Re: Pics or specs for M40A3 receiver cuts
That looks to be the factory 'clip-slot' that Remington did to their very early actions. The M40A3 isn't really clip-slotted, it is strictly notched out for the scope mount. This notching is done to the front and rear of the ejection port. I don't have a picture of this, but maybe another member will respond with it.
DD