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CJF
September 14, 2000, 22:06
Any suggestion on what tubing to use when sleeving an inch flash hider?

All I've been able to find is steel tubing w/ an inside diamer of 3/8" and and outside diameter of 1/2".

The problem is I can bore out an inch flash hider to 1/2" w/o tearing up the prongs - the drill bit gets caught in the gaps between the prongs. Would you call these flutes?

Anyway, any suggestions for tubing w/ an inside diameter larger than .308 (for obvious reasons) and an outside diameter equal to or less than 7/16" (which I have successfully bored out.)

TIA,
Chris

FWIW, I checked out my local auto parts store and their brake tubing didn't solve the problem.

[ July 22, 2001: Message edited by: gary.jeter ]

cooter
September 18, 2000, 15:18
uh, please clarify just what are we trying to do here, you mention sleeving with tubing, yet you mention of boring, and then the drill getting caught up in the flutes, I`m scratching my head here....thanks cooter

mp
September 18, 2000, 15:26
I see what you are saying. I have had the urge to try the same thing. I was going to try a couple of different ways. Drill out flash hider to 7/16 then chuck it up in lathe and try to ream it to correct ID, solder in sleeve, done.
I was also thinking about soldering in sleeve before prpoer ID, then reaming out the whole assembly.
I know there are some RKI's that have done this modification. HOW IS IT DONE??????

Wrangler100
September 18, 2000, 17:53
What is an RKI ?

Rule .308
September 18, 2000, 19:04
Reasonably Knowledgeable Individual
Rule .308 http://www.fnfal.com/forums/biggrin.gif

CJF
September 18, 2000, 22:37
Originally posted by cooter:
uh, please clarify just what are we trying to do here, you mention sleeving with tubing, yet you mention of boring, and then the drill getting caught up in the flutes, I`m scratching my head here....thanks cooter

Hi Cooter,

I'm trying to take a perfectly functional flashhider and make it a non-functional lump of steel that can be permanently attached to a barrel w/o being considered an evil part under the crime bill.

I want the external appearance of an inch flash hider, but I cannot install one of those on a post-ban gun if I also have a pistol grip and detachable mag. So I have to make the flashhider not a flashhider.

So I'm trying to fit a piece of metal tube down the inside of the FH to cover up the slots or flutes that do the flash hiding. The inside diameter (ID) of an unaltered inch FH is roughly .315", leaving room for a .308 round to pass through. This is the sleeving part.

The boring part comes from the fact you need to increase the inside diameter of the FH to accomodate the tubing, while still leaving sufficient room inside the tubing for a .308" round to pass through.

What tubing you use determines how much you need to drill out of the inside of the FH.

(Gunplumber does this w/ Stoll FH's for the STG. I would guess the inch FH is harder, since it has a longer area to sleeve - 2.25" of flutes starting 1/2" from the muzzle.)

I've found tubing w/ a 3/8" ID and 1/2" OD, but I haven't been able to drill out the FH w/ a 1/2" bit (see the original post).

I don't have a lathe and my drill press isn't much help since it's just a bench top model. Using a 1/2inch electric hand drill I've managed 7/16" but then the 1/2" tore it up.

So...
1) I buy DSA's new non-functional flashhider since its close to what I'm looking for, or

2) A gunsmith volunteers to do this for a reasonable price, or

3) I use 3/8"OD brake line tubing and then drill that out once its installed, or

4) Someone posts a workable solution to this problem (please!!!)

I'd love any suggestions you have.

Regards,
Chris

Grunt
September 19, 2000, 18:48
I found 3/8" thin wall brass tubing at a Hobby shop for R/C Cars . The display has various types of tubing and bar stock. The brand I found was K&S Engineering of Chicago.Il 3/8" Round Brass Stock number 135. 12" Brass tubing.
It slides into the Izzy HB flash hider with a little free play but not much. The Inch pattern F/H lets it go in about an inch from the front end before it gets too tight. You might try to get numbered drill bits of the exact size you need. They go up in very small steps. I'm not sure if you can locktite or glue it in or wiether you would need to silver solder it in. If you try it post your results. I haven't tried mine yet

CJF
September 19, 2000, 21:01
Grunt,
I appreciate the suggestion about thin wall brass. I was looking into thicker tubing if possible as I don't know how to assess how much pressure is remaining w/in the barrel at the point the bullet passes thru the F/H.

My concern was that the thin tubing walls would fail under the pressure. Hopefully just tear, but also worried about ruptures causing fragments to cause problems for other shooters on the line.

I know this sounds evil, but shoot yours first, okay?

Seriously, thanks for the suggestion. I'll also look into numbered drill bits.

Regards,
Chris

artifacts
September 20, 2000, 19:18
Chris,
Instead of a regular drill bit you should try and go to a local machine shop and look at their 2-flute reamers. I think they would do a better job for you with less chance of catching on the openings in the flashhider. Just a thought.
artifacts

Snapper
September 20, 2000, 19:37
Also....To be legal... I beleive, you have to turn down the outer diameter..so it can't be used as a grenade launcher....Damn,and Wall-Mart just had grenads on sale!!

CJF
September 20, 2000, 20:08
Snapper,

Thanks for the heads up, but I think I'm okay. Unlike STG flashhiders, Inch flash hiders weren't used as grenade launchers, so the original OD can remain as is.

Regards,
Chris

mg34ss
September 22, 2000, 10:33
My understanding of flash hider function is that the slots are cut at an angle specificly designed to dispurse the flame and cool it by controlled expantion of the gas. ( double the volume, half the temperature ) It would seem to me that if you simply mill out the slots and ruin the gas flow, you would be complying with the law. I did this on my Colt M-16 shorty and it worked great ! Huge ball of flame out the front, which was the point. If it dosen't hide the flash, how can it be a flash hider?
I'm not ready to go to court to test my theory, but perhaps some RKI would give some imput. To me, after it's milled out, it's just barrel stuff and not a flash hider.

gunplumber
September 22, 2000, 12:42
1/2" DOM tubing. Use carbide endmill, not drill. weld end and bottom of flutes. On sample below I welded top of flutes too - unnecessary.

http://www.arizonaresponsesystems.com/webpictures/falflashsleeve.jpg


------------------
T. Mark "Gunplumber" Graham
gunplumber@arizonaresponsesystems.com
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com

[This message has been edited by gunplumber (edited September 22, 2000).]

CJF
September 22, 2000, 20:48
Mark,

Thanks for sharing your method.

I'm sorry about my ignorance, but what does "DOM" stand for?

Chris

Scooby
September 25, 2000, 20:48
Originally posted by CJF:
Mark,

Thanks for sharing your method.

I'm sorry about my ignorance, but what does "DOM" stand for?

Chris

Chris

DOM Stands for Drawn over Mandrel. It's a type of process to form the tubing. Different types of tubing are formed in different ways, depending on the spec's of the tubing.

CJF
September 25, 2000, 21:13
Scooby,

Thanks for the explanation.

Anyone know of a source for small lots of tubing? I've found 1/2" DOM (avail. at hardware store) but I would love to know if anyone knows of a source for small amounts of tubing - that had an OD less than 1/2" and greater than 3/8".

I did pick up some new drill bits, so I'll try drilling again - but this time I'll go from 7/16ths to 1/2 in 3 steps instead of 1. Hopefully that will prevent the bit from tearing up the FH flutes (and breaking my wrists.)

Thanks all.
C

Bubba
September 25, 2000, 21:56
Wow! learned two things here! First, what RKI is. I've been wondering for a while. 2nd, about sleeving. I want to do me R1 F.H.. I think with the inside blank firing threads I should be able to get a tube threaded and then silver solder, is that right do ya think? And alter outside dimensions.

CJF
September 26, 2000, 20:17
ER - thanks for the advice. I will try a machine shop, but out of stubborness, I'm going to try boring out one of the four NIB FH's I purchased.

Then I'll get professional help (hopefully from a machinest and not a doctor...)

Thanks to everyone for their suggestions and help. GP - thanks again for the picture - that will help.

Chris

Scooby
September 29, 2000, 02:49
Chris: If your looking for short lengths of tubing [1ft min.] check out WWW.onlinemetals.com. (http://WWW.onlinemetals.com.) They have 4130 steel tube in 1/2 od. with various wall thickness.HTH

gunplumber
September 29, 2000, 03:09
mark - I think you'll find the BFA too small a diameter. Been there, done that, gave it up and went to tubing - but maybe you'll be more successful.

------------------
T. Mark "Gunplumber" Graham
gunplumber@arizonaresponsesystems.com
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com