I don't know what the 2018-present contour specifically is (I would presume
@Covertnoob5 is correct, as I have read that before), but I do know that it is a heavier contour than pre-2018 barrels).
I only bring it up because of the following, in case that contour fits your needs:
I wanted to have a replacement barrel on hand for the factory barrel that came on my AXSR 300PRC. Since I started looking in July, there were none available from either EO or MH, and neither of them showed an option to backorder. Also, it is Elite Sand - which is the color they just discontinued. Before, I had been able to continue to special-order AI factory 300NM barrels in Sage Green for my AXMC from WinTac (through EO) during the time they had discontinued that color, so I asked EuroOptic to check with WinTac to see if we could put in an order for this one to be built. A few days later the answer came back from WinTac - "Yes, you can order it, and the expected time for production and delivery is 4-5 months." I put in the order through EO on Wednesday. Yesterday, EO received THAT barrel from WinTac and shipped it out to me today, 6 days from the order.
So, if the 2018- profile is acceptable (it IS a fairly heavy contour), you might inquire about ordering an AI OEM barrel (WinTac/Bartlein). I've always been told 4-5 months to deliver, but it has never taken more than 3. But neither have I ever gotten one in six days before, either!