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98Zs Mk12 Mod H in 6.5 Grendel

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12 hours ago, N Doza said:

ave you found out if the collar on the BA 16" 6.5 SPR barrel is in the right location for the AE collar and won't tuck under the rail... looking at the pictures of the barrel I'd looks  farther away than normal



On the 16" they profiled it at 0.700" diameter 0.700" back from the barrel shoulder.  That's common, and they followed SPR specs on it.  Allen Engineering makes the collars:


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I'll break this down, for future historical information. 

This is all from the Mk12 SPR Program, and the original Mk12 Mod 0 gun. And, the innovative Ops Inc 12th Model suppressor.  Ops Inc is gone, But Ron Allen from Allen Engineering was the one that made most of those suppressors for Ops Inc anyway - And Ron Allen is doing well these days.  The direct replacement for an Ops Inc 12th Model can is the Allen Engineering AEM5 can -that IS the Ops Inc 12th Model, with different engravings.  Same can.  That IS the Mk12 SPR suppressor.

Here's what the barrel profile looks like with the SPR collar on the barrel, and the specs for that are below:



the M4 barrel profile.  All Colt M4 (and M4A1) barrels had a 0.700" diameter, and they stepped up 0.700" back from the barrel shoulder.  To mount up the Ops 12th to the M4 and M4A1, this was the collar that you needed to make that happen - as well as the brake, of course.




Here's a pic that shows both the Mk12 and the M4 barrel - with their brakes and collars, to run the Ops 12th/AEM5 cans:


If your barrel is perfect on the Colt M4 barrel pattern, and has a true 0.700" x 0.700" step, then the M4 AEM5 Collar will allow you to mount up the cans, properly.

Lots of "mil-spec" barrels out there that are not truly mil-spec, and they fuk this measurement up.  Don't expect every "mil-spec" barrel to meet that 0.700" x 0.700" true M4 military specification... 

Edited by 98Z5V

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