cartridge snug fit in barrel

[Phyffe]

Hi Wobbly - Advanced Merry Christmas!

Was wondering why you wanted Matthew to make sure the store sold lots of 115gr FMJ?

From the threads I was reading it seemed CZs were optimized for 124gr?

[Wobbly]

Hi Wobbly - Advanced Merry Christmas!
Was wondering why you wanted Matthew to make sure the store sold lots of 115gr FMJ?
From the threads I was reading it seemed CZs were optimized for 124gr?

• And merry Christmas to you and yours.
• 115gr simply has a higher probability of having a shorter OAL. If you never tried the ammo and you don't have your barrel with you, it can be a good decision.
• True. Apparently the twist rate of most 9mm's (at least on paper) favors the 124gr. But if you've watched the 100yd shooting vids of member JoeL on this forum, he does all that with 115gr FMJ.

[tdogg]

That's an interesting thought, building a database of plunk friendly ammo in CZ's.  Those of us that reload could benchmark our barrels with a known bullet to see who has the shortest chamber (push test it).  Then we could use that barrel as the plunk tester or use the benchmark bullet OAL to "normalize" the plunk test results as needed.  At minimum we could at least know approximately how much variability there are in CZ barrels?

I know my shortest barrel chamber is my new Accushadow 2.  It is shorter than my SP-01 Tactical by a fair bit which I thought was short to begin with.

I guess the failure will be that the manufacturers are always changing their components and what works today may not in the future.  It seems like a lot of effort for little reward.  Maybe the value is the barrel chamber data and the plunk database isn't as important?

Cheers,
Toby

[Matthew Rauh]

Your offer is generous, Wobbly.  Will give it a try.

As a new shooter with only 500 rounds under my belt, I am interested in 115 grain for practice.  But I noticed that Scheel's (sporting goods chain around here) has Federal 124 grain on sale for something like $17 a box.  I need to go to Scheel's to finish Christmas shopping on Sunday so I probably will take my barrel and plunk a few.  I will also try out some JHP.

I just got some snap caps for dry fire.  I plunked them and discovered that one stuck a little so I will not use that one.

[Wobbly]

As a new shooter with only 500 rounds under my belt, I am interested in 115 grain for practice.  But I noticed that Scheel's (sporting goods chain around here) has Federal 124 grain on sale for something like $17 a box.  I need to go to Scheel's to finish Christmas shopping on Sunday so I probably will take my barrel and plunk a few.  I will also try out some JHP.

I suggest you print out the "Preferred Ammo List" (found in the stickies) and take that with you too. You'll see that major brands, like Federal and CCI, proabably don't have this issue.

[Matthew Rauh]

Will do, thanks.  All the Federal and CCI I have shot had not problems whatsoever.  Even the Fed JHP 124 defense ammo plunks normally though I haven't shot it yet.  If they are willing I will plunk every available brand and grain they have. 

[Matthew Rauh]

At the risk of dragging out this topic too far, I thought I would give a final "update" if anyone is interested.  I did go to a sporting goods store today and plunked most of what they had on the shelf.  It was not the widest possible selection, but it was what I expected.  I plunked the 9mm Fiocchi 115 grain FMJ (9A) which gave me problems earlier, and it failed the plunk test and stuck in the barrel.  So did its bigger sister, the Fiocchi 124 gr.  Everyrthing else plunked fine including several 147 gr. and all the self defense ammo. 

Needless to say I am relieved that I don't have a defective barrel.  Picky to Fiocchi, yes, but I don't feel compelled to send it in to CZ.  I just have keep testing any "untried" ammo.

There was one interesting thing I learned.  I found some boxes of Fiocchi 9mm 124 grain FMJ ammo marked as "Training Dynamic" (9APB) and not "Range Dynamic" as the rest.  I hadn't seen this before and I couldn't find it on their website, but it plunked just fine.     

Thanks for your time, expertise, and especially patience with a new gun owner who has a lot to learn.

[Wobbly]

That's an interesting thought, building a database of plunk friendly ammo in CZ's.  Those of us that reload could benchmark our barrels with a known bullet to see who has the shortest chamber (push test it).  Then we could use that barrel as the plunk tester or use the benchmark bullet OAL to "normalize" the plunk test results as needed.  At minimum we could at least know approximately how much variability there are in CZ barrels?

If I understand your concern correctly... We already have the beginnings of that in Preferred Ammo List. Our largest issue there is getting people to list the manufacturers' PN. So many times an improved product carries the same name, but the product is so evolved that it gets a new PN.

Sadly your idea won't work as planned for 2 reasons. 1) Back in the early 2000's all CZ's seemed to be reamed with the exact same chamber reamer. Cartridges that fit the P01 would also fit the SP01, etc. That all changed around ~2012 when differences started to be noticed in the Shaddow line. These days my P10c is way different from my SP01.

2) But the main reason it won't help is that bullet-chamber "collisions" are caused by a mixture of OAL and bullet ogive shape. Conical bullets collide at the outside shoulder, while HP collide along the ogive. So knowing the OAL is not enough.

[tdogg]

That's an interesting thought, building a database of plunk friendly ammo in CZ's.  Those of us that reload could benchmark our barrels with a known bullet to see who has the shortest chamber (push test it).  Then we could use that barrel as the plunk tester or use the benchmark bullet OAL to "normalize" the plunk test results as needed.  At minimum we could at least know approximately how much variability there are in CZ barrels?

If I understand your concern correctly... We already have the beginnings of that in Preferred Ammo List. Our largest issue there is getting people to list the manufacturers' PN. So many times an improved product carries the same name, but the product is so evolved that it gets a new PN.

Sadly your idea won't work as planned for 2 reasons. 1) Back in the early 2000's all CZ's seemed to be reamed with the exact same chamber reamer. Cartridges that fit the P01 would also fit the SP01, etc. That all changed around ~2012 when differences started to be noticed in the Shaddow line. These days my P10c is way different from my SP01.

2) But the main reason it won't help is that bullet-chamber "collisions" are caused by a mixture of OAL and bullet ogive shape. Conical bullets collide at the outside shoulder, while HP collide along the ogive. So knowing the OAL is not enough.

Wobbly,

That's the point,  gather data to see how much the chambers vari now.   If we chose say the precision delta 124 jhp as our reference bullet and everyone push test that bullet in their chamber,  we could get a database of chamber lengths. Ideally it would be the same bullet shipped around but it could just be precision delta 124 jhp (different bullets,  same part number).

There would be truth in data once we gather enough.   We would need the year make and model gun and the data from 5-10 push tests.

While collecting the reference bullet push test data we could collect any other bullet push test data from that user as well (stuff from their reloading bench).

Not sure on the logistics but it'd isn't that difficult in my mind.   Just need a committed group to compile data and share the results.

Cheers,
Toby

Sent from my SM-G950U using Tapatalk

[Wobbly]

At the risk of dragging out this topic too far....

At age 72 with 9°F temps outside, it's not like you were keeping me from doing anything else !! 

And we have a huge supply of black HTML text the forum bought before the Obama shortages. I can't think of anyone or anything better to use it on. 

There was one interesting thing I learned.  I found some boxes of Fiocchi 9mm 124 grain FMJ ammo marked as "Training Dynamic" (9APB) and not "Range Dynamic" as the rest.  I hadn't seen this before and I couldn't find it on their website, but it plunked just fine.

That's interesting. Could have been pre-rush, a higher quality level ammo, or made in Europe.

Thanks for your time, expertise, and especially patience with a new gun owner who has a lot to learn.

This is not your usual gun board. We've set this up specifically as a place to get new CZ owners and new reloaders started in the correct direction, without a lot of noise from the 'peanut gallery'. In more normal times, when reloading supplies were plentiful, you would have gotten encouraging replies from 8-10 experienced CZ shooters.

Hopefully we'll get back to that someday.