Some questions about ramping a 9mm bolt

[gunsrfun1]

Hello - I'm thinking of buying a 9mm upper to put on my RRA AR15 lower with a RRA 2-stage trigger that looks like the attached photo. (Yes I know the 9mm uppers are hard to find.) I've been doing some reading, so I understand the concept behind ramping the 9mm bolt.
But I still have two questions:
1) Is it a good idea to ramp the bolt regardless of the type/make of AR hammer in the lower. For example, if I would get another AR lower with a DPMS parts kit and hammer, would I still be advised to ramp the 9mm bolt? (I realize that you don't have to ramp the bolt if you're using a 9mm hammer, but I want to stay with my AR FCG.)
2) Some of the reading I've done says that the 9mm bolt is hard on the lower. In which case I would definitely get another lower, or even a dedicated 9mm AR. Will I damage my RRA lower if I switch back and forth between my 9mm and .223 uppers?
Thanks

 

[ApacheCoTodd]

You're OK without ramping it when using the above hammer. No step, slot or grove to give you trouble.

I still do it even when not necessary in preparation for needing to replace hammers later (as is highly likely with RR 2-stages - though it's usually the disconnector that wears out) and it takes a some of the sting outa that upper.

 

[gunsrfun1]

Thanks. So ... all I need to do is buy a 9mm complete upper, and a magwell adapter, right? I did a little more reading (including the RRA web site), and have read that some other parts are needed, like a specific buffer tube, etc. Is that the case, or will the upper and magwell adapter do it?

 

[Walkalong]

Buffer tube is fine, you may want a heavier buffer. An extended 9MM buffer will help keep from breaking bolt catches. I used a spacer I made with a standard carbine buffer to do the same thing. Nope, not my idea. My (MM AR is an RRA. If I remove the block and my home made spacer, I can run a .223 upper on it.

I also ramped my bolt, even though my hammer is not notched.

 

[gunsrfun1]

Thanks all, sounds like a 9mm buffer will help.
Apache -- Just want to make sure I understand your last answer. Basically what you are saying is that while I don't "need" to get the bolt ramped with my current RRA hammer, it won't hurt anything to do so. Plus, then I will be covered in case I ever replace the hammer. Am I understanding you correctly? Because if so, I will get the bolt ramped "just in case."

 

[ApacheCoTodd]

Yup, that's where I was going. Otherwise putting an incompatible hammer in in a pinch can result in locking things up between a shoulder on the hammer (not yours or many of them out there) and that cross slot on the carrier.

Ramping just sets up a far more harmonious relationship between any hammer and the carrier anyhow.

 

[GE-Mini-Gun]

The main reason for ramping the bolt is to "ease" the battering that IS going to happen with a 9mm, if you don't ramp the bolt you will beat the snot out of your lower and "egg" both hammer and trigger pin holes or break the pins themselves.