Can someone check me on max COAL please?

[bullpen7979]

Just cast several hundred to start of the 356-125-2R.

I took them to work and they dropped at about .359 or so. Weight wise, they averaged about 127.3 grains each. I LLA'd them, and pushed them thru the .357 sizing die.

I'm loading some dummies, checking the fit to the bore and the ability of the round to chamber and eject easily in my cz 75 P01.

At a COAL of 27.82 mm, which comes to a little over 1.09 in, the slide still sticks a little. Can somebody tell me if Im safe going to 1.07 or 1.06 COAL in order to get a little easier cycling of the slide and get some play before the boolit reaches a point where it binds?

I am loading over titegroup, using a remington #5 small pistol primer (which according to remington, is not a magnum primer). I don't crimp much, just enough to remove the bell of the case and return it to flat.

Using a Classic turret press, complete with the factory crimp die.

I am hoping I can make this mold work...Its almost like it would be better if the slug had a little more cone to it, like factory fmj.

[Az Rick]

What you might do is figure out how much of your new bullet is actually in the case. Check that against a reload you have shot with any other like weight bullet, with the same charge of tightgroup. See where I'm going?

What you don't want is to seat deeper reducing the capacity of the case thereby raising pressure.

You'll definitely want to start with a reduced load.

Best, Rick

[Ugluk]

How much powder are you using?

According to quickloads guess 3.6gr is max with coal 1.06 and may give 1016fps. That's really short..
I load mine to a whopping 1.17 for my german luger, but I size to .356.

[bullpen7979]

In seating the sized slugs to a COAL of 1.082675, it looks like there is an additional 0.0409448
of an inch of projectile inside the case. (forgive the ridiculous calculations - excel) I'm operating in mm and converting everything, because, like a moron, I fired off an ebay order for calipers without regard to the fact that they were in metric, and everything with reloading is SAE.

I was using 4.0g of TG for the 124 FMJ. I can go as small (for powder charge) as I need to- i have the lee micro disk. I suppose I just want enough oomph to get the slug out of the barrel and cycle the action, and that's about it for now.

I guess what I need to know is this:

Using Titegroup powder, can someone recommend a starting load for a 127 gr lead boolit (cast by the 356-125-2R mold) in 9mm using an OAL of 1.08? I've been working dummy rounds down incrementally in OAL and this is the first one that didn't seize the slide when chambered.

Greatly appreciated. I would also take a recommendation on a slower powder if that would likely be of benefit in this case.

[MtGun44]

Round or truncate to .001", all the rest of the numbers are meaningless gibberish.

The goal is to have the combustion chamber the same as what the loading book that you
are referring to was using. So - you need to know the length of the particular bullet/boolit
that they are using and the length of yours. Then you can calculate where the base of their
boolit was and where yours is and see if you have a larger or smaller combustion chamber.
If larger - pressures should be lower than the book reports. If smaller the pressures will
be higher - so if going for max loads - decrease the powder charge a bit. You are
being wise and safe by worrying about this, just do the calculations and you will be fine.

Bill

[bullpen7979]

is there any way to quantify "a bit" based upon the reduced capacity that is caused by seating .04 deeper? i could not find any valid data for this OAL. I was hoping to find something that didnt have me just guessing how much of a reduction i needed...

[Atakawow]

Titegroup isn't the powder I would "experiment" with. At 4.0gr, you are already at max suggested by Hodgon. You can try to reduce that load and keep seating the bullet deeper.

For a slower powder, I suggest Universal. I load that same bullet with 4.1gr of Universal, OAL at 1.070. Out of a Sig P226, it was averaging at 1110 FPS, about 138 PF.

IMO, a better alternative is to get a different bullet design. The lee TL 124gr looks like it should feed great for your CZ.

[Ugluk]

1.08" 3.8gr MAX, 34400psi, the usual disclaimer.
(quickload)
Pressure climbs scary quick if you deep seat a 9mm luger

Don't know if you consider ql outcome as "valid".. I do, within reason.

[bullpen7979]

Would 3.5 be a smarter place to start?

[MtGun44]

When in doubt as to what a "bit" is, do the calculation and figure percentage. If you are
around 5-10%, this is pretty small, but by 10% less vol, if I was at a max charge, I'd
want to back off - maybe 10-20% and work back up. If you reduce the volume by 25%
be ready for substantial pressure increases. Life is about percentages - in many places.

Bill