Question on Min. C.O.L.

[Furncliff]

I'm new to reloading for 9mm and I'm testing various bullets. This test is for Berry's 147 over 3.0g of Tite Group. The books call for Min COl of 1.160 to 1.170 depending on the source. This COL will not pass the drop test in a CZ75b barrel. I found the best I could do was about 1.082.

From the reading I've done so far this should be safe. I wanted to post and get a check from y'all.

Thanks

Tom

 

[918v]

You have the fastest burning powder with the heaviest bullet at the shortest OAL. How is that safe?

 

[Furncliff]

Thanks, that was helpful.

 

[gamestalker]

One of the most important aspects about 9mm, and one I learned from my Speer #10, is that 9mm is a high pressure cartridge that is very sensitive to oal variances. Speer states that a load tested to produce an acceptable 28,000 cup more than double in pressure (62,000 cup) when seated .030" deeper.
Now, consider how deep you are seating, bullet weight, and the fast burning powder, and you should be able to answer your own question on this one.

GS

 

[ArchAngelCD]

I'm new to reloading for 9mm and I'm testing various bullets. This test is for Berry's 147 over 3.0g of Tite Group. The books call for Min COl of 1.160 to 1.170 depending on the source. This COL will not pass the drop test in a CZ75b barrel. I found the best I could do was about 1.082.

From the reading I've done so far this should be safe. I wanted to post and get a check from y'all.

Thanks

Tom

You have a word wrong in the above text. The MAX OAL for the 9mm is 1.169" not the MIN. I routinely load 9mm ammo for one of my pistols @ 1.090". If you look at the Hodgdon load data site they list tested OALs as short as 1.010" and 1.020" and up to the max of 1.169" with many steps in between. You said you are new so I suggest you take care to read carefully because Max and Min are very different numbers and of course not interchangeable.

Welcome to reloading...

 

[GJSchulze]

I use 147 gr Precision Delta FMJ-TC for 9mm. I normally use 4.0 gr of Power Pistol and OAL of 1.13 to 1.14. I tried Titegroup at 3.2 gr. My first thought of your OAL of 1.082 was that it was too short. There was another thread about CZ's having a short chamber.

I suggest you call the powder manufacturer for advice before trying this. It makes me nervous thinking about it. .08 inch shorter OAL is a lot. Quickload calculates the pressure to be just under 38,000 psi assuming the bullet length is the same as what I used.

 

[1SOW]

I have two CZ 75 pistols. BOTH accepted Berry's 147grRN bullets at 1.144" (with .015" head space) . I ended up using 1.140" with my tests. They ran smoothly.

Search for "Push Test" to determine the absolute max oal that will chamber, then subtract about .015" to give some margin for error and head space. (RCWobbly wrote it).
This method is simple and gives max oal very accurately---great for CZ's short chambers.

 

[Walkalong]

You are going to have to find an OAL that your pistol will accept and feed. Then you are going to have to adjust your charge accordingly. I agree that Titegroup is not the best powder with a 147 Gr bullet at a short OAL, but it could work. I definitely would pick another powder though. Short decreases in OAL in 9MM can really raise pressures, especially with a fast powder and a heavy bullet.

 

[GJSchulze]

The safety of the load depends on pressure and pressure depends on powder type and weight, case volume after bullet seating, and inertia of the bullet (i.e., weight). Given that bullets have different profiles, you really need to compare the seating depth. SD = bullet length + case length - OAL. Knowing what that number is will help compare. Please post it.