View Full Version : Sig M400 Help
Don't quite understand how to put a new muzzle break/ flash suppressor on my rifle, could use some help.
You will need to secure the barrel or upper in order to remove the old flash hider.
Depending on what you are installing you will need a new crush washer.
I would assume the the barrel is threaded just like the M4.
Did it occur to you that you might want to check and see what will fit first before making a purchase? Since you are deployed I think I would wait until I was back home before I worried about making changes.
Don't quite understand how to put a new muzzle break/ flash suppressor on my rifle, could use some help. I'm overseas right now so
I don't want to buy something and then get home and it doesn't work out. I just want to figure out the steps it takes to install a new flash suppressor and how can I figure out if which one's will work with my M400? Also I purchased i Magpul carbine forend/ hand guard, wondering if it should fit on the Sig?
Also wondering if anyone that has a Sig that might have added something to their rifle that really enhanced the rifle?
I'm deployed so money is not an issue, but then again I don't want to go overboard with it.
Kyle Danhauer
Don't quite understand how to put a new muzzle break/ flash suppressor on my rifle, could use some help. I'm overseas right now so
I don't want to buy something and then get home and it doesn't work out. I just want to figure out the steps it takes to install a new flash suppressor and how can I figure out if which one's will work with my M400? Also I purchased i Magpul carbine forend/ hand guard, wondering if it should fit on the Sig?
Also wondering if anyone that has a Sig that might have added something to their rifle that really enhanced the rifle?
I'm deployed so money is not an issue, but then again I don't want to go overboard with it.
Kyle Danhauer
As long as you did not buy the SIG M400 WELD version (14.5" w/ permanently pinned brake), you can just use an AR15 armorers wrench to twist off the original brake (either clamp it down to a table between towels or rags or have a buddy hold the rifle down stable on a table for you).
http://www.tactical-life.com/online/wp-content/uploads/2009/04/ar15-combo-tool.jpg
I encourage you not to follow this advice. All too often people damage their weapons because they did not follow proper procedures and use the correct tools. Trust me.
As long as you did not buy the SIG M400 WELD version (14.5" w/ permanently pinned brake), you can just use an AR15 armorers wrench to twist off the original brake (either clamp it down to a table between towels or rags or have a buddy hold the rifle down stable on a table for you).
http://www.tactical-life.com/online/wp-content/uploads/2009/04/ar15-combo-tool.jpg
I'd definitely use the proper tools, that means no armorer's wrench. Either use the properly sized crow foot wrench or the combination tool (http://www.brownells.com/.aspx/sid=1992/pid=468/Product/AR-15-M16-COMBINATION-WRENCH?source=pjm&mc_id=400400&gdftrk=gdfV21820_a_7c187_a_7c882_a_7c080216015_d_080216015_d_11454&subid=69044) that Brownell's makes.
You're also going to need a 1/2" drive torque wrench. You definitely don't want to under or over torque a muzzle device. You will also need an upper receiver vise block and obviously, a vise.
I'd definitely use the proper tools, that means no armorer's wrench. Either use the properly sized crow foot wrench or the combination tool (http://www.brownells.com/.aspx/sid=1992/pid=468/Product/AR-15-M16-COMBINATION-WRENCH?source=pjm&mc_id=400400&gdftrk=gdfV21820_a_7c187_a_7c882_a_7c080216015_d_080216015_d_11454&subid=69044) that Brownell's makes.
You're also going to need a 1/2" drive torque wrench. You definitely don't want to under or over torque a muzzle device. You will also need an upper receiver vise block and obviously, a vise.
You were good right up until this part. Pray tell, what is the torque spec for an A2 flash hider?
There isn't one. Muzzle devices are "timed" using a crush washer or shims between the device and the barrel shoulder.
EDIT, to the OP: Couple more things:
1), Do not attach your carry handle the way Sig did for this photo. The front of the carry handle should be flush with the front of the upper receiver. They have it one notch further back than it should be:
http://www.policemag.com/_Images/news/L-ProductNews-SIGM400.jpg
Looking at the picture, it appears to be a standard AR15 DI variant. That being the case, as Iraqgunz has said, any 12/x28 threaded muzzle device should work.
A 3/4" box wrench should be used on the flash hider. Slide a patch or old t-shirt between the wrench and the muzzle device to prevent marking the finish if you wish.
The upper receiver or barrel should be properly secured in a vise while removing or installing a muzzle device.
Don't know for an A2, never installed one. I don't believe he mentioned exactly what he was installing, but it wasn't an A2. The Surefire FA556-212A FH, for instance, requires 20-30 ft-lbs of torque. You also have to shim and time it. You also want the threads, both on the barrel and inside the muzzle device, as clean as possible. I use acetone.
He may theoretically need a torque wrench since he is replacing the A2 hider with something else, which he has yet to reveal. Some comps and hiders do have a torque value.
I wouldn't give this thread much more thought until he returns.
You were good right up until this part. Pray tell, what is the torque spec for an A2 flash hider?
There isn't one. Muzzle devices are "timed" using a crush washer or shims between the device and the barrel shoulder.
EDIT, to the OP: Couple more things:
1), Do not attach your carry handle the way Sig did for this photo. The front of the carry handle should be flush with the front of the upper receiver. They have it one notch further back than it should be:
http://www.policemag.com/_Images/news/L-ProductNews-SIGM400.jpg
Looking at the picture, it appears to be a standard AR15 DI variant. That being the case, as Iraqgunz has said, any 12/x28 threaded muzzle device should work.
A 3/4" box wrench should be used on the flash hider. Slide a patch or old t-shirt between the wrench and the muzzle device to prevent marking the finish if you wish.
The upper receiver or barrel should be properly secured in a vise while removing or installing a muzzle device.
Don't know for an A2, never installed one. I don't believe he mentioned exactly what he was installing, but it wasn't an A2. The Surefire FA556-212A FH, for instance, requires 20-30 ft-lbs of torque. You also have to shim and time it. You also want the threads, both on the barrel and inside the muzzle device, as clean as possible. I use acetone.
Well I'll be damned. I'm out of my lane on that then. Apologies and something learned, thanks!
Don't quite understand how to put a new muzzle break/ flash suppressor on my rifle, could use some help. I'm overseas right now so
I don't want to buy something and then get home and it doesn't work out. I just want to figure out the steps it takes to install a new flash suppressor and how can I figure out if which one's will work with my M400? Also I purchased i Magpul carbine forend/ hand guard, wondering if it should fit on the Sig?
Also wondering if anyone that has a Sig that might have added something to their rifle that really enhanced the rifle?
I'm deployed so money is not an issue, but then again I don't want to go overboard with it.
Kyle Danhauer
I installed the carbine length Magpul forend on my M400 no problem, as well as an MOE grip. Just added YHM BUIS and Aimpoint PRO. MS3 sling.
Besure to use a barrel vice not an upper receiver clam shell block and clamp the barell as far forward as possible.
Would something like this be useful?
http://ins.sears.com/craftsman-strap-wrench-aluminum/p-00945571000P
I was wondering if it would be possible to use a smaller strap wrench to grasp the barrel when spinning off the flash hider.
Pray tell, what is the torque spec for an A2 flash hider?
15-20 ft-lb according to the 23&P C4
ETA: with a peel washer
There is no torque spec for an A2 flash hider when using a crush washer. The most current 23&P which is now change 9 so that is a little behind the times.
15-20 ft-lb according to the 23&P C4
I did forget about the change to crush washers, I got used to answering this same question repeatedly 5 years ago.
Would something like this be useful?
http://ins.sears.com/craftsman-strap-wrench-aluminum/p-00945571000P
I was wondering if it would be possible to use a smaller strap wrench to grasp the barrel when spinning off the flash hider.
I would use a couple of chucks of wood in a vise to hold the barrel.
KalashniKEV
05-23-12, 13:38
EDIT, to the OP: Couple more things:
1), Do not attach your carry handle the way Sig did for this photo. The front of the carry handle should be flush with the front of the upper receiver.
What is the reason for this?
I've always attached my carry handle like that- it gives you 1cm of extra sight radius.
What is the reason for this?
I've always attached my carry handle like that- it gives you 1cm of extra sight radius.
That would be kind of hard to measure with your eyeball.
But I have a flash hider coming in today and was planning on just using an armorer's wrench. I've been anxiously awaiting this sucker and REALLY don't want to wait on an upper receiver block/barrel clamp, though I'll buy them soon as well. Theoretically, If I were strong enough to hold the barrel in my hand right below the bridcage and use a wrench to remove it without twisting the rifle around, then wouldn't that sorta be the same as a barrel vise?? I have like mega-popeye-overdeveloped forearms and grip strength... I don't think it would hurt anything since the barrel wouldn't be moving, and I wouldn't be supporting the rifle by the stock any other part. Could someone please lend their expert advise? I think I hear the UPS man ringing... :big_boss:
You will more than likely not be able to do it. It's your rifle, do what you think is clever.
But I have a flash hider coming in today and was planning on just using an armorer's wrench. I've been anxiously awaiting this sucker and REALLY don't want to wait on an upper receiver block/barrel clamp, though I'll buy them soon as well. Theoretically, If I were strong enough to hold the barrel in my hand right below the bridcage and use a wrench to remove it without twisting the rifle around, then wouldn't that sorta be the same as a barrel vise?? I have like mega-popeye-overdeveloped forearms and grip strength... I don't think it would hurt anything since the barrel wouldn't be moving, and I wouldn't be supporting the rifle by the stock any other part. Could someone please lend their expert advise? I think I hear the UPS man ringing... :big_boss:
Littlelebowski
12-21-12, 20:25
But I have a flash hider coming in today and was planning on just using an armorer's wrench. I've been anxiously awaiting this sucker and REALLY don't want to wait on an upper receiver block/barrel clamp, though I'll buy them soon as well. Theoretically, If I were strong enough to hold the barrel in my hand right below the bridcage and use a wrench to remove it without twisting the rifle around, then wouldn't that sorta be the same as a barrel vise?? I have like mega-popeye-overdeveloped forearms and grip strength... I don't think it would hurt anything since the barrel wouldn't be moving, and I wouldn't be supporting the rifle by the stock any other part. Could someone please lend their expert advise? I think I hear the UPS man ringing... :big_boss:
Not going to happen. Take pictures of your attempt, though.
Sent from my Nexus 7 using Tapatalk 2
You will more than likely not be able to do it. It's your rifle, do what you think is clever.
You're right. I gave up after almost blowing out a muscle. I ended up wrapping the barrel generously with a bath towel, sticking it in a vice, and using a regular wrench. The armorer's wrench I bought that had so many great reviews wouldn't fit around the birdcage - too much powdercoat or something... starting to wonder if I bought a useless tool... I hope the castle nut wrench works at least... I have a Noveske QD end plate coming in... I don't feel like scratching my lower up by using the built in QD slots up with my MS3.. I know.. I know..
crazymoose
12-21-12, 22:54
The armorer's wrench I bought that had so many great reviews wouldn't fit around the birdcage - too much powdercoat or something... starting to wonder if I bought a useless tool...
A couple of the DPMS multi-tools I own had this issue. Solution: sand/file of the powder coat in the FH cutout.
A couple of the DPMS multi-tools I own had this issue. Solution: sand/file of the powder coat in the FH cutout.
Ehh... A regular old wrench works... I see no point...
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