TargetTalk

Does anyone know if the loading gate of the LG400 can be switched from right to left without needing any additional part?

As far as I know it can be made LH with stock parts. The cheekpiece however, might not be.

If "loading gate" means loading lever (the "gate" is symmetric, right in the middle of the stock and assessible from left and right): You can switch the lever from right to left ("Ergonomically shaped loading lever can be placed on the left-hand or right-hand side") within 2 minutes and with the included tools. We in Germany have an own league of shooters shooting supported from a stand (up from 46 years on), and most of these right-handes shooters prefer to pull the lever from the left side and load (from a box stored at the bipod) with the right hand. You can also alter the angle of the lever, perhaps to a 90 degree downward position or to the back for 180 degrees for a more convenient and faster loading.
See this video clip: https://www.facebook.com/video.php?v=1572711612971029

The cheekpiece is ambidextrous; just loosen the screws and change the direction of the metallic base beneath. For changing the right-hand- to a left-hand-version you only need a left-handed grip.

I personally would recommend the Anatomic version with its laminated stock. This Cheekpiece has integrated stops for a quick change and reset to the old position, and the buttplate the same.