Since we were discussing 10.5” barrels, the natural assumption is that either the XM177 or XM177E1 would be the model being replicated, and both of those used 10.0” barrels. Many people incorrectly believe that the XM177 and XM177E1 used 10.5” barrels, so whenever I hear someone in Retro mention 10.5”, I figure they are talking about the 10-incher.
Then again, this thread is about the XM177E2, which certainly did use an 11.5” barrel.