Another 12 o'clock light mount...

[lindertw]

Has anyone with the Hahn mount fired about six magazines through their weapon and then posted a picture of what happens to the light?

I have (link).

Testing occurred at the NRA indoor range in Fairfax, VA. Colt 6920 w/iron sights; magazines were a mix of PMAG/Colt/Bravo Company 30-rounders; ammo was Prvi Partizan M193 55gr BT FMJ - 300 rounds fired. I experienced one (1) failure to feed (round 27 of 28 in magazine #3).

Target was a 3"x5" card @ 25 yards, firing as soon as I could acquire the sights but slow enough to keep 'em on the card. Testing began at 7:00pm and concluded at 7:45pm.

Temp readings were taken with a Fluke mini 62 IR thermometer. I did the best I could to get good temp readings; if something seemed off I ran the temp again to verify - curved surfaces can be tricky The temp reading on the handgaurd was at the 2 o'clock area.

The light held up well. The bottom plate that snaps in the picatinny rail showed no signs of melting/deformation. The plastic side rails that screw into the bottom of the light seem soft. I can't remember if these were the same hard polymer as the bottom plate or not. I'm going to keep and eye on them, and order a replacement set from Surefire just to have on hand...

What's not readily apparent in the pics from my first post is that the mount only touches the barrel at point "A" shown; the rest of the mount is free float.





I have a buddy who is running a Surefire G2 with the Hahn mount on his 6920, but so far he's only subjected it to maybe 200 rounds in an hour range session at a time (no issues related to heat to date).

Hope this helps...

[QuietShootr]

I think there's something wrong with your thermometer, and I say that because I don't find the figure of 316 degrees for the barrel after 6 magazines to be believable.

Anyway, it's not for me. Thanks for the information.

[Pathfinder Ops]

Why don't you attach one of these to your front sight tower and put your x300 sideways on it?

This doesn't qualify as the 12 o'clock position. It would seem to me that its a side mount just high up.

[Pathfinder Ops]

Guys maybe this has been asked and I missed it but the old sniper in me gets weirded out by clamping things to my barrel.

Is this an issue regarding accuracy/ performance to clamp something to a carbine barrel?

Just wondering because I have never really noted any talk about it.

[Bimmer]

I think there's something wrong with your thermometer, and I say that because I don't find the figure of 316 degrees for the barrel after 6 magazines to be believable.

Why not? This seems entirely credible (almost predicatable) to me.

[Bimmer]

Is this an issue regarding accuracy/ performance to clamp something to a carbine barrel?

Honestly, I don't know.

It definitely could change the barrel harmonics, which could impact accuracy and/or POI. Whether it would do so to a significant degree (or positively or negatively), I really don't know.

Mounting a silencer doesn't seem to change accuracy or POI significantly (somebody correct me if I'm wrong), and a mount and light don't weigh any more.

Moreoever, whether it's clamped to the barrel or mounted on an un-free floated handguard or rail, it's still hanging on the barrel.

Maybe somebody more knowledgeable can chime in here...

Bimmer

[Bimmer]

Have you tried a light on this yet?

I just received a Streamlight TLR-1 C4 ($69 shipped, eBay).

I put it on my UTG universal mount ($6.50 shipped, Amazon), and it looks like it'll work.

Sorry, no photos, the digital camera is out of town with the missus...

The UTG mount is held on by four hex-head bolts, and it has contact with the barrel on four sides for its entire length. I only used the short end of the L-wrench that was included (and no Loc-Tite), but it seems really, really secure.
It's going to rain here the next 4-5 days, and then I'm at work, and then I'm out of town, so I won't be able to try to shoot it loose for a couple weeks.

The UTG mount's rail is only 1" or so long, but that's almost exactly the same length of the TLR-1's mount. It's like the two were made for each other.

The front and tail of the light hang over the mount at the ends. I wound up with the rail about 1" forward of the FSB, so the TLR's toggle switches straddle (but don't touch) the FSB.
It's definitely placed further back than the Surefire on the Hahn mount, as posted by lindertw). I can easily wrap my hand around the bayo lug to toggle the light's switch with my thumb (I have orangutan arms and usually have my hands towards the front of my mid-length handguards, anyway).

The front of the TLR-1 protrudes over the base of my FH, and there's about 1/4" clearance.

My TLR-1 sits ever so slightly higher than the Surefire on the Hahn mount in lindertw's photo, but I don't know if it's because the mount is taller or because the TLR-1 is bigger than the Surefire.

The mount is aluminum, and I didn't weight it, but it feels like it doesn't weigh much of anything. The TLR-1 weighs whatever they do. My rifle feels a bit more nose-heavy than I remember, but it still balances at the mag well, so no big deal.

So, I'm completely satisfied, at least so far. I'm not proud to have put something from UTG on my rifle (mercifully, the mount is totally unmarked), but this little piece seems to be a gem.

Bimmer

[Jay Cunningham]

This doesn't qualify as the 12 o'clock position. It would seem to me that its a side mount just high up.

Thanks Mr. Obvious.

If you actually go and read, you'll see that I was answering a specific question from a board member.

[Pathfinder Ops]

Thanks Mr. Obvious.

If you actually go and read, you'll see that I was answering a specific question from a board member.

My bad... sorry.

[DeputyMend]

To those people running a P6 or G2 type light at 12 o clock, how hard is it to activate? Seems like it would be awkward. I ask because I have several G2s floating around..