Unique AR: XM-16 E1 turned SPR (with pics)

[mkmckinley]

The MK-12 SPR is basically a M-16 that's been hot-rodded into a lightweight, mid-range sniper rifle:

44http://en.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle
(http://en.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle)

In addition to being an effective tool from a practical standpoint, I've always loved the Mk-18 because it has the cool-new-toy factor as well as the piece-of-history factor. Most of the Mk-12 SPRs were built on old lower receivers that the armorers had lying around. It's normal to see Mk-12s with old M-16A1 receivers, which is pretty sweet in its own right, however we were doing some inventories at work last week and I noticed something even better: a Mk-12 built on an XM-16 E1 lower receiver. It even has the original bakelite, flat front pistol grip. As far as I know a lower marked XM-16 E1 would be built pre-1967. This one looks to have seen quite a bit of use so it may have been used on one of the first ARs in service. I'm sure there are members on here that could tell us a little more about that. Anyway, on to the pics. Sorry for the crappy iPhone quality, it was all I had on me at the time. I hope you enjoy them.

http://i.imgur.com/J6bxR.jpg
Here you can make out the rollmark. "COLT AR-15/PROPERTY U.S. GOVERNMENT/XM-16 E1/CAL. 5.56 MM."

http://i.imgur.com/e3BHz.jpg
Here's a view of the old-school pistol grip.

http://i.imgur.com/THSt8.jpg
Egads, lower receiver anno doesn't match the upper! It couldn't possibly function, I guess we should send this one back to Crane.

And just for fun here's an XM-16 E1 training video from 1966 I found on the net: http://www.liveleak.com/view?i=e57_1188339173

[TriumphRat675]

That is very cool. Thank you for posting.

It's interesting to see how long the life of these lowers can be. Even if it's seen more rack time than use, that's a long time to be in service.

[Dozer]

That's a very nice and unique build. Congratulations.


A couple of questions, have you shot it yet? The eye relief seems a bit long, is that functional the way it's set up?

[mkmckinley]

That's a very nice and unique build. Congratulations.


A couple of questions, have you shot it yet? The eye relief seems a bit long, is that functional the way it's set up?

I've not shot that particular rifle however the Mk-12s generally shoot very well, on par with my personally owned SS Noveske. As far as the scope location my assumption is that the armorer had to work on the rifle and removed the optic, then put the optic back on to ensure that it stays with the assigned weapon and doesn't wander off. However to indicate that the optic needs to be re-zeroed (or at least checked by the end user) he put it far enough forward to make it obvious that it had been removed. That's generally what he does after a few of optics were mounted incorrectly and end users were pissed. Now they get to do it themselves. Generally the rear of the scope should be about even with the charging handle for good eye relief, as shown in the last two pictures.

[Dozer]

Very nice. Enjoy.

[M4Guru]

The rear sight isn't gonna help there...it is made to nest behind the rail on the PRI handguard.

[mkmckinley]

The rear sight isn't gonna help there...it is made to nest behind the rail on the PRI handguard.

Noticed that too. I'm not sure why the sight isn't mounted correctly.

[Brian1/75]

You guys still have mod 0s in your inventory?

[mkmckinley]

Dunno, is this a Mod 0? The ones we've taken on trips had a different rail and other parts. I'm not a weapons guy so I don't know all the nomenclature. I basically just saw that this gun has an old receiver and thought it was cool. I'm not surprised if this is an older model. We still have M-14s and grease guns kicking around.

[BAC]

That is very cool, thanks for sharing.


-B