Rethinking 308 winchester

T

The Spirit

New member
Rethinking 308 winchester(I need someone to contrast my numbers with other software)

Hi Forum
I hope that you are fine.
I'm planning to put a 308 win into a custom barrel with 308 Winchester chamber and a bore of 7.00mm instead of 7.62 one, to make fly a 7.00mm bullet. According to my modulations says that slow powder like Reload Swiss RS 76 with 54.23gr of propellant goes about 66k psi or 61k psi using a bullet of 155.5gr of solid copper.
The idea it is to give a new air to 308 win that can keep all their advantages and get 7mm performance, also, a better cartridge with countries with not so much options of bullets, ar10 mag availability or without enthusiast gun culture.
From my opinion, i'm not thinking in something impossible, already exists catridges that has an exit area in the bore 10% smaller than the mouth of the the throat where the bolt touch the barrel in the front, many of them are very known and they are not wildcats. Yeah i know, i'm rising pressures.
Could you help me with this please?
I'm using Gordon's reloading tool. I'm waiting your help.

EDIT:
I DID AN UPDATE ABOUT THE LOAD.
 

Attachments

  • 2.png
    2.png
    400.4 KB · Views: 143
  • 3.png
    3.png
    402.5 KB · Views: 127
  • MODEL UPDATED.jpg
    MODEL UPDATED.jpg
    553.4 KB · Views: 122
Last edited:
Sound like you want a 7mm-08.

But a tapered bore to reduce the size seems like a good way to mess up up the bullet profile and bc in an inconsistent manner real fast.

and doing in in solid copper will make it even worse.
 
Sound like you want a 7mm-08.

But a tapered bore to reduce the size seems like a good way to mess up up the bullet profile and bc in an inconsistent manner real fast.

and doing in in solid copper will make it even worse.
Click to expand...

Yeah, but here in my country the rabbit it is the 308, or things for 308 Winchester. The idea it is to do a cartridge with a bullet design that can go out with 7.00m using a 7.82mm bullet with accuracy. So you just need to change the barrel and do handload.
 
Last edited:
7mm-08 already exists. Is it what you are trying to do?

You have a custom made barrel with tighter bore near the muzzle. I read it helps accuracy. But 10% sounds a lot. 0.7mm. <0.1mm or 1.5% sounds more reasonable.

Are you hunting rabbits for meat or to get rid of them. There is probably not much meat left after hitting a rabbit with 7mm-08. .22lr probably works better.

-TL

Sent from my SM-N960U using Tapatalk
 
tangolima said:
7mm-08 already exists. Is it what you are trying to do?

You have a custom made barrel with tighter bore near the muzzle. I read it helps accuracy. But 10% sounds a lot. 0.7mm. <0.1mm or 1.5% sounds more reasonable.

Are you hunting rabbits for meat or to get rid of them. There is probably not much meat left after hitting a rabbit with 7mm-08. .22lr probably works better.

-TL

Sent from my SM-N960U using Tapatalk
Click to expand...
Yes. I know but here doesnt exist 7mm-08 here
The 308 win it is the thing that you always see here.
The idea it is for long range and precision shooting.

Nobody counts that the magic it is the very slowpowder here.
 
I'm struggling to understand what you are trying to do.

You have a .308 win chamber, so a normal .308 round can be chambered. But the bore is 7mm with 7.05mm groove diameter. The 7.62mm bullet will get swaged down to 7.05mm by the force of the propellant. Correct?

I have to say... the idea is crazy as an out house rat. Don't do it! You are not hunting the wabbit. You are hunting yourself. It is going to be very accurate. The first round you fire, you will be gone.

-TL

Sent from my SM-N960U using Tapatalk
 
I have to say... the idea is crazy as an out house rat. Don't do it! You are not hunting the wabbit. You are hunting yourself. It is going to be very accurate. The first round you fire, you will be gone.
Click to expand...

Amen, and Amen.
 
i'm not thinking in something impossible, already exists catridges that has an exit area in the bore 10% smaller than the mouth of the the throat where the bolt touch the barrel in the front, many of them are very known and they are not wildcats.
Click to expand...

Not known to me, please name a few.

Yes, I am familiar with the Gerlich principle.
Yes, I know the work P.O. Ackley did


I think squeezing down a solid copper bullet from 7.82 to 7.0 mm would be dangerous.

I think you have taken GRT beyond the range that it can accurately simulate a real gun.
 
Ok I understand 7mm-08 is not available where you live.

But you can get custom barrels made right? So buy a reamer for a 7mm-08 and have them cut you the chamber.

then make 7mm-08 brass from 308 brass. You just size it with 7mm-08 dies, trim the neck, and turn the neck. Then you have 7mm-08 brass.

What country do you live in?
 
Shadow9mm said:
Ok I understand 7mm-08 is not available where you live.

But you can get custom barrels made right? So buy a reamer for a 7mm-08 and have them cut you the chamber.

then make 7mm-08 brass from 308 brass. You just size it with 7mm-08 dies, trim the neck, and turn the neck. Then you have 7mm-08 brass.

What country do you live in?
Click to expand...
I live in chile. Do you have a software yo contrast my numbers please?
 
I do not know of any software that can do what you want. None that I know of are designed or intended to allow for an internally tapered bore. I also think your gunsmith will have a very very hard time trying to make a barrel like this.
 
Shadow9mm said:
I do not know of any software that can do what you want. None that I know of are designed or intended to allow for an internally tapered bore. I also think your gunsmith will have a very very hard time trying to make a barrel like this.
Click to expand...
where it is supposed where the bullet has to touch the rifling in 308win at 2.2in??
 
I think there is more than a little miscommunication in this discussion.

The Spirit: Are you asking about a tapered barrel, or are you asking about a barrel that is bored and rifled for caliber 7.00 mm with a short transition (similar to the forcing cone of a revolver) immediately ahead of the chamber?

¿Pregunta por un cañón cónico o por un cañón perforado y estriado para el calibre 7,00 mm con una transición corta (similar al cono de forzamiento de un revólver) inmediatamente por delante de la recámara?

You wrote:

From my opinion, i'm not thinking in something impossible, already exists catridges that has an exit area in the bore 10% smaller than the mouth of the the throat where the bolt touch the barrel in the front, ...
Click to expand...

Where the bolt touches the barrel is at the rear -- the mouth of the chamber. The bolt does not come anywhere near the front of the chamber, the neck, the throat, or the leade.

I agree with whoever it was above who suggested using .308 brass and resizing the neck to 7 mm.
 
Aguila Blanca said:
I think there is more than a little miscommunication in this discussion.

The Spirit: Are you asking about a tapered barrel, or are you asking about a barrel that is bored and rifled for caliber 7.00 mm with a short transition (similar to the forcing cone of a revolver) immediately ahead of the chamber?

¿Pregunta por un cañón cónico o por un cañón perforado y estriado para el calibre 7,00 mm con una transición corta (similar al cono de forzamiento de un revólver) inmediatamente por delante de la recámara?

You wrote:



Where the bolt touches the barrel is at the rear -- the mouth of the chamber. The bolt does not come anywhere near the front of the chamber, the neck, the throat, or the leade.

I agree with whoever it was above who suggested using .308 brass and resizing the neck to 7 mm.
Click to expand...
a barrel that is bored and rifled for caliber 7.00 mm with a short transition
 
You want a 7mm-08.

I don't think you even need a forming die, just size your 308 Winchester brass in a 7mm-08 sizing die and trim -done.
 
SDDL-UP said:
You want a 7mm-08.

I don't think you even need a forming die, just size your 308 Winchester brass in a 7mm-08 sizing die and trim -done.
Click to expand...
That's what i have been saying! OP Is saying 7mm-08 is not something they have in their country. But they are getting a custom barrel made and reloading. So buy 7mm-08 reamers ahd have your barrel chambered, and make brass from 308 brass.

The whole idea of a short throat/forcing cone wont work.
 
I think he is also saying 7mm bullets are not available, but not sure.

That said, you can do a lot with a plain 308 win. I would try that in a 10 twist with light copper bullets for best results or 10-11 twist and 168-180gr std match bullets.
 
You must log in or register to reply here.
Back
Top