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Old November 8, 2012, 09:29 AM   #1
Magnum Wheel Man
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OK... I'm not an idiot... really

just saw this today in another thread...

When it's time to change the barrel have it trued up (blue printed) & bed the action if your looking for accuracy.
so is there something I'm not getting here ??? what the heck is "blueprinting"

I've always thought a blueprint was a drawing of a something, or a piece of it... did it somehow become a mechanical process, or is this just some "buzz word" or is someone doing a "drawing" of the assembly, like that will make the rifle more accurate

I mean I understand the concept of "trueing up" & "bedding", but what does blue printing have anything to do with it ( I see this term with engines & other performance improvements on mechanical objects... example "that engine is balanced & blueprinted" ) so is it a process, rather than a drawing ???
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Last edited by Magnum Wheel Man; November 8, 2012 at 09:36 AM.
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Old November 8, 2012, 09:32 AM   #2
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From the Wikipedia article on engine tuning at


In engine blueprinting, all the specifications are double-checked. Usually this indicates closer-than-factory tolerances, with custom specifications appropriate for a street car or a race car. The goals are either to re-manufacture the engine to the rated power for its manufacturer's design (because not all mass-production engines put out the rated power), or rebuild the engine to make more power from a given design than otherwise intended (because custom engines can often be redesigned to different specifications). Blueprinted components allow for a more exact balancing of reciprocating parts and rotating assemblies so that less power is lost through excessive engine vibrations and other mechanical inefficiencies.
Ideally, blueprinting is performed on components removed from the production line before normal balancing and finishing. If finished components are blueprinted, there is the risk that the further removal of material will weaken the component. However, lightening components is generally an advantage in itself provided balance and adequate strength are both maintained, and more precise machining will in general strengthen a part by removing stress points, so in many cases performance tuners are able to work with finished components.
For example, an engine manufacturer may list a piston ring end-gap specification of 0.003 to 0.005 inches for general use in a consumer automobile application. For an endurance racing engine which runs hot, a "blueprinted" specification of 0.0045" to 0.0050" may be desired. For a drag-racing engine which runs only in short bursts, a tighter 0.0035 to 0.0040 inch tolerance may be used instead. Thus "blueprint" can mean tighter or looser clearances, depending on the goal.
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Old November 8, 2012, 09:35 AM   #3
Magnum Wheel Man
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so this loosely translates to guns, & in reality, just means carefully & tightly assembled ???
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Old November 8, 2012, 10:53 AM   #4
Art Eatman
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"...just means carefully & tightly assembled???"

Yeah, basically. Some machining to minimize clearances or tolerances. As example, consider the range for headspace. Blueprinting would result in a chamber with the exact minimum. Another example would be machining of the bolt-face so that it is exactly 90 degrees to the axis of the bore.

Blueprints show dimensions, with some sort of plus/minus tolerances which have been found to allow use of the item. "Blueprinting" means spending the time, effort and money to achieve minimum tolerances. It can be done in manufacturing, but that's why a Rolls Royce costs more than a Ford, or a Purdey costs more than a Remchester.
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Old November 8, 2012, 11:15 AM   #5
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"Blueprinting" is an old race engine builder's term. The goal is to make the engine as good as it can possibly be but still legally be factory stock.
Carefully degreeing a stock cam and matching the combustion chamber volumes with carefully matched stock pistons is "blueprinting".
Putting in a race cam and high compression pistons is modifying.
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Old November 8, 2012, 11:21 AM   #6
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To me it has always meant squaring and truing the receiver and bolt face to the centerline of the bore. If everything lines up straight and true then you'll have an accurate rifle as long as the nut building the ammo and pulling the trigger is doing their job.
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Old November 8, 2012, 11:38 AM   #7
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I also at first didn't know what it meaning was. Went on line, blueprint a rifle. Found it very interesting, When I need to rebarrel my rifle I will have it Blueprinted. Hope I helped Chris

Last edited by cw308; November 8, 2012 at 05:57 PM.
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