1/2x28 thread on 300wm

68Hoyt

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I have a light weight hunting rifle I picked up on line , I didn’t think to check the threads , so when I got it I was surprised to find it had 1/2x28 , but it has a nice shoulder , I have looked at what some have done in the past and present , what are your thoughts , 24 1/2” barrel
 

jimh406

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Some people have noted there is a minimum thread dimension recommended by some suppressor manufacturers for 30 cal. However, if you added a 5/8-24 adapter, I feel like that would increase the barrel strength at the end. I haven't tried it and don't have a 1/2-28 threaded 30 cal.
 

BrBa

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Some people have noted there is a minimum thread dimension recommended by some suppressor manufacturers for 30 cal. However, if you added a 5/8-24 adapter, I feel like that would increase the barrel strength at the end. I haven't tried it and don't have a 1/2-28 threaded 30 cal.
Adding a thread adaptor doesn't add metal onto the barrel at it's weakest point (the undercut). It just adds more weight, which I believe also increases shear.
 

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BrBa

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I have a light weight hunting rifle I picked up on line , I didn’t think to check the threads , so when I got it I was surprised to find it had 1/2x28 , but it has a nice shoulder , I have looked at what some have done in the past and present , what are your thoughts , 24 1/2” barrel
Curious if that is factory threading. Are you wanting to shoot suppressed or just add a brake? TBAC recommends 9/16-24 as the minimum for .30 cal.
 
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68Hoyt

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Yea it is factory 1/2 x28 on a 300 wm , a cooper back country , has a nice shoulder , at one time tbac would do a break that they machined in house that threaded on and seated against the muzzle or muzzle and shoulder perfectly but now they don’t want to do this , sico dosent have a problem with 1/2x28 with their new can ,,,,,,, but I want to run a ultra 7
 

bnsafe

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I bought a howa 300 wm that had 1/2x28 threads from the factory. Same as you in never crossed my mind to check that before I bought. So I called and emailed Legacy, they got back with me and gave me the name of a gunsmith in oregon who had brakes that fit. I called the gunsmith and he assured me he had did lots of them and never had a issue so I bought. It fit perfect and thru prob 50 shots there were no issues. I dont have the gun anymore but assume its all good.
 

BrBa

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You could try an Area 419 Universal Adaptor with 1/2-28 threads and Suppressor Mount that fits the TBAC Ultra cans. Only way to find if it works is to test it out.
 

DanM

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Mar 27, 2024
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Good question and not meaning to hi-jack the original question: But those of us with thin factory barrels are interested to know the potential hazards with "too" small of threads. It seems 1/2"-28 seems to not leave much material between the thread root and the OD of the bore, not even taking into account the undercut at the shoulder and how it is accomplished. Without replacing the barrel - 3x+ investment versus threading - can a 0.660" OD 30 caliber barrel be threaded at all? Or should it?
 

TimeOnTarget

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I’ve got multiple rifles threaded 1/2x28 and then adapted to 5/8x24 due to the barrel profile. I just thought that was the standard when needed. Work was done by very competent gunsmiths.

No issues on any of my rifles.
 
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Send it.
 

BrBa

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Good question and not meaning to hi-jack the original question: But those of us with thin factory barrels are interested to know the potential hazards with "too" small of threads. It seems 1/2"-28 seems to not leave much material between the thread root and the OD of the bore, not even taking into account the undercut at the shoulder and how it is accomplished. Without replacing the barrel - 3x+ investment versus threading - can a 0.660" OD 30 caliber barrel be threaded at all? Or should it?
0.662" OD is the min. TBAC recommends for 9/16x24 which is the min. threading they recommend for .30 cal.

The biggest potential hazard in going too thin is if you accidentally drop your rifle or bang the end of the barrel on something, the end could shear off or bend at the weakest point (undercut).

If you bring up the subject with Bartlein or TBAC, they don't recommend going below 9/16x24 for any .30 cal. My guess is they determined through their own testing that accuracy starts to decline and becomes unacceptable below that threshold. The only way to know if it will have enough stiffness to keep the point of impact from shifting around and be acceptable for your needs is to test it out.
 

jimh406

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My guess is they determined through their own testing that accuracy starts to decline and becomes unacceptable below that threshold.
The only way to know is have them post why somewhere. There are several rifle companies that thread 1/2-28 on 30 cals and call them suppressor ready. And many other suppressor manufacturers that seem to be silent on what size is required for their suppressors. Again, I don't have a 1/2-28 threaded 30 cal.

Should you believe the rifle manufacturer or one of two of the many suppressor manufacturers? Or, is the point to be as safe as possible, but in that case, shouldn't all calibers have the same requirement? For instance, I'm pretty sure a 7 mag or 7 PRC has more power and causes more deflection than a 7.62x39. Also, there is more leverage on a longer barrel/suppressor.

In any case, it would be nice how those two companies came up with that measure. Maybe they will post somewhere.
 
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id contemplate different alternatives if I were threading it but I would just use it as is if I were in your position.

 

BrBa

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The only way to know is have them post why somewhere. There are several rifle companies that thread 1/2-28 on 30 cals and call them suppressor ready. And many other suppressor manufacturers that seem to be silent on what size is required for their suppressors. Again, I don't have a 1/2-28 threaded 30 cal.

Should you believe the rifle manufacturer or one of two of the many suppressor manufacturers? Or, is the point to be as safe as possible, but in that case, shouldn't all calibers have the same requirement? For instance, I'm pretty sure a 7 mag or 7 PRC has more power and causes more deflection than a 7.62x39. Also, there is more leverage on a longer barrel/suppressor.

In any case, it would be nice how those two companies came up with that measure. Maybe they will post somewhere.
Feel free to contact them yourself, which is exactly what I did when I was trying to figure out which direction to take on threading a factory Tikka sporter barrel for a suppressor. Both companies were very helpful and gave more detailed answers than I was able to fully understand. I spoke with them both within the past year and didn't take notes or anything, but their recommendations on a path forward for my project were essentially the same. That carried a lot of weight with me, ymmv.

Here is a pretty interesting thread from a few years back. Opinions certainly vary. The last post in the thread caught my eye when I was searching and trying to read everything I could on the subject:
 
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