Threading a 303 Brit barrel

fightinghamster

fightinghamster

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I want to thread the barrel on my no1mk3 Enfield, sometime in its past the barrel was shortened to 18.5 inches, I want to thread it and add a muzzle break because it would be hilarious, my understanding is that it’s most common for 30cal firearms to be threaded 5/8x24 however every threaded barrel firearm we own including my wife’s 30-06 rem700 is threaded 1/2x28

Should I go with conventional wisdom and thread for 5/8x24 or should I use 1/2x28, I already have a 1/2x28 tap and die from a different project and only having one size thread simplifies muzzle device swapping if I want too but probably harder to find 1/2x28 30cal muzzle devices
Any suggestions or advice is always welcome
 

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There's a company called CNC Warrior that sells threading tools and kits for the DIY type who doesn't have a lathe.

Use an appropriately sized annular cutter to get the barrel cut down to the right size for the thread desired.

Not sure if buying a kit would be worth it, or if you could even have it shipped here. It's essentially just hand tools and machine tools though.
 
1/2 inch is pretty small for a .311 barrel, 5/8's may be large depending on the od of the muzzle.

9/16's is between 1/2 inch and 5/8's.

I threaded many barrels to 9/16 x 24.
 
fightinghamster said:
Should I go with conventional wisdom and thread for 5/8x24 or should I use 1/2x28, I already have a 1/2x28 tap and die
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Running a die over a barrel is, by quite a long way, the worst means to produce threads on a muzzle.


fightinghamster said:
gota thread it with a die I don’t have a lathe,
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Then, IMO you should maybe choose not to bubba the rifle further? 🤷‍♂️

You clearly haven't considered how the barrel OD will be reduced to the correct OD for the thread pitch? You kinda need a lathe for that.


guntech said:
9/16's is between 1/2 inch and 5/8's.
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This is true but there are probably not too many commercial muzzle brakes available in 9/16-24.
 
ssapach said:
There's a company called CNC Warrior that sells threading tools and kits for the DIY type who doesn't have a lathe.

Use an appropriately sized annular cutter to get the barrel cut down to the right size for the thread desired.

Not sure if buying a kit would be worth it, or if you could even have it shipped here. It's essentially just hand tools and machine tools though.
Click to expand...
I’ve got access to a pipe threader, basically a one speed lathe with no cutting tools, I can turn down the end of the barrel to the appropriate size with files if it’s level and spinning, I’ve done fab work and metal work before but I’m only just starting out with gunsmithing work
 
I Dont Care About You said:
Running a die over a barrel is, by quite a long way, the worst means to produce threads on a muzzle.



Then, IMO you should maybe choose not to bubba the rifle further? 🤷‍♂️
Click to expand...
Normally I wouldn’t do anything to change a rifle permanently but this thing was already cut down and cobbled together out of spare drill rifle parts, it didn’t even have an inner barrel band when o got it so I’m not that broken up, whoever shortened the barrel didn’t even cut the front sight keyway or properly stake/pin the sight so it wobbled
 
With respect to using a lathe to thread the muzzle...
This is the best way to do the job. Personally, I would be very hesitant to attempt the work without a lathe. The likelihood of a botched job greatly increases. But then again, I have a lathe.
Doing the OP's rifle on my lathe would be a pain. The barrel is too short to pass through the headstock spindle with the receiver attached. That would leave two options - remove the barrel or use a mandrel in the receiver and the steady rest to support the barrel back from the muzzle. A simpler method would be to use a mandrel in the receiver and support the muzzle on the live tailstock center. Threads will be coaxial with the bore, but the crown will need to be touched up by hand afterwards. No way to bore the brake ID for a best installation.
Turning and threading the muzzle would also allow for the crown to be touched up, and for the ID of the brake to be bored to be absolutely coaxial with the rifle's bore and with an optimal ID. This assumes use of a semi-finished brake.
For a brake to be really effective, coaxial alignment and a proper ID are important. If these conditions are not met, the brake will be more decorative than effective. Ready to screw on brakes, ones designed to go on any and all threaded muzzles, will tend to have larger IDs, to reduce the chances of a bullet strike. This reduces effectiveness.
 
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fightinghamster said:
I’ve got access to a pipe threader, basically a one speed lathe with no cutting tools, I can turn down the end of the barrel to the appropriate size with files if it’s level and spinning, I’ve done fab work and metal work before but I’m only just starting out with gunsmithing work
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Pipe threaders are hardly precsion tools.
 
fightinghamster said:
Normally I wouldn’t do anything to change a rifle permanently but this thing was already cut down and cobbled together out of spare drill rifle parts, it didn’t even have an inner barrel band when o got it so I’m not that broken up, whoever shortened the barrel didn’t even cut the front sight keyway or properly stake/pin the sight so it wobbled
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You could also buy 20 feet of chain and a few hundred feet of rope and have a cobbled up anchor...
 
well this has potential to be a disaster.

the headstock on my lathe sounds like it is similar to tiriaq's

19" is about the shortest I can work on with the receiver attached. A muzzle device you want the barrel threaded concentrically and a die and pipe threader might get you close(ish) and mostly straight but you really need to use a lathe to get it right.
 
Brake manufacturers make brakes in 1/2", 9/16", 5/8", 3/4" as well as metric.
My guess a brake will cost anywhere from $100 to $400.
A good smith crowning your barrel and installing the brake you supply will probably charge upwards of $300.
Most likely the barrel will have to be removed from the action to do the job.
You most certainly are not capable of doing this.

Spend a lot of money which will never be recuperated? Sell it for parts? Hang it on the wall? Buy the chain and rope and put it to use?
 
tiriaq said:
Personally, I would be very hesitant to attempt the work without a lathe. The likelihood of a botched job greatly increases. But then again, I have a lathe.
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LOL, me too. Once you have a lathe, there is simply no substitute.


guntech said:
You could also buy 20 feet of chain and a few hundred feet of rope and have a cobbled up anchor...
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OR ..... he could just chuck the whole rifle into the bay and go on to live a long and satisfying life? :ROFLMAO:
 
Starting at 18 1/2", there is no margin to cut it off and start over. Gotta get it right the first time. ;)
Speaking of brakes on a .303 - I installed a brake and front sight unit from a SVT 40 muzzle unit on a No. 4. The concussion is impressive.
 
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