I am currently in the planning process of a 9mm carbine and was looking at lower receivers, the standard being Quarter Circle 10

I was wondering if any of y'all have experience with either of these two lowers?

Black Creek Precision
or
Gun Point

i like the look of the smaller mag well for the colt smg mags so a mag block or cmmg are out for me

I've got a BCP/GPI lower. It's pretty nice.

I did my build on the Black Creek Precision EF9, good looking reciever and very well made. They have changed from the long finger 9mm bolt catch to a integrated lifter that uses a standard catch, that was a nice suprise. Mine assembled perfect with no issues. Mated it to a Model 1 Slick Side upper, very tight fit with no slop or wiggle. For what it is worth, BCP told me that they are the ones that make the Gunpoint Billet Lowers.

My personal experience is that BCP has excellent customer service, very satisfied!!

+1 for the BCP lower!  

Very well made.  I really like the capture screw setup for the Bolt Catch and the pivot pins.

The BHO lift is an outstanding design.  Here is a link about the good results I had with the BCP lower with a UCIW install.

http://www.ar15.com/forums/t_3_15/673058_LWRC_Ultra_Compact_Users___What_Buffer_are_you_using___UPDATE.html

Mark

Does anyone have pics of the difference between the two bolt catches used on the BCP lowers?

The older GPI (now BCP) lowers used the extended bolt catch.

The newer BCP lowers use a bolt catch lift to engage the standard bolt catch as seen in this photo from the Gun Point website.

Looks like I have the older model,do they have problems with the bolt catch?

I believe the reason for the update to the BCP BHO lifter was to increase the surface area that contacts the mag followers.  

The previous version with the smaller follower contact pad is more susceptible to wearing on plastic mag followers, eventually if the wear is sufficient enough it could fail to lift the follower up high enough to catch the bolt.  This is the explanation I got from BCP.  

No issues if you are using the small lift pad version with metal follower mags, and if you are using plastic just keep an eye on any wear to the follower.

All BCP EF9 receivers shipped since early February should have the large lifter pad design (and unfortunately it's not just an installable part upgrade, but rather a receiver design upgrade).