Gunsmithing Sage heavy chassis install on standard barrel / pic heavy

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Recently I have found myself REALLY wanting a Sage chassis for one of my rifles. I cant explain the desire except to say I like new tech and want to try one for myself. I have four rifles and the only one that does NOT have a unitized gas cylinder is my Springfield scout. The Sage chassis does not use the stock ferrule and is removes from the gas cylinder. Since my other three rifles have them TIG welded in place the scout is the only one that is a price candidate.
I went with a SAGE MOD 1 with the Magpul adjustable stock. Its almost 2 lbs lighter than the MOD 0 stock and for a scout its perfect. My chassis I picked up from Flea Bay for a very good price ( less than a MOD 0 ) because my chassis is for a heavy barrel and the Sage Heavy Barrel chassis is not compatible with a standard barrel…..until now. I am not entirely up to speed on the generations of Sage chassis and the various colors they produce. Mine is anodized a dark color with black handguard plastic with the Magpul furniture in the rear. Its brand new minus the install instruction but who need stinking instructions…..

Sage MOD 1 Chassis / random pics

 

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Scout in USGI Fiberglass and SAGE chassis






Pics of the stock Sage guide block in the chassis~

 

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The major difference between the standard Sage chassis and the heavy barrel only chassis looks to be the OP rod guide block and added clearance in the front of the chassis to clear the larger barrel. More clearance is not a problem using a smaller diameter barrel.

The Sage chassis and guide block demonstrate excellent machining and finishing. The only thing that I consider a minor issue and easily corrected is the way they mark the op rod guide block. The factory / Sage puts a red paint dot on the front of the block that is suppose to go towards the front of the rifle.
I marked (stamped) my block with and “F” for front and “R” for rear. If you stamp the guide block stay away from where the op rod passes thru the guide, you do not want to peen an edge over and cause problems.







Once I have the block stamp marked I am not paranoid of the red paint coming off I can now take some measurement. I placed my action into the Sage chassis and checked for initial fit. The fit was / is excellent. No binding or friction points & the action sits down perfectly flat without any force needed.
I attached the still over sized guide block in the stock. I wanted to take a measurement to duplicate the same position when I install my Sage guide block on my Scout action. Using 8” dial calipers I measured 8.175” from the receiver face / edge to the front of the guide block. If I duplicate this dimension my action should fit precisely in the chassis without binding. The guide block mounting holes ( two ) must line up when the guide block is attached to the barrel. This could be a trick dimension to duplicate without measuring. Now that I have my target dimension I can make a busing for my guide block.

 

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Off with the old barrel stuff…..







Now I can measure my barrel to fit my op rod bushing~




I already measured the Sage guide block and the heavy barrel ID is 1.000”
I need to machine a bushing to press into the Sage guide block to fit my barrel diameter of .805 “
This is a simple job IF you have the skill, machine and measuring tools to do it. I used a piece of 17-4 stainless steel for the bushing material. I need it with a 1.001 “OD with an .804” ID.
I turned the OD diameter in the lathe and bored the ID before removing it from the chuck. This assures that the busing is concentric and will be on location once assembled. There is no way you could do this using a drill press or crappy piece of equipment.
The fit and position of the op rod guide is important for correct cycling, good wear and accuracy. I proper fitting negates the need of beating a guide on or off.

 

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Finished bushing and ready to press into the HB guide block~




Using my precision vise as a press~



Bushing in place~






Now that my modified op rode guide is finished I am slipping it over the barrel and mounting the guide block to the bottom of the chassis using the two machine screws from the bottom of the chassis. I insert my action legs into the chassis and start the barrel into the op rod guide block. The slight counterbore I made allows the barrel to start so I can set the rotational alignment then press to the correct spot.



I removed the action carefully not disturbing the guide block. I pressed it straight on the barrel. I stopped short, measured , pressed again , measure and pressed to the 8.175” target length.



Done correctly the guide mounting holes line up perfectly with the stock~



Mounted and complete~

 

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I can remove and insert my action into the chassis with no binding or excessive force required. I am pretty satisfied with the fit. I am on the fence about doing one more thing but am undecided thus far and would like some others opinions.
I have some added clearance between the space in my bushing and standard weight barrel. I am considering adding a epoxy filler in this void. If anything it would help transfer barrel heat to the large guide block. The air space hurts nothing but I like the idea of full contact to transfer heat.
Would you leave it open or add epoxy??

 

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It's nice when things line up perfectly....
Op rod is centered on the piston and glides as if on bearings.

 

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Well I am ready for a range trip....

My Bassett scope mount needed clearance on the front edge where it made contact with the Sage top rail. I like the Bassett mount over the Sage rail. With the Sage it's attached to the chassis cover / top rail vs the receiver. If you want to pull the action from the chassis you need to remove the top chassis cover and scope rail loosing your zero. The Bassett is receiver mounted and has fewer pieces stacked up so in theory a better chance of returning to zero if removed ( and the Bassett is cheap).