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Thread: blue printing action?

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    Member hntr's Avatar
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    Default blue printing action?

    I'm going to have a rifle put together on a Zastave mauser action that i picked up. It looks like the front of the reciever ring could be cleaned up a bit but i was thinking as long as the action is in the lathe I may as well get everything sqaured up like the threads and the receiver lugs. Then i was thinking if I'm going to have that done I may as well have the bolt lugs turned square as well. Then there is the prethreaded barrel that I have for it. Does it need to be trued up as well.

    How much is necessary? And what could a guy expect to pay for these services around town. Some of the lower 48 shops look like they charge in the $200 ball park for the receiver only.

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    As far as what is necessary, it depends on what you are trying to achieve and what you expect out of the gun. As much as I like mauser actions, I don't think they justify a full blue print along the lines of what would be done with a target rifle.

    You are also limited with what can be done due to having a pre-threaded barrel. If you had the barrel threads squared to the reciever, they would be cut oversize, and hence the barrel thread would be a sloppy fit to the action.

    Personally I'd suggest having the face of the action cut perpendicular to the threads and call it good. If the bolt lugs aren't equally bearing on the recesses in the action, you might want to have them lapped. Not sure what local shop rates are, but I'm thinking having the action faced and the lugs lapped will be in the $75-100 range.

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    Greg Tannel has some interesting comments about action truing.

    http://www.gretanrifles.com/actiontruing.asp
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    So lemme see if I understand this...

    'Blueprinting' an action is basically making every imaginable dimension exactly like the bluepring says?

    How does one know if they need/want this?

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    Quote Originally Posted by hunt_ak View Post
    So lemme see if I understand this...

    'Blueprinting' an action is basically making every imaginable dimension exactly like the bluepring says?

    How does one know if they need/want this?
    Not quite every imaginable:

    Receiver face, bolt face and locking lugs (bolt and receiver), parallel to each other and perpendicular to the bore.
    Receiver threads re-machined to be parallel to the bore.

    The article by Tannel has this info, and a some other interesting stuff you'd like to know.
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    Quote Originally Posted by hunt_ak View Post
    So lemme see if I understand this...

    'Blueprinting' an action is basically making every imaginable dimension exactly like the bluepring says?

    How does one know if they need/want this?
    If you have a factory receiver by any manufacturer, you can just about count on it not being true. How do you know if you need/want this? If you have an accurate rifle, don't bother. If not, it will most likely help. If you are putting a new barrel on a rifle it's silly not to have it blueprinted first, in my opinion.
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    Moderator Paul H's Avatar
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    Quote Originally Posted by hunt_ak View Post
    So lemme see if I understand this...

    'Blueprinting' an action is basically making every imaginable dimension exactly like the bluepring says?

    How does one know if they need/want this?
    Not quite, the term comes from building up race engines, and really isn't properly used in that application.

    Blueprints have tollerances, and factory actions are built to those tollerances. If you tighten up the tollerances, manufactured parts become much more expensive, and most consumers don't care about the "benefits"

    When it comes to racing, for engines, or competition, for guns, you want every possible advantage. In the case of engines, you want them machined to minimize friction, and maximize the ability to bring fuel/air into the engine and exhaust gasses out, so you machine the engine accordingly.

    In regards to competition firemans, to fire perfect or as near to perfect groups as possible, you remove anything that prevents the gun from firing the same shot after shot. You do this by properly bedding the action and sometimes barrel to the stock, so forces are the same shot after shot, and you re-machine the action so that it is as close as possible to a mechanism to perfectly centers the cartridge in a chamber that is as tight as possible to eak out every bit of inherent accuracy.

    As far as what is needed, again what are you trying to achieve? I find with a bit of load work, it is no problem to get a factory rifle to put 3 shots into a 1" group at 100 yds, many of my rifles will produce groups 1/2 that size, some will do 5 shots into 1/2" at 100 yds, but not every group.

    If you're building a rifle for maximum accuracy, then you'll go for the best barrel you can get, have a properly dimensioned and concentrically cut chamber, concentric crown, and have the action "blueprinted". If however you are after "hunting rifle" accuracy, you are unlikely to see the accuracy benefit of "blueprinting" the action. I'd also say that most gunsmiths do a less than steller job of chambering the action, so if the man doing the machine work isn't up to the task, you're wasting your money.

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    Default Whose blueprint?

    If the rifle - or anything else - does not match the dimensions and tolerances on the factory prints that it was manufactured from - it is defective and should have been caught in inspection and rejected. If it got out of the factory and tolerences aren't correct send it back!

    Problem is - I doubt if anyone even has the factory prints to blue print with. I don't think any manufacturer is going to give them out due to possible negative publicity from acceptable tolerences vs another maker etc. There might also be a liability issue - I bet Remington wouldn't like to see the blueprints for their trigger and safety assembies showing up in court!

    So basically you can true up things and make your best guess at assumptions. In the one source referenced the canting of the bolt is discussed so the face of the bolt is perpeducular with the axis of the bore when the rifle is cocked. That sounds good with an empty chamber but what if the headspace is minimal and the face of the bolt is pressing against the rear of the case - wouldn't you have one lug quite not in contact or the bolt face not perpedicular?

    I learned a lot about actions form the late Phil Sauer. He was one of the few great benchrest shooters that was a brilliant engineer, a great shooter, and actually built his own rifles in his machine shop. Wish he was still alive - he would be a great source of knowledge.


    Quote Originally Posted by hunt_ak View Post
    So lemme see if I understand this...

    'Blueprinting' an action is basically making every imaginable dimension exactly like the bluepring says?

    How does one know if they need/want this?
    Living the urban lifestyle so I can pay my way and for my family's needs, and support my country. And you?
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    Quote Originally Posted by tvfinak View Post
    If the rifle - or anything else - does not match the dimensions and tolerances on the factory prints that it was manufactured from - it is defective and should have been caught in inspection and rejected. If it got out of the factory and tolerences aren't correct send it back!

    That's the main problem, is most of their tolerances are sloppy. For mass production they acceptable. The main confusion is that "blueprinting" an action is NOT trying to get it to factory specs. It is making everything square and tightening the tolerances. When it is "blueprinted" it will actually be out of factory specs, with new thread sizing, etc. You can go to different legths "blueprinting" and action also, such as sleeving the bolt for a tighter fit, bushing the firing pin, etc. It all depends on the use of the rifle. For a hunting rifle usually squaring up the bolt face, lapping the lugs, and recutting the threads is what is done. If your gunsmith is making best guess assumptions, find another gunsmith. "Blueprinting" an action is a precision task, and is not for those that guess.

    If you properly "blueprint" and action and install the barrel correctly, with brass fireformed in that chamber, the lugs will make even contact and the bolt face will be perpendicular to the axis of the bore, and centered in the bore. With new brass that may not have a squared case head, there may be some uneven contact.

    There are custom actions out there that are built to the same blueprint as a Remington, but hold tighter tolerances and are square from the beginning, so they don't need "blueprinted". Confused yet?
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  10. #10

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    Quote Originally Posted by Paul H View Post
    I'd also say that most gunsmiths do a less than steller job of chambering the action, so if the man doing the machine work isn't up to the task, you're wasting your money.
    If your gunsmith is trying to chamber an action, you REALLY need to find a new one. Most good ones chamber the barrel :-) Just giving you grief, we know what you mean.
    "Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything."

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    Default Confused?

    The term "blue printing" and the way is used is confusing and ambiguos. Likewise for "sloppy", "squaring", "tightning" etc.

    Everything that can be measured has a tolerance - nothing is absoute and there are always tolerances in measuring also. Manufacturing blue prints always show a dimension with a tolerance and/or a class of fit. Showing a finish for critical mating surfaces is also common on prints.

    So when you want to make everything "square" what tolerence do you want and how much do you need and are willing to pay for? Likewise for "true up" and "tightened" the tolerances? "Fit" would be a better term for many applications like the mating of the threads in the receiver and barrel since V thread measurments esp. on female theads requires some expensive equipment and skill. "Sloppy" tolerance that match up to produce a slight interference fit maybe better than "tighter" tolerances that mate up to produce a non-interference fit.

    A lot of people throw a bunch of money to get their rifles "blue printed" without knowing what they need and what they get. Fortunatly most gunsmiths are decent honest people and give their ignorant customers a fair shake when they "blue print" an action - whatever that term means!


    Quote Originally Posted by blackfoot View Post
    That's the main problem, is most of their tolerances are sloppy. For mass production they acceptable. The main confusion is that "blueprinting" an action is NOT trying to get it to factory specs. It is making everything square and tightening the tolerances. When it is "blueprinted" it will actually be out of factory specs, with new thread sizing, etc. You can go to different legths "blueprinting" and action also, such as sleeving the bolt for a tighter fit, bushing the firing pin, etc. It all depends on the use of the rifle. For a hunting rifle usually squaring up the bolt face, lapping the lugs, and recutting the threads is what is done. If your gunsmith is making best guess assumptions, find another gunsmith. "Blueprinting" an action is a precision task, and is not for those that guess.

    If you properly "blueprint" and action and install the barrel correctly, with brass fireformed in that chamber, the lugs will make even contact and the bolt face will be perpendicular to the axis of the bore, and centered in the bore. With new brass that may not have a squared case head, there may be some uneven contact.

    There are custom actions out there that are built to the same blueprint as a Remington, but hold tighter tolerances and are square from the beginning, so they don't need "blueprinted". Confused yet?
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    Smile

    Didn't mean to infer you were confused, more to the questions posted earlier about what exactly "blueprinting" is. I always refer to it a trueing, but I'm not or do I pretend to be a machinist, engineer, operator, manufacturer, or even know how to properly run a dremel tool. :-)
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    Moderator hunt_ak's Avatar
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    Thanks for the responses, guys. W/O any other changes other than 'truing' the action and possibly the barrel threads, has anyone seen increased accuracy after having this done?

    I'm thinking there are places where they specialize in this (and even places who might specialize in ONLY 700 actions, for example)?

  14. #14

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    The 700 is the most commonly "trued" action. If a gunsmith doesn't know how to true a Remington 700, he's not really a gunsmith. It's not really a specialization, but a basic skill that anybody that is rebarelling, etc. should be able to do. I have a 6BR that has a trued 700 action, but it was a 6mm Remington with a factory barrel before hand. It now has a Shilen Select Match benchrest contour barrel, so you can't really compare accruacy before and after. I don't think there is any dispute that it helps accuracy, but maybe what level of accuracy you are trying to attain and if it is worth it may be a better question. My opinion is that it's not worth trueing an action if you aren't going to put a quality barrel on, and it's not worth putting a quality barrel on if you aren't going to true the action. I have seen rifles that have just had the action trued and barrel threads re-cut (it's necessary to recut the threads and rechamber, or at least re-headspace after your action is trued) that have improved accuracy substantially.
    "Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything."

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    Quote Originally Posted by hunt_ak View Post
    Thanks for the responses, guys. W/O any other changes other than 'truing' the action and possibly the barrel threads, has anyone seen increased accuracy after having this done?

    I'm thinking there are places where they specialize in this (and even places who might specialize in ONLY 700 actions, for example)?
    Gunsmiths specializing in 700s are legion and the kind of work you are considering is routine. However, before you drop several hundred dollars I would take an honest assessment of what kind of accuracy you need and want. I know we all want tack driving rifles, but do we need to pursue BR standards for hunting rifles? If it were me, I would possibly have the lugs lapped (normally 25-40$) and put the extra money in something else rather than truing any further. The benefits of the truing process are real, but a high quality barrel on a good/average factory action should should be capable of fine accuracy (sub MOA) with preferred loads. I doubt you'll notice much increase in accuracy/consistency that is attributable from just the truing process unless the action is known to have a geometry problem. In that case I would sell the action to some other soul that wanted to fix it and start anew.

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    Default 700 actions

    Part of the problem with 700 actions is now they are built.

    The bolt for example is made up of the three pieces: the main bolt body - basically a tube, the bolt head with the lugs and a handle both brazed to the main tube.

    In comparison the orginal mausers, springfields, 1917s, Winchester 70s etc. had a one piece forged bolt. I suspect the lugs and bolt face were machined square using the bolt body as a reference. On a 700 in comparison the bolt head is a seperate piece from the body and can - and apparently often is - attached tilted to the bolt thus the lugs and face must be trued up to correct this misalignment.

    I suspect - but haven't confirmed -that the barrel threads on a 700 are cut using the outside of the receiver as a reference while Mdl 70s etc. use the bolt way to determine location of the threads. This would explain the need to "true" the threads on the 700 in relationship to the bolt way.

    Gunsmiths love 'em - keep the money coming!
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    Back when I was dumber paid to have two Remingtons "trued". If there was a difference in accuracy after the fact it was not noticeable.
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    Quote Originally Posted by tvfinak View Post
    So basically you can true up things and make your best guess at assumptions. In the one source referenced the canting of the bolt is discussed so the face of the bolt is perpeducular with the axis of the bore when the rifle is cocked. That sounds good with an empty chamber but what if the headspace is minimal and the face of the bolt is pressing against the rear of the case - wouldn't you have one lug quite not in contact or the bolt face not perpedicular?
    I'd say, NOPE. I don't know how you get to having "one lug quite not in contact or the bolt face not perpendicular".

    If things were squared with the bolt lugs in contact, (surely, they would be) a case pressing the lugs into contact would be SameO SameO.

    ??????
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    Quote Originally Posted by Snowwolfe View Post
    Back when I was dumber paid to have two Remingtons "trued". If there was a difference in accuracy after the fact it was not noticeable.
    I've only had ONE rifle barrel replaced. Stan Jackson did it, and blueprinted the action. The rifle is way more accurate, now.

    Granted that could have been due to the Douglas Barrel, but, why would I NOT have things squared, when replacing the barrel?

    You could make the case that I don't know beans about this stuff, (So what else is new?)but I CAN say, that I had a good experience.

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    Quote Originally Posted by Smitty of the North View Post
    I've only had ONE rifle barrel replaced. Stan Jackson did it, and blueprinted the action. The rifle is way more accurate, now.

    Granted that could have been due to the Douglas Barrel, but, why would I NOT have things squared, when replacing the barrel?

    You could make the case that I don't know beans about this stuff, (So what else is new?)but I CAN say, that I had a good experience.

    Smitty of the North
    I don't think anyone is saying that an action that is trued is somehow less preferable, so long as the work is properly done. I think the greater question is to do with the most bang for the buck. IME the attributes of truing an action just do not justify the expense. If I am going to build a rifle that requires the tolerances of a trued action I would rather start with a low volume custom action in the first place. Truing an action is not going to make the impact that a quality barrel will make. It is a matter of degrees. A quality barrel is capable of providing substantial improvement in accuracy while truing the action is going to make fractions of MOA in accuracy improvements.

    Whether or not that is worth a couple hundred bucks on most rifles is something every man has to decide to himself. If you decide to sell a trued action you'll get no extra money for it. For me and my money if I need that kind of accuracy I'll spend the extra dough on a Predator or similar action for the field and I am not going to build a competition rifle around a Rem 700--it's just not a wise decision IMO.

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