I have searched the site & google to apparently no avail, apologies if this is common knowledge....

Slight twist to the AR-10B/ DPMS/ KAC compatability question: I know that barrel extensions/ BCGs need to match, and I know that upper recievers/ lower recievers/ mag catches/ magazines need to match... but could I combine the two groups? As in, have an AR-10B platform, but eventually swap out the AR-10B style barrel & bcg to the DPMS style & still have things function?

I ask because I have an AR-10B. Love the rifle, just thinking if down the line (many years ) I want/ need to swap barrels. There are so many more DPMS-pattern barrel extensions/ barrels around, curious if they are usable or if I'm confined to armalite's offering & the few other companies (rainier is the only one off the top of my head) that use AR-10B style barrel extensions.

Thanks.

The short answer is yes, as long as the bolt and barrel extension match...

Thanks, very good to know.

Does the long answer involve reliability of stripping rounds from the mag?

Does the different bolt catch play a factor at all?

Just saying. If you don't mind explaining, or pointing me to a source, I'd be interested to know the details.

The mag catch and Internal mag geometry are basically Identical between  the various AR-10B/SR-25/AR-308 lowers in order for them to
be compatible with the Gen II and Gen III Magpul 7.62 x 51mm/.308 Win. magazines.

On the earlier AR-10 versions they used a different type/style of mag catch for use with modified M14/M1A1 mags, also there was a 5/6 degree
Internal magwell taper...Also, the bolt hold-open catch was different between the old and newer versions of the Armalite AR-10. There are also
minor differences between the bolt carriers/bolts between the AR-10 & AR-308 versions, the forward buffer tower is also different between the
AR-10 and AR-308, one is angled and one has a radius ...

So there are the main differences listed above and why they may have compatibility/reliability between the similar but not the same platforms...