So I picked up a 6.5mm “MPA Premium Bolt Action Muzzle Brake” at a good price (lightly used). The self-timing one that’s black nitride with the 4 ports and has DN3 written on it.
I thought these used the licensed Alamo Four Star “cowl induction” baffles that performed out really awesome in PRB’s brake comparison tests (where the 1st and 3rd baffles don’t quite meet at the bore centerline, or something). All 4 brake baffle geometries are identical on this. Did something change?
Also, the bore on this thing is huge. It laser marked for 6.5mm but the bore measures 0.345”. I’m used to seeing like .290-.310 on a brake for 6.5/.260 (about .025-.050” overbore) so 0.085” overbore just seems huge to me. Hell, this thing has as much or more clearance than many .308 brakes! Is this kind of bore clearance normal?
I thought these used the licensed Alamo Four Star “cowl induction” baffles that performed out really awesome in PRB’s brake comparison tests (where the 1st and 3rd baffles don’t quite meet at the bore centerline, or something). All 4 brake baffle geometries are identical on this. Did something change?
Also, the bore on this thing is huge. It laser marked for 6.5mm but the bore measures 0.345”. I’m used to seeing like .290-.310 on a brake for 6.5/.260 (about .025-.050” overbore) so 0.085” overbore just seems huge to me. Hell, this thing has as much or more clearance than many .308 brakes! Is this kind of bore clearance normal?
Last edited: