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Bench

9mm plunk test 50/50

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I'm loading 125gr Gallant (coated) RN to 1.130 (+/-2) OAL with a crimp of 0.376 on a Dillon SDB and when plunking them I can mostly get the bullets to fall out but when I go to the rotate the bullet in the chamber I get a  resistance in a portion of the rotation.  I've reduced the OAL to the .376 and not looking to go any farther since I'm loading coated. These bullets work just fine in my other pistol with even a crimp >0.376 and I'm just wondering if this issue is more of a barrel specific problem that might be solved by reaming out the chamber a touch or is there something else I'm missing?

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Most factory CZ barrels have short leade requiring rounds to be loaded shorter compared to others. Depending on the round nose bullet’s  profile or ogive, it might needs to be loaded shorter. As a comparison, I can load a blue bullet or acme round nose at 1.130-1.135” for my Shadow 2 but can only load a RMR Rn to 1.120-1.125 for the same gun due to the differing profiles of the bullets.

 

If I were you, I’ll load it at 1.125”, adjust the powder and chrono again.

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Loading shorter is really your only option. Or send the barrel off to be throated. Galant has a pretty round ogive so you have to load even shorter

 

i have throated 8 barrels in the last two weeks for pcc and CZ shooters. If you need it done, let me know.

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2 hours ago, Bench said:

I'm loading 125gr Gallant  RN to 1.130" OAL with a crimp of 0.376 "

 

1.  As mentioned above, I'd try running the Plunk Test with a shorter OAL …   keep shortening until they spin

2.  It's possible that crimping to .376" might be a problem - try backing that off toe .378" and try again

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Posted (edited)
On 6/2/2019 at 7:54 PM, Hi-Power Jack said:

 

1.  As mentioned above, I'd try running the Plunk Test with a shorter OAL …   keep shortening until they spin

2.  It's possible that crimping to .376" might be a problem - try backing that off toe .378" and try again

Ran it all the way down to 1.0  in stages w/ .378 crimp and it still was an issue although less.  Didn't want to try anything shorter than 1.0. The chamber is clean(!). Could this be a chamber issue in this 92 Beretta?

Edited by Bench

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2 hours ago, muncie21 said:

1.13 OAL would be too long in most of my CZs.

This is in a Beretta 92.

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.358 may be too large to fit in the freebore of your barrel at any normal OAL. You may have to load extra short with such a fat bullet. 

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Posted (edited)
On 6/2/2019 at 11:12 PM, chevrofreak said:

.358 may be too large to fit in the freebore of your barrel at any normal OAL. You may have to load extra short with such a fat bullet. 

.378 is the crimp, not the bullet diameter. My bad on the misleading post above. Bullet diameter is .356.

Edited by Bench
change OAL to crimp

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.358 is the OAL, not the bullet diameter. My bad on the misleading post above. Bullet diameter is .356.

You mean the OAL of the bullet itself? That number in itself means little to nothing. The typical OAL of a 9mm cartridge is roughly between 1.040 and 1.169" Anything outside of that range will most likely be outside of SAAMI specs.

 

Sent from my VS987 using Tapatalk

 

 

 

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@Bench

 

You sound very confused...

 

1) 1.13 is your OAL, keep shortening the round until it plunks and spins freely. Some of my guns require OAL's as short as 1.08.

 

2) .376 is your crimp diameter at the case mouth, try .378.

 

3) .356 is your bullet diameter.

 

Try reducing the crimp first to see if that in itself corrects the problem but if it doesn't start shortening the OAL until the round plunks and spins freely.

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Maybe your Cz doesn't like the bullet diameter you are using.. Try 355 vs 356 

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Take a sharpie, and paint the bullet and top half of the case. Do the plunk test and spin to see where the interference is.  If the bullet, shorten the OAL, if the case mouth/lip, increase taper crimp.   I will put money the interference will be the bullet ogive. 

 

I had a heck of a time with the same thing when I started loading 124 fr RN Zeros for my CZs.  Wound up with an OAL of 1.100.  

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6 hours ago, himurax13 said:

You mean the OAL of the bullet itself? That number in itself means little to nothing. The typical OAL of a 9mm cartridge is roughly between 1.040 and 1.169" Anything outside of that range will most likely be outside of SAAMI specs.

 

Sent from my VS987 using Tapatalk

 

 

 

OOPS....358 is the CRIMP...there, I finally got it right...not the OAL...

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5 hours ago, 4n2t0 said:

@Bench

 

You sound very confused...

 

1) 1.13 is your OAL, keep shortening the round until it plunks and spins freely. Some of my guns require OAL's as short as 1.08.

 

2) .376 is your crimp diameter at the case mouth, try .378.

 

3) .356 is your bullet diameter.

 

Try reducing the crimp first to see if that in itself corrects the problem but if it doesn't start shortening the OAL until the round plunks and spins freely.

1.) after some of the first posts last night I did shorten the OAL until I got to 1.0 and it still happened so going any shorter isn't an option.

2.) I did go to .378 crimp and stepped down to 1.0 OAL but still got the issue.

3.) bullet measured at .356.

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5 hours ago, Furrly said:

Maybe your Cz doesn't like the bullet diameter you are using.. Try 355 vs 356 

It's a Beretta 92 not CZ. It should eat about anything within specs.

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7 hours ago, Bench said:

OOPS....358 is the CRIMP...there, I finally got it right...not the OAL...

 

If you are crimping to .358" you are overcrimping by .018" to .020" which would allow the case itself to enter the freebore of the barrel. 

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28 minutes ago, chevrofreak said:

 

If you are crimping to .358" you are overcrimping by .018" to .020" which would allow the case itself to enter the freebore of the barrel. 

I don't know how much more I can screw this up....378 is the crimp...not .358...but still have the issue at the crimp of .378.

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On 6/2/2019 at 7:30 PM, Bench said:

when plunking the bullets fall out but when I rotate the bullet I get resistance

 

Have you tried firing these cartridges ?

 

If they feed properly, and the cartridges will easily fall out of the chamber,

I wonder if they might just be 100% fine to shoot, despite some resistance

when you rotate them ?

 

Not sure what causes a little resistance on rotation in the chamber, but I'd

go to the range and fire 200 of these little devils, and see if you really have

a feeding problem, at the range.

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46 minutes ago, Hi-Power Jack said:

 

Have you tried firing these cartridges ?

 

If they feed properly, and the cartridges will easily fall out of the chamber,

I wonder if they might just be 100% fine to shoot, despite some resistance

when you rotate them ?

 

Not sure what causes a little resistance on rotation in the chamber, but I'd

go to the range and fire 200 of these little devils, and see if you really have

a feeding problem, at the range.

LOL, that was my next thought since it would be the cheaper way to go vs. gunsmith route and tweeking the chamber. A very few will not fall out of the chamber  but when I rotate them there will be that resistance in a portion of the rotation. The initial plunk/fail to fall was probably right to what ever the issue is. I now have the Dillon SDB all torn apart for cleaning just to cover all my bases. Probably ~5k rounds through the press.

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As suggested in previous post, paint the round with magic marker and find out where the high spot is. 

 

Is it the bullet or the brass that caused the problem.

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Posted (edited)

Are you sure you went as short as 1.00? Or did you mean 1.10? To be fair your measurements have been all over the place. If you really got down to 1.00 then there's something else going on probably related to sizing/brass. I keep going back to OAL because you say the completed rounds plunk but do not spin which almost always indicates that the round is too long. 

 

What do you mean by "I get a  resistance in a portion of the rotation"? Can you post a video of you performing the plunk test on a few rounds? What about some pictures of your completed rounds?

Edited by 4n2t0

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4 hours ago, 4n2t0 said:

Are you sure you went as short as 1.00? Or did you mean 1.10? To be fair your measurements have been all over the place. If you really got down to 1.00 then there's something else going on probably related to sizing/brass. I keep going back to OAL because you say the completed rounds plunk but do not spin which almost always indicates that the round is too long. 

 

What do you mean by "I get a  resistance in a portion of the rotation"? Can you post a video of you performing the plunk test on a few rounds? What about some pictures of your completed rounds?

I"m sure that I did go down to 1.00 OAL in spite of my input debacle concerning the crimp actually measuring .378 but my input above being erroneous. I'm going to forgo a video but suffice it to say that I can get <1/2 full rotation of a cartridge in the chamber once plunked. I'm going to take up HPJack's suggestion and head out to the range  with 200 rounds and see if there  is a problem with cycling/function.

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1 hour ago, 4n2t0 said:

Denial ain't just a river in Egypt...

LOL, we'll soon find out...

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