THIS IS GTR'S ORIGINAL DESIGN! NOT A AFTER MARKET.


This is the standard size in stock .705 Reamer Mandrel, for other sizes call us at: 970-878-5421 No extra charge for custom diameter. Up to 60 days for custom size.



This multi purpose precision tool is priceless to the accuracy smith. The tooling is a must for accurizing actions and sleeving bolt bodies. It cuts the cost of having .0005 increment mandrels or stepped mandrels for multi diameter bolt bore raceways. With out a properly fitted mandrel, a canted false axis is set for the bolt bore, and a skewed machining will result!


The precision ground reamer / mandrel takes 4 weeks to manufacture. From it?s start as a blank mandrel, with rough out to hardening, onto cryo then aging to final grinding, this is state of the art tooling.


To start, the reamer is helical for interrupted cuts down the bolt bore. As with a .705 reamer / mandrel that is going to be used to rebore the raceway, it has multi position interchangeable bushings. This is to make sure you rebore down the centerline of the raceway and establish a true and concentric raceway.


As an example take a Rem. 700 action. The bolt will be receiving sleeves as part of the accurizing job. The action rear bolt bearing area has an I.D. of .7015. You install one .7015 bushing in this bearing area. Next to the front bearing area, and this I.D. is .7025. Install a .7025 bushing. Now from the rear of the action, slide in the mandrel section in front of the helical section of reamer through the center of the bushing. As the reamer is advanced through the action it pushes the bushings forward. As it advances it re-cuts the bolt bore to .705.


The rear portion of the reamer is a solid ground bearing area of .7047 as with the reamer section. The reamer maintains alignment on its entire cut from back to front.


This is now a fitted mandrel in perfect centerline of the bolt bore raceway. This is used then to dial in the action in the ACTION BLUE PRINTING JIG. Life is good


There is more! What if the customer doesn't want the action rebored for bolt body sleeves. But wants an accurate blue print of the action. So simple and cost effective! The Winchester action is worn. The rear bearing area is .703 and the front bearing area is .707. You fit the bushings as above in the front & rear bearing areas. Slide the mandrel in from the front and use the rear reamer bearing area as the dial indicator surface for two dial indicators after mounting in the ACTION BLUE PRINTING JIG.


BUSHINGS SOLD SEPARATE