively reduce the unsupported span and minimize deflection. Another option would be to set the barrel into the chuck. I guess that wouldn't exactly be the fastest way, but I'm thinking it would be less likely to damage the barrel.

[imschur]

you guys might like this link

[Glockslap]

<munch>

[Jgun]

In my effort to gain more hands on experience with regards to gunsmithing, and firearms specific machine work, I'm considering fluting the Krieger barrel that I ordered for my M1A build, not so much that I expect to gain any noticeable performance or weight savings, but more to add to my knowledge and experience in performing these operations. If I should do it, I will be sure to post some before and after shots.

[survivalshop]

direct quote from Shilens web site:

"Fluting is a service we neither offer nor recommend. If you have a Shilen barrel fluted, the warranty is void. Fluting a barrel can induce unrecoverable stresses that will encourage warping when heated and can also swell the bore dimensions, causing loose spots in the bore. A solid (un-fluted) barrel is more rigid than a fluted barrel of equal diameter. A fluted barrel is more rigid than a solid barrel of equal weight. All rifle barrels flex when fired. Accuracy requires that they simply flex the same and return the same each time they are fired, hence the requirement for a pillar bedded action and free floating barrel. The unrecoverable stresses that fluting can induce will cause the barrel to flex differently or not return from the flexing without cooling down a major amount. This is usually longer than a shooter has to wait for the next shot. The claim of the flutes helping to wick heat away faster is true, but the benefit of the flutes is not recognizable in this regard until the barrel is already too hot. "

Also other barrel manufactures that do Fluting will flute barrel before any rifling is done . If ya want it done right It has to be stress relieved after ward.

[Jgun]

There you go bursting my bubble!, I'm trying to come up with something that I can do to make my build different from all of the others that are done with the same componants. I thought that doing some machine work on the gun would accomplish that, now I'm not sure. The gun I have planned is going to be a very heavy, bench gun so the weight savings are not enought to justify the risk, but I'm going to have to think of something I can do to make my build unique (at least in my mind).

[survivalshop]

Don't mean to bust any thing Jgun , just want to bring any info up front , so all of us can digest it & make our choices .

If done correctly , you can do what ever you want with a barrel.

I have always thought , that all the fancy machining & or grinding done to barrels , is more for looks, than actual benefiting a barrel & its accuracy. JMO

[Matt.Cross]

If done correctly , you can do what ever you want with a barrel.

I have always thought , that all the fancy machining & or grinding done to barrels , is more for looks, than actual benefiting a barrel & its accuracy. JMO

I pretty much concur, with the exception of stating that weight loss is weight loss, no matter it's significance. However, if I were going to have a finished barrel fluted, I'd also have it cryo-treated to be sure it was stress-relieved.