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Suppressors TBAC CB for SR25

Commander Shepard

Sergeant of the Hide
Full Member
Minuteman
Aug 3, 2004
282
101
NC
Does Thunderbeast make a CB brake for the SR25? I know they make one in 3/4x24 thread pitch, however SR25 barrels index off the muzzle and not the barrel shoulder. I haven’t seen a TBAC CB 3/4x24 in person so I’m not sure how it indexes. I do have a couple in 5/8x24 and they index off the shoulder.
 
Technically yes, but they're unobtanium. Several friends have been hunting for one for literally 18 months, maybe more.

Personal speculation: I think TBAC did a single original run which sold out quickly but they've been so busy ever since (e.g. the 8 month backlog just to get a serial number) that they're not going to take the machine time to spit out another run for the lowest volume production item they've got.
 

This question just sent me down a rabbit hole, as I'm going to put an Ultra 7 on mine. It sounds like a shim kit similar to the one for the M110 FH is the recommended solution, based on the small amount of shoulder remaining when using 3/4x24 threads on these barrels.
 

This question just sent me down a rabbit hole, as I'm going to put an Ultra 7 on mine. It sounds like a shim kit similar to the one for the M110 FH is the recommended solution, based on the small amount of shoulder remaining when using 3/4x24 threads on these barrels.
I don’t think that brake will work, despite being in the correct 3/4x24 thread pitch. If it is shaped internally like the 5/8x24 version, there is no material for the barrel muzzle to index off. Essentially the brake is drilled straight through and threaded all the way to the actual brake chamber, so internal shims wouldn’t be able to push against anything for indexing.
 
Yup, I just checked one of CB brakes and it's also threaded all the way through to the first chamber. I have the CB flash hider on a 5.56, and that looks like it might have a shelf near the muzzle, but it's torqued down so I'm not sure. It's kind of a moot point though, TBAC doesn't show the FH in 3/4x24... back down the rabbit hole!
 
Tried to find one for my 25 and eventually spoke to TBAC and they said no and didn’t like the idea of using their offered brake that would bottom out on the muzzle rather than a shoulder. Only one I know of and I think it’s specially built for the 25 is the Surefire brake. TBAC did kind of offer to make me one but as I remember more expensive than normal one and when they got around to it which could mean a long time at TBAC. Which makes sense cause they are busy as f.

Xcaliber makes a reducer to 5/8-24 that they assured me was concentric enough to which you could attach another brake that bottomed on shoulder on the adapter. I never did try it out though.
 
Tried to find one for my 25 and eventually spoke to TBAC and they said no and didn’t like the idea of using their offered brake that would bottom out on the muzzle rather than a shoulder. Only one I know of and I think it’s specially built for the 25 is the Surefire brake. TBAC did kind of offer to make me one but as I remember more expensive than normal one and when they got around to it which could mean a long time at TBAC. Which makes sense cause they are busy as f.

Xcaliber makes a reducer to 5/8-24 that they assured me was concentric enough to which you could attach another brake that bottomed on shoulder on the adapter. I never did try it out though.

You’re right, Surefire makes both a SOCOM flash hider and brake for the SR25 which uses internal shims to time off the muzzle.
 
I know this is a stale thread, but... please explain to a suppressor noob (just got my 3x Ultra 9’s out of jail) indexing, timing and shimming.

I would like to put one of them on my factory SR25. Also, I put one on my SCAR-20S and on a LMT piston AR. I’m having difficulty using the peel washers to get the CB’s aligned properly. They’re all off-kilter to various degrees. How is this bad / sub-optimal? How does it affect operation?

What options do I have to mount one to an SR25? Will the SF brakes work with the TBAC?

Thanks for any help. Trying to educate myself.
 
Surefire and Thunderbeast aren’t compatible in any way.

A couple degrees either direction you won’t notice functionally. Hell, Surefire used to offset ports for right-handed shooters on some devices. My OCD personally will not allow my brakes to not be aligned, so they have to be perfect.

I would buy a shim kit and throw the peel washers where they belong: right in the garbage. That will be your best bet.
 
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Couldn’t y’all have used tbis?

1331ECF4-046A-49BB-9C6B-22F8CB8F12C0.png
73B1EF74-6567-4839-B357-FD1EA1AD5DA3.png
 
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Yep, Surefire includes them now with all the 7.62 devices.

@TheHorta I probably have some spares if you need one.
 
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Yep, Surefire includes them now with all the 7.62 devices.

@TheHorta I probably have some spares if you need one.

Ummm... well... heck yeah! 😋

If you have a spare, I’d love to try one. PM me if you locate one. Muchas gracias amigo!
 
Wait, FN didn’t bother with a shoulder on the 20S either? Jesus...
 
I use FOP, but I digress...

Two questions:

1) Cerakote or Rattle Can?

2) Did you use an adapter or is the brake/mount directly threaded to the KAC barrel?
I’ll have to watch my language, since this is a public market.

Rattle can.

I had the same issue that everyone else in this thread has. My solution was a custom barrel with 5/8” threads.

I honestly would caution everyone with factory sr25’s wanting to put a Thunderbeast on. TBAC’s gas the system much more so than the Surefires and the Knight’s suppressors do, which is what their barrels are ported for. And then putting an adjustable gas block on a 25 kinda defeats the purpose of it in the first place. I don’t think mod 2 barrels are sized for regular gas blocks anyways. Which means now you’re likely to be modifying the factory barrel, even if it’s just a dimple...again, defeating the purpose and affecting the value of it. I retired my Surefires for TBAC - Ultra 9 initially and then the Dominus. I made peace with the barrel situation from the get go and just had one made. Stash the factory barrel for later if you want to sell the rifle, or sell the barrel off. They’ll pay for your custom one right at 1:1.
 
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I’ll have to watch my language, since this is a public market.

Rattle can.

I had the same issue that everyone else in this thread has. My solution was a custom barrel with 5/8” threads.

I honestly would caution everyone with factory sr25’s wanting to put a Thunderbeast on. TBAC’s gas the system much more so than the Surefires and the Knight’s suppressors do, which is what their barrels are ported for. And then putting an adjustable gas block on a 25 kinda defeats the purpose of it in the first place. I don’t think mod 2 barrels are sized for regular gas blocks anyways. Which means now you’re likely to be modifying the factory barrel, even if it’s just a dimple...again, defeating the purpose and affecting the value of it. I retired my Surefires for TBAC - Ultra 9 initially and then the Dominus. I made peace with the barrel situation from the get go and just had one made. Stash the factory barrel for later if you want to sell the rifle, or sell the barrel off. They’ll pay for your custom one right at 1:1.

Awesome! Any suggestions for which barrel MFG?
 
Yeah, the Mod 2 system uses that keyed gas block journal and castle nut arrangement (which is brilliant IMO).

I went back to the Surefire 7.62 Mini on mine for the reasons you mentioned. I had great luck with the TBAC on my Seekins since I could just choke the gas down as much as needed.
 
Awesome! Any suggestions for which barrel MFG?

As the former owner of a few different complete sr25’s as well as one of the first-gen OBR, I combined the two best things about the Knight’s and the Larue. As much of a Knight’s enthusiast as I am, I’m also a tinkerer and like to follow Knight’s form of always evolving. I reload, and I wanted TBAC to replace my Surefire: make a new system. Barrel is a Lothar Walther LW50.

Sr25’s are smooth.
My sr25 is smooove...
 
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Yeah, the Mod 2 system uses that keyed gas block journal and castle nut arrangement (which is brilliant IMO).

I went back to the Surefire 7.62 Mini on mine for the reasons you mentioned. I had great luck with the TBAC on my Seekins since I could just choke the gas down as much as needed.
Their gas block arrangement is the best evolution of the system. I don’t have any mod 2 barrels presently, but I seem to recall dimensional differences or something with the threads that made it not compatible with throwing a conventional block on there. I need to measure again to refresh my memory. Nonetheless, the best course of action was to re-do my own barrel with the 5/8 threads.
 
Is it possible to re-turn / machine the KAC barrel for standard threading?
 
It is, but then you still have the task of addressing the gas issue. So now you devalue a barrel that would pay for the new one tuned for your use...

If you go the custom route, pm me first as there’s more to consider, especially if you’re thinking of cloning a mod 2 barrel...
 
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Their gas block arrangement is the best evolution of the system. I don’t have any mod 2 barrels presently, but I seem to recall dimensional differences or something with the threads that made it not compatible with throwing a conventional block on there. I need to measure again to refresh my memory. Nonetheless, the best course of action was to re-do my own barrel with the 5/8 threads.

Can you comment on what sort of tuning you tried before deciding to rebarrel, i.e. different buffers or springs, different BCGs, etc. What worked the best? What had no effect?

Thanks!
 
Can you comment on what sort of tuning you tried before deciding to rebarrel, i.e. different buffers or springs, different BCGs, etc. What worked the best? What had no effect?

Thanks!
There wasn’t any tuning. The mod 2 barrels simply aren’t compatible, as they aren’t a standard gas system length, nor is their gas port the same distance off the shoulder. While you can dimple it where it lands and let the block float out there, it loses half its support - and sealing area - because of the mod 2 gas block threads. Now for the ECC and older models, they’re still a standard rifle gas length and you can put a block on them if you desire. It just defeats the whole purpose of having that high-dollar rifle system if you’re going back to square one and tuning it with peasant-level parts. As well as kills the value. That’s why I say do your own barrel. For continuing the tuning of a factory 25, the system needs to be left as it is: bolt group, buffer spring, etc. I made some tweaks in there for mine, but the overall system design and it’s weights are the same.
 
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There wasn’t any tuning. The mod 2 barrels simply aren’t compatible, as they aren’t a standard gas system length, nor is their gas port the same distance off the shoulder. While you can dimple it where it lands and let the block float out there, it loses half its support - and sealing area - because of the mod 2 gas block threads. Now for the ECC and older models, they’re still a standard rifle gas length and you can put a block on them if you desire. It just defeats the whole purpose of having that high-dollar rifle system if you’re going back to square one and tuning it with peasant-level parts. As well as kills the value. That’s why I say do your own barrel. For continuing the tuning of a factory 25, the system needs to be left as it is: bolt group, buffer spring, etc. I made some tweaks in there for mine, but the overall system design and it’s weights are the same.

I'm asking what did you try (if anything) to alleviate the gassiness of a stock SR25 with a TBAC can? Did you try going to a heavier buffer or spring, etc?
 
SR15 barrel threads are normal. TBAC cans are awesome, but those peel washers are the devil spawn.
 
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I'm asking what did you try (if anything) to alleviate the gassiness of a stock SR25 with a TBAC can? Did you try going to a heavier buffer or spring, etc?
I did not. I don’t believe in messing with the stuff in the rear in place of the front when dealing with 7.62 platforms. They are very different than 5.56. Until I have a couple hundred thousand rounds to test - and validate - tinkering with new springs and such, I’m sticking with Knight’s components and as much of their system as I can. Because they’ve already done it. Unsuppressed, the modern sr25 is the most evolved and perfected duty-grade 7.62 platform out there. That’s why certain suppressors - which also happen to then be chosen for the same duty roles - are tuned for those platforms. Example: Surefire. Problem is they are heavy, and built for platforms that are in general made for both a suppressed and unsuppressed function. That unsuppressed function and need was where it was because of the weight and length of those suppressors. Here comes Thunderbeast making heavy duty suppressors at half the weight. They’re tested and proven. I can tell you from personal experience, that the only reason I ever wanted to not be suppressed was because the juice wasn’t worth the squeeze for that particular mission to have to swing around that pound and half hanging off the end of my rifle. That changed with Thunderbeast. Length is not much of an issue as it is the weight. So now that allows me to have a suppressed rifle that feels and swings like it’s still unsuppressed. That’s my new system. Only problem is those Suppressors at the time (Ultra) overpressure the rifle. So in order to restore the system - which is primarily the validated sr25, I just want to bring those gas levels/volumes back in line to what that rifle was designed for. In my opinion, that is best mitigated as close to the source as possible. And until I can fab up a gas tube with a port that I can put a pressure gauge on to to get my readings, then I’ll stick with dialing in a block. Once I get it set, that’s where it stays. Freeze up if it wants to, I don’t care. It’s done the same thing for me that I’d get if I took my drill press to the range with a reamer set and played with port diameters in between firing a whole lot of rounds. I don’t recommend anyone expending ammunition like that with our present circumstances.

The Dominus is the final piece to my ‘system’ as you don’t feel it out there, and it’s only about three inches longer that what the Surefire flash Hider is, and I get to stay suppressed. I Know TBAC says the Dominus has less back pressure than the Ultras, but I didnt notice much. I did not make any adjustments and POI was exactly where it was with the Ultra9. Once a new 5.56 barrel comes in, the Dominus is going on there and I’ll have a better idea of pressure additions.
 
How about for SR15? Same problem(s)?
Not sure with a Dominus yet, but with the Ultra 7 I was running on 5.56, pressure was significant. I’m used to Surefires and not having to turn any switches or adjust anything when it’s on or off. The Thunderbeast, while on a 100% suppressed setup, made me realize it’s too much for what we are all used to for gas length to barrel length ratios. 16” midlength was too much. I’m confident I could put a rifle gas on it and get much better results. I have a new 18” with rifle gas still a couple months out, and it’s going to be built around the Thunderbeasts.
 
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