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Accurizing a receiver

 
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  #1  
Old 12-06-2007, 10:27 PM
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Accurizing a receiver

I have a Model 70 receiver that was accurized when I had a new barrel put on several years ago. Thinking about rebarreling again. Would the receiver need accurized again?
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  #2  
Old 12-06-2007, 10:36 PM
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The receiver should not have to be touched again. All you should have to do is headspace.
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Old 12-06-2007, 11:58 PM
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Ditto; Tom
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Old 12-07-2007, 01:54 PM
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Under most circumstances you should not have to re-true an action if it was done properly the first time. I've had numerous actions come through that were suppose to have been trued. Before I re-barreled I set some up and checked to see how well of a job was done. On 80% or more the threads were never touched, the threads are one of the major things to b re-worked during a blueprint job, a tap can't straighten out the threads just clean the gunk out. Single point re-cutting (by someone who knows how) is the only way to true the threads concentric with the centerline of the action, and remove the taper. On 60% or more the receiver face and locking lugs were out of square to the centeline of the action by more than .003" ( I've had factory actions that were better than that without blueprinting). Then the bolt has got to be set up right for proper trueing as well. This is where alot really fail the trueing part. I use a custom ground mandrel by Greg Tannel and several bushings for the perfect fit in the actions through bore for proper axial alignment. The mandrel is double indicated in to within .0002" (usually a little closer) on a custom 8 leg spyder fixture I built, then the mandrel can be removed and all the operations for trueing the action can be done in the same set-up.
The bolt is held by a spud threaded into the rear of the bolt and the front is supported by the firing pin hole by specially made sized spuds also. The bolt body is indicated in parrallel along the length of the bolt as close as possible. (almost all bolts have a bannanna shape to them) The locking lugs are machined perfectly perpendiculat to the centerline of the bolt, then a steady rest is applied around a sacrificial collar attached to the lugs (making sure the bolt is not knocked out of alignment by checking with the indicators) so the tailstock can be removed for finishing the bolt face square. It takes a min. 6 hours to completely true an action correctly. I wish I could get $150 for the work some people do claiming they "trued" their action.
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  #5  
Old 12-07-2007, 06:10 PM
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Jumpalot, since you said you were thinking about rebarreling after several years, the rifle must have been acceptable to you. That being the case, normal inspection and guaging would verify the action's overall condition before fitting the new barrel and the 'smith would let you know if it needs any rework. If it was ok before, just rebarreling it won't require re-truing.

Good luck, Tom
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  #6  
Old 12-08-2007, 12:05 AM
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The rifle currently shoots between 1/2"-3/4" at 100 yds. Just thinking that I might want to do something different.
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  #7  
Old 12-08-2007, 10:08 AM
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The terms "accurized" "trued" "blue printed" and "reworked" are all very commonly used buy guys that build guns , sadly like Mr. Montour said alot of time some guys oppinion of these terms is not accurate with its actual meaning. At the very least , after your barel is pulled off check to see if the reciever face was cut on , it should have a nice smoot shiney finish not semi rough like the rest of the action then have a good look at the lug embunkments to see where the bolt lugs were making contact , both of them should have rub marks that are the same size and shape. Use a good depth mic and check the distance from the reciever face to the embunkments where the bolt locks up , these should be exactly the same or at the most .0002" out and thats if the smith allows for that much runout in his setup. Also like Mr. Montour said if it were done properly the threads should have been recut , not its hard to tell if they were just taped out or if they were single point recut to be strait with the bolt race way.
Now all that being said I have reciently had the opertunity to talk with and watch and hopefully soon work with a gun builder that holds a couple world records and his guns hold world records in the BR arena he is also in the BR hall of fame. After talking with this great guy about how he builds his guns the topic of "blueprinting" came up and I was wondering how he did his. His response was "I don't" and "I won't waste my time" when he builds on a Rem action he runs a tap through the threads to clean them out and hand laps the lugs and thats it !!! His theory is that the accuracy is in the barrel and chamber and how its cut. He cuts his chambers with reamers that have sets of pilots for them made in .0002" incriments. I have seen his rebarreld Rems shoot inthe .2's and .3's with just this work done , he will have the action fully blue printed but its gonna cost yu and it'll take a while as he sends them to Bob Brackney for it.. Does this mean that a accurately blue printed action is a waste of time? Well thats argueable , but I will say that I will contune to fully blueprint all of my actions that are build one factory recievers as I think you should use any measures possible to to eliminate every possible factor of the accuracy equasion.
It sounds like alot of money to have a Rem action blue printed with an average cost in the $150 range but if you have never set one up for this work you can imagine the time it takes , with the $150 for the blueprint and $150 for the chambering and fitting of the barrel you are getting a hell of a deal considering the average cost at a regular machine shop is $80 per hr !!!

So If it were me I'd send the action to sombody that knows what he is doing and have it checked before its rebarreled and if its not properly "accurized" then have it done correctly , it should be a one time deal.

Sorry for the rambeling , it just chaps my butt for some gun butchers to throw these terms around , kinda like the guys that shoot deer at 1000yds with grandads old 30-30
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