I have 2 HNT26s and like them. Are they perfect? No, but they’re still good for what they are which is an ultra light chassis.
Yes, the forend moves and flexes a bit on the tripod, but it’s an ultra light chassis and I didn’t expect the same rigidity out of it as say my Manners TCS with a double dead shell and a steel ARCA rail, especially if I try to force it that last little bit onto target without unlocking the ball head on the tripod which results in some flex and movement. I’m also running carbon barrels as both are lightweight pack-friendly builds, so I can't comment on forend flexibility with a heavy steel barrel. I can still shoot tiny groups from both my HNT26s, it just takes a bit more attention than with heavier and stiffer stocks.
That being said, the current forend attachment using the flathead screws compressing the carbon fiber could be improved IMO. I have thought about machining and bonding titanium bushings to the carbon fiber forend, that way the forend to center section connection is now a solid metal to metal bolted joint rather than the current design of a flathead screw pinching a thin cross section of carbon fiber.
Look at the pictures below. We use similar bonded bushings all the time on spacecraft composite structures and not only are they stiff they survive launch loads and thermal loads.
Sure, using bushings means the forend attachment hardware would no longer be flush, but they would be smooth with minimal protrusion and snag-free and allow a higher fastener torque to hold the forend on. Consider a bushing similar to the pictures bonded onto the forend, with a boss/nipple on the backside of the bushing slightly taller that the thickness as the carbon fiber forend to allow for a bond line, and the front side slightly counterbored to let a reduced height head socket head bolt sit flush with the top of the bushing or countersunk for a flat head screw to sit flush with the outside of the bushing. This way the boss on the back of the bushing protrudes through the forend to be in direct metal to metal contact with the center section to take the compression load rather than the current design of a flat head screw compressing the carbon fiber forend; now the screw can be torqued more since it’s a metal to metal joint. The larger surface area of the bushing flange gives the epoxy plenty of surface area for a strong bond and distributes the loads to the forend. With the bushing being machined with tapered edges it would be smooth and snag free and barely stick out from the existing forend.
I have a strong hunch that such a bonded bushing attachment method would significantly stiffen the chassis to forend joint while adding very little weight, but it would certainly increase manufacturing and labor costs if such a design change was implemented on MDT’s end. You could probably make the forend to chassis joint even stronger if the 2 side bushings were machined as ovals and utilized both side screw attachment points in the center section of the chassis (the current forend design uses only a single screw on each side of the forend even though the center section of the chassis is drilled and tapped for 2 forend screws on each side. The earliest versions of the HNT26 utilized 2 screws on each side of the forend, current versions only use a single screw on each side AFAIK which is what I was told by MDT.)
Just random thoughts from a guy who designs and works with metallic and composite structures that get sent throughout the solar system…
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