+P chamber throats

[Frank Green]

So, I'm throwing this out here and I'm going to be very blunt about it and I'll also make a post on accurate shooter even though I'm not on there a lot.

Here is my stance on +P chamber throats. You're cutting away the height of the lands as well as making the throat longer (as much as another .750" from what we've seen) as I understand it and from what I've seen in several barrels customers have sent back to us. So, guys think they can run a heavier powder charge and keep pressures down etc... to get more velocity. Ok fine but by doing that you can expect it to have a negative impact on barrel life/accuracy.

This is another variable beyond our control. You want to put a bigger camshaft in your cars engine and a bigger carburetor I get it but then you add nitro methane in your gas tank or put nitrous on it as well to go even faster.... there is a tradeoff for going faster and doing things like this. You don't get to eat your cake and keep it to.

So, I've told all my guys in the office here... I will not warranty any barrel that a customer thinks the barrel died early etc... and they are running a +P chamber set up.

Later, Frank
Bartlein Barrels

 

[ohiofarmer]

It’s sad that common sense seems to be lost on so many. Even in this hobby.

 

[MOUNTIC]

So, I'm throwing this out here and I'm going to be very blunt about it and I'll also make a post on accurate shooter even though I'm not on there a lot.

Here is my stance on +P chamber throats. You're cutting away the height of the lands as well as making the throat longer (as much as another .750" from what we've seen) as I understand it and from what I've seen in several barrels customers have sent back to us. So, guys think they can run a heavier powder charge and keep pressures down etc... to get more velocity. Ok fine but by doing that you can expect it to have a negative impact on barrel life/accuracy.

This is another variable beyond our control. You want to put a bigger camshaft in your cars engine and a bigger carburetor I get it but then you add nitro methane in your gas tank or put nitrous on it as well to go even faster.... there is a tradeoff for going faster and doing things like this. You don't get to eat your cake and keep it to.

So, I've told all my guys in the office here... I will not warranty any barrel that a customer thinks the barrel died early etc... and they are running a +P chamber set up.

Later, Frank
Bartlein Barrels

Rokslide and Long Range Hunting is probably where a lot of the +P guys come from and would good to post there if too, if able.

 

[Frank Green]

Rokslide and Long Range Hunting is probably where a lot of the +P guys come from and would good to post there if too, if able.

I'm on LRH once in a blue moon but thanks for the thought. I will go there and make a post.

There are a lot of forums and it's hard to be on all of them.

 

[M4orturnate]

Who woulda thought higher heat and pressure would lessen barrel life. Huh

 

[Supersubes]

Who woulda thought higher heat and pressure would lessen barrel life. Huh

Right? Shocking!

 

[giumau1]

Would someone school me about what a P chamber is?

 

[Supersubes]

Would someone school me about what a P chamber is?

Its a stepped leade, where the first bit of bullet engraving is only doing so into partial height rifling.

There are quite a few variations on this.

 

[Long Range 338]

Would someone school me about what a P chamber is?

Its a bit of a gimmick. As Frank described, the lands are machined down for less bullet engraving to give the bullet less friction upon ignition. Then more powder is added because the initial pressure is lower. Guys are using this to boost muzzle velocities.

 

[Long Range 338]

I have wondered how long it was going to take before there were reports of short barrel life and people demanding their barrels be replaced. It doesn't occur to people that you are replacing the normal wear pattern that takes a few hundred rounds with a machined feature that does the exact same thing? LOL

 

[Frank Green]

Would someone school me about what a P chamber is?

Someone can correct me if I'm wrong but here is basically what is being done....

They cut away part of the land height in front of the chamber area (as much as 50%... remember the height of the land on average in most calibers is .0025" to .004") and they make the throat longer. Guys .0025" or so is the thickness of a human hair.

By doing this they are maybe to some extent dropping the pressure and in turn they feel they can run a heavier powder charge to get more velocity. Picture WBY chambers. They have really long throats.

But by doing this your shortening the usable throat life of the chamber. No way around it.

I'll lump the bore rider reamers in with this as well. Top F class shooters and the BR shooters all have been consistent in saying..... they can't keep the barrel in tune for a longer period of time as it's changing to fast because of the wear. Top F class guys and the BR shooters have pretty much given up on the bore rider reamer/chambers.

You won't see one of these chambers in any of my guns.

You want to experiment knock yourself out but when it doesn't go according to plan.... your experiment isn't my problem.

Think of this guys....if these chamber designs are so good...how come none of the bullet makers or ammo makers are doing testing with it or use it in testing for accuracy etc....?

 

[SmartDonkey]

Today is the first day that I have ever heard of a +P chamber- so this may be a dumb question- but a custom reamer (for example a 300 win for shooting heavies) would not be considered a +p chamber would it?

 

[Frank Green]

I have wondered how long it was going to take before there were reports of short barrel life and people demanding their barrels be replaced. It doesn't occur to people that you are replacing the normal wear pattern that takes a few hundred rounds with a machined feature that does the exact same thing? LOL

^^^^^^^^^^^^

Exactly!

Then we get the complaint that it was bad steel or in cases of the BB material they felt it should've lasted longer. Either way.... your shortening the barrel life.

 

[Frank Green]

Today is the first day that I have ever heard of a +P chamber- so this may be a dumb question- but a custom reamer (for example a 300 win for shooting heavies) would not be considered a +p chamber would it?

Not necessarily!

We have 300wm and other calibers with custom throats in them. That doesn't make them a +P chamber.

This brings up a good point when I/we get asked a question of..."I want a match chamber!" Define match chamber? Tight case neck? Shorter throat? Longer throat? Tight case body? What is a match chamber? What it means to one guy can mean something else to another guy.

 

[Long Range 338]

^^^^^^^^^^^^

Exactly!

Then we get the complaint that it was bad steel or in cases of the BB material they felt it should've lasted longer. Either way.... your shortening the barrel life.

Thanks for the thread Frank! I'll wager some internet butthurt is about to start..... I need to go get some popcorn now.

 

[Frank Green]

Thanks for the thread Frank! I'll wager some internet butthurt is about to start..... I need to go get some popcorn now.

Your welcome and yep it's coming but I'm done dealing with it. That's why I started the thread and why I said... I'm going to be blunt about it.

Probably have to put disclaimers on our invoice copies etc... that go out to customers and should put it on our website as well.

 

[Huskydriver]

That fudd life is strong...

 

[Taylorbok]

You cut away half the rifling height in the first inch of the barrel and the throat only lasts half as long....go figure.

 

[Mister Ridge]

Someone can correct me if I'm wrong but here is basically what is being done....

They cut away part of the land height in front of the chamber area (as much as 50%... remember the height of the land on average in most calibers is .0025" to .004") and they make the throat longer. Guys .0025" or so is the thickness of a human hair.

By doing this they are maybe to some extent dropping the pressure and in turn they feel they can run a heavier powder charge to get more velocity. Picture WBY chambers. They have really long throats.

But by doing this your shortening the usable throat life of the chamber. No way around it.

I'll lump the bore rider reamers in with this as well. Top F class shooters and the BR shooters all have been consistent in saying..... they can't keep the barrel in tune for a longer period of time as it's changing to fast because of the wear. Top F class guys and the BR shooters have pretty much given up on the bore rider reamer/chambers.

You won't see one of these chambers in any of my guns.

You want to experiment knock yourself out but when it doesn't go according to plan.... your experiment isn't my problem.

Think of this guys....if these chamber designs are so good...how come none of the bullet makers or ammo makers are doing testing with it or use it in testing for accuracy etc....?

Is that similar to the .223 Wylde chamber?

 

[MK20]

Is that similar to the .223 Wylde chamber?

Not really. Wylde has to do with freebore, and leade angle if I remember correctly.

These morons are actually cutting away rifling for speed.

 

[Frank Green]

Is that similar to the .223 Wylde chamber?

No 223 Wylde is a modified 223 chamber but throat design is still conventional/normal. I run the 223 Wylde chambers in my AR’s and I used that reamer in my sons 223 bolt gun.

 

[Terry Cross]

Your welcome and yep it's coming but I'm done dealing with it. That's why I started the thread and why I said... I'm going to be blunt about it.

Probably have to put disclaimers on our invoice copies etc... that go out to customers and should put it on our website as well.

So they are trying to play the Weatherby game but trying to avoid Weatherby issues?

I don't build hunting rifles per se but I refuse to play that game.
Weatherby standardized all of their older magnums with SAAMI that showed really long lead lengths. This was their way to do what the ballistic Karens are trying to do. Try to change the pressure curve to get more powder and higher velocity.

I thought it was hilarious that another shop I know of had a "long range hunter" pay them to build a custom rifle using a modified Weatherby chamber. His standard Weatherby SAAMI chambers weren't giving him the accuracy he wanted. For sure it was likely due to their long ass lead length on the SAAMI chamber.
So...... he talked the builder into ordering a Weatherby mag reamer with a shortened lead length for better accuracy....

Completed rifle could not fire factory Weatherby ammo without having to hammer the bolt open.
Who would have thunk it.
Dumb asses.

I know you know all this but I'm just venting to the great unwashed.
Sounds like you are dealing with the same ballistic Einsteins.

.

 

[Long Range 338]

So they are trying to play the Weatherby game but trying to avoid Weatherby issues?

I don't build hunting rifles per se but I refuse to play that game.
Weatherby standardized all of their older magnums with SAAMI that showed really long lead lengths. This was their way to do what the ballistic Karens are trying to do. Try to change the pressure curve to get more powder and higher velocity.

I thought it was hilarious that another shop I know of had a "long range hunter" pay them to build a custom rifle using a modified Weatherby chamber. His standard Weatherby SAAMI chambers weren't giving him the accuracy he wanted. For sure it was likely due to their long ass lead length on the SAAMI chamber.
So...... he talked the builder into ordering a Weatherby mag reamer with a shortened lead length for better accuracy....

Completed rifle could not fire factory Weatherby ammo without having to hammer the bolt open.
Who would have thunk it.
Dumb asses.

I know you know all this but I'm just venting to the great unwashed.
Sounds like you are dealing with the same ballistic Einsteins.

.

Weatherby: long leads, extra powder, and light for caliber bullets. “Just hold hair and it’s dead!”

 

[DocRDS]

Having had my own XP with internet tough guys who think they know more than myself in my field of expertise, I am surprised Frank doesn't just smack people in the head with a used barrel.

"I read it on the internet so it must be true"

Everybody's a genius on the internet....

Chasing that speed is gonna get you kilt.

 

[CoryT]

Does the warranty issue also cover use of C4 as a propellant? I have these cool idea for a 20,000 fps .338 using tungsten bullets...

 

[RTH1800]

So they are trying to play the Weatherby game but trying to avoid Weatherby issues?

I don't build hunting rifles per se but I refuse to play that game.
Weatherby standardized all of their older magnums with SAAMI that showed really long lead lengths. This was their way to do what the ballistic Karens are trying to do. Try to change the pressure curve to get more powder and higher velocity.

I thought it was hilarious that another shop I know of had a "long range hunter" pay them to build a custom rifle using a modified Weatherby chamber. His standard Weatherby SAAMI chambers weren't giving him the accuracy he wanted. For sure it was likely due to their long ass lead length on the SAAMI chamber.
So...... he talked the builder into ordering a Weatherby mag reamer with a shortened lead length for better accuracy....

Completed rifle could not fire factory Weatherby ammo without having to hammer the bolt open.
Who would have thunk it.
Dumb asses.

I know you know all this but I'm just venting to the great unwashed.
Sounds like you are dealing with the same ballistic Einsteins.

.

Exactly. Terry beat me to the post!

 

[Threadcutter308]

Does the warranty issue also cover use of C4 as a propellant? I have these cool idea for a 20,000 fps .338 using tungsten bullets...

Once.

 

[MK20]

That's called an EFP

 

[mbeavers1]

Does the warranty issue also cover use of C4 as a propellant? I have these cool idea for a 20,000 fps .338 using tungsten bullets...

Forget the warranty, ill buy the barrel if I can watch

 

[mick243]

so, what I'm hearing is that my 243win barrel is not actually burned out, its "naturally" +P'ed......

 

[DJL2]

It's... uh... hard for me to believe this is even a thing, to be honest.
Mr. High Speed: "Hey, how do barrels die?"
FG/TC/BL/et al: "Well, typically we see them die at the throat when the rifling fails to effectively engrave the projectile upon entry and the slippage causes damage to the jacket that degrades precision and affects BC/exterior ballistics. You often see a drop in pressure, and thus velocity, to accompany this."
Mr. HS: "Cool, cool, cool... so, I want to cut away my rifling AND run a longer/hotter pressure curve, that's good to go with no wear or longevity issues, right?"
F/T/B/all: "Did you even listen to what I said?"

I'm staggered by the number of folks in this game that don't understand pressure is what makes velocity. You can run it higher, you can run it longer, but if you're accelerating a bullet, you're using pressure to do it.

 

[912173]

I'm glad to see this brought up. I see lots of 300prc +p setups online and I always figured there has to be a downside.

 

[Triple BB]

Think of this guys....if these chamber designs are so good...how come none of the bullet makers or ammo makers are doing testing with it or use it in testing for accuracy etc....?

Don't know the answer, but I would think the fact that one person owns the patent vs a commercial barrel or rifle manufacturer probably has something to do with it. From a number's standpoint, it's probably not worth an ammo makers time to mess with it. I toyed with the idea of getting a +P mod to one of my rifles. The understanding was just as noted, barrel life would shortened and I'd get another barrel when things went south. I had a 300 RUM built and told my Smith I intended to run hot loads in the gun. He left as much metal as he could on the breech end with the thought that when barrel life started to deteriorate, I could come back and he'd recut everything and extend the life of the barrel. As long as you know what you're getting into, to each his own...

 

[mick243]

Does the warranty issue also cover use of C4 as a propellant? I have these cool idea for a 20,000 fps .338 using tungsten bullets...

funny you should ask.... IIRC, the explosive content of C4 is RDX.
some of the newer tank gun testing found that traditional single and double based powders lacked the energy content to get the desired results - so they added RDX to the mix.

I think that your 338 is going to need to be smooth bore, with sub caliber fin stabilised projectiles (tungsten is ok, but maybe whilst you're getting the RDX you could get some DU....)


be awfully fun to watch

 

[Average guy]

I'm on LRH once in a blue moon but thanks for the thought. I will go there and make a post.

There are a lot of forums and it's hard to be on all of them.

Hard to believe the shit people want to warranty. I burned up my barrel but you should give me a new one

 

[Taylorbok]

Hard to believe the shit people want to warranty. I burned up my barrel but you should give me a new one

It happens in every industry. I had a lady who wanted warranty on a snowmobile jacket because she fell in the fire and melted it.
Much to my reluctance I called the manufacturer for her.... They sent her a new one, they were a new company trying to earn business. I was pissed. That woman needed to learn.

 

[carbonbased]

It happens in every industry. I had a lady who wanted warranty on a snowmobile jacket because she fell in the fire and melted it.
Much to my reluctance I called the manufacturer for her.... They sent her a new one, they were a new company trying to earn business. I was pissed. That woman needed to learn.

Fell into a fire huh

 

[Rio Precision Gunworks]

The amazing part is when you see people who make posts on forums about chasing lands.....but then the same people go pay for a +P chamber to be cut.......