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LOL! I knew that was coming.
To summarize:
I have never let the bolt drop on an empty chamber except for a bad magazine that did it on its own several months ago.
I was using a carbine buffer in a 14.5" (pinned to 16") with very mild PMC bronze 55-grain .223 (has reliability problems with an H buffer).
I tend to agree that for whatever reason if the carry handle shifts to a different position and stays, then leave it there. It's probably achieved its own "fit".
I would like to know more about this.
I personally hate loctite on anything because I keep changing my mind.
As for "what is tight enough" I think I achieve "snug" but not "overtorqued" most of the time (except for a Daniel Defense light mount where I stripped the screw threads but we won't talk about that).![]()
Last edited by Doc Safari; 09-19-12 at 10:10.
In the interests of full disclosure I am required to report the following.
I decided early this evening to unscrew the carry handle and reattach it fully forward as I did originally.
Understand that both thumb nuts (knobs) were beyond hand-tight. I could not budge them with just my fingers.
As I unscrewed them with the edge of a quarter, I noticed that even though the rear thumb nut required a bit of effort, the front one broke with minimal torque. I emphasize again that both thumb nuts were beyond hand tight, but the front thumb nut was noticeably easier to "break" than the rear when I attempted to loosen it with the edge of a quarter.
I moved the carry handle all the way forward as it was originally, and retightened both thumb nuts with the edge of a quarter to the point where my fingers literally did not have the strength to go any further even with the coin.
Unfortunately, with ammo prices lately, I may not go to the range again anytime soon to verify that the "shift" in the carry handle was due to inadequate torque on the front thumb nut originally, but that's my thinking.
I have to allow for the possiblity that the recoil impulse has something to do with it, and here's why.
My 14.5" carbine with pinned flash hider and carbine buffer has a noticeably stronger recoil impulse than my 16" carbine with "H" buffer.
That could be a factor, too.
It's kind of funny, but when I shoot full power 5.56 ammo in the 14.5 carbine and the H buffer, the recoil impulse is less than using mild .223 in the same carbine with a standard carbine buffer.
As Ripley would say, "Believe it, or not."
So, my take?
Until I get another range session or some enterprising member decides to experiment with my info, I'm thinking that the front thumb nut was just barely not torqued enough to allow movement.
The other likely possibility is that if you mount an upper with recoil characteristics that suggest an "H' buffer with 5.56 ammo, you may experience loosening of your flat-top accessories when switching to .223 ammo and a standard carbine buffer.
If anyone is able to offer any other analysis, I'd love to hear it.
Remember that Loctite 242 or 222MS are easily overcome with standard handtools and no heat needed. It's no way permanent, but does keep bolts and nuts in place.
The whole "1/4" to "1/2 turn past finger tight" is where the problem is. Despite what the makers of those mounts want you to believe, it isn't enough. How dare I say this? Because I have seen many many many mounts tightened as advertised come loose. It isn't the gun (I've dealt with this issue on guns that recoil a hell of a lot more than any 5.56 gun), it's the mounting.
So what to do with these troublesome mounts?
First, get some blue loctite.
Unscrew your knobs as far as they will go.
Hit the threads with non-chlorinated brake cleaner and let dry.
Place a generous dab of loctite at the termination of the threads where the threads pass through the angled tensioning plate.
Pressing forward on the rear of the sight base, tighten knobs by hand until tight.
Grab a pair of pliars/leatherman/BFS (big ****ing screwdriver).
Tighten at least 1/2 turn further than you were able to do by hand.
Personally, I go 1/2 turn further, and then continue on until the slot is either perfectly horizontal or vertical.
Take a paint pen and make a witness mark that crosses both the knob and the tensioning plate (this is a way to quickly check to see if the mount loosened).
Let loctite cure for at least 48 hours.
Go to range and shoot. After 100 rounds or so, check for drift/looseness, check witness marks, and try to tighten mount with firm handtool pressure.
I have been doing it exactly this way for several years, and I have never had an issue since.
Just to echo what was mentioned all optics magnified or red dot get a push forward in the slot before tightening. Again, general rule is that thumb nuts require more tightening than advertised.
Well, somebody call Myth Busters and have them do an episode on the matter (full forward or rearward in the slots) to settle the issue.
F2S probably has the ultimate answer - make sure the damn thing is tight and won't come loose regardless of location.
Sticks
Grasseater // Grass~eat~er noun, often attributive \ˈgras-ē-tər\
A person who is incapable of independent thought; a person who is herd animal-like in behavior; one who cannot distinguish between right and wrong; a foolish person.
See also Sheep
I agree with everything, but I sub Vibra Tite instead of Blue Loctite.
It's designed to pre treat fasteners, and is set up in about 5-10 minutes depending on the humidity and temp.
I got hooked on this stuff after getting the blister pack that comes with GearSector Light mounts.
"You people have too much time on your hands." - scottryan
Quite! Boils down to, when folks jam out a manual or instructional material, and want to do it in such a way as something technical like an actual torque spec is defined, some noodnik will pipe up with something like "Well, is this user issued or have access to a torque wrench...?"
Liability concerns are broached, arguments ensue, fisticuffs break out, Hatfield-McCoy type feuds go on for generations, because nobody wants to publish 2-3 different ways to achieve the same end under the guise of not confusing the reader....the whole "The Way vs. The WAYS (plural)" partisanship thing.
Ultimately, the hand-wringing worryworts seem to win out more often than they truly deserve, and we get crapy, soupy compromise instructions like "1/4 to 1/2 turn past blah blah..." So, something deliberately undefined, based upon something that varies from one person to another pretty significantly. Do some technical writing and curriculum development, you'll end up sitting in these meetings and get equally amazed/mortified at how entrenched the Poindexters are.
Anyhow...pushing forward on the rail is what makes sense from a sheer physics standpoint, seems to work in 9.99 out of 10 iterations. I've heard of folks doing the rearward push, but I wouldn't dismiss it without getting the "why/how" explained to me. Ultimately, if the rail is in spec and the interface is made to fit the rail, it should stay and the whole pushing-forward thing is mostly the same kind of insurance that staking is (effective, takes but a moment, virtually fool-proof, short of being performed by the legendary Sufficiently Talented Fool...)
I'm not a big fan of having to shim a rail, but when the conventional wisdom ain't cutting it, doing something unconventional is hard to argue, especially if it uses commonly-available stuff and is easily reversible: If the rail the thing's mounted to is JUST out of spec enough for one of the mounting interfaces to not engage as it should, putting a layer of tinfoil down might provide what's needed to get it to mate as it should.
Contractor scum, AAV
FWIW, The Troy sight I just installed... directions indicate, push forward and use blue thread locker.
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