What model M16 is this based on the pictures.

[Johnny in Texas]

Recent acquisition by Texas Sheriff Office near port O'connor

It looks like an early upper with an A1 bolt carrier and full fence lower in

like new condition.
I think if I was in LE I would want the forward assist added.

[paul v]

Late 604 model. Probably around 1970 or later configuration
http://www.retroblackrifle.com/

[joem]

"I think if I was in LE I would want the forward assist added."

I have never used the forward assist. If a round will not chamber them there is something wrong most likely in the chamber. Using the assist only makes it worse and I saw a U-tube where a guy had what he thought was a misfire. Used the charging handle and hit the forward assist had several times. When he fired it the rifle exploded. The M16 I carried had no forward assist.

[Johnny in Texas]

I have used mine more than once for various reasons. For me the forward assist is only the first step of the repair process or you have to push the pins and seperate the upper from the lower to clear the jam if it will not eject.

Most of the time I have used it was to push the BCG home because a never fired a "Black Rifle Person" pulled back on the charging handle and milked it closed almost!

[bombdog]

Yup
bombdog, out!!!!!!!

I have used mine more than once for various reasons. For me the forward assist is only the first step of the repair process or you have to push the pins and seperate the upper from the lower to clear the jam if it will not eject.

Most of the time I have used it was to push the BCG home because a never fired a "Black Rifle Person" pulled back on the charging handle and milked it closed almost!

[usmc69]

Without a Forward Assist it is prior to 1970 or earlier. I enlisted in the Corps (March, 1969) and never saw one without a Forward Assist. We qualified with M14's in Boot Camp. Saw my first M16 in mid May '69 in Infantry Training at Camp Geiger then. All had a Forward Assist (IIRC). In fact we were taught to smack the Forward Assist with the heel of our hand every time we chambered a round from a fresh mag. Was that a hold over from someone's experience in Viet Nam in combat, can only assume so.

[epa223]

I would concur with paul v.

[usmc69]

This is copy from Wikipedia ( http://en.wikipedia.org/wiki/M16_rifle )

XM16E1 and M16A1 (Colt Model 603)

An early M16 rifle: note "duckbill" flash suppressor, triangular grip, forward assist, and the lack of brass deflector
The U.S. Army XM16E1 was essentially the same weapon as the M16 with the addition of a forward assist and corresponding notches in the bolt carrier. The M16A1 was the finalized production model in 1967.

To address issues raised by the XM16E1's testing cycle, a closed, bird-cage flash suppressor replaced the XM16E1's three-pronged flash suppressor which caught on twigs and leaves. Various other changes were made after numerous problems in the field. Cleaning kits were developed and issued while barrels with chrome-plated chambers and later fully lined bores were introduced.

With these and other changes, the malfunction rate slowly declined and new soldiers were generally unfamiliar with early problems. A rib was built into the side of the receiver on the XM16E1 to help prevent accidentally pressing the magazine release button while closing the ejection port cover. This rib was later extended on production M16A1s to help in preventing the magazine release from inadvertently being pressed. The hole in the bolt that accepts the cam pin was crimped inward on one side, in such a way that the cam pin may not be inserted with the bolt installed backwards, which would cause failures to eject until corrected. The M16A1 is no longer in service with the United States, but is still standard issue in many world armies.

[fjruple]

Definitely a late Model 604 M16 probably for the US Air Force. The US Air Force saw the forward assist as an unnecessary expense, only the US Army and Marines went to the XM16E1 and M16A1 with the forward assist. M16 (Model 604) production ran concurrently with the M16A1 (Model 603) production.

--fjruple

[Johnny in Texas]

Now the Air Force use makes sense! Barely used or only dropped once condition!
When was the Colt AR-15 logo dropped?