Action truing/blueprinting

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by hemiford, Jan 19, 2014.

  1. hemiford

    hemiford Well-Known Member

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    I'd like to get a feel for just how out-of-whack an action really is
    before it is "corrected". This primarily concerns Rem 700s but may
    of course apply to other brands.

    1.) The barrel face. Is this surface not flat enough and/or not typically
    cut at 90 degr to the bore centerline from the factory ?

    2.) Barrel threads. If the threads are not rusted/damaged, why would they
    need recutting ? Are they also not typically 90 degr to the bore coming
    from the factory ?

    3.) Bolt lugs. Do the locking ramps wear down enough to need resurfacing ?

    I do appreciate the potential benefits of "blueprinting" an engine but I
    wonder if all the benefits translate to a rifle action. In a 700 it seems to me
    that even a brand new action/bolt assembly is a bit loosy goosy, but I don't
    have years of experience here and my suspicions may be unfounded.

    Now, when rebarreling, I understand that in order to set headspace,
    several dimensions must be juggled and set to work together.
    So is the rebarreling scenario primarily when an action would need
    any "corrective" machining ?
     
  2. westcliffe01

    westcliffe01 Well-Known Member

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    Very honest custom rifle builder commentary between Rem 700 and custom action (Stiller). He also has several videos of trueing a Rem action (about 8 different stages to the job)

    [ame="http://youtu.be/fR8H4Xx_Nnk"]Remington action compared to Custom action Part 1 - YouTube[/ame]

    [ame]http://youtu.be/ZnX78HLFGiY[/ame]
     

  3. upacreek

    upacreek Well-Known Member

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    I watched the videos. Really left me wanting to know what is done to true or blue print.
     
  4. westcliffe01

    westcliffe01 Well-Known Member

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    If you go to the guys Youtube channel, he has a 12 or more part series that shows every step of the process that HE does. I believe that trueing the action is $250 and timing it adds another $175 which includes a new bolt 100% of the time.

    This video is the first of the many part series and he will walk step by step through the process and do the machining on camera. If you use a smith like this, you are clearly getting what you pay for. But for every 1 of him there are a couple hundred scam artists.

    [ame=http://youtu.be/n191F9c1YiQ]Remington 700 action trueing Part 1 - YouTube[/ame]
     
  5. airborneike

    airborneike Active Member

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    In my experience not all Rem 700 actions are in need of blueprinting. In the production process, tooling wear and Monday morning causes some 700 actions to be less than good. This shows up mostly as uneven lug fit and non concentric end cut on the action. Threads are not usually a problem as long as they are loose enough to allow the barrel shoulder to mate squarely to the action end.Bolt faces can be off but not a huge amount generally speaking.

    There is no easy way that I know of to tell if the action is in need of truing short of taking the existing barrel off. If you have a 700 that no mater how many loads you try, you just can't seem to get good groups with then there may be problems.

    These problem actions can and will show very good gains in accuracy with blueprinting. The age old question of "is blueprinting worth it" can only be answered by what the individual wants out of the action. If you are building a bench rest competition rifle then everything you can do to make even minor improvements are helpful. If you are satisfied with 1 MOA hunting accuracy then blueprinting is probably not worth it because most 700 actions will achieve that level.

    What I have seen is most newer 700's are really very well made and you won't see a big increase in accuracy with blueprinting. An exception that I worked on was a sendero 25-06 that the owner could not get to shoot no mater how hard he tried so I bought it for a reasonable price as a donor action and found the bolt lugs were not only very uneven but the action lugs were cut on a bevel angle. Don't know how that action passed quality control but when I trued it up it shot very good. Go figure!

    All the best

    Mike
     
  6. westcliffe01

    westcliffe01 Well-Known Member

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    If you watch the videos, it clearly shows that nothing is square or straight about any feature. How much out of square is the question... The receiver threads are generally tapered, since Remington cuts them with a tap, vs single point turned on custom actions. Typically also off center.

    Remington is flat out making the receivers and bolts using worn out and outdated equipment. They chamber barrels in a vertical mill. No lathe, no dialing in the bore. Nope, clamp it in the fixture and down comes the spindle of the mill... With the cost of modern CNC equipment, they could pitch all of that junk in a heap and be making custom quality receivers much cheaper than the existing guys since Remington has so much volume. I'm pretty sure that all their sniper contracts are re-worked in the back room and they fit aftermarket match barrels or else they would never pass the requirements.
     
  7. benchracer

    benchracer Well-Known Member

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    I remember reading a number of years ago that the Marine Corps armorers tear all the 40-X rifles down when they receive them to fix all of the as issued deficiencies. Then the rifles are built back up and issued.

    At the time, they were testing a sniper rifle from another manufacturer and were raving about how it was ready to go as received. I don't remember what make and model the rifle was, though.
     
  8. hemiford

    hemiford Well-Known Member

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    OK. Some of my questions have been addressed. Very good instructional
    videos. Some of the factory machining is undeniably improved.

    Now I have another question. If a factory built rifle shoots one MOA using
    GOOD bullets, all the stacked up out-of-whack tolerances still produce
    a certain repeatability.
    Isn't the repeatability, the one MOA groups, the name of the game ?
    If you take the same action and blueprint it and put the same barrel back
    on it (assume here that the barrel threads were OK just for this example),
    won't it still shoot the same groups ?

    If you change the equation by installing a better (longer, heavier, etc.) barrel,
    then using the SAME bullets I would expect better repeatability, i.e., smaller
    groups.

    If you perform a good pillar bedding, you could expect possibly even better
    grouping.

    I still have a couple of concerns, and I think what I am getting at here is,
    other things besides the action truing will produce better overall rifle accuracy.

    Maybe I'm incorrect to think this.

    I'm also not happy about requiring non-standard/oversize threads on any
    future barrel for the gun.
     
  9. AZShooter

    AZShooter Well-Known Member

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    I can imagine I will be hammered for my comments......

    I have owned over 80 different barrel/action combinations over the last 30 years. I have never had any of the actions blueprinted. Have owned Rem 700s, Ruger M77 tang safety and Mark IIs, Mark X, mausers and Winchester post 64s.

    I have had many of these rifles shoot 1/2 MOA or better. Sure I have had a few lemons which I moved along. A few, the ones that used custom reamers from PT & G shot even better. I am talking about hunting type rifles not BR rifles. I do have a few like my 30BR/308 wildcat that shoots tiny groups in the 2s if I do my part. Some of my LR hunting rifles will shoot 1"-2" groups at 500 M which suits my needs quite adequately.

    Based on my past experiences, I cannot be convinced that I need to blueprint an action. I understand the argument and agree that it IS possible that an action might need to be squared up for better performance. I would rather spend the money on a custom action if I wanted more performance. I haven't seen the need to buy a custom action to date.

    One of my friends is involved in the 1000 BR game. He uses Bat actions. I have seen the quality of this action and the results down range. I KNOW if I were to try 1000 yd BR I would have to go with a custom action to be competitive.

    Now that I am doing my own barreling and chambering I am amazed at how well a rifle can shoot with a properly made reamer with good specifications. I have yet to rebarrel with anything other than a Remington takeoff and one used Lilja and the results are quite stunning leading me to believe the reamer might be more important than a perfectly trued action.

    I own a bore scope and inspect many rifles other than my own. The one thing I keep seeing in other rifles is poor chambering with the lands short on one side, long on the other AND poorly machined crowns. This includes custom rifles that were blueprinted and machined to perfection.

    IMO if your current barrel isn't shooting to your expectations and the bedding is sound I would go with another barrel with a good reamer. You might be surprised how well it will shoot.

    Okay guys roast me......
     
  10. FEENIX

    FEENIX Well-Known Member

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    ... but you already leave in Tucson. :D
     
  11. AZShooter

    AZShooter Well-Known Member

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    Good one but it isn't toasty just yet....only close to 80 today.
     
  12. FEENIX

    FEENIX Well-Known Member

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    I know what you mean, I was stationed at DM from 1991-1996 and my son is a senior year at U of A.
     
  13. westcliffe01

    westcliffe01 Well-Known Member

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    The blueprinting of actions really has its roots in benchrest shooting, where a 0.5MOA group is terrible. Its all a question of where to stop and the knowledge that everything tends to stack up to make repeatability worse and not better.

    So if you want all of the potential out of your equipment, then every single detail counts. The more details you skip, the more you are guaranteed to get mediocre performance.

    Usually, in the field, we have sufficient factors beyond our control that it is worth putting every control we can into the action, barrel, chamber, crown, brass, bullets, powder etc. What the wind is doing 600 or 1000 yards away in conjunction with the terrain, that is just an educated guess and some of us are less educated than others.