Threading barrel for muzzle brake

[zobster]

Hi guys, I'm toying with the idea of threading my barrel so that I can fit a muzzle brake.

Now, there are many different thread sizes available. What should I choose? Do different threads have different strength?

Would 1/2 28 be enough on a 223 n 308?

[sandgroperbill]

Number 1: choose the muzzle brake you want first, then have the threading done.

Number 2: I'm assuming you're wanting to add some tacticool to your rifle?

[zobster]

I'm ordering it from the US, custom piece, so I get to choose the threads as well.

No, not adding any tacticool. l just want to reduce the recoil to be able to see my shots land.

[Baronvonrort]

What should I choose? Do different threads have different strength?

Would 1/2 28 be enough on a 223 n 308?

The 1/2- 28 is common for .223 and even 22lr

The 5/8 - 24 is more common for .308.

Sometimes depending on the model a .223 brake can be drilled bigger for larger guns by the gunsmith who threads your barrel.

For a .308 I would go 5/8-24 , I like the look of the m11 severe duty by precision armament.

[lole]

Number 1: choose the muzzle brake you want first, then have the threading done.

+1 for this.

Getting it threaded first will limit your choice and you might have to go with a second choice if the one you decide on come in another thread.

[lole]

P.S.

Have you looked at the clamp on HSS brakes?

[BBJ]

The HSS ones will save you a bit of cash.

Was about $120 to get a barrel threaded and capped when I got a quote a while ago.

[Homer]

G'Day Fella's,

Zobster, what I generally do is to cut a muzzle thread that is as close to muzzle diameter as possible.
The main reason I do this is, IF the barrel has not been properly Stress Relieved, it is best to cut as large a diameter thread as possible!
What can happen, is if the barrel has not been properly stress relieved and you then machine it down from say 5/8" muzzle diameter to cut a 1/2" diameter thread, the Bore of the barrel at this point (the muzzle), can actually expand out a couple of thousands of an inch at this critical location! NOT A Good Thing!!!
So what I do is cut as large as possible muzzle thread, and machine a shoulder flat at the very end of the barrel, for the Brake or "Can" to butt up against!

Here is a grubby example (half cleaned off carbon etc and Anti-Seize compound on thread) of what I'm talking about, on a standard Rem 700 muzzle (M-16 x 1mm pitch thread).

.308 Win, Rem 700 muzzle

026.JPG (294.84 KiB) Viewed 10846 times

Also, please note how I cut the Crown of the muzzle and also, the Copper bore fouling in the bore.

Hope that helps

Doh!
Homer

[Homer]

Here's another image of the same muzzle and a better image of the Copper fouling etc....

.308 Win Muzzle.

027.JPG (290.9 KiB) Viewed 10846 times

Doh!
Homer

[Chronos]

i'd also reccomend trying a clamp on brake first as well. the reason is as Dye found out you may not like the added noise/blast the brake generates at the butt and at least you can sell the clamp on brake and keep your losses small rather than clow $100-200 having it threaded then deciding you don't want to use the brake

Chronos

[bigtone]

Seriously who needs a brake on a 223? 308 maybe but the extra noise..........really? Get a better recoil pad and shoot heaps then you wont notice the thump. If that doesnt work, go get a 300 winmag and put 100 rounds through it before you use the 308 and you wont even feel the 308. There is nothing worse than sitting next to someone with an unneccesary muzzle brake. It seems like muzzle brakes are becoming like cars with really long bonnets nowadays.

[Browning]

Agree bigtone...

[Homer]

G'Day Fella's,

Bigtone etc, you need to remember that muzzle brakes can have more than one functional purpose!
Recoil reduction is one of these, and depending on the design, they can also reduce or eliminate muzzle rise as well.
You don't need a semi-auto to capitalise on this function, as being able to watch the bullet make contact with the target, can be a real bonus!!!

Doh!
Homer

[AusC]

Seriously who needs a brake on a 223? 308 maybe but the extra noise..........really? Get a better recoil pad and shoot heaps then you wont notice the thump.

He said it wasn't about reducing recoil for his shoulder, he wants to reduce it for the muzzle rise so he can see his shots land

[Homer]

Seriously who needs a brake on a 223? 308 maybe but the extra noise..........really? Get a better recoil pad and shoot heaps then you wont notice the thump.

He said it wasn't about reducing recoil for his shoulder, he wants to reduce it for the muzzle rise so he can see his shots land

G'Day Fella's,

AusC, thats not the way I read it!
And besides AusC, go back and read what Zobster said, when he started this thread....

Doh!
Homer

[Chronos]

Seriously who needs a brake on a 223? 308 maybe but the extra noise..........really? Get a better recoil pad and shoot heaps then you wont notice the thump.

He said it wasn't about reducing recoil for his shoulder, he wants to reduce it for the muzzle rise so he can see his shots land

G'Day Fella's,

AusC, thats not the way I read it!
And besides AusC, go back and read what Zobster said, when he started this thread....

Doh!
Homer

Quote: "No, not adding any tacticool. l just want to reduce the recoil to be able to see my shots land."

sounds like that's what he said

Chronos

[AusC]

AusC, thats not the way I read it!

Well you read it wrong then

[zobster]

G'Day Fella's,

Zobster, what I generally do is to cut a muzzle thread that is as close to muzzle diameter as possible.
The main reason I do this is, IF the barrel has not been properly Stress Relieved, it is best to cut as large a diameter thread as possible!
What can happen, is if the barrel has not been properly stress relieved and you then machine it down from say 5/8" muzzle diameter to cut a 1/2" diameter thread, the Bore of the barrel at this point (the muzzle), can actually expand out a couple of thousands of an inch at this critical location! NOT A Good Thing!!!
So what I do is cut as large as possible muzzle thread, and machine a shoulder flat at the very end of the barrel, for the Brake or "Can" to butt up against!

Here is a grubby example (half cleaned off carbon etc and Anti-Seize compound on thread) of what I'm talking about, on a standard Rem 700 muzzle (M-16 x 1mm pitch thread).

026.JPG

Also, please note how I cut the Crown of the muzzle and also, the Copper bore fouling in the bore.

Hope that helps

Doh!
Homer

Thanks for your explanation. It certainly clears things up for me.

Now, the confusion lays here. According to the Howa catalog, the muzzle diameter of my 223 is 15.8mm which would not be an issue if I threaded it for 1/2x28. At the same time, the muzzle diameter of my 308 is 15.8mm as well.

If I thread the 308 at 5/8x24, would there be enough material for the threads to be cut properly? 5/8" is just 15.875mm

What should I do?

[sbd3927]

Just an opinion, but it doesn't seem to be much of a concern.
5/8 = 0.6250" =15.875
ANSI Standard, not listing 24 pitch thread though...
http://www.engineersedge.com/screw_threads_chart.htm
0.6250 nominal for 18 pitch, 0.6163 minimum = .6163x25.4 = 15.625
If you look higher in the chart for a matching 24 pitch thread, the tolerance between max & min is .0070" on a 3/8" or 0.17mm
that puts your .075mm better than halfway in the 0.17mm tolerance.

Another way to look at it, 15.875 - 15.8 = .075mm, =75 micron.. = fine human hair, and that's on a round thread, so it's half a hair depth on each side.
I doubt the gunsmith would machine it to that tolerance, if you cut to the correct specified depth, it would be equivalent to miniscule wear on the outside (non working part) of the thread. Finally it's more about the thread pulling it into the shoulder and sitting true to the bore.

Hope this helps.

[zobster]

That's exactly my concern, there's hardly any material for threads to be cut properly and it's putting a lot of faith in the smith's skills. Think I might just go with 1/2*28 threads. Its common enough and I could always bore out a 223 muzzle brake to fit a 308.

[sbd3927]

I'd go with the 5/8 for the same reason, the difference is insignificant, the barrel may well be thicker or thinner by that amount already. The effects on the crown outlined by Homer above seem far more important.

https://en.wikipedia.org/wiki/Unified_Thread_Standard
Look at the thread picture, the external thread already has a flat on top, and the barrel is within the tolerance for thread, the flat would be very slightly wider.
The chart has the 24 pitch spec, 5/8 UNEF. Subtract the tapping drill (14.68mm) size from the external, the overall thread depth is 1.19mm

You could get a bolt of that size (specialised bolt shop), hold a hair against it and see how little difference it would make.

Alternatively, go for a clamp on style brake?

[Chickenhawk]

Thinning the barrel wall through threading it is an interesting concern.

Does anyone know if someone like SAAMI provide a standard a standard on this or is it completely up the to the knowledge/skill of the gunsmith?

[Oldbloke]

Thinning the barrel wall through threading it is an interesting concern.

Does anyone know if someone like SAAMI provide a standard a standard on this or is it completely up the to the knowledge/skill of the gunsmith?

Pressure will have been well and truly reduced by the time the projectile gets to the end of the barrel. Don't worry.

[Xerox]

Hmm, it's an worthwhile question though.

If a bullet lodged at the muzzle or entering the brake for some reason I suspect there would be more than enough pressure to still octopus the thing in anything but the smaller calibres.

.223 may be relatively safe, surely not a .30 though.

[zobster]

Hi Guys,

I've bit the bullet and have sent the gun in for threading.

Was told the following "Your barrel is a sporter profile, I can cut a 5/8*24 thread on it but there isn't any shoulder for the brake to screw onto".

Please help, what is my next move? I really want to use the brake.

[bladeracer]

Hi Guys,

I've bit the bullet and have sent the gun in for threading.

Was told the following "Your barrel is a sporter profile, I can cut a 5/8*24 thread on it but there isn't any shoulder for the brake to screw onto".

Please help, what is my next move? I really want to use the brake.

Use a locknut.

[zobster]

Problem solved! Smith told me to get 223 brake in 1/2x28, he'll bore it out to 308, no charge!!