Flash Hider Install Method

Razorhunter · #1 05-20-09, 23:27

I think 20 ft/lbs is the average torque rating for an A2 type FH install, correct? My torque wrench might not spec out that low, so I'll probably just torque to an estimated "feel" of 20ft/lbs.
Gun is an FN SCAR, and I'm installing a VLTOR A2 type FH, which is sized with exactly the same outer dimensions as a standard A2 FH.

I have read some guys posts about using red loctite, and also either anti-seize or moly grease/etc. Is any of this supposed to be used here??
I didn't think so, but thought I'd check to make sure.

Anything else I'm missing here? I've always just used crush washers and good old hand torque, without any chemicals/lubes/compounds/loctite/etc.
Any tips on timing these things? Again, I've always just put the ol' good eye on it, and then used some long straight edges on each flat of the FH, in an attempt to magnify the alignment/timing. Is this what most of you guys are doing?

Frens · #2 05-21-09, 02:23

this is what Iraqgunz told me a few days ago

Quote:

Originally Posted by Iraqgunz

Old style washer for flash hider requires 15-20 ft. lbs. IIRC. There is no torque value when using the crush washer.

Iraqgunz · #3 05-21-09, 04:33

Quote:

Originally Posted by Paul Cataldo

I think 20 ft/lbs is the average torque rating for an A2 type FH install, correct? My torque wrench might not spec out that low, so I'll probably just torque to an estimated "feel" of 20ft/lbs.
Gun is an FN SCAR, and I'm installing a VLTOR A2 type FH, which is sized with exactly the same outer dimensions as a standard A2 FH.

What type of washer does it use? Crush washers do not have a torque value. On the A2/M4 you tighten it until it bcomes tight, the washer crushes and the center slot of the flash hider is in line with the center of the FSB.

I have read some guys posts about using red loctite, and also either anti-seize or moly grease/etc. Is any of this supposed to be used here??
I didn't think so, but thought I'd check to make sure.

You could probably use Rocksett, but I just put a small amount of anti-seize on the threads and call it a day.

Anything else I'm missing here? I've always just used crush washers and good old hand torque, without any chemicals/lubes/compounds/loctite/etc.
Any tips on timing these things? Again, I've always just put the ol' good eye on it, and then used some long straight edges on each flat of the FH, in an attempt to magnify the alignment/timing. Is this what most of you guys are doing?

On an A2/M4 it's fairly easy to use a Mk 1 MOD 0 eye ball to get it lined up. Having zero experience with the SCAR I can't really say. Common sense would say that a similar procedure could be used.

Razorhunter · #4 05-21-09, 08:03

Should have mentioned this is a crush washer application for sure. I've never seen a crush washer actually CRUSH in my life, and I've always used Colt brand, and I've tried EVERY thing in the world from "pre-crushing" them in a vise, to flipping them around 180 degrees, etc, etc, etc.
I mean, every one I have ever REMOVED from a Colt rifle has not been crushed, so I finally just gave up trying to produce a "crush".
I was really more concerned with what you guys thought about loctite/anti seize/etc.
I really would like to know what the TDP says. Does the TDP state anything about molygrease or anti seize/etc on the muzzle threads when using an A2 FH on an M4????

Iraqgunz · #5 05-21-09, 08:17

Quote:

Originally Posted by Paul Cataldo

Should have mentioned this is a crush washer application for sure. I've never seen a crush washer actually CRUSH in my life, and I've always used Colt brand, and I've tried EVERY thing in the world from "pre-crushing" them in a vise, to flipping them around 180 degrees, etc, etc, etc.

You may not see the washer "crush" but rest assured it does compress when properly tightened and they are anot reusable as per the TM.

I mean, every one I have ever REMOVED from a Colt rifle has not been crushed, so I finally just gave up trying to produce a "crush".
I was really more concerned with what you guys thought about loctite/anti seize/etc.
I really would like to know what the TDP says. Does the TDP state anything about molygrease or anti seize/etc on the muzzle threads when using an A2 FH on an M4????

The TDP determines how the weapon is built and other technical info, it has nothing to so with the installation of the flash hider. The applicable TM does that. No it does not state use moly/ or anti-seize on the threads. It is highly beneficial to you to do so in the even that you have to remove it later. JM2CWYMMV

lanceriley · #6 05-21-09, 12:06

I had moly grease in mine. It helped in putting the FH on. it was really tight!

Razorhunter · #7 05-21-09, 17:20

Iraqgunz,
Yes, I actually have a copy of the TDP, but TM is the document/info I'd like to have a printed copy of. Anyone know a direct link to the TM document?
I'm just a little on the fence about the anti seize, as I've never seen evidence of it having been used on any of my weapons from the factory, and I've certainly never encountered a FH that was difficult to remove due to a lack of anti seize.
IOW's, why would all of my factory Colts, Ak's, FN SCAR, and others never have experienced this thread seizing issue???
My SCAR had some light oil on the threads when I removed that funky assed, butt ugly muzzle device, and I'm wondering if this was possibly used to act as an anti seizing "lube" or what?
Isn't the purpose of moly grease to act as an anti seize as well? (which we generally use on our bbl nuts for this same reason, correct?)
Just trying to decide if this A2 FH install, onto my SCAR, warrants a trip to the store to buy anti-seize or should I just use oil or moly grease (which I currently still have)?
Thanks guys.

Iraqgunz · #8 05-21-09, 17:26

Paul,

I have experienced flash hiders that were a PITA to remove. Do what you think is right. Send me your email and I'll see what I can do about a TM in pdf format.

Quote:

Originally Posted by Paul Cataldo

Iraqgunz,
Yes, I actually have a copy of the TDP, but TM is the document/info I'd like to have a printed copy of. Anyone know a direct link to the TM document?
I'm just a little on the fence about the anti seize, as I've never seen evidence of it having been used on any of my weapons from the factory, and I've certainly never encountered a FH that was difficult to remove due to a lack of anti seize.
IOW's, why would all of my factory Colts, Ak's, FN SCAR, and others never have experienced this thread seizing issue???
My SCAR had some light oil on the threads when I removed that funky assed, butt ugly muzzle device, and I'm wondering if this was possibly used to act as an anti seizing "lube" or what?
Isn't the purpose of moly grease to act as an anti seize as well? (which we generally use on our bbl nuts for this same reason, correct?)
Just trying to decide if this A2 FH install, onto my SCAR, warrants a trip to the store to buy anti-seize or should I just use oil or moly grease (which I currently still have)?
Thanks guys.

Eric Kozowski · #9 05-21-09, 23:04

When I took the Colt factory armorer's course, they didn't call for anything on the FH threads. And, unless it's high temp rated, it won't last anyway. Don't bother with Loctite, the heat will make it useless. If you want to use something like Loctite, Rocksett will hold up to the heat.

Additionally, if you plan on using a sound suppressor that mounts to a NATO standard flash hider (like the Gemtech HALO), don't use a crush washer or lock washer. You should use the standard peel washer. They other kinds can induce a slight cant to the FH which could translate in to a baffle strike on the suppressor.

Hope that helps.

Razorhunter · #10 05-22-09, 00:10

Thanks Iraqgunz for sure! Email inbound.

Eric,
I have also heard about crush washer "cant" in the past, but I must admit I've never fully understood just why it is that a standard crush washer is prone to causing any degree of cant to the FH? I mean, you've got two finely threaded parts screwing together, and once the FH is threaded down onto the bbl, I cannot see how a crush washer could cause any degree of "cant" or mis-alignment (even if its thickness were slightly out of spec)??
Is there really enough slop/play between the FH and threaded bbl, to allow any amount of "cant" if the crush washer is not of an equal thickness around its perimeter??

lanceriley · #11 05-22-09, 00:17

that's an interesting thought... there was somebody in my club who had a can. sometimes the bullet impacted the can. I think he use a crush washer. he was fond of crush washers.

Eric Kozowski · #12 05-22-09, 00:40

Quote:

Originally Posted by Paul Cataldo

Is there really enough slop/play between the FH and threaded bbl, to allow any amount of "cant" if the crush washer is not of an equal thickness around its perimeter??

The short answer is yes. If the crush washer doesn't crush evenly, then it is possible for a slight (not readily visible) cant to occur. A cant of .01" probably wouldn't be visible, but when you carry that out to the end of the can 6-8" further from the muzzle, it can be come a problem when you're trying to send a .224" diameter projectile down a .250" hole. In addition, the factory threads may not be perfectly concentric to the bore (it's not critical for just a flash hider) and you end up with a receipe for possible baffle strikes.

Shihan · #13 05-22-09, 17:17

Quote:

Originally Posted by Iraqgunz

The TDP determines how the weapon is built and other technical info, it has nothing to so with the installation of the flash hider. The applicable TM does that. No it does not state use moly/ or anti-seize on the threads. It is highly beneficial to you to do so in the even that you have to remove it later. JM2CWYMMV

I never thought of using moly on the threads. We learn something new everyday

Razorhunter · #14 05-23-09, 14:50

Guys,
Another fellow GA member of this forum, sent me a PM regarding some info that John Noveske gave him a while back, regarding anti-seize compounds.
Here is part of his comments.

"I have an SBR with a KX3 attached. The directions say to use an anti-seize compound when reassembling the KX3. I thought the directions were a little vague, so I called John Noveske and asked. He said to use a nickel-based anti-seize compound, because those have higher temperature ratings than copper-based anti-seize compounds do. He specifically recommended Bostik nickel “Never-Seez.”

(this can be found at most of the industrial supply houses, such as MSC, and probably McMaster-Carr, etc)

-What do you guys think? Anyone here ever found copper based anti-seize to be a problem? I guess I would think that it doesn't really matter THAT much, but maybe the nickel based anti-seize really is best? I'm sure both would work, but I thought I'd post up this Noveske info for anyone interested.
I think I'll buy some myself.

I guess I am just wondering WHY some guys are using ROCKSETT, and others are saying to use moly grease/anti-seize.
I think Rocksett would be a bad idea, but that's just me. I'll probably just use my moly grease, or order up some of that nickel based anti-seize.
Thanks guys.

Now I just HOPE that I can get this crush washer to work out, so that this closed-bottomed VLTOR VC-A2 FH will time properly. After finger tightening it this morning, I'm now worried that it is going to have to be rotated a LONG way just to get it to time properly. We'll see how it works out I guess.
I don't have a lathe any longer, nor do I have a surface grinder, so I cannot turn down the shoulder of the bbl, nor can I surface grind down the thickness of the crush washer, in an attempt to help properly time the FH.
I really wouldn't want to mess with the shoulder of the bbl, but it would be nice to surface grind down the crush washer however....
What do you guys do when this becomes an issue, and the FH won't time properly without removing some steel from either the crush washer or the shoulder of the bbl? Do you just keep trying different crush washers? I've tried 3 different COLTs and one VLTOR crush washer, all of which are basically the same thickness.
Maybe when I get some GOOD SOLID torque applied, it will crush a little, and the timing will work out??
We'll see.

I don't really want to use one of those funky glue-based peel washers on my SCAR if I don't have to...
I'll report back as to what happens in a few....

Magsz · #15 05-23-09, 14:55

Paul.

The guys using Rocksett are probably also the guys throwing cans on their rifles.

If i was rocking a QD can like an AAC i would definitely want to ensure that the flash hider would NEVER come off unless i specifically wanted it to.

Razorhunter · #16 05-23-09, 15:17

Yeah, I hear ya Magsz,
Actually, I should have stated that I am really just wondering WHY so many guys feel like anti-seize, moly grease, or etc should be used, when the TM manual doesn't even call for using ANYTHING on the FH/Muzzle device threads.
I mean, when I removed my Colt and BCM M4 FH's, and also my FN SCAR FH, I found nothing on the Colt and BCM threads, and it appeared as if FN had put a considerable amount of oil on the threads of the SCARs FH.
I guess I just wonder IF anti-seize is really advantageous at all? I mean, I would think that moly grease/etc would actually help the FH to come loose, since it's really kind of like a lube on the threads of a FH that I am trying to prevent from shooting loose. I know it's not a big deal, and it's not rocket science though. I was just trying to figure out what most everyone was doing here.
As stated, I'll probably just go with either moly-grease, nickel based anti-seize, regular Slip 2000 oil, OR maybe just nothing at all.

Iraqgunz · #17 05-23-09, 18:30

Paul,

I have an upper here (Colt M4) that I put together and I used a light coat of C5-A anti-seize on the threads and locked down the flash hider. Over a period of 4 days I put just over 1400 rds through that upper and the flash hider is still solid.

I think you are over-thinking this too much.

Quote:

Originally Posted by Paul Cataldo

Yeah, I hear ya Magsz,
Actually, I should have stated that I am really just wondering WHY so many guys feel like anti-seize, moly grease, or etc should be used, when the TM manual doesn't even call for using ANYTHING on the FH/Muzzle device threads.
I mean, when I removed my Colt and BCM M4 FH's, and also my FN SCAR FH, I found nothing on the Colt and BCM threads, and it appeared as if FN had put a considerable amount of oil on the threads of the SCARs FH.
I guess I just wonder IF anti-seize is really advantageous at all? I mean, I would think that moly grease/etc would actually help the FH to come loose, since it's really kind of like a lube on the threads of a FH that I am trying to prevent from shooting loose. I know it's not a big deal, and it's not rocket science though. I was just trying to figure out what most everyone was doing here.
As stated, I'll probably just go with either moly-grease, nickel based anti-seize, regular Slip 2000 oil, OR maybe just nothing at all.

Razorhunter · #18 05-23-09, 19:45

No, no, no dude. I'm not really even sweating this at all. I think YOU think I am overthinking this.

I'm just trying to do my research, and be done with it. As I said, it's not rocket science, and I'm quite sure that I could use almost any of the above mentioned methods, OR I could use nothing at all on the threads, (just as Colt and almost all others do) Have you ever seen any of these AR manufacturers use anything on their FH threads? I haven't.
Anyhow, thanks for the advice guys. I surely appreciate it gentlemen. As stated, my biggest concern is getting the crush washer to allow proper timing of the VLTOR VC-A2 FH!
Thanks guys, and especially you Iraqgunz!

lanceriley · #19 05-23-09, 20:29

yes manual doesn't say so. the same way as the manual in my car says not to put anti seize on the nuts of the rims. believe or not. I had a nut seize on me once.... after that I have anti seize on my nuts

Razorhunter · #20 05-23-09, 20:40

"nuts of the RIMS"????? WTF?

Did you just mean the LUG nuts?

If so, then I can see that IF you have a need, then by all means, use it. However, I've been overtorquing lug nuts on automobiles for YEARS, and never once had a need to use anti-seize. I don't think I've ever seen or heard of a mechanic using it on lug nuts either...
However, IF you need it, then by all means, use it my friend.