9mm AR build: M4 feed ramps or not?

[Tactically Fat]

I have a CMMG Mk9 dedicated 9mm lower.

I'm waffling between buying a completed upper or piece-mealing one together.

I think that I'll have to piece-meal it due to spreading out the costs over time vs. making my Roommate angry with a ~$600-800 purchase all at once.

So - uppers. Does it matter if the upper has M4 feed ramps if I have the CMMG Mk 9 lower? Lower Receiver Sub-Assm, Mk9, SMG

From the link, it says that this lower has feed ramps.

So do I need an un-ramped upper?

Or will there be sufficient overlap where the upper's ramps will be effectively blocked by the lower's ramps?

I'm so confused... And I probably missed out on a thousand different sales on uppers because I simply don't know which upper will be compatible. :-(

 

[OneBadV8]

Do you have another AR upper around? You could always put it on your lower to see if it covers the feed ramps. Or if you're ever close you can try with one of my uppers.

I think it will cover the feed ramps on the upper, I'm pretty sure the 9mm magwell blocks do the same.

You might check with Indy_Guy_77, I think he was researching a 9mm build a while back but he doesn't post as much as he used to anymore

 

[Tactically Fat]

Do you have another AR upper around? You could always put it on your lower to see if it covers the feed ramps. Or if you're ever close you can try with one of my uppers.

I think it will cover the feed ramps on the upper, I'm pretty sure the 9mm magwell blocks do the same.

You never slum it around on the south side, so trying one of YOUR uppers probably won't work out very well!

And I honestly never thought about comparing my lower with someone else's upper. Yeah - I'm not very bright at all. Sheesh.

A better question: Should the M4 feed ramps NOT be covered up - will they cause feeding issues?

 

[OneBadV8]

I can look at my 9mm build when I get home for you. I don't think they'll be an issue at all though.

 

[Trigger Time]

The feed ramps on the upper are not important because on a 9mm your Feedramp is built into the lower and the chamber is not like that on a 5.56. So if your upper has feed ramps they will just be there but not be of any harm nor of any use.
It's a non issue. Use whatever upper you like.
my first 9mm build I used a cmmg dedicated lower and they are awesome!! Now I have a rock river dedicated 9mm lower and I love it too!

 

[Tactically Fat]

The feed ramps on the upper are not important because on a 9mm your Feedramp is built into the lower and the chamber is not like that on a 5.56. So if your upper has feed ramps they will just be there but not be of any harm nor of any use.
It's a non issue. Use whatever upper you like.
my first 9mm build I used a cmmg dedicated lower and they are awesome!! Now I have a rock river dedicated 9mm lower and I love it too!

I figure that was the case.

And here I am thinking of all the uppers that I didn't buy this week... *sigh*

I need a slick-sided upper!

 

[Sausagecake]

Someone correct me if I am wrong because I am not terribly familiar with ARs, but I thought that M4 feed ramps only apply to the 556 round? Is there even an option for M4 ramps on a 9mm barrel?

 

[nipprdog]

You never slum it around on the south side, so trying one of YOUR uppers probably won't work out very well!

And I honestly never thought about comparing my lower with someone else's upper. Yeah - I'm not very bright at all. Sheesh.

Nice way to thank someone who took the time to try to help.

 

[OneBadV8]

Nice way to thank someone who took the time to try to help.

I know him outside of here