Sig 716i proprietary problems

[Hunters Mark]

So I'm trying to upgrade some parts on the Sig 716i that I just bought and nothing seems to work with it.

I bought a raptor radian charging handle and the hole lines up for they gas key, but the lip is too short and pulls back on the bolt cam pin instead of the groove in the bcg, so the bolt assembly won't release from the chamber using the charge handle.

Another problem is the buffer tube. I bought a JP silent capture set for an AR 10 with an H2, and it comes up a full centimeter short from the buffer retainer pin. I put a spare carbine buffer tube next to it and it's almost a centimeter shorter than the one installed.

I plan on bringing a new drop in trigger and a new gas block. Lord help me with the problems I'm going to encounter there...

Has anyone else ran into these problems before?

 

[BCP]

Couple things.

Some 308 carbine buffer tubes are longer than others, some 308 carbines use an AR15 A2 buffer spring instead of a "carbine" buffer spring (armalite, POF, VLTOR tube did at one time). A DPMS pattern 308 carbine buffer and spring will fit a regular carbine buffer tube.

Sig makes an ambi charging handle for the 716i that's 50$ on their site if you want that functionality.

Gas block is pinned on and is a rifle length setup with a heavy buffer, it's already tuned quite well so there's not much of a reason to change to adjustable if that is your idea. Trigger shouldn't be a problem but one thing to watch on 308s vs AR15s is that occasionally the hammer will drag on the bottom of the bolt carrier when cocked. My DPMS SASS had this issue with a giessele.

 

[Hunters Mark]

I will try that charging handle, thank you.

The gas block is tuned quite well, I like it very much for unsuppressed fire, but unfortunately I've had brass caught up 3 times with a suppressor on. Looks like it's cycling way too fast. And the brass comes out at like 1 o'clock. What do you think about an adjustable gas key or some other way to bleed the pressure when suppressed?

What issues will come of the hammer dragging on the bcg? I plan on putting a cmc drop in trigger in it.

 

[BCP]

I will try that charging handle, thank you.

The gas block is tuned quite well, I like it very much for unsuppressed fire, but unfortunately I've had brass caught up 3 times with a suppressor on. Looks like it's cycling way too fast. And the brass comes out at like 1 o'clock. What do you think about an adjustable gas key or some other way to bleed the pressure when suppressed?

What issues will come of the hammer dragging on the bcg? I plan on putting a cmc drop in trigger in it.

I don't see why you couldn't put an adj gas block on it, factory one is pinned so you'll have to bonk them out and then make sure the ports line up etc.

Trigger take a look at this thread to see what I am talking about, really rare issue tbh I'd throw a CMC trigger in it without thinking twice great triggers.

how to fix hammer drag? - AR15.COM

Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.

www.ar15.com

 

[rpoL98]

proprietary bolt carrier, proprietary rail, proprietary lower, proprietary mag catch button, proprietary receiver rail height, proprietary gas block, proprietary charging handle.

from the pics, it looks like the gas block is taller than the AR-15 standard gas tube height-above-barrel. that would jive with the taller gas key, taller receiver rail height.

now the buffer tube.

 

[RUTGERS95]

proprietary bolt carrier, proprietary rail, proprietary lower, proprietary mag catch button, proprietary receiver rail height, proprietary gas block, proprietary charging handle.

from the pics, it looks like the gas block is taller than the AR-15 standard gas tube height-above-barrel. that would jive with the taller gas key, taller receiver rail height.

now the buffer tube.

yup, no disrespect intended but can't believe someone would spend 1300k on a rifle and not be aware of how many prop parts are on it.

 

[srt-4_uk]

Another problem is the buffer tube. I bought a JP silent capture set for an AR 10 with an H2, and it comes up a full centimeter short from the buffer retainer pin. I put a spare carbine buffer tube next to it and it's almost a centimeter shorter than the one installed.

You shouldn't run a buffer tube retainer with the JP SCS. It isn't needed and makes for a real bitch removing it. But a fix for this is to drop a quarter or 2 down the empty buffer tube and reinstall the SCS.
I would also make sure that you are getting full bolt travel once you do this. For an normal AR it isn't an issue. But for the sign, it might have a longer carrier and needs that little extra travel.

 

[BCP]

Take off the handguard and post up some pics of gas block + tube and measurements? You can't be the only one who wants to put an adjustable gas block on one of these sig rifles.

 

[Tx_Aggie]

Couple things.

Some 308 carbine buffer tubes are longer than others, some 308 carbines use an AR15 A2 buffer spring instead of a "carbine" buffer spring (armalite, POF, VLTOR tube did at one time). A DPMS pattern 308 carbine buffer and spring will fit a regular carbine buffer tube.

Sig makes an ambi charging handle for the 716i that's 50$ on their site if you want that functionality.

Gas block is pinned on and is a rifle length setup with a heavy buffer, it's already tuned quite well so there's not much of a reason to change to adjustable if that is your idea. Trigger shouldn't be a problem but one thing to watch on 308s vs AR15s is that occasionally the hammer will drag on the bottom of the bolt carrier when cocked. My DPMS SASS had this issue with a giessele.

@Hunters Mark, as @BCP suggests, as far as replacing the buffer system with a SCS, the juice might not be worth the squeeze. Especially since your really need the rest of the JP system to get the most out of the SCS.

As for the 716i, I'm almost positive it uses a buffer system that is dimensionally similar to the VLTOR A5, so not something that would easily accept the SCS without a custom spacer. At one point JP shipped the SCS kits with a delrin spacer for rifle buffer tubes. You could probably have that cut to length if one was included with yours. Alternatively, you could remove the stock buffer altogether and just add a standard carbine tube for the SCS. But again, might not really be an improvement over stock.

 

[Tx_Aggie]

Lots of pics in this thread:

The SIG 716I TREAD .308 may be the best AR-308 / AR-10 type battle rifle for the money.

https://www.sigsauer.com/sig716-tread.html This is my first AR-308/AR-10 type rifle and so far it has been reliable, accurate and fun to shoot. Build quality and finish are top teir. Online reviews and reports have confirmed the 716I is a quality shooter. Some owners and reviewers have suggested...

www.snipershide.com

including some of the barrel with rail removed and the gas block here:

The SIG 716I TREAD .308 may be the best AR-308 / AR-10 type battle rifle for the money.

https://www.sigsauer.com/sig716-tread.html This is my first AR-308/AR-10 type rifle and so far it has been reliable, accurate and fun to shoot. Build quality and finish are top teir. Online reviews and reports have confirmed the 716I is a quality shooter. Some owners and reviewers have suggested...

www.snipershide.com

Gas block looks to be retained by two taper pins.

 

[Hunters Mark]

Take off the handguard and post up some pics of gas block + tube and measurements? You can't be the only one who wants to put an adjustable gas block on one of these sig rifles.

I will once I get back from Oklahoma.

 

[Hunters Mark]

@Hunters Mark, as @BCP suggests, as far as replacing the buffer system with a SCS, the juice might not be worth the squeeze. Especially since your really need the rest of the JP system to get the most out of the SCS.

As for the 716i, I'm almost positive it uses a buffer system that is dimensionally similar to the VLTOR A5, so not something that would easily accept the SCS without a custom spacer. At one point JP shipped the SCS kits with a delrin spacer for rifle buffer tubes. You could probably have that cut to length if one was included with yours. Alternatively, you could remove the stock buffer altogether and just add a standard carbine tube for the SCS. But again, might not really be an improvement over stock.

There was a spacer included with mine. And I can turn it down on a lathe. Though I think what I might wind up doing is just putting that on a different AR 10 lower.

 

[Hunters Mark]

Lots of pics in this thread:

The SIG 716I TREAD .308 may be the best AR-308 / AR-10 type battle rifle for the money.

https://www.sigsauer.com/sig716-tread.html This is my first AR-308/AR-10 type rifle and so far it has been reliable, accurate and fun to shoot. Build quality and finish are top teir. Online reviews and reports have confirmed the 716I is a quality shooter. Some owners and reviewers have suggested...

www.snipershide.com

including some of the barrel with rail removed and the gas block here:

The SIG 716I TREAD .308 may be the best AR-308 / AR-10 type battle rifle for the money.

https://www.sigsauer.com/sig716-tread.html This is my first AR-308/AR-10 type rifle and so far it has been reliable, accurate and fun to shoot. Build quality and finish are top teir. Online reviews and reports have confirmed the 716I is a quality shooter. Some owners and reviewers have suggested...

www.snipershide.com

Gas block looks to be retained by two taper pins.

I have dealt with those pins before on a different sig AR-15. They are a pain in the ass! We will see if I can get those pins out and switch the gas block out, otherwise I'm just going to keep the gun loud.

 

[Hunters Mark]

Thanks everyone for your replies, you guys are awesome!

 

[Tx_Aggie]

I have dealt with those pins before on a different sig AR-15. They are a pain in the ass! We will see if I can get those pins out and switch the gas block out, otherwise I'm just going to keep the gun loud.

If you decide not to go with the SCS, you could look into buying a heavier VLTOR buffer, assuming the stock one is the same length as an A5. I think they offer up to an H4, and individual buffers are usually available from Midway. That might slow things down enough to run the gun suppressed without the hassle of an adjustable gas block.

 

[BCP]

So once you get the flash hider and gas block off the things to look at would be the length of gas tube and where the port is drilled in relation to the barrel shoulder. Little doohickey on the front of the gas block almost looks like one of those switchblocks that noveske/larue do.

Also I don't think the gas tube sitting a little higher will be a problem at all, unless the length is wonky.

 

[Hunters Mark]

View attachment 7771598

So once you get the flash hider and gas block off the things to look at would be the length of gas tube and where the port is drilled in relation to the barrel shoulder. Little doohickey on the front of the gas block almost looks like one of those switchblocks that noveske/larue do.

Also I don't think the gas tube sitting a little higher will be a problem at all, unless the length is wonky.

The gas tube can be bent easily enough if needed, shouldn't be a problem. Just have to find an SLR from somewhere. Is the Sig a .9 gas block or a .75?

 

[Hunters Mark]

If you decide not to go with the SCS, you could look into buying a heavier VLTOR buffer, assuming the stock one is the same length as an A5. I think they offer up to an H4, and individual buffers are usually available from Midway. That might slow things down enough to run the gun suppressed without the hassle of an adjustable gas block.

I may look into that, we will see. I'm not going to bother with it too much because I have two other AR 10's to build. A 6.5 creed precision and a .375 raptor.

 

[RUTGERS95]

Thanks everyone for your replies, you guys are awesome!

best of all the gunboards to be honest. Sure we can be sarcastic and right to the juglar but it's with love! lol

 

[rpoL98]

View attachment 7771598

So once you get the flash hider and gas block off the things to look at would be the length of gas tube and where the port is drilled in relation to the barrel shoulder. Little doohickey on the front of the gas block almost looks like one of those switchblocks that noveske/larue do.

Also I don't think the gas tube sitting a little higher will be a problem at all, unless the length is wonky.

gas tube roll pin looks to be a little further forward than on a std AR-15 gas block. does not bode well for standardized gas tube length? unless that's a really really short gas block. can't say without measurements.

pic lifted from GLD1980 thread.

 

[BCP]

Maybe that stub on the front is the gas tube? I actually think the proprietary stuff is interesting, usually the cheap ARs are just off the shelf parts that they put into a big box, shake it up and out comes a rifle.

 

[msgriff]

Maybe that stub on the front is the gas tube? I actually think the proprietary stuff is interesting, usually the cheap ARs are just off the shelf parts that they put into a big box, shake it up and out comes a rifle.

I wonder if the gas block body is shorter than a 1" standard. If so, the journal is short too.

 

[hlee]

Unless my can had a matching taper, that doesn’t look like a barrel I’d want to screw a suppressor on to…

 

[Vivacious Stallion]

Unless my can had a matching taper, that doesn’t look like a barrel I’d want to screw a suppressor on to…

I bet you can use a taper adapter like those that come with the MCX virtus. But I think those are more intended for mounting QD muzzle devices.

 

[The King]

Consider a Ez-tune gas tube instead of other ways of messing with it. The BRT one. It looks like a standard gas tube and a .75 length gas block with a nipple for the rest of a standard gas tube. Kinda stupid in some ways - if you have a system to make your own gas block just do up a gas tube to match it.

 

[BCP]

Consider a Ez-tune gas tube instead of other ways of messing with it. The BRT one. It looks like a standard gas tube and a .75 length gas block with a nipple for the rest of a standard gas tube. Kinda stupid in some ways - if you have a system to make your own gas block just do up a gas tube to match it.

The gas block on their 223 rifles looks the same way with a doohickey sticking out.

 

[Hunters Mark]

The gas block on their 223 rifles looks the same way with a doohickey sticking out.

I think they call that the wenis

 

[sinister]

GLD's photo looks like they're using a standard 5.56-style pinned gas block and rifle=length gas tube. The little "Wenis" at the end is just to protect the end of the gas tube -- see the gas tube roll pin location.

The barrel "Coning" behind the threads would help taper / center-align a single-point suppressor.

 

[Hunters Mark]

Update on the rifle:

I have not yet messed with the gas block, but I did take the screw out that holds the pistol grip in. Unfortunately this was a button head screw that was cross threaded into the lower.

I stripped the flippity flapping fuc* out of that thing to get it off, to no avail. Then finally reverted to a screw removal bit and it came right out. I called customer service and they answered and promptly made me an account while explaining to me the process of sending back the lower. The return label was free and they said turn around time would be roughly 2 weeks. I assume I'm going to get another lower since this type of problem is not easily fixed, and I don't want helicoil threads in my lower. I have yet to ship it out because I'm currently traveling for work. When I get back I will work on the gas block while they have the lower, and see if I can fit an adjustable one on there. A three and a half pound, single stage CMC trigger is going in once I get the lower back.

I will keep you all updated on the project.

 

[Hunters Mark]

Unless my can had a matching taper, that doesn’t look like a barrel I’d want to screw a suppressor on to…

The rifle comes with a tapered ring to match up flush to a can or brake.

 

[Hunters Mark]

After much dremeling, the pressed taper pins are finally free. I had to dremel them off before I could punch them out. Afterwards they punched out with a 4 lb hammer and a steel dewalt punch tool. The second one went flying after the final blow... It has yet to be found.

I slid a spare Aero Precision .750 non adjustable gas block on to see if it fits, and it is a tiny bit loose. Usually gas blocks are a little tough to slide on but this one spins around too easily. So, I will be Installing the clamp style adjustable gas block from SLR, the Sentry 7. When I get that in I will install it and update the thread. Here are some other pictures for those who are curious as to what the barrel looks like after the gas block is off.

 

[Steve_In_29]

Update on the rifle:

I have not yet messed with the gas block, but I did take the screw out that holds the pistol grip in. Unfortunately this was a button head screw that was cross threaded into the lower.

View attachment 7789798

View attachment 7789800

View attachment 7789801

I stripped the flippity flapping fuc* out of that thing to get it off, to no avail. Then finally reverted to a screw removal bit and it came right out. I called customer service and they answered and promptly made me an account while explaining to me the process of sending back the lower. The return label was free and they said turn around time would be roughly 2 weeks. I assume I'm going to get another lower since this type of problem is not easily fixed, and I don't want helicoil threads in my lower. I have yet to ship it out because I'm currently traveling for work. When I get back I will work on the gas block while they have the lower, and see if I can fit an adjustable one on there. A three and a half pound, single stage CMC trigger is going in once I get the lower back.

I will keep you all updated on the project.

While it sucks the screw was cross threaded, a properly installed heli-coil is actually stronger then aluminum threads.

 

[msgriff]

snip....
I slid a spare Aero Precision .750 non adjustable gas block on to see if it fits, and it is a tiny bit loose. Usually gas blocks are a little tough to slide on but this one spins around too easily. So, I will be Installing the clamp style adjustable gas block from SLR, the Sentry 7. When I get that in I will install it and update the thread. Here are some other pictures for those who are curious as to what the barrel looks like after the gas block is off.
snip....

It's probably best to to use a clamp-on GB anyway. Set screw blocks on previously drilled taper pin holes can be a pain.
It would be nice to know a few measurements if so inclined, but you would need calipers, etc :
Gas journal length and diameter
Gas port diameter
Distance from shoulder to center of gas port
Distance from shoulder to muzzle
Gas tube actual length

 

[Hunters Mark]

Gas tube length is 15 and 1/8 in

Distance from the shoulder to the center of the gas port is .3 inches from the rear of the gas port (most proximal side when installed)




Gasport diameter is .137 inches

I assume the gas journal length is this measurement?






Gas block actual length:



Gas port diameter:



Shoulder to muzzle: 3.25 inches





Hopefully that gives people some insight.

 

[Hunters Mark]

Also this

 

[rpoL98]

maybe this is a good time to swap out the barrel for 6.5CM? Be the first kid on the block to do so...

since all that's left to do is the barrel nut, looks like std USGI wrench will do that, and since you're going with a clamp-on adj gas block.

obtw, gas block journal is the surface on the barrel that the GB is seated on, in front of the shoulder. diameter & length is what the fan club is asking about, appx nominal 0.750" dia x looks-like 0.780" length, thereabouts, since it seems to be the same length as the gas block.

 

[Hunters Mark]

maybe this is a good time to swap out the barrel for 6.5CM? Be the first kid on the block to do so...

since all that's left to do is the barrel nut, looks like std USGI wrench will do that, and since you're going with a clamp-on adj gas block.

obtw, gas block journal is the surface on the barrel that the GB is seated on, in front of the shoulder. diameter & length is what the fan club is asking about, appx nominal 0.750" dia x looks-like 0.780" length, thereabouts, since it seems to be the same length as the gas block.

I'm already building a precision 6.5 creedmoor, I do not need to make another AR 10, 6.5 creedmoor. This is the first weapon I bought that shoots 308, so I'll be sticking with it. Hopefully though, someone can use this information that I posted to change it to 6.5 creedmoor, should they wish.

 

[TurboTrout]

Per the spring, I had a slight difference when I built my rifle, I found a composite washer at lowes, belt sander to spec, pushed it into the back of the tube, perfect.

 

[bfoosh006]

View attachment 7771598

So once you get the flash hider and gas block off the things to look at would be the length of gas tube and where the port is drilled in relation to the barrel shoulder. Little doohickey on the front of the gas block almost looks like one of those switchblocks that noveske/larue do.

Also I don't think the gas tube sitting a little higher will be a problem at all, unless the length is wonky.

FWIW... the gas tube sitting higher is a good thing, that extra height allows the gas tube to freely clear the larger diameter barrel nut.

A typical AR15 gas block sits just low enough that the gas tube "can" make contact on the larger 308 barrel nut.

The SLR Adj. GB's sit a little higher... enough that the gas tubes freely clear my Large Frame barrel nuts.

 

[GLD1980]

@Hunters Mark
How did this project end up? This is great information to share on the 716I threads. Out of curiosity did you attempt to shoot it suppressed as is? Several owners have reported no issues shooting suppressed. In fact no issues have been reported yet but your work to remove the gas block is impressive and the first I've seen done. Are you a member at AR-15.com or SIG Talk?
Thanks for your time. Have a good evening.

 

[Hunters Mark]

Sorry I haven't updated this in a while. Here is the finished product. I will update this post completely with a video when I get back in town. Any questions, please don't hesitate to ask.

 

[Yoter8600]

Curious what you did about the taper at the end of the barrel to use a suppressor. I just bought the 716i Tread SE and want to remove the loud brake and install the Silencerco flash hider fro my quick detach Omega can. Have not take the brake off yet so I am assuming mine will be the same. It appears to have a spacer behind it.

 

[Hunters Mark]

Curious what you did about the taper at the end of the barrel to use a suppressor. I just bought the 716i Tread SE and want to remove the loud brake and install the Silencerco flash hider fro my quick detach Omega can. Have not take the brake off yet so I am assuming mine will be the same. It appears to have a spacer behind it.

Sorry I'm only just now seeing this.

The weapon should come with a taper washer. All I did was put that on and then crank down the QD muzzle device for the suppressor. I think I have about 200 rounds through that contraption and nothing has moved. Torqued it around 30 something foot pounds.

 

[Yoter8600]

Sorry I'm only just now seeing this.

The weapon should come with a taper washer. All I did was put that on and then crank down the QD muzzle device for the suppressor. I think I have about 200 rounds through that contraption and nothing has moved. Torqued it around 30 something foot pounds.

That is what I thought then. What did you do as far as gas block and tube? Will an adjustable work or is it a proprietary system? Looking to run my suppressor on mine also.

 

[Hunters Mark]

That is what I thought then. What did you do as far as gas block and tube? Will an adjustable work or is it a proprietary system? Looking to run my suppressor on mine also.

I did not change the tube, it fit in the new gas block. Superlative Arms .750 clamp on adjustable.

 

[JB556308]

@Hunters Mark Any chance you took the barrel nut off? Or has anyone for that matter? Wanting to swap that barrel out for an 18".

 

[Thanos]

I know this is an old thread, but it’s so full of information. Did you ever put a different barrel on it? I’d like to get a Krieger or other 20 inch stainless heavy barrel to make it more of a DMR. Does anyone have any success stories around that? Much appreciated.

 

[BCP]

Someone in another thread stated they put a satern barrel on theirs. The past sig 308s had a dpms barrel and extension with armalite threads for barrel nut. When I was messing with my 716i I used my regular old dpms 308 receiver block just had to dremel a little bit on the sides of it.

 

[Thanos]

Much appreciated thank you very much.