Suppressors Muzzle abnormality ? (w/photos) - Tikka CTR

[PFG]

Tikka CTR.

Unthreaded the cap protector to install the TBAC break, and found this when I slid the crush washers over the threads:

Surely this small diameter of unthreaded barrel is an abnormality, yes? I can't imagine the crush washers will seat against this and do me any good.

Or maybe this is normal and I'm out of the loop on muzzle threading specs.

 

[Zak Smith]

Does not have thread relief cut as it should
https://thunderbeastarms.com/tech/thread-specifications
see "C" and Detail E

 

[PFG]

Thanks @Zak Smith .

And thanks a lot Tikka. Is this a "oops" on their part? Or normal, every CTR is like this?

Sounds like a good excuse to go get 2 inches chopped off and re-threaded by someone competent.

 

[Zak Smith]

Not sure if they are all like that or not. It's cheaper/easier to leave the root cut out so some places do it that way.

The existing setup can be touched up and checked, you don't need to cut off a bunch.

 

[PFG]

Thanks @Zak Smith. Happy to find this now, while I still have 4-6 months of wait time before the Ultra 7 is out of jail. I'll either get the root touched up, or just re-cut the barrel. Its a 6.5 at 20inches, and I wouldn't mind making this a shorty 6.5

 

[Sniperwannabee]

Hmm no problems with my ctr

 

[Sniperwannabee]

Just make a washer/spacer for it

 

[PFG]

@Sniperwannabee thats an idea. Thanks.

 

[Lmatt]

Hmmm, mines almost as bad

 

[Lmatt]

 

[PFG]

@Lmatt yeah...such BS. I wish I would have looked this over before buying.

IMO, its not worth b*tching with Tikka's CS over this. So instead, I'm just going to get it chopped and timed for the break I want to use (TBAC).

 

[SubOptimal]

You don't have to cut anything off that barrel, Just have a machinist trim the unthreaded portion down to the root diameter of the threads. Most lathes will take this and if needed use a 4 jaw chuck to center up the bbl to perfection with small leather strips to avoid marring the barrel. Worst comes to worst, you may have to remove the trigger and even the action to achieve some semblance of balance out of the thing.

 

[Lmatt]

Mines getting a washer or a new barrel.

 

[PFG]

What material are you using for your washer?

@SubOptimal I was thinking chop and re-thread would create the best scenario by getting rid of the need for crush washers. Time the threads to the TBAC break, a couple dabs of loctite, and rock on.

 

[SDet]

What material are you using for your washer?

@SubOptimal I was thinking chop and re-thread would create the best scenario by getting rid of the need for crush washers. Time the threads to the TBAC break, a couple dabs of loctite, and rock on.

You could time it by just cutting the relief and facing the shoulder. If you didn't want to lose length.

 

[Lmatt]

I’m just getting around to ordering some cans. So I haven’t looked into anything yet. I’ve been very tempted to replace the barrel after seeing Frank’s results with the tac a1. I opted for the 20” so I should gain a ton if I go that route.

 

[TexasTightwad]

I am a machinist, and it is impossible to thread all the way to a shoulder. You either cut a thread relief or pull out of the thread before you get to the shoulder. A thread relief makes things weaker, so if I was threading a barrel I wouldn't cut a relief. As long as a brake/suppressor contacts the shoulder, it is fulfilling its intended purpose.

 

[bidet]

Not a machinist, but I have a question on a possible alternate approach. Could you mount the muzzle break into the lathe chuck and carefully open it up for just the last couple of threads, so that the threads are removed and you end up with a hollowed-out area just long enough and wide enough to slip over this area between the shoulder and the end of the threaded muzzle? It's not like those last couple of threads are going to be doing anything when the brake is mounted if there is a relief cut.

Seems like this would be easier than pulling parts off of the rifle, especially if you ended up having to remove the barrel from the action. The brake is going to be permanently mounted, so it's not like you're going to have to worry about converting multiple brakes or anything.

Of course, I wouldn't advise this for a direct thread suppressor, just a brake-mounted model.

 

[PFG]

@bidet - thats not something I'm qualified to answer.

Right now, I'm going to work on getting some measurements taken and, with the help of a gracious poster here, get a washer made that fits over the un-cut root and times the muzzle break to nearly the noon position so I can loctite and rock without have to use crush washers or get the gun chopped and re-threaded.

Bummer that Tikka didn't get this right from the jump, but to hell with attempting to use their customer service. The gun shoots, I like the rifle, and I'll handle this minor annoyance on the muzzle. Wouldn't be a problem if I was using a self timing break like Area 419 and their system, but I'm choosing to go with TBAC's thread over break since its their suppressor I'll be mounting.

 

[TexasTightwad]

As soon as he gets some dimensions to me, I'll be making him a set of flat washers. I'm thinking 7 of them, each .005 thicker than the last. That will give just over a whole revolution of adjustment on a 24 pitch thread, in approximately 1/8 turn increments.

 

[PFG]

I'll report back when Texas and I finish up this little project. Good peoples here on the Hide.

 

[Zak Smith]

You could just throw another peel washer on there, super easy

 

[SRSDriver]

I have a T3 sporter with metric threads, and my TBAC brake went right on, so they changed something at some point. Bummer.

 

[bidet]

@bidet - thats not something I'm qualified to answer.

I'd like to hear from any machinists on the forum as to whether that is a valid option. If it's not, can you please explain the flaw? I'm trying to learn.

 

[Shane C.]

bidet, the back of the brake is relieved like you suggest and would go over the unthreaded portion, but it probably won't time right without the washers. Looks like the unthreaded portion is over size, not allowing the washer to slide back to the shoulder.

 

[bidet]

OK, good point in the case of a brake. But for a flash hider, such as the SilencerCo 3-prong unit, which doesn't have to be timed - would there be a problem?

 

[spife7980]

OK, good point in the case of a brake. But for a flash hider, such as the SilencerCo 3-prong unit, which doesn't have to be timed - would there be a problem?

I doubt a TB guy will answer a question about a product that isnt his.

But I think that the base of the SiCo flash hider is relieved enough already.

 

[PFG]

Looks like the unthreaded portion is over size, not allowing the washer to slide back to the shoulder.

Correct. This is the problem with my CTR. The crush washers won't go over the unthreaded portion. So I can't get the break to snug up with the shoulder. Extra crash washers won't help. I'm going to get the diam of the unthreaded root and get a washer made for it.

 

[Shane C.]

OK, good point in the case of a brake. But for a flash hider, such as the SilencerCo 3-prong unit, which doesn't have to be timed - would there be a problem?

Shouldn't be a problem unless the unthreaded portion of the barrel is to long, or the diameter is to big to go into the relief. Our flash hider doesn't need timed and has a very similar relief cut, most brands do.

 

[TexasTightwad]

I'd like to hear from any machinists on the forum as to whether that is a valid option. If it's not, can you please explain the flaw? I'm trying to learn.

It is a valid option. And echoing what Shane said, most things that get an internal thread will have at least a 45° chamfer, and many muzzle brakes and suppressors have a counterbore which is even better.

It will probably all thread on there just fine, but if it needs to be timed, washers with a bigger ID will be required.

 

[JGR1953]

I bought a set of these for my CTR and they are sized inside to fit over the lip.
They are a little pricey but make indexing simple with the different sizes.
https://precisionarmament.com/product/accu-washer-system/

 

[Snuby642]

The "custom" washers are the way to go. Faster cheaper, no fuss.
Do your self a favor and rockset that on when your happy with the timing.

I had an adapter losen and damage a can.

 

[Sniperwannabee]

I bought a set of these for my CTR and they are sized inside to fit over the lip.
They are a little pricey but make indexing simple with the different sizes.
https://precisionarmament.com/product/accu-washer-system/

Thanks I'll give these a try I hate peel washers

 

[ranchodrive]

Forget using a washer/shim altogether.... Just direct thread your can to the barrel and hand snug it down. I have a Rem 260 CTR mated with a TBC 30 P1 can and have had no issues what so ever... Gun shoots fine

 

[JGR1953]

Forget using a washer/shim altogether.... Just direct thread your can to the barrel and hand snug it down. I have a Rem 260 CTR mated with a TBC 30 P1 can and have had no issues what so ever... Gun shoots fineView attachment 6928918

This is about side vented muzzle brakes that do not have an indexing locknut/ring and has to use an indexing washer to level the brake TDC.

 

[Zak Smith]

If the muzzle does not have a relief cut a DT can will probably not shoulder either.

 

[Tuukka]

Due to for example the CTR barrels, we made a larger relief on our 5/8"X24 UNEF thread pieces

( there were a couple of accuracy issues with domestic customers here and we commoe'd with the Sako guys at that time )

Best Regards!

Tuukka Jokinen
Ase Utra sound suppressors

 

[PFG]

I went forward with having the barrel cut back 2 inches, and new threads cut and timed for the TBAC break. Now the break threads on and times up perfectly, no washers needed. Just more piece of mind for me. Had a local guy do all the work for $125.

 

[TBACRAY]

Tuukka tell them to start putting the relief cut in.