Glad to be of service.
If the Gas Block on your gun has been damaged any at all, especially the area around the edges of the holes and slots, inserting the Gas Valve can be problematic. But a small round file removing these inward facing burrs can easily remedy that. If the gun is in "unissued" condition, and the gas tube/hand guard does not have any forward/backward movement, installing the Gas Valve is no problem, but the gas tube/hand guard may then have too tight a fit to go back into position. (we have machined our "oversized" GV to original length on request)
If you're having ejection issues while using an original magazine, (not a metal aftermarket detachable) it is likely the culprit is a leaky gas system and our Valve does a good job at fixing that.