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Rifles, Reloading, Optics, Equipment
Gunsmithing
Is Blue Printing an Action important?
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<blockquote data-quote="Kevin Cram" data-source="post: 452033" data-attributes="member: 2215"><p>I blueprint actions that when finished I can make them work just a good if not better than some custom actions. I charge $150 as I feel that's worth the time I have involved. If any one is willing to pay me $300 though I'd gladly except it <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite11" alt=":rolleyes:" title="Roll Eyes :rolleyes:" loading="lazy" data-shortname=":rolleyes:" /> Blueprinting a production action is definitely worth it from an accuracy stand point. The process is hard to describe but I'll do my best to explain my process.</p><p></p><p> I use a GTR Action Bolt Bore Reamer Mandrel and several different sizes of bushing in .0002" increments. I built my own action fixture as well. Each actions bolt bore usually has 2 different sizes. Lets say under the rear bearing area the bolt bore diameter is .701" and the front bearing area is .705" Now with some other methods I know of, riflesmiths would have several different solid ground mandrels of varying sizes to find the one that fits best through the action. In this case the mandrel sized just under .701" is the one they would have to use because it would snugly fit through the action. What they might not have known was that they're really only making contact with the rear bearing area and not the front. So as they're indicating the mandrel in they're really not dialing in the true axial alignment with the center line of the action. They're probably making the action worse than what it was from the factory. I've seen this on a few actions that the customer said the action was already blueprinted by the last smith. Unless I knew the smith well and knew his process for action blueprinting I had a hard time believing the action was blueprinted properly so I set a few up to check my way and sure enough everyone was out at least .002" and most of the actions I checked the smith never did anything with the receiver threads.</p><p></p><p> Now the method I use is, I have several bushing with a perfect honed .500" inside diameter and varying sizes from .697" - .707" in .0002" increments outside diameter. I found the bushing that just fits snug in the rear bearing area. Next I would find the bushing that fit snug in the front bearing area. Now both bushings have identical inside diameters and are kept in line with the center line of the action but the outsides are different to take up the difference in bolt diameters from the rear bearing area and front bearing area. </p><p></p><p> I'll slide my GTR Bolt Bore Mandrel through the bushings which is next to a perfect slip fit. I'll place the action in my blueprinting fixture and with 2 .0001" dial indicators on the mandrel, one right ahead of the action and one about 5" out I start dialing in the action for true axial alignment through the center line of the action. I normally can dial an action to less than .0002" of being perfect. I can then slide the mandrel out leaving the receiver face, internal locking lugs and threads open to machining in one set-up. </p><p></p><p> With a razor sharp solid carbide single point tool I remove just enough material off the receivers face for a full clean up. I then switch to a 3/4" solid carbide boring bar and remove just enough for a full clean up of the internal locking lugs. I'll then bore the tops off of the threads, again just enough for a full clean up. The receiver thread are usually the worst. I've found most receiver threads to be out of round, like an egg and usually tapered smaller towards the rear. I'll then switch to a internal single point threading tool and pick up the thread pitch. I'll slowly find the bottom of the thread and call that zero. I'll single point re-cut the receiver threads .001" per pass until I get a full clean up which is normally the same amount it took when I bored the tops off the threads. I now know that the action threads have been straightened up and over sized and I know by how much they've been over sized so I can transfer this onto the barrel tennon.</p><p></p><p> The action itself has now been fully blueprinted. The only other thing that I can do is use the GTR Bolt Bore Reamer Mandrel for its other use. It has solid carbide cutters braized onto mandrel in the middle so you can align your action with the bushing and then drive the mandrel through the action while the cutters take the bolt bore to a perfect .705" diameter the entire way through the action. This a great idea if your going to use custom PTG bolt ground to fit your actions bolt bore.</p><p></p><p> The next step to blueprinting an action is squaring up the bolt face and rear of the bolt lugs. I prefer to use a Labounty fixture for holding the bolt body in place while I indicate. Most production bolts are not straight so I sometimes don't have a predominate high and low pot while indicating. I sometimes have to split the difference and just work on 2 sides until they are equal then work on the next. For example I may indicate in the bolt and find that the needle reading at jaw 1 is on 0. On jaw 2 the needle is reading .002" on jaw 3 it reads 0 and on jaw 4 it reads .002" The bolt itself is out of round by .002" I've spit the difference so I get the same reading on opposite jaws. The bolt is now dialed in true and I take a cut on the bolt face with a custom solid boring bar I ground to clearance the factory extractor. I'll remove only enough to get a full clean up. I'll then use a solid carbide left hand facing tool and face off the rear off the bolt lugs just enough for a full clean up.</p><p></p><p> With my process I'm absolutely sure the actions receiver face and internal locking lugs are perfectly perpendicular to the center line of the action. The receiver threads are now straight and in true axial alignment with the center line of the action as well, and the bolt face and lugs are perfectly perpendicular to the bolt body. </p><p></p><p> With my action blueprinting process I've been able to do testing with the same action and barrel prior to action blueprinting to see how rthe rifle performs. I then blueprint the action, cut the threads off of the barrel, re-thread and chamber then test again. I've found in most cases that the rifle after blueprinting will be much more accurate and consistent. I made a video of how I blueprint an action a while ago. I just need to find the time to sit down and edit it together so I can post it.</p><p></p><p>Thanks</p></blockquote><p></p>
[QUOTE="Kevin Cram, post: 452033, member: 2215"] I blueprint actions that when finished I can make them work just a good if not better than some custom actions. I charge $150 as I feel that's worth the time I have involved. If any one is willing to pay me $300 though I'd gladly except it :rolleyes: Blueprinting a production action is definitely worth it from an accuracy stand point. The process is hard to describe but I'll do my best to explain my process. I use a GTR Action Bolt Bore Reamer Mandrel and several different sizes of bushing in .0002" increments. I built my own action fixture as well. Each actions bolt bore usually has 2 different sizes. Lets say under the rear bearing area the bolt bore diameter is .701" and the front bearing area is .705" Now with some other methods I know of, riflesmiths would have several different solid ground mandrels of varying sizes to find the one that fits best through the action. In this case the mandrel sized just under .701" is the one they would have to use because it would snugly fit through the action. What they might not have known was that they're really only making contact with the rear bearing area and not the front. So as they're indicating the mandrel in they're really not dialing in the true axial alignment with the center line of the action. They're probably making the action worse than what it was from the factory. I've seen this on a few actions that the customer said the action was already blueprinted by the last smith. Unless I knew the smith well and knew his process for action blueprinting I had a hard time believing the action was blueprinted properly so I set a few up to check my way and sure enough everyone was out at least .002" and most of the actions I checked the smith never did anything with the receiver threads. Now the method I use is, I have several bushing with a perfect honed .500" inside diameter and varying sizes from .697" - .707" in .0002" increments outside diameter. I found the bushing that just fits snug in the rear bearing area. Next I would find the bushing that fit snug in the front bearing area. Now both bushings have identical inside diameters and are kept in line with the center line of the action but the outsides are different to take up the difference in bolt diameters from the rear bearing area and front bearing area. I'll slide my GTR Bolt Bore Mandrel through the bushings which is next to a perfect slip fit. I'll place the action in my blueprinting fixture and with 2 .0001" dial indicators on the mandrel, one right ahead of the action and one about 5" out I start dialing in the action for true axial alignment through the center line of the action. I normally can dial an action to less than .0002" of being perfect. I can then slide the mandrel out leaving the receiver face, internal locking lugs and threads open to machining in one set-up. With a razor sharp solid carbide single point tool I remove just enough material off the receivers face for a full clean up. I then switch to a 3/4" solid carbide boring bar and remove just enough for a full clean up of the internal locking lugs. I'll then bore the tops off of the threads, again just enough for a full clean up. The receiver thread are usually the worst. I've found most receiver threads to be out of round, like an egg and usually tapered smaller towards the rear. I'll then switch to a internal single point threading tool and pick up the thread pitch. I'll slowly find the bottom of the thread and call that zero. I'll single point re-cut the receiver threads .001" per pass until I get a full clean up which is normally the same amount it took when I bored the tops off the threads. I now know that the action threads have been straightened up and over sized and I know by how much they've been over sized so I can transfer this onto the barrel tennon. The action itself has now been fully blueprinted. The only other thing that I can do is use the GTR Bolt Bore Reamer Mandrel for its other use. It has solid carbide cutters braized onto mandrel in the middle so you can align your action with the bushing and then drive the mandrel through the action while the cutters take the bolt bore to a perfect .705" diameter the entire way through the action. This a great idea if your going to use custom PTG bolt ground to fit your actions bolt bore. The next step to blueprinting an action is squaring up the bolt face and rear of the bolt lugs. I prefer to use a Labounty fixture for holding the bolt body in place while I indicate. Most production bolts are not straight so I sometimes don't have a predominate high and low pot while indicating. I sometimes have to split the difference and just work on 2 sides until they are equal then work on the next. For example I may indicate in the bolt and find that the needle reading at jaw 1 is on 0. On jaw 2 the needle is reading .002" on jaw 3 it reads 0 and on jaw 4 it reads .002" The bolt itself is out of round by .002" I've spit the difference so I get the same reading on opposite jaws. The bolt is now dialed in true and I take a cut on the bolt face with a custom solid boring bar I ground to clearance the factory extractor. I'll remove only enough to get a full clean up. I'll then use a solid carbide left hand facing tool and face off the rear off the bolt lugs just enough for a full clean up. With my process I'm absolutely sure the actions receiver face and internal locking lugs are perfectly perpendicular to the center line of the action. The receiver threads are now straight and in true axial alignment with the center line of the action as well, and the bolt face and lugs are perfectly perpendicular to the bolt body. With my action blueprinting process I've been able to do testing with the same action and barrel prior to action blueprinting to see how rthe rifle performs. I then blueprint the action, cut the threads off of the barrel, re-thread and chamber then test again. I've found in most cases that the rifle after blueprinting will be much more accurate and consistent. I made a video of how I blueprint an action a while ago. I just need to find the time to sit down and edit it together so I can post it. Thanks [/QUOTE]
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