Author Topic: "Push Test OAL"  (Read 5116 times)

pilgrim05

  • Guest
"Push Test OAL"
« on: December 22, 2014, 06:53:26 PM »
I have been reloading for only about six months now, and am finding it a very interesting and enjoyable part of my shooting hobby. 

When I started, I read on this forum about finding the best OAL for your barrel by using the "push test".  Well that length is larger than most all OALs listed on load data charts.  What should rule, the length I found for my CZ 75 or the OAL in the load data?  I figure that longer OAL I got from the push test is more conservative (safer), but maybe I could load beyond the max listed for the shorter length and get better performance and not exceed safe pressures.

Any advice would be appreciated.

Thanks, Pilgrim

Offline chfields

  • Administrator
  • Hero Member
  • *****
  • Posts: 1620
Re: "Push Test OAL"
« Reply #1 on: December 22, 2014, 11:08:09 PM »
Welcome to our forum!!! I expect to be doing some reloading myself next year. The research I've done suggests you generally don't want the OAL longer than the chamber. I have seen some that have done it, but I haven't seen where it was consistent..Just my 2 cents.....I'm sure someone with more experience will jump in and correct me if I'm wrong....


Again, welcome to our forum!!
CZ 75B SA
Hogue Wraparound Rubber Grips with Finger Grooves
CZ Compact (Steel, No Rail)
CZ Rami BD 9MM
CZ 712 G3 W/extended mag tube
Member USPSA
Member IDPA
Life Member NRA
Captain of the CZForum.com shooting team
Proud Army Dad

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: "Push Test OAL"
« Reply #2 on: December 23, 2014, 06:29:03 AM »
  Well that length is larger than most all OALs listed on load data charts.  What should rule, the length I found for my CZ 75 or the OAL in the load data? 
Thanks, Pilgrim
There is another test that you need to do before making a bunch of ammo. 
What maximum length cartridge fits in your magazines ?

pilgrim05

  • Guest
Re: "Push Test OAL"
« Reply #3 on: December 23, 2014, 09:40:46 AM »
My measurements of the chamber is very very close to the standard 9mm  1.169...doing the push test it sometimes gets to 1.170 but I think that is due to the (in)accuracy of the calipers.  So according to the "push test" found in this forum, I subtracted a setback of 0.015, which brings me to 1.154 for OAL.  In load tables I have been reading lengths of 1.110 and 1.125.  I have been setting my seating die at 1.150.  The CZ 75 long slide shoots great using that, but I want to know if I can load a bit more than the maximum designed for the shorter length because there is more space for expansion using my OAL in the casing and still be safe.  I guess another was of putting it is...am I losing some performance by using loads designed for a shorter OAL?

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: "Push Test OAL"
« Reply #4 on: December 23, 2014, 02:04:02 PM »
You should be very careful going over the recommended charge.  I doubt that you are loosing much velocity with the 1.150 OAL.  See if you can shoot them over a chrony for an actual measurement. 

pilgrim05

  • Guest
Re: "Push Test OAL"
« Reply #5 on: December 23, 2014, 07:46:25 PM »
I think I will stay on the conservative side until I get a chronograph.  Maybe Santa will bring me one.  Thanks

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: "Push Test OAL"
« Reply #6 on: December 24, 2014, 07:20:30 AM »
Years ago I bought an inexpensive CHRONY brand chronograph.  It suited me fine until a friend made a .308 hole in it.  The friend replaced it with a model with more features.  I never thought that I needed more readings, but after instantly having standard deviation readings , I recorded them in all of data log readings.  The data log is another "must have" for reloading.  The standard deviation readings point out loads that are more consistent.  Not that they are the most accurate, but they are in the ball park.