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556 SBR Handguard comparison
6/18/2011 11:22:01 PM
On my 556 SBR project I decided to try for as much of a 552 look as possible without using a 550 lower.
For the handguard, it is not possible to use a 552 handguard as the 556 SBR and patrol versions have a slightly longer gas system than a 552. This makes the 552 handguards too short to work on the 556 SBR.
A Swiss 552 handguard is made from a 550 handguard that has been cut short and 5 round vent holes are drilled into each side toward the forward end. A metal handguard cap is used to mate the front of the handguard to the gas block.
MFI makes a handguard and end cap to fit the 556 SBR that looks very much like a 552 handguard. I originally bought these along with their 552 style flash hider on Gun broker for around $150 as this was a simple and fairly cost effective way to reach my goal of a near 552 clone. I was pretty happy with the these at first. They installed fairly easily with the hardest part of the job being the removal of the gas block by driving out the two roll pins that hold it on.
After the first trip to the range I heard something ratting around loose inside my handguards. Upon removal I saw that the right rear tab that holds the upper and lower halves of the handguards together had broken off. The handguards still held together but they were a bit looser feeling now. After the next range trip I found that the left rear tab had now broken off as well. At this point the handguards still stayed attached to the gun, but were now too loose to suit me. I contacted MFI about buying another lower half to replace mine with the now broken rear tabs. I was informed that the halves were a matched set. I was told to send mine in and they would replace them. I did this and they replaced them free of charge. Excellent customer service on their part.
Unfortunately the new set suffered from the same issue after just a couple of trips to the range. First the right rear tab went and then the left rear. The two front ones remained in tact as did the ones on the first set. This time I decided not to try for another set as I now believed these handguards to be too thin and made of a plastic that was too brittle.
Still wanting to keep my 556 SBR project as close to a 552 as I could, I decided to go with the only other option I knew of. I decided to have a set of 550 handguards cut down to the proper length and have the vent holes drilled in them to fit the length needed for a 556 SBR gas system.
Fortunately Double Diamond Law Enforcement Supply offers this service for your customer provided 550 or 551 handguards. They also sell their own end caps for each of these. Now I set out to find a black SIG 550 handguard set. I looked around the usual gun boards and gun broker but couldn't find a set. So I turned to the only place I knew of that had them for sale. I bought a set from Colorado Gun Sales. Their parts are a little pricey, but they are the go to source for original 550 series parts.
The 550 handguards set me back $125 from Colorado gun sales. The superior quality of construction and material was immediately apparent. Then I sent them off to DDLES to have them cut down and drilled, and to purchase their handguard cap. This cost a total of $145. After about 2 months I got my handguards and end cap back in the mail.
When I installed the new handguards and cap I had to sand off a millimeter or two from the front of the handguards to get them to go on, but they fit super tight on the SBR.
Here are some pictures to illustrate the difference between the MFI handguards and the 550 handguards cut and drilled by DDLES.
Here they are (MFI on top, DDLES on bottom)
Here is a view of the inside of the bottom halves. Notice the thickness of the plastic and the broken tabs on the MFI (top).
Here are the top halves. Again MFI is pictured on top. I would like to point out that the lighter color and uneven texture of the inside of the MFI handguards is from carbon build up from the exhaust gasses being vented inside the handguards from the gas tube ports.
Here are the end caps. MFI on left, DDLES on right.
The MFI handguard cap fit loosely in the gas block and were held there by the handguards. When the handguards were removed the cap would fall out of place from the gas block and rattled loose around the barrel and gas tube. The DDLES end cap was a tight fit into the gas block. I had to use a rubber mallet to tap it into place in the gas block. When the handguards are removed the cap stays firmly in place.
The fit of the end cap to the handguard also more closely follows the contour of the handguard with the DDLES cap than the MFI cap making for a much more solid set up on the DDLES.
Here is the fit of the MFI cap:
And here is the fit of the DDLES cap:
Here is the look of the MFI handguards installed:
And here is the look of the 550 handguards cut down and drilled by DDLES:
I hope this post provides some insight to those that may be wishing to do a similar 556 SBR project.
P.S.
You may notice I also took this opportunity to change out the MFI 552 style flash hider with an AAC Breakout comp/flash hider. I did this as I intend to get an AAC M4-2000 to mount on it.
As for the MFI 552 style flash hider, I was very happy with it. It provided the best 552 style look available in my opinion and it performed it's flash hiding function extremely well.
For the handguard, it is not possible to use a 552 handguard as the 556 SBR and patrol versions have a slightly longer gas system than a 552. This makes the 552 handguards too short to work on the 556 SBR.
A Swiss 552 handguard is made from a 550 handguard that has been cut short and 5 round vent holes are drilled into each side toward the forward end. A metal handguard cap is used to mate the front of the handguard to the gas block.
MFI makes a handguard and end cap to fit the 556 SBR that looks very much like a 552 handguard. I originally bought these along with their 552 style flash hider on Gun broker for around $150 as this was a simple and fairly cost effective way to reach my goal of a near 552 clone. I was pretty happy with the these at first. They installed fairly easily with the hardest part of the job being the removal of the gas block by driving out the two roll pins that hold it on.
After the first trip to the range I heard something ratting around loose inside my handguards. Upon removal I saw that the right rear tab that holds the upper and lower halves of the handguards together had broken off. The handguards still held together but they were a bit looser feeling now. After the next range trip I found that the left rear tab had now broken off as well. At this point the handguards still stayed attached to the gun, but were now too loose to suit me. I contacted MFI about buying another lower half to replace mine with the now broken rear tabs. I was informed that the halves were a matched set. I was told to send mine in and they would replace them. I did this and they replaced them free of charge. Excellent customer service on their part.
Unfortunately the new set suffered from the same issue after just a couple of trips to the range. First the right rear tab went and then the left rear. The two front ones remained in tact as did the ones on the first set. This time I decided not to try for another set as I now believed these handguards to be too thin and made of a plastic that was too brittle.
Still wanting to keep my 556 SBR project as close to a 552 as I could, I decided to go with the only other option I knew of. I decided to have a set of 550 handguards cut down to the proper length and have the vent holes drilled in them to fit the length needed for a 556 SBR gas system.
Fortunately Double Diamond Law Enforcement Supply offers this service for your customer provided 550 or 551 handguards. They also sell their own end caps for each of these. Now I set out to find a black SIG 550 handguard set. I looked around the usual gun boards and gun broker but couldn't find a set. So I turned to the only place I knew of that had them for sale. I bought a set from Colorado Gun Sales. Their parts are a little pricey, but they are the go to source for original 550 series parts.
The 550 handguards set me back $125 from Colorado gun sales. The superior quality of construction and material was immediately apparent. Then I sent them off to DDLES to have them cut down and drilled, and to purchase their handguard cap. This cost a total of $145. After about 2 months I got my handguards and end cap back in the mail.
When I installed the new handguards and cap I had to sand off a millimeter or two from the front of the handguards to get them to go on, but they fit super tight on the SBR.
Here are some pictures to illustrate the difference between the MFI handguards and the 550 handguards cut and drilled by DDLES.
Here they are (MFI on top, DDLES on bottom)
Here is a view of the inside of the bottom halves. Notice the thickness of the plastic and the broken tabs on the MFI (top).
Here are the top halves. Again MFI is pictured on top. I would like to point out that the lighter color and uneven texture of the inside of the MFI handguards is from carbon build up from the exhaust gasses being vented inside the handguards from the gas tube ports.
Here are the end caps. MFI on left, DDLES on right.
The MFI handguard cap fit loosely in the gas block and were held there by the handguards. When the handguards were removed the cap would fall out of place from the gas block and rattled loose around the barrel and gas tube. The DDLES end cap was a tight fit into the gas block. I had to use a rubber mallet to tap it into place in the gas block. When the handguards are removed the cap stays firmly in place.
The fit of the end cap to the handguard also more closely follows the contour of the handguard with the DDLES cap than the MFI cap making for a much more solid set up on the DDLES.
Here is the fit of the MFI cap:
And here is the fit of the DDLES cap:
Here is the look of the MFI handguards installed:
And here is the look of the 550 handguards cut down and drilled by DDLES:
I hope this post provides some insight to those that may be wishing to do a similar 556 SBR project.
P.S.
You may notice I also took this opportunity to change out the MFI 552 style flash hider with an AAC Breakout comp/flash hider. I did this as I intend to get an AAC M4-2000 to mount on it.
As for the MFI 552 style flash hider, I was very happy with it. It provided the best 552 style look available in my opinion and it performed it's flash hiding function extremely well.
6/19/2011 8:36:18 AM
I would like to add that if MFI could beef up the locking tabs more that they would still be a very viable alternative. They fit a little looser, but not as much as a typical M4 handguard does on an AR. This texture is a little more smooth and shiny. Their cap didn't look or fit quite as good as the DDLES, but it looked and worked just fine in my opinion. None of these would have been a deal killer for me given the price point.
With the tabs breaking off though I had to go another route. Sorry MFI. I was really wanting these to work out.
Now the DDLES modified SIG handguards feel substantially more rigid and are rock solid on the gun. Also since the original handguards were from a Swiss SIG 550 the plastic's texture more perfectly matches the Swiss 550 stock I have on my SBR as well.
I wasn't thrilled that the handguards didn't just drop right in, and I had to do a fair amount of sanding to get them to fit, but in the end I am glad they were a bit too big and I had to take a little at a time off to get them perfect. There is zero movement in the handguards now.
Also, to be perfectly fair to MFI, I have not yet had the chance to shoot the SBR with the new handguards, and as far as I know the tabs could break off on them the first time out as well. Given the thicker tabs and stronger feeling plastic, I doubt it, but only a live fire test will tell for sure. I will update this post after I have a chance to fire the gun with them on.
With the tabs breaking off though I had to go another route. Sorry MFI. I was really wanting these to work out.
Now the DDLES modified SIG handguards feel substantially more rigid and are rock solid on the gun. Also since the original handguards were from a Swiss SIG 550 the plastic's texture more perfectly matches the Swiss 550 stock I have on my SBR as well.
I wasn't thrilled that the handguards didn't just drop right in, and I had to do a fair amount of sanding to get them to fit, but in the end I am glad they were a bit too big and I had to take a little at a time off to get them perfect. There is zero movement in the handguards now.
Also, to be perfectly fair to MFI, I have not yet had the chance to shoot the SBR with the new handguards, and as far as I know the tabs could break off on them the first time out as well. Given the thicker tabs and stronger feeling plastic, I doubt it, but only a live fire test will tell for sure. I will update this post after I have a chance to fire the gun with them on.
6/21/2011 1:13:04 AM
thanks for the write up
i've been trying to decide between the mfi and ddles end caps, think i'll be ordering the ddles end cap
i've been trying to decide between the mfi and ddles end caps, think i'll be ordering the ddles end cap
6/21/2011 4:48:45 PM
So the MFI guards tabs broke while firing the weapon? Is that right? And man does that cut down 550 HG look awesome. Job well done! You'll have no problems. 552 HGs are 550 guards cut down and those stand up to FA action.
6/21/2011 8:31:16 PM
Originally Posted By Magnus:
So the MFI guards tabs broke while firing the weapon? Is that right? And man does that cut down 550 HG look awesome. Job well done! You'll have no problems. 552 HGs are 550 guards cut down and those stand up to FA action.
So the MFI guards tabs broke while firing the weapon? Is that right? And man does that cut down 550 HG look awesome. Job well done! You'll have no problems. 552 HGs are 550 guards cut down and those stand up to FA action.
Yup just normal firing at the range. Handheld and from a rubber rest made from recycled tire. I think shooting it rested may have done it. With the little bit of fore and aft play they had, I think the locking tabs banged into each other and broke themselves apart. Both sets I had did this. First the right side one would go and then the left. It really pains me to say it since MFI seems like a good small company and I really like the 556 accessories they are making. If they could just beef up these tabs and make the handguards just slightly longer to take out any play in them, they would probably hold up better. They really should be able to hold up to being fired while rested on something without breaking. If they could use a plastic more like that used in P-mags too, they would be awesome, but probably cost as much as SIG handguards from Switzerland.
6/21/2011 8:33:12 PM
Oh and update on the new handguards, First range trip and 100 rounds fired from rest and standing. No signs of any stress on the tabs and they are still rock solid fit.
This one is me
This one is me
6/22/2011 3:52:19 PM
Awesome write up, This helps me make the decision as well!
6/30/2011 7:24:44 PM
Hello Guys,
I would like to add that if the customer sends us the upper we will install the handguards for a perfect fit. When the customer does not send in the upper we do leave the handguards a little bit long so they can be fitted to the customers upper by the customer.
I would like to add that if the customer sends us the upper we will install the handguards for a perfect fit. When the customer does not send in the upper we do leave the handguards a little bit long so they can be fitted to the customers upper by the customer.
7/1/2011 10:55:30 AM
I appreciate that.
At first I was slightly put off that they didn't just drop right in, but all I had to do was lay a piece off 150 grit sandpaper flat on my work bench and work the forward end of the hand guards back and forth on it until they fit perfect. I couldn't imagine a more solid feel to them. Night and day to how the others were.
At first I was slightly put off that they didn't just drop right in, but all I had to do was lay a piece off 150 grit sandpaper flat on my work bench and work the forward end of the hand guards back and forth on it until they fit perfect. I couldn't imagine a more solid feel to them. Night and day to how the others were.
