School me on muzzle threads

[Micky Duck]

I was looking to try and save a bit of coin and buy a second hand supressor when it came up, even if it was a different thread than my barrel, and just have the barrel cut and rethreaded to whatever the supressor thread was. I’ll just save up a bit more and buy a new one. Or just buy a new DPT and keep the length the same for now. Take a look at the comparison pic(obviously bottom is hardy not dpt), mine is the top one. Same length barrels in both photos, but mine is significantly longer. It just feels too long in the hand, especially as half of my wallaby shooting is on the back on a canam.

Attachment 165035

now RETAKE photo with rifles properly side by side....bottom rifle is 2" further back..look at the trigger guards and ends of forestocks...

[Delphus]

now RETAKE photo with rifles properly side by side....bottom rifle is 2" further back..look at the trigger guards and ends of forestocks...

I was lining up where the barrels meet the receivers one is a .270 one a .223

[ChrisW]

Generally you want to make sure that the major diameter of the thread is as close to the original external barrel dimeter as possible - to maintain as much wall thickness in the barrel as possible.
This is why the fatter the barrel, generally the large dia the muzzle thread will be because you want to maintain as much thickness as possible.

Basically muzzle threads are usually chosen because A. popularity of accessories in a given thread. B. remaining meat left on the barrel with chosen thread.

Its debatable what if any effect an undersized thread would have on a large dia barrel - The main effect id be concerned about is the potential for the thin parts of the barrel to heat faster than the thick parts. When steel gets hit it distorts. This could potentially lead to inconsistent distortion caused by heat where the end of the barrel changes (due to heat) at a different rate/degree to the rest of the barrel; potentially causing consistency issues at different barrel temps.

[timattalon]

Generally you want to make sure that the major diameter of the thread is as close to the original external barrel dimeter as possible - to maintain as much wall thickness in the barrel as possible.
This is why the fatter the barrel, generally the large dia the muzzle thread will be because you want to maintain as much thickness as possible.

Basically muzzle threads are usually chosen because A. popularity of accessories in a given thread. B. remaining meat left on the barrel with chosen thread.

Its debatable what if any effect an undersized thread would have on a large dia barrel - The main effect id be concerned about is the potential for the thin parts of the barrel to heat faster than the thick parts. When steel gets hit it distorts. This could potentially lead to inconsistent distortion caused by heat where the end of the barrel changes (due to heat) at a different rate/degree to the rest of the barrel; potentially causing consistency issues at different barrel temps.

Also note that you also want enough taken off the outside for the suppressor to have a shoulder to contact. If there is not enough shoulder then you can run into issues where the harder barrel metal can damage the starting parts of the thread.

[Cordite]

Useful summary - thread options for different muzzle diameters.

[Ftx325]

So I have been wondering this for a while. I understand the difference between threads, the fact that there are a certain amount of turns cut per inch etc. What I don’t know is what the different threads are used for? Can any thread be cut into any barrel? Are some threads used for specific barrels? I’m looking to cut down my .223, but also want to replace the current gunworks suppressor for a dpt. I have passed up on a few second hand supressors in the past because they were the wrong thread for the rifle. Can I buy another threaded suppressor and cut the barrel to suit?

The short answer is there are thread sizes suitable for different calibers . If the two rifles you have in the pic are the same caliber but different threads it is quite likely they are just metric vs american threads , possibly depending on whether they are factory threaded and the manufacturer - ruger or howa for example - or threaded aftermarket . If you can identify the thread on your rifle chances are you can buy a supressor in the required thread , but if dpt will probably need the bush machined to suit the barrel .
For example the common rimfire thread used in nz is 1/2 x 20 but the americans always seem to like 1/2 x 28 ....

[ZQLewis]

Most of mine are metric threaded.
The old JW15 (1980's) is 1/2x28, sons ex Ar was 1/2x20,
Heavy barrel 223 and 243 are 14x1,
Light barreled 358 is 14x1, possibly could have been 16x1 but would not have had much shoulder at the end of the thread to butt the inside of the silencer up against.
Z
That bottom silencer looks like a Hardy, very short front overhang of about 80mm on the compact version.

[Micky Duck]

your gunworks suppressor also appears to be one of the early ones....posibly made by Robbie himself....you could go fatter and shorter in same brand.... but I compared a long skinny spartan,SIMILAR to yours,and 5 baffle DPT on same rifle...my old 270...overall length difference was about an inch so I DONT BELIEVE YOU WILL GAIN A HECK OF A LOT,unless you decide to shorten barrel at same time.
DUCKHUNTERS add says 5" forward of muzzle for the 35mm spartan.... check and see what DPT says then weigh it up. I dont have a DPT here to measure. you COULD run dpt with less baffles of course which would decrease length at expense of more noise.....