Maybe I'm totally off base here, but on another forum a load got mentioned that just seemed totally nuts.

quote:

how does that compare to an 18" 3 groove 1/12 twist barrel shooting a 110 gr bullet at 3200fps like the 6.8spc will do?

now in my experiance a 270win has to be worked pretty damn hard to get those speeds in a 22" rifle bbl. The thought of a cartridge with about half the case capacity exceeding 270's ability in a shorter barrel leaves me to question the sanity of anyone who would shoot these loads.

Anyone care to speculate on what the chamber pressures involved would likely be

My software doesn't have the 6.8 in it. However if you take the velocity and pressure measurements from the Hogdgon site and extrapolate them you are in the 76,000PSI range.

Sounds Way too hot-dangerous. Speer 14 shows 2815 with 24" barrel and a 100 grainer as highest velocity recorded

Hodgdon gives 2697fps as the fastest velocity for a 110gr bullet & a compressed load of H322.
Pressure at 53,600psi.
I don't want to be near anyone who thinks they can get 3,200fps out of that combination.....

only way to get that velocity out of a 6.8 is with a 500 grain compressed load of blasto #2

quote:

Maybe I'm totally off base here, but on another forum a load got mentioned that just seemed totally nuts.

That's what you get from reading other forums.

It is certainly not too hard to get a 110-grain bullet up to 3200 FPS with the .270 Win. But, despite the efficiency deriving from its small capacity, I doubt that the 6.8 SPC will do it safely!

quote:

Originally posted by ramrod340:
My software doesn't have the 6.8 in it. However if you take the velocity and pressure measurements from the Hogdgon site and extrapolate them you are in the 76,000PSI range.

at least.....I'd forecast quite a bit more!

Shine it on and enjoy your 7.62x39. Haven't heard much of that lately. roger

quote:

Originally posted by bartsche:
Shine it on and enjoy your 7.62x39. Haven't heard much of that lately. roger

I haven't shot the bench 762x39 much lately, However I have some 100grn Lapua HP's on the way that may give me cause to remedy that situation.

NO, of late I've been shootin the pee out of my new 7.62x39 AR15, I killed a doe with it a couple weeks ago at a range of 278yds with a 125grn Nosler b-tip

I suggest probably the same fellow measured that velocity as did many of the velocities in Ackley's books.

It is a long-known, simple, efficient process, called the Wild-Assed Hopeful Guess! Doesn't work for those bound by the now-considered-archaic limits of scientific facts, but suits some of the others right up to the chin.

quote:

Originally posted by butchloc:
only way to get that velocity out of a 6.8 is with a 500 grain compressed load of blasto #2

Hmmmm, where can I buy some of that Blasto #2????

quote:

I suggest probably the same fellow measured that velocity as did many of the velocities in Ackley's books.

Now! Now! Some of us got started into wildcatting because we believed all those velocities. Heck over the years I've even duplicated most of them. Of course I used a Gibbs style case to achive AI velocities or pressures that gave me one shot brass.

Even my younger self would not go after 3200 from a 6.5SPC.

Paul-

Yeh, that's just my tilted sense of humour!

Actually, I had great respect for Mr. Ackley and considered him a good personal friend. (He likely thought of me as just another dumb kid who was also a bit of a pest.) Anyway, he gave me an awful lot of help when I opened my first gun shop. I have saved all my correspondence from him, and treasure having known him.

The velocities in his books though, often are simply fantasies. That's because P.O. reported them exactly as the cartridge "inventors" claimed them to be. Most of them had no access to chronographs and some striking % of them had not much common sense either apparently.

Standard tests back then for excess pressure included "Did the rifle disassemble itself on firing?" The more conservative amongst them also seemed to use ancillary tests such as " After firing, can I get the bolt open by fair means or foul?" and " After the first shot can I reprime the case for re-use with anything smaller than 209 primers?"

Still, they were great days for rifle loonies such as I, and in many ways more interesting to me than today. I too believed the reported velociies back then, and the "magic" of improved cartridges. I treasured all my correspondence from P.O., and have saved every bit of it for all these 50+ years since I used to correspond with him.

But I don't rely on undocumented data from ANYONE anymore if it doesn't match my experience. I once got a load from P.O. for a new cartridge of the day (7m/m Rem Mag), and promptly melted part of the head off the cartridge case on the very first shot, even though I had reduced the load somewhat before using it!

I think that's called either blind luck or the beginning of an education, or perhaps both.

I figured it out after a few minutes with QL, (now i can't duplicate the 3 groove & twist, but it should be close):
80,000 PSI redline from a 28" barrel with 125% case full of 3031 will just make 3200 fps with a 110 pill in 6.8 Rem.
Just goes to show what you guys think you know...