I have a post 64 Model 70 that I rebarreled to a 6.5 Creedmoor. The original trigger is not that great for target shooting. I was thinking of replacing it with a Timney. Are they difficult to replace? Most of the Timney's I've purchased for my other rifles simply dropped right in. Someone told me that with the M70 you lose the safety when you replace the trigger?? Is that correct? That makes no sense?? 