Quickload users - please help

takbok

Well-Known Member
Hi guys. I'm after a favour, please. Out of interest I'd be interested to find out what pressure and velocity the following load is producing (theoretically) in my tikka T3:

.270 Win
Norma cases (don't know water capacity)
568mm barrel (22.4in)
56.0gr IMR4320 powder
GS Custom 110gr HV drive band bullet

Conventional jacketed bullet Quickload data will not be accurate(needs to be GS bullet selected), as these GS drive band bullets generate much lower pressures hence the higher loads.

FYI:

A 57.0gr load showed a light extractor mark on the case head.
A 58.0gr load blew the primer out.
 
Takbok,

Step away from the rifle....slowly and carefully!!!

With GS Custom 110 HV 068 bullets and a standard SAAMI spec & case capacity of 67 grains of water and a COAL of 3.34" ,56 grains of IMR 4320 is generating a peak pressure of 67955....almost 3000 psi into the red! MV is est at 3378fps from a 22.4 barrel.

If your COAL is shorter and the case capacity is less then the pressure will be even greater. Im not convinced that drive band bullets do create a lower pressure. All mono metal bullets tend to create HIGHER pressure. Nosler and Barnes always warn to start on the low side as pressure signs are often reached way before those of lead bullets.

I'd suggest looking for a node a bit lower down the scale. No wonder the 57 and 58 gr loads went BANG!
 
Last edited:
What COAL are you using? - The 56 grain load is indicating pressure 4.5% above maximum in QL. It isn't surprising you are getting pressure signs! -- Especially as you have test fired higher charge weights. You would need (theoretically) to drop down below 55grains of powder to get within max SAAMI pressure limits. To be safe you should be working up from about 50 grains (10% below max pressure charge) That level of load is still not excessively low.

DON'T BEND THE SAFETY RULES - YOU MIGHT GET BITTEN!!

Ian
 
Thanks for your replies. My COAL was 3.330". I worked up my loads from 51.0gr.

I'll reduce my load accordingly.

Thanks again for your advice and concern.
 
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