Ultradyne Rem 700 Picatinny Chassis PRS Build

We’ve done a lot of work with Ultradyne’s UD Chassis – this time we are putting together a Remington 700 PRS rifle with the UD Picatinny chassis!

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About the UD Picatinny Chassis

The UD Picatinny Chassis takes the features and performance of the UD chassis but with a 1913 Picatinny rear mounting interface. This allows for even greater versatility in ease to swap buttstocks as well as increased ergonomics.

This design allows quick detachment and reattachment of a buttstock for tight storage without compromising zero!

Ultradyne used to offer chassis with options of three, five, or seven M-LOK slots. The new Picatinny chassis has two options to choose from: three or six.

From Ultradyne:

All the performance of the UD Chassis, now with a 1913 Picatinny rear mounting interface for instant-detach stocks and next-level ergonomics.

The UD Picatinny Chassis takes the proven platform of the UD Chassis, and replaces the traditional buffer-tube interface with a robust, rear Picatinny mounting interface so the buttstock detaches quickly for compact transport or tight storage without compromising repeatable return-to-zero. The chassis accepts our new adjustable grip system so shooters can customize trigger-finger distance to their preference, and the adjustable thumb rest lets you tune positioning for repeatability and comfort.

General:

- 6061 T6 Aluminum
- Cerakote® Finish
- Stock Interface: 1913 Picatinny
- Grip Interface: Mil Spec A2 OR UD Adjustable Grip
- Magazine Interface: AICS
- 1.35” Max. Barrel Diameter

UD3 Short Action:

- 18.5-20.2 oz depending on inlet
- 16.625” Overall Length, 6.9″ Forend/Arca Length
- 9 total M-LOK Slots

UD6 Short Action

- 21.1-22.8 oz
- 21.35” Overall Length, 11.8″ Forend/Arca Length
- 18 total M-LOK Slots

Bill of Materials and Assembly

I decided to upgrade a 6mm ARC barreled action (BAT TR Rem 700 clone) complete with Leupold Mark 5HD scope, Hawkins Precision brake, and Bix’n Andy trigger.

In addition to the UD3 Picatinny chassis, I also have the Picatinny Gen 2 buttstock, length of pull spacers, bag rider, thumb shelf, adjustable vertical grip, weights, and spigot.

The Arrow Products Rock Vise is extremely well-suited for working on the UD chassis.

Its ARCA jaw securely holds the chassis in place at whatever angle is most convenient for installing the buttstock and accessories.

The Picatinny buttstock attaches quickly with two screws. I ran the adjustable vertical grip all the way back and installed all four spacers to give me the greatest length of pull possible. I also added six M-LOK weights, one to each slot in the chassis.

One of my must-have accessories with the UD chassis is the spigot. This allows me to mount a bipod further out on the rifle for greater stability without adding much weight.

The barreled action went in quickly and easily.

Shooting

One of the top benefits of a full-length ARCA rail is the ability to quickly and easily mount to a tripod. This offers great stability, especially for odd-angled shots.

My first shots hit above the steel targets at 400 yards. I had no issues connecting once I held the bottom of the target. After this experience, I went to the concrete bench to confirm my zero.

I was about three clicks high. After making the correction, I went prone to engage steel rock chucks at 335 yards, then our 660-yard hard-to-see IPSC.

Conclusion

6mm ARC is a great cartridge with solid long-range ballistics. Adding the UD chassis greatly expanded the versatility of my rifle and improved the ergonomics.