Tikka Threading Questions

[Boltgun]

I’ve read through a bunch of old threads but couldn’t find an answer, so here’s yet another threading thread.

Took the Tikka plunge. Bought a T3x Lite in 6.5CM.

My suppressor uses QD mounts that are only threaded for 1/2x28 or 5/8x24. I’d like to cut the barrel down to 18”, and the barrel outside diameter at that length is 0.677.

My smith says that’s not a safe diameter to thread to 1/2x28 or 5/8x24. Do I need to use a different pitch and run an adapter, or find a different smiths and thread to 1/2x28?

After investing a bunch in Nightforce, Trijicon and UM, I don’t want to create a weak point right at the end of the project!

 

[wyogoat]

I’m sure others will pipe up with different experience so go with what you feel is best for you but I have the same rifle and left it at 24”. Thunderbeast had zero issue threading that at full length with a smaller barrel diameter (since it wasn’t cut down). It may come down to your smith and what they’re comfortable with.
I did the CB attachment for my TB Ultra 7.

 

[Kimmo H]

Many american gunsmiths seem to over mystify muzzle threading for some reason.

That diameter is way more than what is necessary for making a solid shoulder for a 1/2x28, and with a 6,5 bore the wall thickness is accectable that way aswell. No reason why it couldn't be done.


The 1/2x28 is not the best thread size for that particular application, but as you don't do metric threads for suppressor application, its easier to do than 5/8x24 due to shoulder diameter needed for most smiths.


I work as a gunsmith in Finland, and we are licensed to do chopping and threading for Sako and Tikka rifles without the owner losing warranty. The basic rule for choosing the right thread size is to have 2mm or more difference on thread OD to barrel OD at the shoulder. Doesn't sound like much, but having done hundreds and hundreds of threads I know fully well that 2mm is enough. Sometimes even a little less must and can be done, but it requires a very snug fitting thread for extra support when getting close to 1,5mm difference in diameter or so.

On your application the 5/8 thread would leave a shoulder of 1,3mm in diameter. I'd look at chopping an extra inch off for more shoulder, or in a pinch you could get away with a snug fitting thread and thread locking the QD insert on your barrel as an extra safety. Maybe just do the smaller thread size, depending on how you prefer.


We use metric threads more often than imperial, and the most common metric muzzle device thread sizes are M14x1, M15x1 and M18x1. So M14x1 thread means OD of 14mm, with a pitch of 1mm per revolution and so on.
Add the common imperial sizes 1/2" (12.7mm) and 5/8 (15.9mm) and you have thread sizes to choose from nearly at every millimeter, always making sure to have a good shoulder and the biggest possible wall thickness at the muzzle.

It puzzles me how the american market has so few options for muzzle thread sizes, when you guys are on the top of the world at barrel making and all the cool custom stuff that is just not available on this side of the pond.

 

[grfox92]

Many american gunsmiths seem to over mystify muzzle threading for some reason.

That diameter is way more than what is necessary for making a solid shoulder for a 1/2x28, and with a 6,5 bore the wall thickness is accectable that way aswell. No reason why it couldn't be done.


The 1/2x28 is not the best thread size for that particular application, but as you don't do metric threads for suppressor application, its easier to do than 5/8x24 due to shoulder diameter needed for most smiths.


I work as a gunsmith in Finland, and we are licensed to do chopping and threading for Sako and Tikka rifles without the owner losing warranty. The basic rule for choosing the right thread size is to have 2mm or more difference on thread OD to barrel OD at the shoulder. Doesn't sound like much, but having done hundreds and hundreds of threads I know fully well that 2mm is enough. Sometimes even a little less must and can be done, but it requires a very snug fitting thread for extra support when getting close to 1,5mm difference in diameter or so.

On your application the 5/8 thread would leave a shoulder of 1,3mm in diameter. I'd look at chopping an extra inch off for more shoulder, or in a pinch you could get away with a snug fitting thread and thread locking the QD insert on your barrel as an extra safety. Maybe just do the smaller thread size, depending on how you prefer.


We use metric threads more often than imperial, and the most common metric muzzle device thread sizes are M14x1, M15x1 and M18x1. So M14x1 thread means OD of 14mm, with a pitch of 1mm per revolution and so on.
Add the common imperial sizes 1/2" (12.7mm) and 5/8 (15.9mm) and you have thread sizes to choose from nearly at every millimeter, always making sure to have a good shoulder and the biggest possible wall thickness at the muzzle.

It puzzles me how the american market has so few options for muzzle thread sizes, when you guys are on the top of the world at barrel making and all the cool custom stuff that is just not available on this side of the pond.

Awesome, thanks for chiming in.

Sent from my SM-G990U2 using Tapatalk

 

[Marshfly]

My son's Tikka T3X Lite 6.5 CM is cut to 20" and threaded to 1/2x28 for a Griffin adapter for their suppressor. It works perfectly. Tell your smith to cut and thread away or find a different smith.

 

[thinhorn_AK]

Cut to 18" get a permanent adapter/collar installed and direct 5/8x24.

 

[Boltgun]

Thanks for all the replies, and all the good info Kimmo!

He did offer to do 9/16x24, which would make it 14.28mm, though I’d have to run an adapter then. Should I just take him up on that, or find another smith?

 

[Weatherby_Eyebrow]

My smith used an adapter when I had my 6.5 lite barrel cut down to 19". Using a single port ASR brake currently.

 

[LeftyWilbury]

when i had my tikka 7 mag threaded they used a collar to get me a proper shoulder for my 5/8-24 threads. it's not overly sexy but it serves the purpose.

 

[Wapiti1]

Min barrel diameter for 1/2-28 is .600" per Thunderbeast. .610" if you look at the SAAMI chart that no one uses, but is a good reference.

I would agree with Kimmo that 2mm is a better shoulder height. The min shoulder given above is not going to keep the suppressor tight as well as a larger shoulder. 2mm is 0.079". Times 2 plus 0.500" major thread diameter and you get 0.158+.500=.658". So, you have plenty of meat at 0.677".

Thunder Beast Arms Corporation [TBAC] | Tech | THREAD SPECIFICATIONS

https://saami.org/wp-content/uploads/2023/06/Suppressor-Thread-CFR-.5-28.pdf

Jeremy

 

[HandgunHTR]

Thread it to 5/8-24 and have a permanent collar installed so that you have a good shoulder. Like this:

If your smith won't do that, then find a new smith, or send your barreled action to Kampfeld to have him do it.

 

[VuduDoc]

I had a Tikka T3x Lite 6.5 Creedmoor cut down to 16" and threaded 1/2x28. Not enough meat for 5/8x24 which I would have preferred. I didn't know about the permanent collar option or if my 'smith even does it. I put a Dead Air KeyMicro Brake (9mm bore, 1/2x28 threads) for my Nomad 30. No issues with it.

 

[M&C2]

Cut to 18" get a permanent adapter/collar installed and direct 5/8x24.

Is there a difference between a permanent adapter / collar versus a thread adapter? I am considering having my barrel threaded for a suppressor. My suppressor is 5/8" thread but I may have to my barrel threaded at 1/2" due to existing diameter unless the barrel is shortened.

 

[skipper907]

I’ve read through a bunch of old threads but couldn’t find an answer, so here’s yet another threading thread.

Took the Tikka plunge. Bought a T3x Lite in 6.5CM.

My suppressor uses QD mounts that are only threaded for 1/2x28 or 5/8x24. I’d like to cut the barrel down to 18”, and the barrel outside diameter at that length is 0.677.

My smith says that’s not a safe diameter to thread to 1/2x28 or 5/8x24. Do I need to use a different pitch and run an adapter, or find a different smiths and thread to 1/2x28?

After investing a bunch in Nightforce, Trijicon and UM, I don’t want to create a weak point right at the end of the project!

1/2x28 is way to small of a thread for the rifle the best you could do is 9/16x24. 1/2x28 is mainly used on .22cal

 

[thinhorn_AK]

Is there a difference between a permanent adapter / collar versus a thread adapter? I am considering having my barrel threaded for a suppressor. My suppressor is 5/8" thread but I may have to my barrel threaded at 1/2" due to existing diameter unless the barrel is shortened.

The permanent adapter eliminates tolerance stacking if you care about that. At least that’s what I was told. In the end you get a slightly flared end to your barrel but you never have to mess with little adapter pieces again.

 

[Alex Genereux]

I have used a lot of 9/16x24 on on tikka rifles cut down at the 18-20' mark with thunderbeast brakes.

 

[5811]

1/2x28 is way to small of a thread for the rifle the best you could do is 9/16x24. 1/2x28 is mainly used on .22cal

Too small in what way? What do you believe are the risks imposed by removing another 0.020" of material inside the barrel?

 

[omicron1792]

Many american gunsmiths seem to over mystify muzzle threading for some reason.

That diameter is way more than what is necessary for making a solid shoulder for a 1/2x28, and with a 6,5 bore the wall thickness is accectable that way aswell. No reason why it couldn't be done.


The 1/2x28 is not the best thread size for that particular application, but as you don't do metric threads for suppressor application, its easier to do than 5/8x24 due to shoulder diameter needed for most smiths.


I work as a gunsmith in Finland, and we are licensed to do chopping and threading for Sako and Tikka rifles without the owner losing warranty. The basic rule for choosing the right thread size is to have 2mm or more difference on thread OD to barrel OD at the shoulder. Doesn't sound like much, but having done hundreds and hundreds of threads I know fully well that 2mm is enough. Sometimes even a little less must and can be done, but it requires a very snug fitting thread for extra support when getting close to 1,5mm difference in diameter or so.

On your application the 5/8 thread would leave a shoulder of 1,3mm in diameter. I'd look at chopping an extra inch off for more shoulder, or in a pinch you could get away with a snug fitting thread and thread locking the QD insert on your barrel as an extra safety. Maybe just do the smaller thread size, depending on how you prefer.


We use metric threads more often than imperial, and the most common metric muzzle device thread sizes are M14x1, M15x1 and M18x1. So M14x1 thread means OD of 14mm, with a pitch of 1mm per revolution and so on.
Add the common imperial sizes 1/2" (12.7mm) and 5/8 (15.9mm) and you have thread sizes to choose from nearly at every millimeter, always making sure to have a good shoulder and the biggest possible wall thickness at the muzzle.

It puzzles me how the american market has so few options for muzzle thread sizes, when you guys are on the top of the world at barrel making and all the cool custom stuff that is just not available on this side of the pond.

What a great post. Thanks!

 

[skipper907]

Too small in what way? What do you believe are the risks imposed by removing another 0.020" of material inside the barrel?

Most gunsmith will tell you one it does not leave enough material between to bore and the base of the threads to support any kind of muzzle device and you would be much more susceptible to altering the bore size causing a restriction or having the bore enlarge when torqueing on a muzzle device.
you can try it if you can get a gunsmith that will do it but you run a strong risk of having problems and then having to get the barrel cut down again or possible get a new barrel.
generally if a good gunsmith wont do something means they don't to have problems with the work they did because that's just what a customer wanted.

 

[TreeDog]

My smith had zero issue cutting my superlite to 18" and threading 1/2x28. I put an adapter to 5/8x24 on and so far so good. Only 50ish rounds though, but I'm not concerned.