You will need a barrel specifically tapered for the SPR or Mk12. Your barrel will not work. This is a very specific taper, and only works on 0.75" journal barrels, specifically tapered for this collar and adapter.

No. For any of the Ops Inc. / Allen Engineering / Otter Creek collars, which are made to accept an AEM5 suppressor, the barrel must be profiled to SPR specifications. A barrel smith can do that for you on a lathe. For other solutions, contact us at sales@charliescustomclones.com

the AEM-5 is made for 5.56mm and that is what this collar supports.

yes, it will fit fine. But, the DD profile will not support the suppressor. If you want the look of a Mk12, the DD Mk12 barrel and Allen brake and collar are fine. If you want to actually attach a suppressor, you will need a different barrel.

It will not work. We do have a 12.5" Psusedo Gordon barrel comming available this week, and an authentic suppressor with the true 14.5" barrel next year. The Gordon gun was 14.5", but the shortcut to make it look the part is to use a 12.5" barrel, specially fitted with a collar made for the barrel. What we will lack is the doughnut collar that was used, but we can get you 90% there.

try this: https://charliescustomclones.com/gordon-carbine-12-5-barrel-with-aem-collar-and-brake-727-733-from-black-hawk-down/