Home Forums Hunting & Shooting Hunter's Campfire 270AR SPR (New AR-15 cartridge coming this fall)

65K is about what numbers i have in my chart with a 2775fps for a 130gr.

Every time (and this goes back to the 1930's) a wildcatter dreams up and loads a cartridge that gets much higher velocity than the case capacity says should be possible, the price always has been and always will be excessive pressure.

The old ICL Grizzly made higher velocities than the 300WBY, with a case that was essentially the same. Until someone pressure tested the loads.... OOPS! Back to the old drawing board....

I love wildcatting, built and still hunt with one of my own that I call the 340 Tyrannosaur. But case capacity X and bore area Y and bullet weight Z is always going to get you to exactly the same place unless a new powder has been developed that is more dense and more progressive in its burn than what we have now, and we have a LOT of great powders now! And in this scenario, the other 8 or ten cartridges that look like yours are going to also benefit from that same powder development. My 340 Tyrannosaur gets 100fps more velocity that a 340 WBY not because its case capacity is a tiny bit more, it is because we now have Reloader 25 and IMR 7828SSC that were not even dreamt of when old Roy W breathed life into his big 33. Well, that and Molybdenum Disulfide coatings on my bullets with PTFE treatments in my hand lapped cut rifled barrel. And even all that got me a relatively meager 100-150fps. I am under no illusion that MY 'magic' .338 cartridge is really and truly any more effective than the mighty - and excellent by the way - 340 Weatherby. I love it because it is MINE

Here's a hint: stick with factory AR pressures.

It's a free country and you are free to do what you want, including paying for reconstructive surgery after pieces of AR-15 tear through your face. I hear the eyepatch look is in.

TAK..I was in the sandbox with 3rd ID...and as someone claiming you were there...it's absurd you even say something like that [bleep]. What was your MOS again? I can't believe anyone who was actually there talks like that....

I got an answer from the developer over on the 68forum.

If the barrels are running faster with the same loads, it's because they are generating more pressure.


For a guy who trumpets the physics of killing power, you sure seem to ignore the physics of pressure.

I dont understand all the hoopla in this thread, when they become available, chrono a box of factory loads, reload to that velocity and accept the little cartridge for what it is.

200 fps means nothing in the real world, would I like to be hit with a 110 gr TTSX at:

2800 fps.....NO
2600 fps.....NO
2400 fps.....NO
2200 fps.....NO

Gunner

Are you addressing me as if i'm the developer again? Pressure is one part of the equation as so is resistance in the barrel caused by rifling type.

Have you shot the [bleep] thing? No, so STFU. Nice to tell folks about possible upcoming cartridges/changes etc etc. To pronounce said things that don't exist yet as better than, is a foolish endeavor

Facts trump guessing, always will.

Look up what velocity those Barnes TTSX need to be going before they expand or instead create a pencil hole. Thats why i hope this round works out. I would like to hunt boar with a 120gr Barnes TTSX. I bought a couple of boxes for my grendel then looked at the reloadding guide and saw the velocities and compared them to the required impact velocity for the Barnes TTSX and shelved the boxes. Can't use them in the Grendel. They simply don't go fast enough.

Ok.

Gunner

Compelling, so again no first hand experience.

Ok.

Gunner

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I'm using 123gr SST rounds for boar know but i like the idea of a copper bullet instead. My son't using Hog Hammer 223 rounds in our 5.56mm carbine that are running the barnes copper.

Gunner


I'm using 123gr SST rounds for boar now but i like the idea of a copper bullet instead. My son't using Hog Hammer 223 rounds in our 5.56mm carbine that are running the barnes copper.

Sorry for that. So you have used the 120 gr TTSX for hunting and killed something with it? Have you used the 110gr TTSX for hunting and killed something with it?

In that case, go and load ALL your questionable 6.8's with 85 gr TSX's, use them for crackheads/HD, go buy yourself an AR-10 in 308W, load the 130 gr TTSX's to 2800 fps and kill the hell outta anything.

Gunner

Pig shooter, we are just trying to educate you so you have realistic expectations regarding what can, and cannot be done with a new wildcat.

We've seen the promises that never materialize, and know the tricks to maximize velocity.

Once you've lengthened the throat, lengthened the barrel, matched the most modern powder to the barrel length/bullet choice, and increased the case capacity, all that's left is to ramp up the pressure.

Since many of us on this forum own custom rifes and chronographs we've been testing what does, and does not work since the 80's. We are familiar with the effects of custom barrels and changes in OAL.

Oh by the way, if you increase OAL, which way does the pressure go?

SCPH, are you in a lead free zone? If not, there is also a 110gr Accubond, that several folks here have used on deer & pigs, out of 6.8's.

If a bill passes in the house all cali will be a condor zone snd lead free.

Iv'e tried to back out of this idiocy.

But here you go, what Barnes says they need to be going not to pencil.

Rule of thumb and thats all. I've run a lot of barnes under what they claim impact speed has to be. Every last one has expanded. And I have seen pictures of some run faster than needed that did not...

phuggin computers are great though ain't they.