CZ 75B 9mm chamber question.

[Mikej]

90gr vs 124gr. That is near 30% less weight to get moving.

When I started reloading there was a nice gent at the club that suggested HS-6 for our long barrel guns in 9mm and .40 due to the fact HS-6 as a slower burning powder it will continue to burn/push the bullet down the barrel where Titegroup would release all it's energy quicker, and be done. What "I" take from that is that a faster powder would be more appropriate in a short barrel/defensive gun.

So everything is looking good so far but here's where it get's interesting as the target shows I loaded some Sierra V-crowns 90gr. and at max charge which I did work up my final readings were at 1528, 1545, and 1601 fps...

according to my Lee manual velocity should be around 1400fps. longer barrel of a CZ giving extra velocity maybe?

Don't forget, the manual isn't saying what you should get, it is telling you what they got. There's a lot of variables if you think about it. Primer, bullet coating, air temperature/density/humidity etc. I'd be more inclined to associate the velocity your getting with chamber pressure. It would scare me a bit to be running up at 1500+ FPS.

 

[The Courier]

How is pressure calculated with a load like that? What I like about the 90gr. Load at that speed is 511 foot lbs of energy for a 9mm is right up my alley, and recoil is very manageable. BTW my start data was clocking in at 1,482fps so either pressure is high or HS-6 is a good powder for light 9's. More research is needed for any conclusions.

 

[Mikej]

Just using what my Lyman book says as a base, a 90 gr bullet at 1300fps is running 31,000 with HS-6. Don't know off hand what max pressure is on 9mm, but if you are hitting 1500fps I'm thinking......

I wish I had a chrono and a place to use it, but I don't, but if I were seeing that kind of velocity I personally wouldn't be loading that fast. I have no need for that.

I'm pretty new to reloading compared to most of the members here. I'd be interested in other input.

Edit to ad: That 8.0 gr of HS-6 under the 90gr FMJ is .5 grain more that either one of my books say is max.

 

[The Courier]

According to Hodgdon a 90gr Speer Gold Dot at 1,413fps is 30,900 CUP. Their listed OAL is 1.010" which my tested was 1.040". Good lord the equation to formulate chamber pressure is beyond me and seems to be inaccurate anyways, maybe just back off to starting load...

 

[jordanka16]

Quickload says that your 9mm load (90gr gold dot with 8.0 grs of HS-6 loaded at 1.040) is at 36,680 PSI and 1480 FPS, which would be a +P load. Since both of those guns are rated for +P and if you aren't seeing pressure signs that should be a fine load, just watch what guns you run it through.

 

[Mikej]

Quickload says that your 9mm load (90gr gold dot with 8.0 grs of HS-6 loaded at 1.040) is at 36,680 PSI and 1480 FPS, which would be a +P load. Since both of those guns are rated for +P and if you aren't seeing pressure signs that should be a fine load, just watch what guns you run it through.

Right on! I forgot about that Quickload program folks have. Thanks for that. Seeing as I don't/haven't used a chrono it's good to see that my inner common sense was apparently correct in assuming pressures considerably higher.

 

[The Courier]

Much appreciated for all the help so far everyone it's awesome having some input on these things. I will probably back off the charge by .2grs for the v-crown load as I don't see a reason to push blasting ammo to +P tolerance unless necessary. And thanks alot to jordanka16 for the quickload info, I'm looking at getting that program now as that seems a very helpful reference.

 

[jordanka16]

Much appreciated for all the help so far everyone it's awesome having some input on these things. I will probably back off the charge by .2grs for the v-crown load as I don't see a reason to push blasting ammo to +P tolerance unless necessary. And thanks alot to jordanka16 for the quickload info, I'm looking at getting that program now as that seems a very helpful reference.

Quick load is awesome for estimating pressure and velocity, and my favorite use for it is figuring out the best powder, I can punch in what I want the load to do, and it gives a list of the optimum powders.

 

[klmspider]

So I've been trying to set an overall length for some 124gr fmj round nose and I am running into a problem, even at minimum seating depth the rounds will not pass the plunk test. The data from lee states that for a 124 fmj round nose using Titegroup minimum COAL is 1.150, so first I thought the bell on the case was to blame but I dropped several unloaded cases in and they cleared no problem. After browsing CZ forums and discussions it seems I'm not the only one with this issue, some where saying they have to set their length at 1.10 for proper function. What bugging me is I'm trying to make a nice happy medium that works nice in my Glock 19 and my CZ and going below listed safe depth makes me a little nervous.
I understand that Glock chambers and CZ vary greatly in design and allowable length will be different as well. The only conclusion I can come up with is set charge at minimum and keep dropping the length until they chamber, Can anybody shed some light on this subject?

I've used the 1.1 successfully with my cz SP01. It can be fussy and jamb some hard lead 124's. I take problem rounds and put them in my stock High Power and shoot them flawlessly. My cz shoots practically all factory loads without a hick up. I use a lot of titegroup, bullseye, and some CRP? (That new copper-eraser stuff)