For DCC applications, I only use flat cable. My suggestion is to ditch the round cable and stick with flat cable.
Rich
Alton Junction
I have literally never had any trouble getting 4-pair to punch down into either blocks or modular connectors. Be sure you're using a good tool that is compatible with the connectors you're using, in particular make sure that the blades punch the wires fully down into the channels in the connector without deforming anything or getting one end lower than the other. I do not like handheld versions of any four-pair tool -- I barely like them for 2-wire use on RJ11 connectors, which is about as simple as punchdown tool use is likely to get.
Know the 'default' color code for the wires in your cables when "connected for Ethernet". Be aware that some conductors are 'crossed' in connector pairs and some are not -- I'll leave the discussion why to others. One of the great revolutions in the use of 8-pin modular patch cables came when devices like routers were made to 'autoconfigure' to use standard and crossover cables interchangeably; whole generations have grown up now thinking it's just 'plug and play'. IF YOU ARE MAKING PROPRIETARY CABLES THE CROSSOVERS MAY NOT BE ETHERNET STANDARD. Look into the clear ends of the modular connectors on known-good cables of the kind you're replacing, and see how the colors 'pin out'. Do the same in the same places with however many pairs you're propagating...
What I did -- it won't matter for most modeling situations -- was keep the 'twist' right up to the end of the pairs in round cable when punching down, and then work a blob of something like adhesive silicone caulk around the back of the connector and up into the jacket as a strain relief and to keep the pairs from shifting around in torsion.
Got a great deal on a 1000' box of cat6 cable. I knew it would be 4 pair of wires that are twisted in pairs. removed about 2" of the sheath and straightened the wires then cut off one pair and added the connectors using the tool to do that. did not have continuity in half the connections. Learned why flat cable is made. Anybody got any tips for making a successful cable using round wire? Thank you