?? For CZ Reloaders............

[HesedTech]

1 hour ago, twodownzero said:

Obviously that's not ideal, but it's also clear that the chamber was cut to allow for normal variations in factory ammunition, in both bullet weight and profile.  Cutting a 9mm Luger chamber such that ammuition has to be significantly shorter than SAAMI max with a common bullet profile does not seem like a sound decision to me. 

 

two

 

You're hitting on two different subjects. The first is your rifle, it was probably cut long because many precision shooters (i'm not one) prefer a long OAL over a short one, so I don't think it's totally about ammo compatibility.

 

As far as the CZ goes it is foreign gun designed to be shot with typical 9MM FMJ profile, which is a long tapered round nose. I found the CZ will load out to at least 1.14 with these profiles. However, we competitors like to buy those fat nosed coated RN bullets and they need to be loaded shorter.

 

Basically I believe the manufacturers have made decisions about the chamber sized based on their markets and where they are made.

 

Just a couple of ideas.

[HOGRIDER]

1 hour ago, twodownzero said:

 

That's very dependent on bullet profile.  I don't buy factory ammunition anymore, but for some bullet profiles, that might be normal.  For round nose/truncated cone heavies like we're likely to shoot in USPSA, 1.080 is quite a bit shorter than what I've been loading for my other 9mm pistols, so rather than develop a new load for them, I'd simply modify the gun.

 

There are a lot of different ways to skin a cat, so this is just the one I propose.

 

Also, just because there is factory ammunition that short, it does not follow that the chamber should be that short.  Someone made mention of precision rifle.  My .308 has a chamber that is 2.930" or more with certain bullets, even though every book puts .308 at 2.800".  I think that chamber is a bit long and if I had a custom barrel fitted, I would likely have the chamber a bit shorter than that, but any factory ammo shot in that rifle would necessarily have .130" to jump to get to the lands, assuming a similar bullet profile to that which I'm already using.  Obviously that's not ideal, but it's also clear that the chamber was cut to allow for normal variations in factory ammunition, in both bullet weight and profile.  Cutting a 9mm Luger chamber such that ammuition has to be significantly shorter than SAAMI max with a common bullet profile does not seem like a sound decision to me.  I prefer my guns to have a chamber that will run all common bullet profiles at SAAMI max for that cartridge.

 

My STI Eagle (40 S&W) will chamber ammunition at 1.3", ammunition that is so long that it can't eject that cartridge.  Maybe that's a bit much but I don't worry about the bullet hitting the rifling right out of the magazine, either.

 

You're free to have a different opinion, but this is mine.

I too primarily shoot my reloads except for the fact that I shoot/carry factory ammo in my CCW weapon.  And I have several boxes of factory ammo that I purchased when I started making the transition to 9mm.  I fully realize after plunk testing a few different bullets in the S2O's barrel, that bullet profiles and weights will require different OALs!

 

I don't prefer a shorter chamber either.  Maybe it's because CZ is producing these pistols in European markets that normally use the shorter chambers.........I'm not sure, but I do know they are much shorter than my 1911/2011/Glock platforms.  But I can learn to adjust for that. 

 

According to the USPSA 2020 Equipment Survey, 40% of those reportedly shooting in Production class were shooting Factory Loaded ammo!  And I'm sure there are more people shooting factory ammo than those of us that prefer to reload our own.  Could be why the manufacturers make pistols that will shoot all types of available 9mm ammo.

 

FWIW, I will always respect your opinion whether I agree with it or not.

 

Again, thanks for your feedback!

 

 

 

[cnote]

Remember, prior to covid and the election, lots of people chose to shoot factory 9,  do to its easy availability and cheap cost.  Their time was more valuable to them.  Well that bird flew the coop. 

[CocoBolo]

9 hours ago, twodownzero said:

I never said it was dangerous, I'm not sure where you got that idea.

I shoot a lot of 9mm pistols and they all use the same minor ammunition, and I'd want to keep it that way.

 

That said, it doesn't seem sensible to me for the chambers to be cut that short, so I wouldn't leave it that way.

 

If it was my only 9mm, maybe I wouldn't care.

My apologies, you said it was ridiculous, not unsafe.   I really love my Edge, a Dawson specially prepared hard chromed version (2007), I like it better than my dual caliber SVI, with the replaceable breach face.  The Shadow I just converted to CO I have had since 2010, so nothing new about loading shorter on fat profiles, just like the other CZ's I have owned in the past.  The nose of the bullet will drag on the mag if you go beyond 1.165, that is how long my Montana Gold 124gr JHP's are I use in the gun, 124gr FMJ's I load to 1.150, the RN's feed a little better.   My gun may be throated, I have a throat reamer, and don't remember everything I did in the last 11 years, sometimes I can't remember what I had for dinner yesterday, that's why I have a reloading journal, well its a database since I am a retired database administrator/application developer.  The down side is you can run cost reports. 

[twodownzero]

9 hours ago, CocoBolo said:

My apologies, you said it was ridiculous, not unsafe.   I really love my Edge, a Dawson specially prepared hard chromed version (2007), I like it better than my dual caliber SVI, with the replaceable breach face.  The Shadow I just converted to CO I have had since 2010, so nothing new about loading shorter on fat profiles, just like the other CZ's I have owned in the past.  The nose of the bullet will drag on the mag if you go beyond 1.165, that is how long my Montana Gold 124gr JHP's are I use in the gun, 124gr FMJ's I load to 1.150, the RN's feed a little better.   My gun may be throated, I have a throat reamer, and don't remember everything I did in the last 11 years, sometimes I can't remember what I had for dinner yesterday, that's why I have a reloading journal, well its a database since I am a retired database administrator/application developer.  The down side is you can run cost reports. 

 

More ridiculous because of how out of touch it seems to be with all of the others.  I've got 1911s, an M&P, a Glock, and probably a few other 9mm pistols and the CZ is the outlier.  Like I said, if I only had one, or they were all that way, I might just pull a few tenths of powder and leave them short, but I like to load at least 1.130" for my 1911 and the other guns take that ammo just fine. CZs have had these short chambers forever, I really don't understand it myself.  I don't think it's dangerous or unsafe, it's just strange that they choose to chamber their guns that way.

 

Now if my CZ would just get here (ordered, paid in full in February, no ETA, and "first responder" orders are supposed to be filled first--so much for that!

Edited April 23, 2021 by twodownzero

[bigdave24]

As a starting point, I’ve used 3.3 gr N320 at 1.132 oal with xtreme 147 bullets and made 130PF in an SP-01 Shadow.

[HOGRIDER]

1 hour ago, bigdave24 said:

As a starting point, I’ve used 3.3 gr N320 at 1.132 oal with xtreme 147 bullets and made 130PF in an SP-01 Shadow.

Thanks big!

 

[Tunachaser]

I have used 147 Zero JHP with N-320 @ 3.4 grs. with 1.14 COL in my CZ's for a 129 pf.

[HOGRIDER]

2 hours ago, Tunachaser said:

I have used 147 Zero JHP with N-320 @ 3.4 grs. with 1.14 COL in my CZ's for a 129 pf.

Tuna:

That falls in line with data another shooter has shared with me.  Your COAL was just a tad longer; but only accounted for a few fps difference.

 

THANK YOU!!!!

 

 

[Siberian]

Another data point:

Shadow 2 Optics, 147 RNFP (plated CamPro), 0.220 g N320 (about 3.4 grain in your units) = 128 PF

Shadow 1, 124 RN (plated CamPro), 0.265 g N320 = 130 PF

Shadow 1, 115 RNHP (plated CamPro), 4.5 grain N320 = 128 PF

 

COL as per bullet mfr's recommendations, tested to plunk

 

Edited April 25, 2021 by Siberian

[HOGRIDER]

1 hour ago, Siberian said:

Another data point:

Shadow 2 Optics, 147 RNFP (plated CamPro), 0.220 g N320 (about 3.4 grain in your units) = 128 PF

Shadow 1, 124 RN (plated CamPro), 0.265 g N320 = 130 PF

Shadow 1, 115 RNHP (plated CamPro), 4.5 grain N320 = 128 PF

 

COL as per bullet mfr's recommendations, tested to plunk

 

Thanks Siberian!

 

 

[motosapiens]

On 4/22/2021 at 2:25 PM, HesedTech said:

As far as the CZ goes it is foreign gun designed to be shot with typical 9MM FMJ profile, which is a long tapered round nose. I found the CZ will load out to at least 1.14 with these profiles. However, we competitors like to buy those fat nosed coated RN bullets and they need to be loaded shorter.

 

this is the truth. cz has no trouble in my experience with typical factory ammo, but if you compare that fatter ogive of many of the popular coated bullets with typical factory (or plated, or jacketed) bullets, the difference is pretty easy to see. As an RO, I am amazed how common it is for people to load bullets long enough to stick in the rifling and be hard to eject at ULSC.

[cnote]

lots of new cz shooters in CO, great thread to review

 

[paltrypoultry]

Zero 147 JHPs have a profile that's very friendly to the CZ barrels.  With a factory SP01 barrel and Zero 147 JHPs I found 1.155 would reliably plunk and spin.  But that was long enough it'd bind up in the mag.  This is the first bullet I found where the mag was the limit and not the throat.  I backed it down to 1.142 for reliable mag feeding.  3.4gn of titegroup is what I'm using now, which just made 137pf at a chrono stage.  3.6gn of n320 should be in the same ballpark with the same OAL.

 

Re: the other conversation about OAL and what's too short, it's not really OAL you should be looking at when considering what's dangerous, it's seating depth.  Personally I stay away from anything that requires me to seat deeper than .300" but I'm just going by what someone told me on a forums once with that number.

[HOGRIDER]

@paltrypoultryI would highly recommend trying 3.5 of N320 with the Zero 147 JHP!  OAL of 1.125”.

 

Produces under 1” groups from my S2 Orange @ 20yds.

 

Edited April 29, 2022 by HOGRIDER
sp

[paltrypoultry]

I misremembered.  It was 1.165 that cleared my 2 factory SP01 barrels' throats, but was too long for mags.  1.155 cleared mags, but then I had to drop it to 1.142 for a new CZC barrel with an even shorter throat.

 

How did you end up at 1.125?  That's 2 or 3 hundredths shorter than necessary for any of my barrels, including the super short throated CZC barrel.  Did you work your way there testing accuracy, start with something super conservative, or is the s2o throat way shorter than others?

 

I had good results with my n320 ladder too (7moa 5 shot group offhand with 3.6gn / 1.155, at 131pf)

[HOGRIDER]

14 minutes ago, paltrypoultry said:

I misremembered.  It was 1.165 that cleared my 2 factory SP01 barrels' throats, but was too long for mags.  1.155 cleared mags, but then I had to drop it to 1.142 for a new CZC barrel with an even shorter throat.

 

How did you end up at 1.125?  That's 2 or 3 hundredths shorter than necessary for any of my barrels, including the super short throated CZC barrel.  Did you work your way there testing accuracy, start with something super conservative, or is the s2o throat way shorter than others?

 

I had good results with my n320 ladder too (7moa 5 shot group offhand with 3.6gn / 1.155, at 131pf)

After plunking the S2O which has a short, CZ hardened chamber, I could take the Zero 147 JHP out to ~1.158.  However, after plunking the Blue Bullet's 147 FP I also wanted to use, it was going to have a safe, max OAL of 1.120".  

 

I then remembered the "classic" 3.5 N320 load at 1.125" which shot excellent in the STI and other 9mm pistols, so I decided to do a ladder from 3.3g to 3.7g in 0.1g increments, and chrono from there.  The 3.5g load at 1.125" showed very good results from a bench rest, so I decided to take it to the Ransom Rest.  My best, consistent results are shown above.

 

Of course, YMMV...........