9mm blast baffle

[CMV]

I'm about 75% finished with my 9mm can. Nothing fancy - 2024 tube, 7075 K baffles, & endcaps. For the first K, I'm not sure the best way to profile it for this application. Primary hosts will be a Beretta 92 & CX4 carbine so the different barrel lengths may be a factor. I'm going for very light weight in an effort to get at least some of my 9mm pistols to cycle it w/o a recoil booster. I can always turn this one into a regular K baffle & remake out of 6AL4V if that is necessary for the application - I haven't made the last couple baffles yet so I still have the option of re-purposing this one and using something else in its place.

This baffle has a .540 long extension (not counting the slanted part) to serve as the blast baffle. That part is bored to .445" depth to make the blast chamber. Cone walls are .090" & sapcer/extended base walls are .050". Plan A was to just finish it like a regular K - similar to what I did for my .22 pistol & what many people do with their K's. 3/8" ball endmill scoop, 3/8" standard endmill down the inside of the cone, rounded wide groove around the face. But before I cut it I wanted to get some opinions if I should do something different than 'typical' K baffle profiling.


















Pretty much should I add a Dater hole? If so where in relation to the scoop? I've also seen designs where the blast baffle has several holes but no other features on the inside face like my last picture. The remainder are basic K's, 1.148" diameter, .910" long. They will be profiled similar to these:

[a_canadian]

You left out the 90° offset Dater hole option. That's the most common placement. Start small, like 1/16", then you can always drill it bigger later if it seems necessary for some reason. A quarter-offset Dated hole with a generous scoop next to the bore seems ideal for a K.

As for the last picture; why is the hole finishing outside the cone such that there's a knife edge on the inner face? Mirroring the face port with a ball-end mill would seem preferable, going half diameter of or a little deeper with the mill bit.

[CMV]

No idea. Plunge cut from the inside with a square end mill.

[a_canadian]

Sorry, it was intended rhetorically; that knife-edged lip is getting in the way of would-be gas flow coming from the milled face vent. I expect the mill cutter was angled into the cut rather than parallel to the bore, putting the whole cutter outside the cone instead of finishing with the middle of the mill cutter point just at the outer edge of the bore as is most commonly seen. I prefer to do mine in two cuts, one as I described with the ball-end mill centre meeting the outer edge of the bore hole, the second, not quite so deep pass a millimetre or so further out such that it opens out the exit port a bit more. This seems to provide a superior pathway, lining up better with the milled face port provided that one is deep enough.

[CMV]

You got me thinking about those baffles. It's a straight plunge cut with a 1/4" ball end mill on those. Made kind of an oval. Probably should have had it more toward the outside edge or used a square end to get a better shape.

But they work as they are...