[hotwings]

Hey guys,

I have put ~1000 rounds through my RFB with zero issues until this week. My top rail came loose after firing ~200 shots at the range. I didnt even notice it until i went to pack up, as the scope was still holding zero!

Is this common? I re-tightened the 2 screws by hand as snug as i felt comfortable with... (Is there a torque spec?) I was going to throw some blue loctite on there if needed. I am kind of questioning the integrity of the whole top rail mounting design now seeing how it is two very small steel arms with just those two small screws.

One would think KT would have a checked Torque spec on all parts...
Has anyone had any issues with this?

Thanks,

Jon


EDIT: New time RFB owners - i would monitor the torque on these 2 screws when you go to the range.

 

[gderf]

See post #11 in this thread:

http://www.thektog.org/forum/f91/rfb-rail-screws-lessons-learned-257657/index2.html

I'd be wary of using the suggested red locktite unless I knew I would never want to remove the screws. I wouldn't hesitate to use blue locktite.

 

[ronmar]

I would be wary of the reccomendation also if it wasn't for the fact it was reccomended by the manufacturer... The forward screw in particular is right next to the gas vent. It gets pretty hot up there and blue locktight will probably soften up pretty quickly under those conditions.

The front screw if I recall is usually the one that comes loose. I can't think of a reason to ever remove the rail crews anyway, as I do not have the specialty tools to do any further disassembly such as removing the gas block...

I agree the rail mounting is a weak spot in this design. I would have prefered 2 screws up forward, or at least one larger one. But this would have required a larger gas block top/shoulder...

 

[TNC]

Seeing these reports about the loose top rail got me concerned, so I checked mine out this evening. I have about 800 rounds through mine now. KT must have realized the issue because mine were freakin' welded in place. It almost concerned me a bit as I loosened them, but they broke free. There was definitely evidence of some form of Loctite. I re-loctited them, and at least I know for sure there's no issue at this point.

On the types of Loctite/threadlocker out there, Permatex has a red threadlocker that is not the stud-and-bearing-mount stuff most of us are used to as red Loctite. It's just a heavy duty form of blue level stuff that resists heat a bit better. I've been using it for awhile now for some applications, and it's only marginally tougher to break loose. I'd report the number, but it was on the card that I no longer have. It's described on their site. Remember, it's Permatex, not Loctite brand...if you try it.

 

[hotwings]

TNC - what # is your gun? Mine is in the 8000's (Dont remember exact off hand)


Edit:
I would not want to use Red loctite personally... Loctite makes 100s of variants that are not commonly found in retail stores. (i am an automotive engineer and we use these in our assembly process on several products)

Next time i have the Loctite rep in for a meeting ill ask him

For now i tightened them down to what i would consider "good/strong-hand tight" using just a standard long allen wrench. I am going to the range today and will see if it holds up. Unfortunately my torque wrench is on loan to a buddy right now - i will try and grab it on my way back from the range.

 

[TNC]

hotwings, on red "Loctite" I would agree, but the Permatex high temp is not Permatex high strength. The high strength is similar to the red Loctite stud and bearing mount, but the Permatex high temp is only marginally more robust than the blue Loctite or blue Permatex. Even though Permatex states you might need heat occasionally to remove a fastener, I have not found that to be the case. I still like to use blue Loctite or Permatex for most applications, but for heat and severe applications the red high temp seems to fit the bill better. I use it a good deal on motorcycle and automotive engine fasteners or where high vibration is present...like my dirt bike.

On the serial number, mine doesn't sound similar to yours. Mine is a T1X followed by two additional numerals. It's a Gen II.

Edit: It's been awhile since I got on this forum and saw the "serial # thread". I forgot about the different methodology KT uses to series their production numbers. I don't know what my real production number is, and I'm too lazy to research it...LOL.

 

[hotwings]

Thanks TNC... I should give that stuff a Try. Ive always been a loctite fan, but permatex sounds like it may be good for my bikes as well. (had same issue)

I will check it out. Thx.

 

[Jamesonehr]

Use red. Used blue after reading something and ended up knocking it loose again. Definitely will heat it upwards of 300 to burn off the blue if you shoot it a lot.

 

[Leebob102669]

Has anyone thought of staking the rail screws? It's somewhat permanent, but pretty foolproof. It's worked from years on gas keys.

 

[124166]

See post #11 in this thread:

http://www.thektog.org/forum/f91/rfb-rail-screws-lessons-learned-257657/index2.html

I'd be wary of using the suggested red locktite unless I knew I would never want to remove the screws. I wouldn't hesitate to use blue locktite.

Red Loctite isn't permanent, with all the heat it gets brittle and gives, so the screws will eventually walk out again. I tried Guerrilla Glue on my rail screws, details to follow.