Originally Posted By Augee:

The easiest visual discriminator of whether you're looking at a SOPMOD equipped M4A1 or an MWS M4 is usually the identity of who is holding it.  If it's a SOF troop, it's probably a SOPMOD M4[A1].  If it's a conventional troop, it's probably an M4 MWS.

SOPMOD = SOF
MWS = Conventional

The SOPMOD program was initially fielded in 1996, and the two have not significantly converged or crossed over at all since then, and there is almost no commonality between systems used in the two.   They are separate lines of development and evolution managed by two totally different components (Army and Navy).

SOPMOD is run by NSWC-Crane to equip SOF M4A1 Carbines with accessories.  There are two distinct "blocks" as identified by NSWC-Crane PowerPoints as the primary source of information, however, there was a "transitional period" of several years in which carbines with items from both blocks were used.  Because of a PowerPoint slide that was published (IIRC?) 2006 showing a block labeled "phased replacement," it has become the colloquial term for "transitional" configurations.

"Block x" does NOT refer, in an "official" sense to a specific configuration of rifle.  It refers to specific modifications (read accessories) to the SOF M4A1 weapon system that are managed by Crane.

Colloquially we refer to M4A1s with accessories from the first block of the SOPMOD program as "Block 1," while using "Block 2" to describe carbines with the RIS II, one of the last components of the second block of the SOPMOD program to be fielded.  Carbines with the accessories/features of both blocks of the SOPMOD program, but without the RIS II, we refer to as "Phased Replacement."  It is important to note, however, that this colloquial classification is generally limited to this thread, and others both here and on other sites that feed off of it.

The important thing to understand is that the SOPMOD program is almost always limited to SOF only, and 99% of the time, the "actual" weapon in question will be an M4A1, not an M4.

The M4 is a conventional forces weapon system, and is totally separate from the SOPMOD program and SOF modifications, though they were "inspired" by the SOPMOD program, almost every single actual item is different.

The M4 is managed by the Army overall through TACOM, though the Marine Corps also manages their own programs through their own directorates for their specific incarnation of the M4.

The M4 is a conventional forces platform, and is upgraded through modular weapon system (MWS) upgrades.  There are no specific blocks, increments, or generations, and their specifics vary by time period, unit, and MTOE.

~Augee

Originally Posted By Super_Trouper:


Not retaining zero. It wasn't shifting much, but enough that at 300m and out I was missing c zone sized steel. I thought it was ammunition related at first until it did it multiple times.

And when I was rezeroing following those occasions, the elevation lock was stuck. And I mean STUCK. I'm not sure what the exact issue is stemming from, but this is one of my grab and go rifles that I carry with me daily, so it put a bad taste in my mouth.

To clarify, this isn't a surplus or old unit either. I bought it brand new from Eurooptic and haven't put a ton of rounds through it - maybe 1k or so max. The Elcan is definitely a vibe, I love the reticle and the look of it on the Block II. Definitely a bummer.

Originally Posted By LsuJon:
Same reasons to like an acog but with better eye relief, 1/4x, and controllable illumination.

Originally Posted By LsuJon:
Not to insult your intelligence, I'm genuinely asking, but did you unlock the elevation?

Originally Posted By Loonytik:
Is there a website or reference where I can get my correct cage code/part # for my lower? I want to get one of those UID labels.

Thanks

Originally Posted By MK318:
@Combat_Diver

How uncommon would it be for the M203 to be paired with the Block II? I know the Block II has mounts specifically for the M203 but I think the M320 was pretty much in heavy use by then. I’m wondering if it would be weird to mount my faux M203 to my FSP Block II.

Originally Posted By LsuJon:
It's extremely common among marsoc. I've only seen a handful of pictures of none marsoc units using it but almost every MSOT was using it. Probably in part to the Corps extremely late adoption of the 320.

https://www.ar15.com/media/mediaFiles/316069/IMG_9032_jpeg-3034891.JPGhttps://www.ar15.com/media/mediaFiles/316069/IMG_7162_jpeg-3034892.JPG

Originally Posted By tarheel7734:
What brand lower do you have?

Part number for m4a1 is  12972700  your cage code goes off your brand. For instance if you have a psa lover cage code is 7XC20

Originally Posted By Duck_Hunt:
Hunting with the block ii this year.  

https://www.ar15.com/media/mediaFiles/463094/IMG_3595_jpeg-3034956.JPG

Originally Posted By MK318:


Dang. Plus it looks like they used the NT4 mount over the SF mount so I'd have to redo my entire Block II upper to justify the M203. I do kind of like the look of the M203 attached to the RIS II. Too bad the M203 was on its way out when the Block II was coming in.


https://www.ar15.com/media/mediaFiles/557335/IMG_5884_jpeg-3035315.JPG

Originally Posted By brodband8:
I got some 3 position selectors that are idenitical to the colt ambi ones, but are cage marked 1KW91.  Anyone seen these?

Originally Posted By Combat_Diver:
Range day
https://www.ar15.com/media/mediaFiles/32677/50504FFB-6FB7-433F-AD9E-00D11DAC611D_jpe-3035993.JPG

Originally Posted By LsuJon:
While we are on the topic of ambi safeties and NSW rifles, one thing I have noticed is that they typically don't have them. (Usually Army rifles have the "colt" ambi and Marine rifles would have the KAC ones.) However, when you do see them with the contract ambi safeties with NSW, they are using new FN Lowers.

Examples:
https://www.ar15.com/media/mediaFiles/316069/E0B7A6CF-06D6-4292-BD5F-689A54F7B5AD_jpe-3036392.JPG
https://www.ar15.com/media/mediaFiles/316069/6D59B2A0-65D4-41C1-8961-5F1AB61AC669_jpe-3036393.JPG

Originally Posted By MK318:
@Combat_Diver

How uncommon would it be for the M203 to be paired with the Block II? I know the Block II has mounts specifically for the M203 but I think the M320 was pretty much in heavy use by then. I’m wondering if it would be weird to mount my faux M203 to my FSP Block II.

Originally Posted By MK318:



I love seeing the old M9 still kicking around. A lot of shit gets talked about it but mine were always reliable. I will always have a place in my heart for the M9.

https://www.ar15.com/media/mediaFiles/557335/IMG_6751_jpeg-3036364.JPGhttps://www.ar15.com/media/mediaFiles/557335/IMG_5970_jpeg-3036369.JPG

Originally Posted By GallopingOstrich:


Wrong thread

Originally Posted By GallopingOstrich:


Wrong thread

Originally Posted By PA-Minuteman:
It's probably because I'm too tired to notice, but why is it wrong?

Originally Posted By MK318:



If it was rattle canned I doubt many would even notice the lower. I’ve seen a pic or two floating around with a block II sporting a T1. It may have been a MARSOC one. I don’t remember exactly but the T1 has been around and issued. It’s not unreasonable for them to end up on Block IIs and MK18s.