CZ Shadow 2 - 147 gr tumbling

[luketmv]

I understand this topic has been brought up before but ive already eliminated most of the comments people have suggested,

Loading 147 gr polymer heads with N320 3.3 gr which used to work flawlessly in an M&P Pro.

I now am getting about 1/5 rounds tumbling in the Shadow 2.

Crimp is not removing any polymer off the heads.

Tried reducing the powder.

can anyone help me with this as i am stuck.

Note: i would like to stick to 147 gr heads

Edited September 6, 2016 by luketmv

[Bullets]

If you would like to stay with 147s i would try either switching to a different brand or type. Maybe try jacketed. Or try increasing powder. Are you shooting competition with this load?

[luketmv]

27 minutes ago, Bullets said:

If you would like to stay with 147s i would try either switching to a different brand or type. Maybe try jacketed. Or try increasing powder. Are you shooting competition with this load?

Yes i am shooting competition with this load. PF is 130-132PF with the changes ive made. Jacketed are impossible to get here in Malta. Only find lead or these polymer coated.

[robertbank]

What diameter are the bullets?  I cast my own and size them .357.  I used to cast them .356 but ran into tumbling problems like you are getting,  At the time I was running a Shadow and M&P FS.  I would suggest the 124 gr bullet if you can get them.  You will get a bit more felt recoil at the same PF but accuracy should improve.

Take Care

 

Bob

[Bullets]

55 minutes ago, luketmv said:

Yes i am shooting competition with this load. PF is 130-132PF with the changes ive made. Jacketed are impossible to get here in Malta. Only find lead or these polymer coated.

Wow im shocked you are getting that high of a pf with that load. I only get a 125pf with 3.3gr n320 with a plated 147.

[IDescribe]

There is a good chance your problem is velocity.  Some 147gr bullet/powder/gun combinations will work fine as light as 131/132 PF, and some won't.  

A couple of years ago while at the range with my ShadowLine, I noticed that a particular 147gr load would group better than a particular 135gr at 15 yards, but when I moved the targets out to 25 yards, the 135gr load grouped better than the 147gr load.  Both loads were ~133PF.   Shortly thereafter, I brought out different 147gr and 135gr loads to check, all again at 133PF, and they turned out the same.  Why?  It would seem that at 895-915 feet/sec, some of the 147gr bullets were starting to destabilize quickly, and it was showing up in group size by 25 yards.  There was never any actual key-holing, but it showed up in groups.  After that, after some playing around with 147gr loads, I discovered that with just a little more velocity, groups tightened up significantly at 25 yards.   I learned that with an average velocity of about 905/PF133 where I had been operating, groups were going to be a little loose at 25 yards, and that with an average velocity somewhere between 910 and 925, groups were going to tighten up, and that it seemed to vary a little bit based on what bullet and powder I was using.  My solution was to start loading all my 147gr bullets to an average velocity of 935 feet/sec, so a PF of about 137. 

If you are having tumbling problems, increasing powder charge will often fix it.  INCREASE your powder.  You might find that just a .1gr increase will fix the issue.  And you might find that a .2gr or .3gr increase will both fix the issue AND produce more accurate rounds overall.  

 

Edited September 6, 2016 by IDescribe

[fellas]

As i told you ,  just increase the load a bit and check the crimp, there aren't any laws dictating the use for the  147 bullets , try the 124 as well if you find them better stick with them .

[dillon]

Another possibility is that excessive crimp is being applied. Too much taper crimp will resize the bullet inside the case. I have done this with cast lead 124 grain RN projectiles. Be sure your crimp is no smaller than .378".

[luketmv]

15 hours ago, IDescribe said:

There is a good chance your problem is velocity.  Some 147gr bullet/powder/gun combinations will work fine as light as 131/132 PF, and some won't.  

A couple of years ago while at the range with my ShadowLine, I noticed that a particular 147gr load would group better than a particular 135gr at 15 yards, but when I moved the targets out to 25 yards, the 135gr load grouped better than the 147gr load.  Both loads were ~133PF.   Shortly thereafter, I brought out different 147gr and 135gr loads to check, all again at 133PF, and they turned out the same.  Why?  It would seem that at 895-915 feet/sec, some of the 147gr bullets were starting to destabilize quickly, and it was showing up in group size by 25 yards.  There was never any actual key-holing, but it showed up in groups.  After that, after some playing around with 147gr loads, I discovered that with just a little more velocity, groups tightened up significantly at 25 yards.   I learned that with an average velocity of about 905/PF133 where I had been operating, groups were going to be a little loose at 25 yards, and that with an average velocity somewhere between 910 and 925, groups were going to tighten up, and that it seemed to vary a little bit based on what bullet and powder I was using.  My solution was to start loading all my 147gr bullets to an average velocity of 935 feet/sec, so a PF of about 137. 

If you are having tumbling problems, increasing powder charge will often fix it.  INCREASE your powder.  You might find that just a .1gr increase will fix the issue.  And you might find that a .2gr or .3gr increase will both fix the issue AND produce more accurate rounds overall.  

 

ok will try that this weekend and let you all know how it goes

[StreetsAhead]

On September 6, 2016 at 8:59 AM, Bullets said:

Wow im shocked you are getting that high of a pf with that load. I only get a 125pf with 3.3gr n320 with a plated 147.

In my Shadow Target, I get 130pf with 147gr bayou bullets with 3.0gr n320 at 1.125" OAL. 

70F Denver altitude

[IDescribe]

Right.  The only 147gr coated lead data I have with N320 is a Blue Bullets RN.  3.3 just got me in the PF 129 neighborhood.  If I were going to shoot that combo for 9mm minor, I would likely go up to 3.5/3.6 grains of N320.

 

[Gcarr]

Have you slugged your barrel? I bet your barrel has a large bore size and the coated bullet is not large enough to get into the rifling enough... Causing the bullet to skip thru the barrel... And then tumble. I have had the same issue with coated bullets. The coating is a lube and should not be counted when measuring the OD of the bullet. Jacketed bullets are hard enough to get a good grip in the rifling without being deep into the rifling... Lead is soft and needs to be deeper into the rifling. Try a larger diameter bullet and the tumbling should go away ... I found that I could not get a coated bullet large enough to chamber that would give good accuracy and/or not tumble.  I shoot .358 non-coated with very good results. Hope this helps. 

[biglou13]

what distance's are you seeing the tumbling?

 

[luketmv]

8 hours ago, biglou13 said:

what distance's are you seeing the tumbling?

 

Ive seen tumbling even at 10 Meters

[noylj]

Twist rate for stability with 147gn bullets is about 1:30. You are probably shooting a 1:10 to 1:16 barrel, so twist rate is NOT an issue--though one could argue that OVER stabilization could be.

What makes you believe that you have tumbling bullets? Below are pictures of REAL tumbling bullets. In many cases, what folks think is tumbling is simply NOT having sufficient target backing and getting oval holes. Were your targets backed by at least stiff cardboard?

So, if you really do have tumbling bullets, In almost all cases, undersized bullets are the problem. If shooting lead, you should be using bullets that are at least 0.002" over ACTUAL MEASURED groove diameter (normally, one would say at least 0.001" over, but for 9x19, I find that 0.002" works a LOT better). So, if you are shooting a barrel that has a groove diameter of 0.3555", you need bullets that are at least 0.3575" in diameter. I'll bet you are using 0.3555 to 0.356" lead bullets and they are simply too small for YOUR barrel. All of my 9x19s take 0.358" lead bullets without any problem.

In most cases, if you check GOOGLE, you'll find the biggest problem for 9x19 has been PLATED bullets that are groove diameter or less.

Another possibility would be damage to the barrel's muzzle that throws the bullet off as it exits and hot gasses shoot out of the damaged part of the muzzle, giving the bullet a "kick in the ass."

[fellas]

tanfoglio stock 3 has the same barrel lenght of the shadow 2 , when i started shooting 147 gr bullets with a PF of 130 i found that the gun was no grouping so well , after increasing the load to a PF of 135 s it went perfect . contrary to the stock 2 that work perfect with PF of 130 .

[uewpew]

I had similar issue with 147gr coated bullets in my VP9 (polygon rifling).  One brand, sized at .356 and had lube ring tumbled.  The other brand sized at .357, no lube ring did not tumble.  Same powder charge and velocity:  915fps = 134 PF

 

 

Edited September 10, 2016 by uewpew
replaced "grease" with "lube"

[adamge]

While we are on the topic of 147s at minor PF and measuring our PF, what tricks are you guys using for chrono'ing your 147 loads?  We always have trouble in these parts getting reliable readings on subsonic 147 loads.  At a big match I went to they had a cardboard target before the chrono sensors, I think to block the shock wave or combustion gasses from going over the sensor.  Kind of a PITA and puts the sensor at risk though.

[IDescribe]

The exact same tricks as with every other weight bullet -- shoot it over the top of the sensors.  Bullet weight has nothing to do with it.  

[uewpew]

8 hours ago, adamge said:

While we are on the topic of 147s at minor PF and measuring our PF, what tricks are you guys using for chrono'ing your 147 loads?  We always have trouble in these parts getting reliable readings on subsonic 147 loads.  

Strange....  How far away is the chrono from the muzzle?  Do you have good lighting?  Or to IDescrire's point, if you're shoot left/right of the sensor it's not going to pick it up.

Edited September 10, 2016 by uewpew
added more info

[adamge]

10' roughly?  I would consider the lighting good.  The last time I tried I had just finished chrono'ing my AR and had no trouble getting good readings with same distance and aim points.

[oddjob]

OP,

What I did was measure the thickness of an empty case  (just the wall).  Multiply that times two.  Measure the diameter of the bullets.  Empty case measurements + bullet diameter = No crimp diameter.  I got this idea from a thread here on the forum.  At the very least you'll have a baseline for a crimp diameter.  My crimp is just about none.  It solved my tumbling problems.  

Edited September 12, 2016 by oddjob

[luketmv]

On 9/9/2016 at 1:05 PM, noylj said:

Twist rate for stability with 147gn bullets is about 1:30. You are probably shooting a 1:10 to 1:16 barrel, so twist rate is NOT an issue--though one could argue that OVER stabilization could be.

What makes you believe that you have tumbling bullets? Below are pictures of REAL tumbling bullets. In many cases, what folks think is tumbling is simply NOT having sufficient target backing and getting oval holes. Were your targets backed by at least stiff cardboard?

So, if you really do have tumbling bullets, In almost all cases, undersized bullets are the problem. If shooting lead, you should be using bullets that are at least 0.002" over ACTUAL MEASURED groove diameter (normally, one would say at least 0.001" over, but for 9x19, I find that 0.002" works a LOT better). So, if you are shooting a barrel that has a groove diameter of 0.3555", you need bullets that are at least 0.3575" in diameter. I'll bet you are using 0.3555 to 0.356" lead bullets and they are simply too small for YOUR barrel. All of my 9x19s take 0.358" lead bullets without any problem.

In most cases, if you check GOOGLE, you'll find the biggest problem for 9x19 has been PLATED bullets that are groove diameter or less.

Another possibility would be damage to the barrel's muzzle that throws the bullet off as it exits and hot gasses shoot out of the damaged part of the muzzle, giving the bullet a "kick in the ass."

i know what tumbling is, i get keyhole shaped targets on proper IPSC targets. need to check on the diameter of the heads, did a bit of an experiment yesterday with a reduced crimp where i literally tossed aside the caliper and opened up the crimp die and just kept increasing until a bullet would chamber in the shadow 2 barrel. 

[luketmv]

2 hours ago, oddjob said:

OP,

What I did was measure the thickness of an empty case  (just the wall).  Multiply that times two.  Measure the diameter of the bullets.  Empty case measurements + bullet diameter = No crimp diameter.  I got this idea from a thread here on the forum.  At the very least you'll have a baseline for a crimp diameter.  My crimp is just about none.  It solved my tumbling problems.  

It seemed to solve the problem but still not 100% convinced as there were 1 or 2 throughout the day and i may have mixed up some old rounds when filling mags, will be able to confirm next weekend, i increased powder and reduced crimp, which one solved it we will never know as if it keeps working i wont change anything

[GARD72977]

My CZ will not shoot coated bullets at all. I get best accuracy with .358 lead lubed bullets. The coated bullets need to be a little larger than lubed bullets.