Elevation Drum Binding

[Gulfton]

I have a detachable carry handle sight with the two-part elevation drum held together by an allen screw. The bottom part of the drum actually raises and lowers the rear sight apertures, while the top of the drum bears the elevation markings. With the allen screw removed, the top portion of the drum is supposed to rotate freely. On my carry handle sight, the top part of the drum will only rotate freely when I have raised the sight almost all the way up; it binds in the lower positions. This makes it difficult to set calibrations, for example to back off a certain number of clicks from the very bottom position and then move the "6/3" back into alignment by rotating the upper part of the drum. What's up with that?

[lysander]

First question: Do you have M16A2 rear sight parts in your detachable handle? There are differences in the elevation drum, index and rear sight base.

Have you inspected everything for burrs?

For those that may not know: The way the sight was designed to work was the elevation drum is set at 6/3, loosen the setscrew so that it locks the elevation index in place and zero the rifle at 300 meters. Then screw the setscrew back into place.

[Gulfton]

First question: Do you have M16A2 rear sight parts in your detachable handle? There are differences in the elevation drum, index and rear sight base.
Have you inspected everything for burrs?
For those that may not know: The way the sight was designed to work was the elevation drum is set at 6/3, loosen the setscrew so that it locks the elevation index in place and zero the rifle at 300 meters. Then screw the setscrew back into place.

I actually have two carry handle sights with this same problem: a PSA mil-spec and a UTG PRO mil-spec; the description of the UTG specifically states that it has an A2 sight assembly and will fit the M4.

[markm]

I actually have two carry handle sights with this same problem: a PSA mil-spec and a UTG PRO mil-spec; the description of the UTG specifically states that it has an A2 sight assembly and will fit the M4.

It's curious that PSA and UTG would call it mil spec. I'd seriously consider finding a Colt take off if you want to use the field sight.

[markm]

I actually have two carry handle sights with this same problem: a PSA mil-spec and a UTG PRO mil-spec; the description of the UTG specifically states that it has an A2 sight assembly and will fit the M4.

It's curious that PSA and UTG would call it mil spec. I'd seriously consider finding a Colt take off if you want to use the field sight.

[lysander]

I actually have two carry handle sights with this same problem: a PSA mil-spec and a UTG PRO mil-spec; the description of the UTG specifically states that it has an A2 sight assembly and will fit the M4.

Shows what they know . . .

Did they think to consider that the M4 carry handle rear sight takes one revolution of the elevation knob to go from a 300 meter zero to a 600 meter zero, but an M16A2 goes from 300 to 800 meters in that same one revolution?

You may want to drive out the bottom spring pin and check all the parts for burrs and damage.

[grizzman]

There's a Colt A2 carry handle assembly in the Equipment Exchange right now that's priced at $120 shipped.

I bought two of them a few years ago for about $100 each, so considering the current market, this is priced fairly.

Or keep using bottom tier components, with the problems they cause.

[grizzman]

Here we go again, with the duplicate posts.......

[lysander]

There's a Colt A2 carry handle assembly in the Equipment Exchange right now that's priced at $120 shipped.

I bought two of them a few years ago for about $100 each, so considering the current market, this is priced fairly.

Or keep using bottom tier components, with the problems they cause.

If you are vigilant you might find one at a gunshow for $50-75.

To the OP:

The probable cause of your binding is rough finish on the parts, With the knob all the way down the spring is full compressed, when all the way up the spring is at its longest length.

[lysander]

There's a Colt A2 carry handle assembly in the Equipment Exchange right now that's priced at $120 shipped.

I bought two of them a few years ago for about $100 each, so considering the current market, this is priced fairly.

Or keep using bottom tier components, with the problems they cause.

If you are vigilant you might find one at a gunshow for $50-75.

To the OP:

The probable cause of your binding is rough finish on the parts, With the knob all the way down the spring is full compressed, when all the way up the spring is at its longest length.