Load testing for my CZ527

[Nukes]

I'm not going to advocate anyone push past a point they aren't comfortable with, but there are some barrels that will hit 2700fps with CFE and 123gr in the AR15.

Heck, Bwild97 got 2662fps with the 129gr SST from a 24" AR15 using 31.0gr of CFE.

I think 2700fps is child's play in a bolt gun with CFE and 123gr. Some barrels will produce more speed than others. I would be happy with a 20" in the mid-2500fps range though, especially in an accuracy node.

[Buck2732]

Hi folks, I am going to try and get faster than the figures I posted above but I am having to wait for 123SSTs (think rocking horse poo), my side of the pond.

Just a quick question is there anyone/way of finding out what pressures I an getting with the above loads?

[kmon]

Hi folks, I am going to try and get faster than the figures I posted above but I am having to wait for 123SSTs (think rocking horse poo), my side of the pond.

Just a quick question is there anyone/way of finding out what pressures I an getting with the above loads?

Ran your loads through an internal ballistic program, its predictions are right inline with your data. Below included its predictions of pressure and velocity. This should at least give you an idea of pressure. Only one load shows above CIP max average of 58740

The rife CZ527, 22 inch tube, with my moderator and vortex scope.

The following all had a COL of 2.255

30.9 Average fps 2586.9 52160 psi 2588 fps
31.2 Average fps 2612.3 53886 psi 2613 fps
31.5 Average fps 2628.3 56289 psi 2647 fps
31.8 Average fps 2664.5 57537 psi 2664 fps
32.1 average fps 2700.4 59467 psi 2690 fps

The following all had a COL of 2.285

30.9 Average fps 2578.5 50940 psi 2572 fps
31.2 Average fps 2634.7 52290 psi 2597 fps
31.5 Average fps 2641.5 53999 psi 2622 fps
31.8 Average fps 2675.7 55771 psi 2648 fps
32.1 Average fps 2684.2 57608 psi 2673 fps

[LRRPF52]

You'll find that Quick Load shows 7k-8k more pressure in the Grendel that what is really there, when compared with piezoelectric and pressure trace systems. It's way off from reality.

With CFE and a 123gr, 31.9gr is still under 50,000psi with a SAAMI chamber. If you go back and look at the development I did with CFE and 123gr A-MAX, I was able to push way above that even without seeing a departure from the trend line.

Quick Load needs some serious calibration to generate accurate pressure results with the 6.5 Grendel, and many other cartridges.

If you look at Hornady's data, for example, the max load for a 129gr cup and core bullet is 31.7gr, and they are not going to publish data that exceed the SAAMI working pressure or MAP. Granted, they set a 52,000 MAP with SAAMI, when 50,000 provides betters margins.

Without spilling too many beans, I'll just say that 31.9gr is still under 50,000psi with a 123gr A-MAX at 2.245" COL, and this concurs with what I saw in my pressure ladder testing with that powder/bullet combo. I was also using a 2.275" COL, so I think that helped me a little for start pressure, as I am not jammed into the lands in my chamber with that COL and the 123gr A-MAX. The 123gr SST seems to need a little bit shorter COL since the cannelure has affected the ogive shape, with earlier land engagement being the result.