Lets Assume You Are Building a 6"-10" 458 Win Mag Handgun ...

[PappyM3]

Broc’s 6” 458 WinMag muzzle flash:

 

[Mesatchornug]

Broc’s 6” 458 WinMag muzzle flash:

View attachment 883044

 

[PappyM3]

I, for one, approve of this senseless excess.

 

[Broc]

It is happening.

I will look at barrels this weekend.

Emailed Bullberry today. Let's see what they say.

 

[Mesatchornug]

Emailed Bullberry today. Let's see what they say.

 

[Broc]

If they can't make it happen, I will message SSK and the other manufacturer (I just forgot their name).

Worst case I buy a full length barrel and have it cut here.

That being said, Encore bro's help me out - I dont think the handgun furniture and rifle furniture mount the same. Right?

So if I order a rifle barrel and want furniture I might have to have the barrel cut longer.

However, if I go with 6" I might not use any furniture (ain't nobody got time for extra weight).

Thoughts?

 

[Mesatchornug]

If they can't make it happen, I will message SSK and the other manufacturer (I just forgot their name).

Worst case I buy a full length barrel and have it cut here.

That being said, Encore bro's help me out - I dont think the handgun furniture and rifle furniture mount the same. Right?

So if I order a rifle barrel and want furniture I might have to have the barrel cut longer.

However, if I go with 6" I might not use any furniture (ain't nobody got time for extra weight).

Thoughts?

I'm sure come combination of me, @chris_1001, @Yazz, and @pastera could design/print handgun furniture that fits your ex-rifle barrel...or, you could make like @DW357 and have a 16" pistol

 

[nm1]

Rifle and pistol forend bolt spacing is different. For the rifle there’s also the barrel profile that was a factor (factory profiles were regular / heavy / etc. and had different forends - so you’ll need to pick)

Also, with a 6” barrel and a case length of 2.8” you’ll have about 3” of rifling - I think you’ll need a threaded barrel and a properly designed muzzle brake to disperse all that unburnt powder goodness…

 

[pastera]

Rifle and pistol forend bolt spacing is different. For the rifle there’s also the barrel profile that was a factor (factory profiles were regular / heavy / etc. and had different forends - so you’ll need to pick)

Also, with a 6” barrel and a case length of 2.8” you’ll have about 3” of rifling - I think you’ll need a threaded barrel and a properly designed muzzle brake to disperse all that unburnt powder goodness…

Disperse?
@Broc is looking for a hand cannon that doubles as a flame thrower
Punch a fist sized hole and cauterize it in a single operation.

 

[Broc]

Rifle and pistol forend bolt spacing is different. For the rifle there’s also the barrel profile that was a factor (factory profiles were regular / heavy / etc. and had different forends - so you’ll need to pick)

Also, with a 6” barrel and a case length of 2.8” you’ll have about 3” of rifling - I think you’ll need a threaded barrel and a properly designed muzzle brake to disperse all that unburnt powder goodness…

Why would I want to disperse the unburnt powder to the sides?

I am checking MGM, I have the options selected. I just need them to confirm the barrel is long enough to accommodate a forend.

 

[Broc]

Disperse?
@Broc is looking for a hand cannon that doubles as a flame thrower
Punch a fist sized hole and cauterize it in a single operation.

This guy knows me.

 

[nm1]

This guy knows me.

Having a threaded barrel is all about options.

Some days you may feel like:

 

[Broc]

Having a threaded barrel is all about options.

Some days you may feel like:

No. I feel like sending it all down range.
But I might ask about threading it just in case.

 

[milktree]

I have no idea why your 2 examples have the same twist;

They don't.
The longer barrel (18") has the tighter twist of 1:16.
The shorter barrel (4") has the loose twist: 1:18

My real world examples are the opposite of what you're saying.

Think of it this way: once the the gun is fired and bullet is on it's way, it doesn't start twisting immediately. There's a little "skip" until it fully engages the rifling.

Sure, but that jump to the rifling is *VERY SHORT*, like 0.02" (for .308 win), which is basically zero compared to even a very short 12" barrel. Even if you include the entire bearing surface of the bullet as part of the "jump", it's still very short. But if the bullet doesn't spin at full speed almost instantly, in that first couple thousandths of an inch, the rifling on the bullet would be all smeared. And we know it doesn't do that by looking at fired bullets.

Let's use the example of the 223, because that's what I'm most familiar with. A 26" 1-8 twist will reliably shoot 82 Bergers. A 20" barrel wants a 1-7 to shoot the same bullet. What? Because it's possible the shorter barrel hasn't imparted its full twist to the bullet. The 26", because it's longer, and the bullet is in the barrel longer, has time to get that complete 1-8 twist.
Now compound that by comparing a 20" rifle barrel to a 10" pistol barrel.

What do you mean by "complete 1-8 twist"? It's a rate, not a 1:8 is 1:8 in a 4" barrel or a 24" barrel, or even a 1" barrel The bullet doesn't even need a full rotation to get the correct spin. (since it's rotations PER DISTANCE, not just "rotations")

I find the "hasn't imparted its full twist to the bullet" to ... sound like nonsense. It's impossible to spin the bullet slower than the rifling without smearing the surface of the bullet, which we know doesn't happen.

We're taking about pure, theoretical accuracy here, and extremely small degrees of difference.
Sound like bullshit? Probably is. But that's how it was told to me by someone who earns a living doing "barrel stuff".

It's his own snake oil that works?

Physics says unless the bullet is getting smeared, a bullet is going to spin at whatever rate the rifling twist is, regardless of length of the barrel.

It's not like you can shoot 88 grain bullets out of a 40' barrel with a 1:50 twist.

 

[KMM696]

Why would I want to disperse the unburnt powder to the sides?

I am checking MGM, I have the options selected. I just need them to confirm the barrel is long enough to accommodate a forend.

View attachment 883080

View attachment 883079

Love the order setup, but why not the 6 hole scope mount? If I ever saw a barrel build that deserved 2 extra screws, it's this one.

 

[PatMcD]

They don't.
The longer barrel (18") has the tighter twist of 1:16.
The shorter barrel (4") has the loose twist: 1:18

My real world examples are the opposite of what you're saying.



Sure, but that jump to the rifling is *VERY SHORT*, like 0.02" (for .308 win), which is basically zero compared to even a very short 12" barrel. Even if you include the entire bearing surface of the bullet as part of the "jump", it's still very short. But if the bullet doesn't spin at full speed almost instantly, in that first couple thousandths of an inch, the rifling on the bullet would be all smeared. And we know it doesn't do that by looking at fired bullets.




What do you mean by "complete 1-8 twist"? It's a rate, not a 1:8 is 1:8 in a 4" barrel or a 24" barrel, or even a 1" barrel The bullet doesn't even need a full rotation to get the correct spin. (since it's rotations PER DISTANCE, not just "rotations")

I find the "hasn't imparted its full twist to the bullet" to ... sound like nonsense. It's impossible to spin the bullet slower than the rifling without smearing the surface of the bullet, which we know doesn't happen.



It's his own snake oil that works?

Physics says unless the bullet is getting smeared, a bullet is going to spin at whatever rate the rifling twist is, regardless of length of the barrel.

It's not like you can shoot 88 grain bullets out of a 40' barrel with a 1:50 twist.

I know what bullet jump is. That's not what I said.
I said the rifling doesn't immediately start that bullet spinning at 1-7 (or whatever) as soon as it "engages". It takes a short distance.
Dont believe me. I don't care. Like I said; it kinda sounds like bullshit. But, that doesn't mean there's not some truth to it. Again, we're taking about minute degrees.

Going back to your examples, the lo ger barrel (rifle) may have a tighter twist because it's more likely a rifle will be using heavier bullets.

Heavier bullets-tighter twist. We can talk about that too, if you think it's incorrect.

 

[nm1]

Why would I want to disperse the unburnt powder to the sides?

I am checking MGM, I have the options selected. I just need them to confirm the barrel is long enough to accommodate a forend.

View attachment 883080

View attachment 883079

This is a good example of what one looks like:

SSK Thompson Center Encore stainless 12” .458 Lott 458 WinMag pistol barrel - TC Contender Barrels at GunBroker.com : 1037099035

Buy SSK Thompson Center Encore stainless 12” .458 Lott 458 WinMag pistol barrel: GunBroker is the largest seller of TC Contender Barrels TC Contender Parts Gun Parts All: 1037099035

www.gunbroker.com

Looking at it - there looks to be a min length below which you’re looking at custom forends since you’re too close to the forward screw.

 

[Broc]

This is a good example of what one looks like:

SSK Thompson Center Encore stainless 12” .458 Lott 458 WinMag pistol barrel - TC Contender Barrels at GunBroker.com : 1037099035

Buy SSK Thompson Center Encore stainless 12” .458 Lott 458 WinMag pistol barrel: GunBroker is the largest seller of TC Contender Barrels TC Contender Parts Gun Parts All: 1037099035

www.gunbroker.com

Looking at it - there looks to be a min length below which you’re looking at custom forends since you’re too close to the forward screw.

Yes, I got an Email back.


"For a rifle, shotgun or muzzleloader forend, you would need 13" in barrel length. For a 7" barrel you would have to cut and modify one of these forends to work. The standard pistol forend would not work with a 1" bull barrel either unless you cut/sand out the barrel channel to 1". The heavy factory contour would need no modification to the forend but you do run the risk of stripping out the forend holes from recoil. Please let me know if you have any other questions."

 

[chris_1001]

Yes, I got an Email back.


"For a rifle, shotgun or muzzleloader forend, you would need 13" in barrel length. For a 7" barrel you would have to cut and modify one of these forends to work. The standard pistol forend would not work with a 1" bull barrel either unless you cut/sand out the barrel channel to 1". The heavy factory contour would need no modification to the forend but you do run the risk of stripping out the forend holes from recoil. Please let me know if you have any other questions."

I can help.

I have a dremel and some files.

 

[Broc]

I can help.

I have a dremel and some files.

I am checking to see if the standard pistol forend fits. Sanding the barrel channel to 1" is not hard.

 

[chris_1001]

I am checking to see if the standard pistol forend fits. Sanding the barrel channel to 1" is not hard.

What’s the current channel diameter?

A dowel and some sandpaper, and a bunch of strokes and prob good to go.

 

[jkelly1229]

View attachment 882854

Think thatll buff out?

Crazy fact i heard the other days something like men 29-54 are more likely to break a bone now that men 16-29

 

[Broc]

What’s the current channel diameter?

A dowel and some sandpaper, and a bunch of strokes and prob good to go.

I don't remember, I think around 0.8 or 0.7.

 

[nm1]

I think it was 0.8 with the chamber end being 1”

The factory forend was set up for a 10”+ barrel if both screws are used.

Pre COVID/while TC was still around there use to be multiple boutique stock makers that could make you a custom setup for whatever you had. Last time I looked most weren’t around anymore.

 

[milktree]

I know what bullet jump is. That's not what I said.
I said the rifling doesn't immediately start that bullet spinning at 1-7 (or whatever) as soon as it "engages". It takes a short distance.

How short? That implies that the bullet is "slipping" for some period, which would mean the grooves on the bullet are moving *around* the bullet, or the grooves on the bullet end up wider than the lands in the rifling. That would lead to a lot of gas blow-by.

That bullet better be up to the full twist rate almost instantly or there will be lots of bullet deformation and gas blow-by.

The bullet when it first touches the rifling is moving really slow compared to muzzle velocity even on little snub-nose revolvers. It's not like the bullet has to go from zero to 330,000 RPM instantly, it does that over the course of the entire barrel length (assuming M193 @3259fps from a 20" barrel w/ 1:7 twist).

What's far more likely is that the bullet slows down just a smidge as it touches the rifling so the pressure can build up enough to force it through and cut the grooves.

I guess it's possible there's some elastic deformation of the bullet when it first hits the rifling and the bullet recovers, but even that would happen *really fast*, we're still talking about copper

Going back to your examples, the longer barrel (rifle) may have a tighter twist because it's more likely a rifle will be using heavier bullets.

That doesn't really make sense. It's .357 Magnum. There's a limit to how heavy or light a bullet you can get, and they're all used in handgun rounds too. People regularly shoot 158gr .357 Mag. bullets out of 4" barrels.

Heavier bullets-tighter twist. We can talk about that too, if you think it's incorrect.

Technically it's *LONGER* bullets: tighter twist, because longer bullets have a longer lever arm for the wind/air to push on. But "heavier" is a good proxy because the two go together (assuming the same material). A solid copper bullet will require tighter twist than a lead core for the same weight, because the copper one will be longer. And, yes, "longer" is in relation to diameter. .22 bullets require a lot more twist than .30 bullets of the same weight because the length:diameter ratio is higher.

 

[CrackPot]

What twist rate would you go with on the barrel?

Bullets = 350gr plated Berry's

I was looking online, most forums say the 458 typically uses a 1:14, but some companies sell 1:20, 1:24. I checked the Winchester Model 70 and their rifle is 1:12.

But this is for a short barrel, so I need the smart people to tell me what is a good twist rate.

FAQ:
1. Broc, why? - Because I can.

If you are going to commit public suicide, can you at least update your will so I get everything of yours except your hi-points and 40 cals?

 

[Broc]

If you are going to commit public suicide, can you at least update your will so I get everything of yours except your hi-points and 40 cals?

You are only getting the hi-point. But it will be awesome by the time you get it, if we ever finish milling the slide.

 

[PatMcD]

How short? That implies that the bullet is "slipping" for some period, which would mean the grooves on the bullet are moving *around* the bullet, or the grooves on the bullet end up wider than the lands in the rifling. That would lead to a lot of gas blow-by.

That bullet better be up to the full twist rate almost instantly or there will be lots of bullet deformation and gas blow-by.

The bullet when it first touches the rifling is moving really slow compared to muzzle velocity even on little snub-nose revolvers. It's not like the bullet has to go from zero to 330,000 RPM instantly, it does that over the course of the entire barrel length (assuming M193 @3259fps from a 20" barrel w/ 1:7 twist).

What's far more likely is that the bullet slows down just a smidge as it touches the rifling so the pressure can build up enough to force it through and cut the grooves.

I guess it's possible there's some elastic deformation of the bullet when it first hits the rifling and the bullet recovers, but even that would happen *really fast*, we're still talking about copper


That doesn't really make sense. It's .357 Magnum. There's a limit to how heavy or light a bullet you can get, and they're all used in handgun rounds too. People regularly shoot 158gr .357 Mag. bullets out of 4" barrels.


Technically it's *LONGER* bullets: tighter twist, because longer bullets have a longer lever arm for the wind/air to push on. But "heavier" is a good proxy because the two go together (assuming the same material). A solid copper bullet will require tighter twist than a lead core for the same weight, because the copper one will be longer. And, yes, "longer" is in relation to diameter. .22 bullets require a lot more twist than .30 bullets of the same weight because the length:diameter ratio is higher.

All I know is what I've learned by being a competitive rifle shooter for 20+ years, and by talking to barrel manufacturers and precision rifle builders while engaging in that sport.
Heavier bullets ("longer" if you must) require a faster twist for optimal accuracy.
Longer barrels "may" NOT require as fast a twist to realize that same optimal accuracy.

Again, as to the twist differences for the 357mag example, I have no idea. I don't play with those. I'll probably get jumped all over for this, but that caliber isn't really used for any sport/use that requires precision, so it probably doesn't matter.