Pressure signs from brass and primers are totally unreliable.  If you're seeing them, it's too late in most cases.  Here is the order of pressure test and pressure analysis from industry down to the shooter:

Piezoelectric meter system, calibrated by a competent engineer.  These are only available at the big name companies due to cost and staffing requirements.

Pressure Trace System, calibrated by a competent engineer.  These are available on the market for $600 on up that direct in to your PC or Laptop.  They have very finicky issues with them that require someone that knows how to calibrate them after correctly installing them on a test barrel.

Velocity Measuring Equipment, analyzed by a competent hand-loader with an understanding of applied physics.  This can be your Oehler 35P, Magnetospeed, Labradar, or optical chronograph.

The top 2 systems will give you pressure data.  Before piezoelectric meters, they used copper crush systems with a hole drilled in the test barrel's chamber that would drive a gas-checked piston and deform copper.  It took a very knowledgeable engineer to interpret those systems as well.

Piezoelectric meters were developed in the last 3 decades of the 20th Century. They provide a tracked set of data of the pressure over time, not just the peak pressure like a copper crush system did. Pressure trace systems do this too.

As Joe blow, with access to chronographs, you can get an idea of where you are by consulting not one, but as many published reloading resources as possible from names like Hornady, Hodgdon's, Vihtavuori/Lapua, Sierra, Western Powders, etc.

After following the directions for the particular set-up of your chrono, Magnetospeed, or other speed measuring device, work up a pressure ladder with 1% case volume increments to see where your pressure trend falls in comparison to 1% charge weight increases.  This is why I don't ignore starting loads, and use them when starting a pressure ladder.

Your measured loads should be close to what you are seeing in published load data.  This gives you a sanity check on your rifle, chamber, and load formulation, as you follow sound hand-loading procedures.

According to Quick Load, this is entirely doable and safe with a maximum pressure of 54000 psi.  Using Reloader # 17, a MAXIMUM charge of Re # 17, 31.0 gr., QL predicts a velocity of 3168 fps, and as I mentioned before, while QL often errs with many powders on predicted velocities, with Re #17 it has been spot on.
If a 70 gr. TSX at 3168 fps does not open a can of whoop ass on something then I don't know what will.

Just a minor correction, I have never been in the business of making barrels or selling them.  You might be thinking of the owner of ADCO who goes by the handle BigBore, whereas I am Big-Bore.
I am just a reloader/wildcatter who takes his hobby very seriously and have been doing so for for over 46 years without an accident of any kind.  I have also been building ARs/LRs, mostly non traditional AR/LR calibers, for personal use in calibers from .22 LR to .500 Phantom for the last 15 years.  I love speed, but only if it can be done safely, but more important than speed, accuracy must be there and speed for speeds sake does not interest me, it must have something else to offer also, such as a flatter trajectory or some other tangible benefit.  That is why I favor the heavier 70 gr +- bullets in the 5.56 x 42.  At range, the heavies hold velocity better and have a flatter trajectory when you are wanting to reach out there and touch something, be it pasture poodle or paper.

Are those QL numbers for a 20" or 24" barrel Big-Bore?

The 70gr TSX is no joke from a 10.5" 5.56 barrel.  I'd be happy for a DM rifle with it or the 75gr A-MAX at 3000fps.

All are with a 24 inch barrel.

What does QL say from a 20in barrel?

I am shooting a Grendel cased 22 cal and my loads have the 75gr AMAX at 3000fps from 18 inches.

Will be doing some testing with the Berger 80gr VLDs and the 80gr AMAX in 20 and 22 inchers.

If you ever get in the Cody area you can give it a spin.

As a side note you are not going to like the numbers for your hoop stress and the new DPMS G2. Chamber wall (308 Win 63,000 psi ) is 0.150 at the gas relief cuts.

Same info for the 70 gr. TSX, RE #17, 31.0 gr.
24 " = 3168 fps
22" = 3107
20" = 3036
18" = 2955.

If one is getting over 3000 fps with the Grendel case, which has a larger case head than the 6.8, and less capacity, and a shorter barrel, then it is most certainly above 54000 psi.

Grendel has slightly more case capacity.  35.0gr of H2O vs. 34.8gr for the 6.8.  I don't know about the .224 AR, but 75gr in 6.5mm can be shot to 3000fps from an 18" and stay under 50,000psi with the right powder.  A 78gr-85gr can be run to 3000fps and still be easily under 50,000psi with the optimum powder.  

I don't have any calibrated pressure trace data for the .224 AR, but I wouldn't be surprised to find at least one powder that would drive the 70gr TSX to 3000fps from an 18" barrel and still be at 50ksi. 90gr Bergers with .551 G1 BC will mag-feed from the .224 AR.

Pretty sure I am over 54000 psi and the Grendel case has more capacity than the 6.8.

Personally I am comfortable running up to the brass yield in the Grendel case and the AR-15. Not matter how you dice it the case head will fail before you crack the chamber.

In other words there is no way to cause the chamber to fail because the primer pocket will blow at the extractor cut first, classic KABOOM, cracked bolt, banana peeled carrier, split upper, cracked mag well, splintered mag.

The new DPMS G2 has the same chamber wall as the AR-15 Grendel case and is chambered for the 63,000 psi .308 Win.

The advantage the Grendel case has is the short length. No need to trim and lots of straight bullet shank laying in the throat before ignition.

It seems one could load dead cats in it and still have it shooting great.

I think the 22-42mm looks great also and am not disparaging it in any way. I do think the velocities posted are a little over where most will find decent brass life and in ARPs defense those are listed as absolute MAX.

One way or another the 22 VLD or AMAX bullets in either case loaded to pressures the end user is comfortable with are going to be the apex of AR-15 performance in regards to reach.

The information I have (Ammoguide)  shows the Grendel case as having LESS capacity than the 6.8.  If that is wrong then I stand corrected.  There is more than enough room for more wildcats and the more the merrier.  All pressure data I have is generated by Quick Load.

Unless one is using a beefed up bolt for 6.5 G based wildcats, which I am pretty sure AA does, keep in mind that as case head size goes up, maximum pressure must go down in order to keep the back thrust on the bolt lugs the same as it is with the 5.56 round.  That is why the 5.56 is fine with 55K, the 6.8 is at 54K, and the SOCOM is stuck with 35K.  All give the same back thrust on the bolt lugs and while the rifle is not going to blow up if those limits are exceeded, it will shorten bolt life.  I see that Hodgdon lists no reloading data for the 6.5 Grendel above 50,100 psi though.
I have no idea what the AA bolt is rated.

Not that I have a horse in the race, but when Nosler lists that you can run a 52 grain bullet out of a .223 at 3540 with Benchmark, its hard to get excited about something else running a 55 grain bullet at the same speed. Seems like a lot of work/powder etc to get there. I can see the advantage on the heavier bullets, but otherwise...eh. Hell, you can push a 40 grain bullet to 3800 with Benchmark in .223. That's flat out to 250 and drops 42 inches at 500. I feel like if I'm going past that I'd want a bigger step up than this cartridge looks to offer. Don't get me wrong, its not a bad idea for 75 grain stuff, I just don't see the attraction for lighter bullets.

You and I are on the same page.  IMO it is with the heavies where this little puppy shines.

That was his original intent.
To push the 75 grain Amax to near 22-250 speeds from an AR15

wow, so what we basically have here is this.  yama_raja (super H FanBoi), LRRP (Super 6.5G FanBoi), and BigBore (SuperFan of everything wildcat)!!!  Would the prior 2 mentioned please continue to piss in their own playgounds, and quit posting (obviously) antagonizing threads into other forums???  You both make good points, but it always ends up in a dick measuring contest.  Thank You

Funny how I get labeled an ARP fanboi when I run a Bison barrel.
Has one other person posted a bad experience from ARP?
I just hate seeing BS against a product that a whole lotta guys love.
Take a poll to see what the favorite 6.8 barrel is.

I am a 6.8 fanboi - guilty. But someones gotta stand up for it here.
I brought this new cat here because its what I have been looking for in a .22 based on the 6.8 case (strongest bolt, highest pressure, other than a 5.56) and thought others might like it as well.
Which they do.

When do you see me going into a Grendel thread with anything negative towards the G?
I stay on my side of the fence unless I have a legitimate question or have something positive to say.
The 2 recent threads I have been active I'm the farking OP dude.

Reports are coming in of 3300 fps from the 62gr Fusion pulls with MOA accuracy.
Thats smoking right along.

I think the powder probably can be tweaked. These can be pushed to 3000 fps in a 16" 223. The 70 tsx can be pushed to 2750+ In the same gun.

The results of this are nice but with the extra powder, it should be faster.

I see the biggest benefit being the ability to use the 75 amax at mag length but the 77 tmk is pretty much it's ballistic equal. I need more than 10-15% extra velocity to be excited.

I get 2950 out of a 16in at 5.56 data, 62gr Fusion's.
2950 from the 70gr TSX from the same gun. 5.56 data.

Its still early in powder trials, I am hoping to see the 62gr Fusion at 3400 to 3500.

I think anything less than about 3500 makes it not worth it in my opinion. Even then, I'm not sure that the gain is that much given the longer barrel length in the 6.8 case. I think the 6mmAR shooting the 95 or 107 smk approaching 3k is more appealing to me.

The guys have been trying new powders.
This just in today. 62gr Federal Fusions  
"H4895 today. 28.2gr avg 3362 with no pressure sign, 28.4gr avg 3477 with very mild swipes. Sub moa accuracy. "
Thats bumping right up at 3500 fps

Just to keep it real....

Yama_Raja=AR Performance if you look back almost all of his post deal with AR Performance and history has shown the man behind ARP is a nut case. But those idea of the yote smoker sounds great until they start getting crazy worth the pressures. Done might not like it but LP knows his shit as does Big-Bore

62gr TSX-2.245"OAL-20" barrel
Lever-31gr-3321fps-54265psi
Lever-32gr-3466fps-58320psi
Load it like you want it.

There is no way to get 70grs to 2950fps in a 16 inch 5.56 with "5.56 data"

16 inch 5.56 data gets 1200ft/lbs.

55gr @3100fps

70gr @ 2825 fps.

77gr @2700fps.

LRRPF52:
"You can't spec a land-to-groove ratio as part of the SAAMI pressure rating, and land-to-groove ratio is not going to reduce pressures substantially."

Absolute bullshit.
Your guru has a bunch of you hoodwinked.

Twist, minimum bore groove area are SAAMI spec.
See for yourself.
6.5 Rem Mag SAAMI spec

5.56 load data from WP
LC Case
70 gr TSX
25.2 AA2230
No Crimp
OAL 2.27
BR-4 Primer
70*
5000 ft
2942 avg fps
Please pardon me for rounding 8 fps.

I got a barrel to try.  What diameter bushing are you using for the neck.  I have new hornady brass

.248

On mine I step down in about .010 increments.  It means a lot of pumping of the press handle and quite a few bushings but so far I have not lost a piece of brass.  After final sizing I outside neck turn then anneal, then run them over the M die expander.  So far, so good and the brass is lasting quite well.  IIRC I have 6 loadings on the first lot and it is ready for retirement because the primer pockets are starting to get a bit more loose than I like even though I have never seen any pressure signs on the primers.  However, this is older pre Nosler SSA brass and one thing I noticed on the very first loading (before even firing once) was that the primer pockets were more loose than I normally experience with new brass.  I use Hornady brass on a couple other 6.8 SPC based wildcats and the primer pockets are considerably more tight and consistent so my new lot of 5.56 x 42 brass will be Hornady.  Unfortunately, I have to work up the loads again and that means a lot more shooting.  Darn the luck!

+1

LOL. You had better calibrate your chrono. This does explain some of the high velocities with your 6.8 stuff.

You're 0.3 grs under the Accurate Powders Max load and a 16 inch barrel yet less than 200fps behind their 24 inch test barrel with the Max load. Right.

Its been checked against an Oehler.
I don't find 25 fps per inch that unreasonable.......

Well we are not talking about 25fps/ inch  which is low.

You started out @ 2950fps and the data from Accurate gives 3111fps for the max load and 24 inch barrel.

Difference is 161fps or 20fps/ inch.

Let us not forget you are 0.2 grains of powder below the Accurate max load.

2950fps with the 70gr TSX is not going to happen in 16 inches @ 63,000psi.

They are using a Win WSR primer, with a WIn case.
I use a CCI BR4 with a LC case
That alone is enough for the difference sir.

Today at the range, ran them again, the exact same loads. I have about 300 loaded up from last summer.
When crono'ed at 2940 it was in 85* weather, today's temp was 63*
10 rounds, average of 10
Crono

Brass

Result

Ok.  I got redding full length bushing dies.  Im using hornady brass.   I plan on stepping down in this order.  .288, .277, .267, .255, .248.  At .267 it crushes the case every time.   Yes I am lubbing cases.   I even tried a .269 bushing and it still crushed the case.  Any suggestions.   Dont understand wh i can get by this .08.
   Thanks

Make sure the bushing is not in the die upside down.
You may need to adjust the die to allow the bushing to float a bit higher.

The bushings were in correctly.   Im an idiot.  I took rhe expander out but left the stem.  Once removed worked fine.  One of those days man.

Glad you figured it out sir.

Finally got out and shot mine.  Im using hornady brass so its not the hardest brass.  I started to show slight ejector marks at 29 grs of LEVER.  speed was 3089fps.  Have not shot for accuracy just got the scope zeroed