Precision Barrel Fitting, Part Eight

By now you have become familiar with John Hinnant’s book as I’ve picked a pathway through it. Hopefully you have completed any trigger work, rejoined barrel to receiver, returned the action to the stock, test fired the result of your labors with great success and are feeling real good about calling the rifle owner with news of the gun being finished. Not so fast my friends.

If you have been hired by a demanding and knowledgeable hunter who insists on the ultimate in accuracy, you will be asked to blueprint the rifle first. There is nothing unusual about this request from those seeking record trophy or large, dangerous game and all words spoken by you regarding additional cost are not likely to cause a change of mind. Such hunters, male or female, will merely seek out another ‘smith eager to finish the job you started.

Blueprinting Defined Mercifully, I’ll spare you the time I wasted looking for a definition on the web. It appears on page 163 of John’s book. He quotes a letter published in 1996 by S. L. Wormsley, Jr, then Associate Technical Editor of American Rifleman, "Blueprinting a rifle action encompasses the steps a gunsmith takes to eliminate machining errors, ensure all dimensions are to proper specifications and to align all critical action surfaces with a standard reference point.

Usually, this point is the hole in the receiver body for the bolt. Blueprinting would involve setting up the receiver in a lathe with the axis of the bolt hole on centers.

The set up would be used to reface the receiver, the locking lug seat and, in a thorough job, recut the barrel threads inside the receiver ring." Wormsley continues to mention that to achieve the totally thorough job just described it should first be determined that the bolt hole itself is straight, round and of consistent On the right, the tool is shown positioned to cut internal receiver threads of a Model 700.

It can also be used with classic Winchester M70 actions but is not intended for Winchester push-feed models. diameter. It is then made clear that a failure to comply with making that determination could result in a necessity to perform significant corrective measures on the receiver. I think you are beginning to gain a fair idea of why blueprinting, whenever requested, can be no simple request to satisfy.

Blueprints And Blueprinting Since way back when there was a telephone hot line I received quite a number of calls and, presently, receive emails from members wanting working drawings to fabricate replacement parts for a variety of guns. I’ve had to turn down every request. Manufacturers refuse to provide blueprints and American Gunsmith has never had them inventoried. Both those facts remain true but perhaps—just perhaps—so does hope.

I, your humble and obedient Technical Editor, came across something on the web: The-Blueprints.com. They claim to have over 66,000 available on line. Guess who couldn’t resist finding out more about this? Right! Turns out The-Blueprints.com is an Amsterdam-based outfit. They offer more than 66,000 blueprints and 11,000 vector drawings but they’re not exclusively for rifles. You want to build a car, overhaul an out-of production handgun, or build a World War I combat plane? How about a tank?

Interested in knowing more? There’s a hitch. You can’t download any blueprints or vector drawings until you have registered a screen name, password and subscribed to a newsletter using a credit card. To tighten the hitch the lengthy "terms and conditions" legaleeze never mentions cost. That omission prompted me to remain in the just-shopping-around category and break off the web site visit. If the company or group offering the merchandise were US-based I might have moved further into a relationship.

I avoided doing so. Due to a couple of totally-separate-from-thisarticle but bad prior financial experiences, I no longer release my credit card data for offshore consumption. I therefore leave any decision to make The-Blueprints.com part of your operation entirely up to you. Besides, I 072" major diameter.

It reams 0.005"-0.010" from M700 minor thread diameter and all the threads from a push-feed M70. quit building airplanes when U-Control model kits and familiar-to-me glow plug engines powering them vanished from my local hobby shop. Traditional Blueprinting I want you to re-read the definition Mr. Wormsley provided in his letter.

Be sure to add his later comments on On the right the tool is shown as it would be applied to truing the receiver. the bolt to the effect it must be installed in a lathe, have front and rear lugs trued, along with its bolt nose and face trued. There’s more. Firing pin protrusion gets checked. Inside the bolt and outside the striker are polished. So are the locking cam surfaces, receiver feed ramp and extractor cam on the receiver bridge.

On bottom, a carbide bolt face burr with tooling block. Both are employed in blueprinting a receiver. An electric, variable speed hand drill drives the burr in performing the clean-up. Any dedicated High Power rifle competitor has very likely come up against a Master-classified opponent sending bullseye hit after bullseye hit down range from a Remington 40XBR. By the way, the "BR" stands for "Bench Rest" and that rifle was introduced in 1969.

Its receiver is based on the Model 700 except it has been heat treated to between 41 and 46 Rockwell and had its larger outside diameter ground true between centers. Since their introduction 40XBR rifles have been produced exclusively in Remington’s Custom Shop. They have always been individually blueprinted. They still are. I hope you’re not getting discouraged but if you yearn for more disheartening words you’ll find them on pages 152-200 in John Hinnant’s book.

Therein he itemizes the traditional method of blueprinting turn bolt actions and reveals the high degree of machinist knowledge and skill required to execute it.

Smile For Good News Thanks to Dave Manson and Manson Precision Reamers (manson- Additional Reading and Sources Reference Author/Publisher Date/Contact The Complete Illustrated Guide to Precision Rifle Barrel Fitting John Actions and Triggers Stuart Otteson amazon.com "Blueprinting" Shooting Times November 2003 "Lathe Installation & Check Procedure" Precision Shooting May 1991 Precision tooling Manson Precision Reamers reamers.com, the need for extensive training in order to blueprint actions has been greatly lessened.

Dave’s successful career as a toolmaker, manufacturing engineer and sales representative with Clymer Manufacturing (clymertool. com, 877/REAMERS) dates back to 1981, a relationship that only concluded when he started his own company in 1998.

To put it mildly, Dave’s specialized tooling has revolutionized blueprinting and is used to perform the following operations without a lathe: Recut the receiver lugs square to the bolt way and to the same height, recut those same lugs 0.010" oversize in diameter, true the front receiver ring, and ream a Remington-style recoil lug. A fifth element, the Manson Bolt Face Truing Kit, enhances a gunsmith’s ability to achieve exactly what the kit title says.

It consists of a precision fixture, the tooling block and various face-cutting carbide burrs. An electric, variable speed hand drill is used to drive a burr to clean up and square up a bolt face to the axis of a bolt and bolt raceway. The instructions accompanying Manson tooling is detailed and, as instructions go, easily understood. While it isn’t unusual for a single well-performed blueprint job to take a day to one and a half days on a lathe, Dave’s tooling makes completing three in one day feasible.

In his current catalog tooling is listed for 144 rifle and handgun calibers. Wildcat cartridge tooling is not on the list but is available. I will not here, elsewhere, or ever dispute John Hinnant’s comment, "Any perceived concerns these tools will not produce a blueprinting job equal to the traditional method will have to be proven to this writer." This writer, too, Mr. Hinnant. AG