Let's talk about High pressure catridges. taking the 308 win to 62000psi (saami max)

The Spirit

The Spirit

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Mar 15, 2021
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#1
Hello people
I think that 308 win can/need have a refresh by closing the bore. Is it so dangerous push a 308 to 62000 psi?
why?
it is a popular catridge around the world, and changing the barrel and using the same catridge of always you can reach a performance similar to 300 win mag.
Yeah, burns the barrel, yeah but death also exist
i know exist 277 fury and creedmore, but in other parts of the world we have in hand the good ol' boy of always, the 308 win.

in my stimations you can reach 3000 fps with 180gr and 3227 with 155.5 at 25"
i see your coments
 
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#2
Just buy a cartridge that does what you want without needing a saami redesign.

SAAMI is just a recommended, voluntary standard. You are free to order a barrel with a tighter bore, or load ammunition hotter than they recommend. You do so at your own risk.

But, no ammo manufacturer is going to deviate from SAAMI and risk someone putting the ammo into a rifle that can't handle the pressure. And SAAMI will never raise their recommended pressure for the same reason. Which answers the "why" in your question.
 
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#3
Rio Precision Gunworks said:
Just buy a cartridge that does what you want without needing a saami redesign.

SAAMI is just a recommended, voluntary standard. You are free to order a barrel with a tighter bore, or load ammunition hotter than they recommend. You do so at your own risk.

But, no ammo manufacturer is going to deviate from SAAMI and risk someone putting the ammo into a rifle that can't handle the pressure. And SAAMI will never raise their recommended pressure for the same reason. Which answers the "why" in your question.
Click to expand...
Thank you. But with a hand load. I mean take the 308 to 62000psi nothing more. Saami is just max dangerous pressure? i have heard, just heard that rifle are designed about 20% stronger to resist pressure well. In this case it would be 52000(51666) of pressure.
 
#4
The Spirit said:
Thank you. But with a hand load. I mean take the 308 to 62000psi nothing more. Saami is just max dangerous pressure? i have heard, just heard that rifle are designed about 20% stronger to resist pressure well. In this case it would be 52000(51666) of pressure.
Click to expand...

SAAMI is max pressure in which most every rifle can function. The lowest common denominator. If you run 62k psi in any rifle, it should be fine barring any problems with the rifle and such.

Actions and such are designed to sustain X amount of PSI. You'd have to look into individual manufacturers to get their specs. However, they will all be well above max SAAMI pressure.


So, yes, you won't have any issue running 62k psi. Rifles won't start exploding right as the reach SAAMI or a little over.
 
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#8
The Spirit said:
Thank you. But with a hand load. I mean take the 308 to 62000psi nothing more. Saami is just max dangerous pressure? i have heard, just heard that rifle are designed about 20% stronger to resist pressure well. In this case it would be 52000(51666) of pressure.
Click to expand...
You wanna blow up the gun and yourself?

Godspeed. Look up what happened to KentuckyBallistics when he pushed the envelope with a 50 cal
 
#9
The Spirit said:
in my stimations you can reach 3000 fps with 180gr and 3227 with 155.5 at 25"
Click to expand...
Splain to me how your doing that? I've ran triplex powder loads in a 308 and have never achieved anything close to those numbers. Even with way past book loads of H-380 & H-4350 I've seen huge increases in speed to the point when you open the bolt the primer falls out (of the best brass built)do to max/max brass pressure vs time.
Give us the data on the loads you're using to allow 3K fps with a 180gr want ever from a 308 win.
 
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#12
TheBigCountry said:
You wanna blow up the gun and yourself?

Godspeed. Look up what happened to KentuckyBallistics when he pushed the envelope with a 50 cal
Click to expand...
Yeah i saw that, but he did somwthing different, he putted other type of bullet inside the chamber in a pretty cheap 50 cal
Gunfighter14e2 said:
Splain to me how your doing that? I've ran triplex powder loads in a 308 and have never achieved anything close to those numbers. Even with way past book loads of H-380 & H-4350 I've seen huge increases in speed to the point when you open the bolt the primer falls out (of the best brass built)do to max/max brass pressure vs time.
Give us the data on the loads you're using to allow 3K fps with a 180gr want ever from a 308 win.
Click to expand...
the bor of a 308 is .30, so go to .28 or may be .271,that where i think my numbers goes totally wrong. But with the force of that pressure i can reach that speeds i stimate
 
#13
The Spirit said:
Yeah i saw that, but he did somwthing different, he putted other type of bullet inside the chamber in a pretty cheap 50 cal

the bor of a 308 is .30, so go to .28 or may be .271,that where i think my numbers goes totally wrong. But with the force of that pressure i can reach that speeds i stimate
Click to expand...
No, he played with fire and got burnt. Kinda like what your implying….

So you wanna stuff a 28 or 271 bullet in the bore?

Tell me your trolling us, because nothing your saying is making any sense

If you want magnum performance, step up to a 300 Win or 300 Norma like someone else stated
 
#15
TheBigCountry said:
No, he played with fire and got burnt. Kinda like what your implying….

So you wanna stuff a 28 or 271 bullet in the bore?

Tell me your trolling us, because nothing your saying is making any sense

If you want magnum performance, step up to a 300 Win or 300 Norma like someone else stated
Click to expand...

The bore size for a .308 is .300.

He's talking about taking the bore size smaller. But you'd only be looking at something like .298 or .299.

Smaller bore = more built up pressure = more speed.
 
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#19
Rio Precision Gunworks said:
The bore size for a .308 is .300.

He's talking about taking the bore size smaller. But you'd only be looking at something like .298 or .299.

Smaller bore = more built up pressure = more speed.
Click to expand...
how you calculate that? im using an excel and adjusted 2711 fps for 180 gr and calculated the pressure for a 20 inch barrel. But doesnt soud convincent. anyways it is a big improvement, raise the bc because has an smaller radius.
 
#20
www.snipershide.com

.308 high pressure?

I started to play with some .308 loads this weekend. I'm using 43.5 grains Ramshot Tac and pushing a 168 Sierra Matchking. I chrono'd the loads and came up with about 2800 FPS. This seems a little hot to me and is significantly faster than the speeds published on Western Powders website with...
www.snipershide.com www.snipershide.com
 
#21
TheBigCountry said:
No, he played with fire and got burnt. Kinda like what your implying….

So you wanna stuff a 28 or 271 bullet in the bore?

Tell me your trolling us, because nothing your saying is making any sense

If you want magnum performance, step up to a 300 Win or 300 Norma like someone else stated
Click to expand...
I've ran a 30-06 with in 100fps of average 300wm factory (& some as fast as) but the numbers he is stating, in a 308 win, I want to see it first hand.
 
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#22
The Spirit said:
how you calculate that? im using an excel and adjusted 2711 fps for 180 gr and calculated the pressure for a 20 inch barrel. But doesnt soud convincent. anyways it is a big improvement, raise the bc because has an smaller radius.
Click to expand...

Calculate what? SAAMI bore size is usually .300 for .308 projectiles. And anytime you decrease bore size, pressure goes up. No calculation needed to know that it's going to go up.

I'd strongly advise you to stop now and work on learning more. You can't just decrease bore size and increase BC as well as speed. It's not that simple. And it definitely doesn't happen without raising pressure significantly.
 
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#24
The Spirit said:
how you calculate that? im using an excel and adjusted 2711 fps for 180 gr and calculated the pressure for a 20 inch barrel. But doesnt soud convincent. anyways it is a big improvement, raise the bc because has an smaller radius.
Click to expand...
Raising the BC will lower friction, to a point. However lower friction also lowers pressure, even when using a 299 or 298 bore
 
#25
Rio Precision Gunworks said:
Calculate what? SAAMI bore size is usually .300 for .308 projectiles. And anytime you decrease bore size, pressure goes up. No calculation needed to know that it's going to go up.

I'd strongly advise you to stop now and work on learning more. You can't just decrease bore size and increase BC as well as speed. It's not that simple. And it definitely doesn't happen without raising pressure significantly.
Click to expand...
I suspect what he is doing is trying to extrapolate a rimfire or lead bullet "squeeze/swage bore" design onto a .308 while ignoring those are much lower pressure and a more malleable bullet.
 
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#29
I think some here are confusing bore dia. with groove dia. Normal 0.308" groove, 0.300" bore. Now then, a thinner land width might come into play with a smaller bore dia. for some imaginary (or real?) gain. The older 8x57 bore of 0.311" comes to mind.
 
#30
Rio Precision Gunworks said:
Calculate what? SAAMI bore size is usually .300 for .308 projectiles. And anytime you decrease bore size, pressure goes up. No calculation needed to know that it's going to go up.

I'd strongly advise you to stop now and work on learning more. You can't just decrease bore size and increase BC as well as speed. It's not that simple. And it definitely doesn't happen without raising pressure significantly.
Click to expand...
yeah, i know. But how much i need to reduce the bore.
Yeah, i'm learning that's why i'm asking. What do you advice? talk with a barrel maker? or a gunsmith? i'm using © 1993 Developed by Sam Raheb of Close Focus Research (CFR) but i see that has a problem with chamber pressure and muzzle pressure
 
#33
I've ran some 310's & 311's jacketed bullets from 54R & 7.62x39's in a Bartlein & Pacnor barreled 308, while there was a pressure increase it was not near as high as I thought it would have been. On the other end of the spectrum, running those same bullets in subsonic mode was eye opening, but not to be discussed openly here.
 
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#35
ok people, at 62000psi a bullet of 155.5gr goes at 3227 fps(in theory with a highly explosive powder)with a 0.3 land diameter, if i reduce the land diameter to 0.296 i have 63687psi with the same force used in 62000psi which is 4382.52 force-lb. Does the force which really breaks barrels or is it dangerous?
 
#36
I got to find the post, but if I understood it correctly, someone was using 277 fury cases, with the stainless case head, and getting high velocity with 30 cal bullets in the modified cases. (Maybe it was @45-90 ?)

Not exactly a 308.
But maybe those cases can be made for 308 so that 70,000 psi or higher is ok?

Got to find that post…
 
#37
Rio Precision Gunworks said:
The bore size for a .308 is .300.

He's talking about taking the bore size smaller. But you'd only be looking at something like .298 or .299.

Smaller bore = more built up pressure = more speed.
Click to expand...
Exactly.

What's scary is his statement about going to a "smaller" bore diameter;

the bor of a 308 is .30, so go to .28 or may be .271, that where i think my numbers goes totally wrong. But with the force of that pressure i can reach that speeds i stimate

He clearly does not have any grasp of numbers as they relate to dimensions. He's in the neighborhood of .029" off (.300" - .271" = .029").

An accident that is in the final stages of finding a place to happen.......
 
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#38
Threadcutter308 said:
Exactly.

What's scary is his statement about going to a "smaller" bore diameter;

the bor of a 308 is .30, so go to .28 or may be .271, that where i think my numbers goes totally wrong. But with the force of that pressure i can reach that speeds i stimate

He clearly does not have any grasp of numbers as they relate to dimensions. He's in the neighborhood of .029" off (.300" - .271" = .029").

An accident that is in the final stages of finding a place to happen.......
Click to expand...
was a miscalculation
this would be similat to a landing bullet in the air from a 308 win

 
#41
Advice it give for OP, sounds more good it augment powder for the more pressurize. Makes the moar sense than the dig onto copper jacket tighter bore. Procure one drop tube for the excellent case filling. One full case most popular Varget crunch crunch= good ol’ boy makes magnum improvements.
 
#42
I have taken the 308 to 80,000 + psi with hybrid cases...like 168 gr to 3255 fps in a 30" 308 win, and 200 gr SMK at 2951 fps
The Spirit said:
Hello people
I think that 308 win can/need have a refresh by closing the bore. Is it so dangerous push a 308 to 62000 psi?
why?
it is a popular catridge around the world, and changing the barrel and using the same catridge of always you can reach a performance similar to 300 win mag.
Yeah, burns the barrel, yeah but death also exist
i know exist 277 fury and creedmore, but in other parts of the world we have in hand the good ol' boy of always, the 308 win.

in my stimations you can reach 3000 fps with 180gr and 3227 with 155.5 at 25"
i see your coments
Click to expand...
So can you reach it and is practical for you?
I do not shoot 180s in 308.
But I shoot 200 gr SMK with standard Lapua brass 2740 in 22" 2856 in 30" 2673 in 18" AR 10.
155 gr will go 3100 fps in 22" 308 bolt gun
230 gr SMK 2550 fps in 22"
Fastest smokin load is 3256 fps for 168 gr Long Action feeds 3.4" cartridges from the detachable box, 8 twist 30" heavy palma, hybrid cases.
Or 2952 fps 200 SMK .715 BC in the 30" with hybrid cases.
Can you do this or should you do?
Short answer...No.
I build these rifles, so it's not just load data, and hybrid cases. I was going for the 250 Atip at 2500fps but throating makes it a one bullet rifle mag feed, and 2400 fps is doable now, but it takes alot of powder to push a 250 gr bullets an extra 100 fps faster, requires a lot of time testing and evaluating existing powders.
The 230s are 2620 fps without hybrid cases and 225 are 2675 fps in the 8 twist 30".

But the 308 can be substantially improved upon with standard and factory chambers...cause I do that too, and post to that fact.
But too many eager beavers lacking common sense, and know everything "dudets" with rude behavior, makes it difficult to share knowledge, or what one has learned in 308 high performance loads.
 
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#45
Gunfighter14e2 said:
OK I'll bite, where does one find these hybrid cases? Or just tell me the metal used & I''ll whittle some out on my lathe.
Click to expand...
Yep, military 6.8X 51 is the head stamp on the case ...civilians have the 277 Fury in 2 varieties, all brass and hybrid SS heads ...not likely that you'll whittle some out on the lathe.
But you can buy them, not always readily available, like most everything else. But they can be formed to 308, 6.5 CM, 358 win, as I have, or any 308 based cartridge, 277 length or shorter. They appear like these with the marked ladder load for the case. Yep some 308 loads contain 55 grs of powder, they have more capacity than brass cases. Live and learn...the cartridge world is changing. Better powder blends are needed to make these really go like the 277 powder used in military cases. The military is running machineguns with these 80,000 psi loads.
The 6.5 CM will run 140s at 3156 fps 24" barrel and the 308 will run 200 SMK 715 BC to 2952 fps. And 168s to 3256 fps.in long barrels, and 4000 ft-lb of energy out of a 308 case.
So who needs the big old full brass style magnums? Big magnums could be much smaller in size and be more powerful, in hybrid form.
Similar performance less powder and brass...if all this moves forward. Or dies on the vine... but the 277 hybrid case and 80,000 psi is the real deal.
These cases will take more than 80,000 psi with ease... so be careful with any endevor you pursue, in the hybrid case arena.
For educational purposes only, enter at your own risk.
Definitely not a place for morons, and nothing can beat the Hornady’s "New" lines of ARC. & PRCs ..it says do on the box, and in their advertising, & ballistics hype talks, propaganda, & charts...but none of its new or improved...but the hybrid case and 80,000 psi IS...
 

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#46
45-90 said:
I have taken the 308 to 80,000 + psi with hybrid cases...like 168 gr to 3255 fps in a 30" 308 win, and 200 gr SMK at 2951 fps
Click to expand...

How are you measuring pressure? Pressuretrace?

Gunfighter14e2 said:
OK I'll bite, where does one find these hybrid cases? Or just tell me the metal used & I''ll whittle some out on my lathe.
Click to expand...

IIRC, hopelite had started on some machined alternate material cases before they ... disbanded( is that the polite word?). Wait, no, they were 3D printed stainless. I'm sure the posts are still floating around here somewhere...
 
#48
TheOfficeT-Rex said:
How are you measuring pressure? Pressuretrace?



IIRC, hopelite had started on some machined alternate material cases before they ... disbanded( is that the polite word?). Wait, no, they were 3D printed stainless. I'm sure the posts are still floating around here somewhere...
Click to expand...

3d printed stainless. Likely would end up needing to be a hybrid. Stainless steel neck and shoulder is hard to work with.
 
#49
Gunfighter14e2 said:
I've ran some 310's & 311's jacketed bullets from 54R & 7.62x39's in a Bartlein & Pacnor barreled 308, while there was a pressure increase it was not near as high as I thought it would have been. On the other end of the spectrum, running those same bullets in subsonic mode was eye opening, but not to be discussed openly here.
Click to expand...
I think I'd be shaking like a dog trying to shit a peach pit before pulling the trigger on my 308 with my 303B .311-.312 bullets! :ROFLMAO:
 
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#50
FredHammer said:
I think I'd be shaking like a dog trying to shit a peach pit before pulling the trigger on my 308 with my 303B .311-.312 bullets! :ROFLMAO:
Click to expand...
Naw, running those bullets is no different than a 308 bullet in a 299 or 298 bore, running high speed. In subsonic mode is where it gets interesting.
 
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