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7/10/2026 6:21:25 PM EDT
[Last Edit: ArtifactDecay][Edited]
I have been on a streak this year of building out old Colt AR parts kits, and my friend sent me the link for this one a few days back and I decided to roll the dice. They went OOS right after my order, so it was likely the last one, but I'm wondering how many of them were up in total.

https://www.bluemountainsupplyllc.com/colt-723-car-15-145-parts-kits--usedpolice-trade-in.html

I have a cobbled together mixmaster Bushmaster/Colt/H&R 723 clone, but the idea of a "real" upper is something I've always been after. The listing said these were "police trade ins", but the first thing that popped up in my head was "what PD was using old 723 carbines in 2026 or slightly earlier?". I emailed Blue Mountain Supply asking for a little more info on the history of it, and the rep who replied just said "Sorry we don't know".

On Reddit I posted up a similar thread to this hoping to find the history of them or if anybody also purchased any, and a user told me that he also emailed Blue Mountain about these, but they actually gave him some sort of answer. They disclosed to him that it was used for simuntion training at a PD, or so they thought as evidence by the traces of pink paint on the receiver. Is that even a thing, simunition training on a select fire 90's piece of kit? They also sent him some close up images of the receiver, which he kindly provided for me (last two in the set).

On inspection of the photographed example in the listing (strangely it does have the same wear as the photos blue mountain sent to him, so maybe the exact same gun) it appears to be a dark color anodizing of the later type Colt was using in the 1990s. There are no forge markings on the carry handle, but there are acceptance stamps on the front of the receiver near the barrel nut. The listing example shows what looks like a government profile barrel with "C MP 556 NATO 1/7", without the (C) in parenthesis that I have read many of the latter 723s had. By the looks of the same barrel in the listing the GL cut taper looks the same as any run-of-the-mill M4 style barrel, so I'm wondering if that would be par-for-the-course for a 723, assuming this is an example towards the end of the run of these in the mid to late 1990s.

I haven't got tracking yet but the last Colt I ordered on there took a while to ship, so I reckon I will post photos of whatever they do send when it gets here next week sometime as an update. In the meantime, anybody else on here happen to have rolled the dice on a $1500 parts kit ? Any insight on what these could have been or the likely history/production time would be appreciated, I've read up a bit on these but not nearly as knowledgeable as some of you.







7/12/2026 12:31:48 PM EDT
[#1]
I answered your post on Reddit, but figured I would add what I know about Simmunition guns.

My depart ment had 10 we use for training, mostly for us guys on the SWAT Team.

They are flat top Windham Bushmasters. The bolts and magazines get changed so they will only run sim rounds, but they are title 1 firearms otherwise.

I think we have 2 that are NFA Full Autos.

it makes sense that older carry handle guns would be repurposed for training.

This upper seems to be of a similar vintage to yours and is barrel dated 4/98.

https://www.gunbroker.com/item/1189947349

Curious what the date on the barrel under the handguard is when you get it.


7/12/2026 1:49:39 PM EDT
[#2]
That's funny you posted that one on GB as right when I posted this up I was also browsing there and came across that same ad and noticed it basically was the same 723 setup. That guy is in my neck of the woods and he sells a lot of Colt stuff, some of it is mixmaster stuff it appears he's rebuilding and flipping, so I wasn't even sure if I could trust that ad as an example of a "real" factory example (nothing against him or what he's doing). But yeah that sort of makes sense. I have a friend who is SWAT in a local department and he's pretty open to share about a lot of the stuff they do for training, and most of the stuff I've seen them do in shoothouses and what not seem to let them convert over their existing issued modern carbines over to sim rounds so they could train with the same guns and peripherals they work with, but I guess every dept is different and maybe using dedicated guns for training even if they aren't flat top is just how they do it.

Thanks again for providing that info here and Reddit, I'll be sure to post up images of it whenever it does show up.
7/13/2026 12:25:28 PM EDT
[#3]
Quote History
Originally Posted By ArtifactDecay:
That's funny you posted that one on GB as right when I posted this up I was also browsing there and came across that same ad and noticed it basically was the same 723 setup. That guy is in my neck of the woods and he sells a lot of Colt stuff, some of it is mixmaster stuff it appears he's rebuilding and flipping, so I wasn't even sure if I could trust that ad as an example of a "real" factory example (nothing against him or what he's doing). But yeah that sort of makes sense. I have a friend who is SWAT in a local department and he's pretty open to share about a lot of the stuff they do for training, and most of the stuff I've seen them do in shoothouses and what not seem to let them convert over their existing issued modern carbines over to sim rounds so they could train with the same guns and peripherals they work with, but I guess every dept is different and maybe using dedicated guns for training even if they aren't flat top is just how they do it.

Thanks again for providing that info here and Reddit, I'll be sure to post up images of it whenever it does show up.
View Quote


That GB 723 upper looks like a legit factory Colt assembled upper.
7/21/2026 3:53:39 AM EDT
[Last Edit: tac556][Edited] [#4]
Just FYI, with drop in simunition bolts, we used our actual swat rifles for simunition training monthly, so some paint on the outside is not really an indicator of a dedicated training sim rifle.  Could just be that it wasn’t cleaned well after its last use, which was sims.  The paint on the outside is from incoming projectiles…

Now when running patrol folks thru training, we did grab a few rifles and used them for the whole training cycle as sim guns, because you know the regular folks won’t always clean them as well as they should….

But I saw swat guns and gear that folks would have paint on for months because they didn’t get it cleaned well.

Also it would not surprise me if they were using them as dedicated training guns, typically older equipment is gonna be used for that, not the newest stuff.  So not surprising at all if that was what up.  Just kind of pathetic that they didn’t even clean off the paint, it is literally just colored soap…
a loaded gun won’t set you free, so you say…

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