So I have been doing a lot of cleaning and ran across a few pieces that have never been used. As well as some guns that need to be finished.

So my question to the experts, "you people" I mean all of you who have been so helpful in the past years.

What is the ideal barrel length for the Comp M4s?

I am using this optic for running NOD's, so barrel length I would think needs to be over 11.5" to cut down on flash either way.

16"

I don’t understand what barrel length has to do with a RDS? That said, I have an AAC blackout on my 10.5” barrel and flash is barely discernible in the dark with naked eye.

quote:

Originally posted by GroundedCLK:
What is the ideal barrel length for the Comp M4s?

No such thing. A CompM4 (or other red dot) works just as well with a 10" barrel as with a 20" barrel. Barrel length doesn't matter when it comes to red dots.

You may be thinking of something like a scope with a bullet drop reticle, some of whose graduated marks are calibrated towards a certain load in a certain barrel length. Or with iron sights, where a greater sight radius (distance between the front and rear sights) can allow for greater potential accuracy. Neither of those apply to red dots.


However, bulk and weight is a consideration. If you're going for an ultra compact and lightweight short barreled AR build, sticking a big chunky CompM4 on top could be less ideal than utilizing a micro red dot.

And there would certainly be other considerations (besides the red dot) that guide barrel length choice.

The original question mentioned muzzle flash, and in answer to that I have CompML3 sights on a couple of my rifles and my agency has a number of surplus CompM2 sights on its rifles. With the 16 inch barrels and flash hiders they’re equipped with, the muzzle flash isn’t a problem using those sights. But then we’re not using night vision devices, so perhaps that would be a different matter. Perhaps it was some sort of anomaly, but one deputy had an SBR with integral suppressor and the muzzle flash from that gun was literally blinding in low light—at least when viewed from the side; I never fired the gun myself.

Because my rifles that are equipped with the Aimpoint sights are sometimes used under low light conditions, I always focused more on flash hiders as muzzle devices than brakes. There used to be some videos showing the differences in muzzle flash among various types of devices, and as expected, the dedicated flash hiders work much better for that purpose than brakes. Some muzzle brakes in fact enhance muzzle flash even as compared to a bare barrel.

quote:

Originally posted by RogueJSK:

quote:

Originally posted by GroundedCLK:
What is the ideal barrel length for the Comp M4s?

No such thing. A CompM4 (or other red dot) works just as well with a 10" barrel as with a 20" barrel. Barrel length doesn't matter when it comes to red dots.

You may be thinking of something like a scope with a bullet drop reticle, some of whose graduated marks are calibrated towards a certain load in a certain barrel length. Or with iron sights, where a greater sight radius (distance between the front and rear sights) can allow for greater potential accuracy. Neither of those apply to red dots.

You are 100% correct, I was thinking more along the lines of a ACOG when I posted the question.

However I do have a follow up question though as you mentioned in your post weight. Is the CompM5B just as good of an optic? Being that it would be half the weight as the CompM4S maybe it would be worth the upgrade.

Muzzle flash I originally mentioned as I was more thinking we would have a debate on preferred barrel length with the optic. However since that actually isn't an issue I do plan on running the rifle suppressed primarily but now always. So your commentary about a flash hider over a muzzle device is spot on which throws out my original purchase and sends me looking for a different item.

I have a CompM5 and although I haven’t used it under low light conditions, I don’t anticipate that it would perform any differently than the 2 or 3 I’m familiar with. It’s just as easy to use and doesn’t have the inconvenient requirement to push buttons to turn the unit on or adjust the brightness of the reticle. Because it’s smaller than the other models it may be a little less noticeable in one’s field of vision when scanning with both eyes open and “seeing through” the sight, but none of the models is difficult to use in that regard. Some similar sights have motion activated turn on features, but that’s not necessary with the commercial Comp series sights because of their battery life that allows them to be left on continuously and to change their batteries every couple of years or so.

There are no doubt many good similar sights available these days, but for a nonmagnifying sight I like the Aimpoints for their ease of operation, battery life, and demonstrated ruggedness.

You would have to be chasing a pretty darn serious weight budget to care about the difference between an M5 and a 4S. I personally find all the modern aimpoints essentially equal at the point of use. They do have some differences in price, battery life and type (which can matter), size, etc. etc. but as a dot on a rifle they are all the same and I never notice any difference. And literally I have them all.

I agree that the question seems mis-framed, WRT barrel length.

That said I have a Comp M4S on a 16" 6.8 build and it is about perfect.

If you are running NODs I'd look at an IR laser setup, an Aimpoint will get you out to 300m easy. Barrel length will depend on what you want to do.