Quote:
Originally Posted by jepp2
A couple of things. My experience is the CZ's have the shortest throat of anything I load for or anything I read about. First thing I do is to establish the max OAL for all the 9mm's I load for. Then I set my max OAL length so everything I load for will function in all my pistols.
What you found is you can't necessarily take the OAL listed in the manual as a given the round will function in your pistols. If you load with a shorter OAL the pressure will be higher. If you load longer the pressure will be less. And that is only if you are using exactly the same bullet. Same grains but different bullet with the same OAL the pressure could be diferent because the seating depth can be different due to bullet length (even though they are the same grains and type). The way I keep track of this is to record and establish my max OAL. Notice with lead the CZ's are the shortest.
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Good advice so far, interesting table above, and Rule3's post mirrors my experience with CZ. I've got a CZ Custom Shop SP-01, great gun! But, as others have mentioned, CZs have short leades, and requires the right shape bullet to avoid reducing the case volume via short OAL.
As has been mentioned, you need to be careful with 9mm, as it is a relatively high pressure round, and you don't want to get too cute with short OALs. Always start low with your new loads, and check for signs of pressure. Your powder throw sounds pretty stout for 1.07 OAL, especially for range fodder. You may be OK, but I personally would back down on the powder. Definitely pay close attention if you fire those rounds.
I had been loading some Precision Bullet LFPs, and had to size them at 1.08 OAL to keep from hitting the rifling in the CZ (I had slide lock up with longer OAL...). I used 4.2 gr of W-231, and that was OK, but I ended up ordering a different bullet shape so I can bring the OAL out to a more comfortable length (my primers were definitely ironed pretty flat with that load). The flat point bullet shape hits the rifling quicker than RN bullets.
I would think that your RN should allow you to come out with your OAL, but I know you did the drop test, so it just depends on the bullet... I'd find a new bullet, if I were you. In the meantime, I'd reduce your powder to around 4.2 gr of W-231, at your 1.07 OAL with 115gr lead round nose in that gun, and I'd be careful to check how they are working. To put this in perspective, I use 4.3gr of W-231 with Precision Bullet 115gr LFP, with an OAL of 1.16 in other 9mm guns, and that load shoots well.
Hope this helps, be safe.