M*CARBO Brotherhood

Red Dot Scopes For SUB2000 (Gen 2)

Does the Primary Arms Microdot Sight (Gen II) MD-RBGII co-witness at 100% with the sights when using the MI Gen2 SUB 2000 Mini Picatinny Rail Optic Mount from Midwest Industries, or do I need to purchase a riser?

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I’m gonna let the third time I’ve read this question be “the charm.”

It does not cowitness. A riser will only put your dot sight higher. The mount floats the optic very high - well above the irons. MI’s design spec put the optic where it landed after clearing the bolt tube when folded. The stowed location drove their mount’s height over bore.


Excellent explanation Milton…,


Yes, thank you @Dred, I didn’t really understand the question until I read your answer. I’m glad I didn’t move the thread somewhere else, mighta face planted you again😆


Thanks Dred! Now that I’m 60 and the eyes aren’t what they use to be I have to wear glasses. Had problems focusing on the front sight post and the target at the same time.
Sorry about the grammatical question but, wanted all the information in that question so members of the group know exactly what scope I was talking about, since there are so many variations of scopes for each maker.

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Butch … stop trying, Focusing on both is only possible with the muzzle jammed into/on to the target. You want to fix your focus onto the front sight and aim it into the blur of the target. Running your focus back and forth and back again is a habit you want your training to correct. Once you’ve identified your target - it’s all about the front sight and sight alignment. The next time you focus on your target, it should be down.

Aim small to help ensure the target falls quickly. E,g, if a BG tattoo’d his face or neck - I’d target the tattoo and be done quickly.


Do I want to co-witness?

I’m preparing to buy SIG Romeo5 with tall riser for my Gen 2. Have Red Lion Flip-up front sight and Mcarbo rear peep sight.

What are the pros and cons of co-witnessing?

Yep – another newbie question.

Co-witnessed on a Sub 2000 puts the optic as close to the barrel as possible. The closer you get the optic to the barrel, the flatter your trajectory gets. Both 9mm and 40 drop relatively early comparing to a rifle round, but less bullet drop compensation is required when mounted close to the barrel.

Extreme examples:. Mount optic centerline 6" above bore centerline and zero at 25 yards. Your dot will be on target in two places:. 25 yards where you zero’d and again somewhere between 100 and 200 yards where it will dive bomb a consistent position. Gotta shoot something at 50 yards - expect to shoot a couple inches high. No biggie if you’re point of aim is center mass on a bad guy, but you are SOL if you are try’n to get the squirell that moved into your attic.

I don’t care for witnessing. I got the irons out of the way irregardless. But, I prefer my POI to match my POA with minimum mathematics.

Conversely, optics mounted up in the stratosphere are sure comfortable (read easy) to mount. So, if you can’t mount the irons on the Sub 2000, don’t try to cowitness with them.

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