Quickload max pressure & the 300 BLK??

[Sgt_Jamez]

Ok so part of my ongoing research into my BLK overpressure issues, I am trying to calibrate my copy of Quickload.

The SAAMI spec for the BLK is 55000 psi. However Quickload uses 50763 psi.

Calculating load ranges based on 50763 psi, I am getting casehead marking at mid range powder charges.

Using a measured case capacity for LC brass of 24.3gr H2O, a charge of 17.9gr of W296 gives a QL pressure of 47496 psi and that's where I start getting casehead marking. 7500 psi below max. QL predicts 18.7grs as the max safe load but I top out at 17.7gr?

I appreciate any light you guys can shed on this for me.

The question is why the difference? If I am trying to create safe loads that can span the useable pressure range... where am I going wrong? Why am I topping out on pressure so soon?

 

[MALLARD]

Re: Quickload max pressure & the 300 BLK??

quickload isnt that accurate ,the program has its flaws

 

[Sgt_Jamez]

Re: Quickload max pressure & the 300 BLK??

Thank you... that doesn't answer my question at all though.

Anyone else?

 

[Clark]

Re: Quickload max pressure & the 300 BLK??

You might work up a load in 308 until the threshold of lose primer pocket in one shot, then fine tune to the threshold of lose primer pockets in 5 shots, and then back off a 4% powder charge safety margin for handloading a large quantity for use in one rifle.

Plugging your final load into Quickload, it will estimate it ~69,000 psi.
That is higher than the SAAMI registered max average pressure for 308 by 15%.

But if you do the same load development process for a the BLK, Quickload will be estimating your pressure closer to 50% over the 55kpsi you seek.

 

[MALLARD]

Re: Quickload max pressure & the 300 BLK??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sgt_Jamez</div><div class="ubbcode-body">
The question is why the difference? </div></div>

the difference is the result of quickloads inaccuracy ,the program is flawed, i dont understand how you can not understand that.

 

[Clark]

Re: Quickload max pressure & the 300 BLK??

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">" If you must carry a .25acp, don't load it. If you load it you might shoot it. If you shoot it you might hit somebody with it and he'd then be justified in killing you because you attacked him."</div></div>
In the 1990s I was on the pre www gun forum rec.guns and sold a shotgun receiver to Flim Flam. He had a pawn shop in Crystal Springs FL.
A big strong guy failed the background test to buy a 357 mag at the pawn shop.
He got mad, went out into the parking lot and came back with a samurai sword and ran Flim Flam through. Flim Flam shot the guy with a 25acp, and the guy staggered out of the pawn shop and died.
Flim Flam [J Philips] eventually recovered from the sword wound, sold the pawn shop, moved, and died of something else.

That was factory ammo.
I have found that the typical published load for 25acp is:
1.3 gr Bullseye, 50 gr FMJ
I have found that 3.2 gr Bullseye will fit, but that is still wimpy.
I have found that most people cannot tolerate the recoil of a 25acp with 4.0 gr Power Pistol.
I have found that the primer pocket gets lose ~ 6.0 gr Power Pistol.
I have found that the primer falls out and the case fails to extract above 6.0 gr Power pistol, and the case must be pounded out.
I have found that some 80 year old cheap Spanish 25acp pistols have poor firing pin to firing pin hole fit, and will pierce the primer before the brass strength is the limit in a work up. Higher quality 25acp pistols, like Colt and Beretta, do not have this problem.

Quickload is worthless in predicting hot rod loads in straight wall cartridges, like the 25acp, that can blow a fire ball out the muzzle.
But Quickload can be used to very accurately predict the velocity of bottle necked cartridges, like the 223 and 260.
And Quickload can be used to very accurately predict the threshold of long brass life for families of case head design.
In order to get this kind of performance with QL, the OAL, starting pressure, and powder must be characterized.
My Varget jug is dead on the the QL library.
But my H4350 jug is 5% wimpier than the QL library.