708.

[jackieschmidt]

Skip Talbot had that at their shop in Fallon in 1985. I don't know if your friend had it or it was already copied/claimed. But, that's a 1980's thing and I wish it would have been forwarded/patented with a twist suitable to super heavy 7mm bullets. No need whatsoever to limit it to 160 something bullets. The 7-08 will push 180-197 gr. bullets at competitive speeds.

Nothing it seems is really new. Since the Swede has been around for over 100 years, I suspect it’s been tried in about every configuration one can amagine.

It seems no die maker lists a 7mm/6.5x55 Ackley Die set. But send Redding 3 fired cases, and they will make them special order. That’s probably what I will do.

They do not even list a 6.5x55 Ackley body die. Just the standard case.

 

[std7mag]

Why not just do a 7X57AI?

 

[Mulligan]

Why not just do a 7X57AI?

What is the volume of the 7x57AI?
CW

 

[sandwarrior]

Why not just do a 7X57AI?

Because you can use Lapua Brass if you do the 6.5x55. That makes a huge difference in what you can do with the cartridge.

FWIW, just because it's 2mm shorter doesn't mean you lose case capacity either. The neck is shorter on the 6.5 and the body is wider as well. So, the actual capacities are about the same.

I'm not a huge fan of the 40 deg. shoulder (Ackley) case. The powder stack shoves into the sharp shoulder and compresses. It's all good, and very efficient, right up until you get to the top. When the stack 'compresses' during ignition, the burn rate goes up. Sometimes to the point of detonation. Think of it in motorhead terms. Detonation will destroy an engine (your rifle). when ignition is too soon the gas doesn't burn, it explodes.

It's the limited band range you work with at top pressures that bother me. People work up, it all looks good, then they BLOW primers. Thus the reason I like 30 deg. shoulders better is you still get good flow of pressure out of the case, while still increasing compression.

There are caveats to this, lower volume cases and closer neck to body diameter ratios help. .223 and 6mm BR based cases are prime examples.

 

[jackieschmidt]

Why not just do a 7X57AI?

lapua does not make brass fo it.

If they did, it would be great. Probably just The 7x57 with the case straightened out to a minimum taper and a 30 degree shoulder would be a great shooter.

 

[std7mag]

Peterson is asking what casings people would like to see.
I've already mentioned the 7X57 Mauser case.

 

[sandwarrior]

Peterson is asking what casings people would like to see.
I've already mentioned the 7X57 Mauser case.

As jackieschmidt said, the best thing would be to come up with a new cartridge with a straighter body and 30 degree shoulder, based off the 7x57. Fred Huntingdon also improved cases, but they never achieved the fame that Ackley did. His were typically a 28 deg. shoulder. Maybe he thought they were better, but nice round numbers make for far better marketing.

Added: Of note is that the 6.5x55 already has a 26 deg. shoulder. A little improvement to 30 will help and of course a much wider shoulder. Say .450" not too much less taper or it won't fit and feed out of anything built for 30-06 or .308.

 

[std7mag]

Sandwarrior,

At least it's not the 60° shoulder like the JDJ cartridges.

I need to call Stan Taylor & find out exactly one of his barrels is going to run me.

I will be using the 7mm-08 improved 40° reamer i got from PTG.

 

[sandwarrior]

Sandwarrior,

At least it's not the 60° shoulder like the JDJ cartridges.

I need to call Stan Taylor & find out exactly one of his barrels is going to run me.

I will be using the 7mm-08 improved 40° reamer i got from PTG.

Shave that back to 30 deg. while there's still time! ....

Just watch the top end. And use slow powders.

 

[std7mag]

I've had the reamer for a few years now.
Same one i chambered my Stevens 200 with.

As i've stated, my plan is to use the 160gr Sierra TMK. I could throat the barrel to shoot the 180gr Berger, but i'd rather not stress my cases, or action. I don't feel the case capacity supports it. (Just my belief)
Plan is something with a burn rate in the RL19 class.

 

[sandwarrior]

I've had the reamer for a few years now.
Same one i chambered my Stevens 200 with.

As i've stated, my plan is to use the 160gr Sierra TMK. I could throat the barrel to shoot the 180gr Berger, but i'd rather not stress my cases, or action. I don't feel the case capacity supports it. (Just my belief)
Plan is something with a burn rate in the RL19 class.

You are not stressing cases or action until you start loading too hot. I had to go back and see what you are all doing and noted that jackieschmidt is running a 1-9" twist. That probably won't cut it for 180's, but might. It does do it for 168's of the VLD flavor.

 

[std7mag]

Yeah, the 1:9 works with the 168gr VLD.

 

[rardoin]

1:9 is fine for the 180 hybrids. Some F open national champions will attest to that. I’ll qualify that statement assuming they are running near 2700fps and above.

 

[jackieschmidt]

As jackieschmidt said, the best thing would be to come up with a new cartridge with a straighter body and 30 degree shoulder, based off the 7x57. Fred Huntingdon also improved cases, but they never achieved the fame that Ackley did. His were typically a 28 deg. shoulder. Maybe he thought they were better, but nice round numbers make for far better marketing.

Added: Of note is that the 6.5x55 already has a 26 deg. shoulder. A little improvement to 30 will help and of course a much wider shoulder. Say .450" not too much less taper or it won't fit and feed out of anything built for 30-06 or .308.

I didn’t think of it at the time, but instead of using 7x57, you could start with the 6mm/244 Remington cases. Most of the major ammo manufacturers (except Lapua), make it. It’s parent case was the 7x57.

 

[sandwarrior]

1:9 is fine for the 180 hybrids. Some F open national champions will attest to that. I’ll qualify that statement assuming they are running near 2700fps and above.

I agree, I think the velocity gets enough spin on a projectile that it can stabilize it. I have a 1-9.5(?) twist 7x57 that won't stabilize 180's, but does stabilize 168's. I would assume most of those shooting the 180's are 7mm mag of some sort.

Mathematically, a projectile will spin 3285 RPS when launched from a 7x57 @ 2600 with a 1-9.5 twist. They are spinning @4050 from my 7mm-08 pushed at 2700 fps from a 1-8" twist. With either bullet I've been able to get stability through the transonic realm. Although, I cannot stabilize 175 or 180's. Added: D'oh!, in the 7x57

 

[std7mag]

I didn’t think of it at the time, but instead of using 7x57, you could start with the 6mm/244 Remington cases. Most of the major ammo manufacturers (except Lapua), make it. It’s parent case was the 7x57.

Simply because the parent case is the 7X57, or 8X57.
They have both been around a long time, and many countries still shoot/make them.

Plus they are usually less expensive.

 

[rardoin]

@sandwarrior

Predominantly .284’s running them at upper 2700’s to mid 2900 fps.

 

[std7mag]

I love my wife!
I mentioned that i didn't get to have any fun with my portion of our stimulus check.
She asked what i would have done with it.
Duh!!
Build my range gun.
How much do you need?
Told her.
I think we can work something out.

Yup, i luv my wife!!

In keeping with the thread, i'm that much closer to a 7mm-08AI again!!

 

[sandwarrior]

@sandwarrior

Predominantly .284’s running them at upper 2700’s to mid 2900 fps.

.284 Win?

 

[rardoin]

.284 Win?

Yes, straight and improved