Tactical Sport accuracy

[twister]

I shoot my 9mm Tactical Sport in NRA action pistol, and a PPC league, and want to know if there's any work I can have done to make the gun more accurate? I've already installed the Cajun 10x bushing. Any help is appreciated, thanks, Dave.

[tanks]

What is the accuracy like now? What ammo are you using?

[twister]

I'm using my own hand loads of 4 gr. Of VV320 with a 115gr. Hornady JHP. The accuracy is pretty good, but if there's anything I can o to make it better, I'd like to get it done now. Thanks for the quick reply.

[Jmo2011]

25 minutes ago, twister said:

I'm using my own hand loads of 4 gr. Of VV320 with a 115gr. Hornady JHP. The accuracy is pretty good, but if there's anything I can o to make it better, I'd like to get it done now. Thanks for the quick reply.

What does this load chrono?  When I went to115 grain bullets in my Cz LS-P accuracy got much better as I sped them up. 

[twister]

They're right at 1120 god. I also found when my rounds got to 1100 fps,the group started to tighten up. I was thinking of trying a 125 gr. Hornady jhp, I'll probably load some up before I go to the range again.

[Jmo2011]

I'm having good results at 1175-1200 with 115 gr  from precision delta

[twister]

What powder and charge are you using to get that Jmo2011?

[Jmo2011]

My last batch I loaded was 4.3 grains titegroup. Prior to that I loaded a batch with n320 but it did require more powder to achieve the same speed. 

[himurax13]

My CTS Longslide has tighter groups than my SP01 Shadows out of the box. I am going to install a CGW bushing down the road and maybe a CZ Match barrel.

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[twister]

I didn't know they made match barrels for the CZ, where can I find one? Thanks, Dave.

[Ken6PPC]

1 hour ago, twister said:

I didn't know they made match barrels for the CZ, where can I find one? Thanks, Dave.

 

Here is one place:  

https://czcustom.com/cz-parts-all/barrels-complete-upper.html

[twister]

I thought those were replacement barrels, I'll have to call CZ Custom and find out about them, thanks for the help.

[IDescribe]

Keep in mind the diminishing returns.  If you already have a 10X bushing, you shouldn't expect much more from the barrel.  In fact, if you have a 10X bushing and no crown damage, but accuracy is in need of improvement, I would try to adjust ammo first. So...

 

On 7/17/2017 at 0:09 PM, twister said:

I'm using my own hand loads of 4 gr. Of VV320 with a 115gr. Hornady JHP.

 

You say 115gr JHP.  Do you mean 115gr HAP?  115gr XTP?  I have found 115gr Hornady HAPs to be exceptionally accurate in my CZ pistols, and if you buy in bulk, you can get them down to 10-11 cents per bullet, which is a good price for that quality.  The XTP is also exceptionally accurate, but much more expensive.  If you are talking about some other Hornady bullet, and you want to stick with Hornady, I'd upgrade to the HAP.  The 125gr HAP is also supposed to be exceptional, though I haven't shot it myself.   You may also want to look into using Precision Delta or Zero Bullets .357 Sig bullets, which are sized .356 instead of the standard 9mm Luger .355.  This slight .001 over-size often makes a better bullet to barrel fit in 9mm pistols, and improves accuracy.  

 

 

On 7/17/2017 at 3:29 PM, twister said:

They're right at 1120 god. I also found when my rounds got to 1100 fps,the group started to tighten up.

Don't get tricked into thinking faster is more accurate.  It is common to find accuracy nodes with a particular bullet/powder/pistol combination.  When someone is working up a ladder, and they get to a load where groups tighten up, it can seem like groups tightened up because they got faster, when in fact they tightened up because they got into an accuracy range/node, and if you continue to go faster still, you may see accuracy drop back off.  So it's not about a faster velocity, but about the right velocity.

 

I recently ran some accuracy tests with the same 124gr jacketed bullet in my CZ-75 ShadowLine with six different powders.  With all powders, there was a charge weight that was distinctly more accurate than the others, and the average muzzle velocities for those loads with the same bullet and six different powders ranged from 1066 and 1081. And with all six powders, a tenth of a grain higher saw groups loosen back up.  That's my pistol with those bullets, but I will say that after I recognized the trend, I realized that every minor PF pet load I've got for that pistol with ANY 124/125gr bullet falls into a PF range of 132-135, so a velocity range of roughly 1060 to 1090 .  I doubt that's a random coincidence.  I'm pretty sure that pistol likes that bullet weight in that velocity range.  NOW, that doesn't mean there's not another accuracy node somewhere higher.  In fact, there certainly is.  But if I wanted to find it, I would want still want to stay out of what's called the transonic range, which is where you are with those 115gr bullets.

When a bullet travels supersonic, it creates a bow-wave of compressed air.  As the bullet slows down, it sort of catches up (not exactly what happens, but easy to conceptualize) with the bow wave and passes through it. You have probably seen video at some point or another of a fighter jet slowing down, and these large disks of water vapor appear around the jet as if the jet is passing through them.  That's what that is -- the bow wave.  The jet is passing through its own bow wave, and some air is passing around the jet at super sonic speeds, and some air at subsonic speeds, and it pushes the jet around.  It's the same with a bullet.  When the bullet slows down and goes from supersonic to subsonic, it is buffeted about while passing through its own destabilizing bow wave, and precision is affected negatively.  It doesn't happen just at the sound barrier.  It might start 20-30 feet/sec over the sound barrier and continue 15-20 feet below the sound barrier.  That range that straddles the sound barrier is the transonic range.  If you are looking for ultimate precision, your goal should be to stay out of that range for the entire flight of the bullet.  If the sound barrier is 1120, you should want to keep your bullet outside of 1100-1150 from muzzle to target, and since bullets decelerate in flight, you need to start higher than 1150.  At 50 yard targets, you might want to keep the muzzle velocity at 1200 or over, to make sure the bullet hasn't decelerated into the transonic range before hitting the target.  

This doesn't usually matter for action shooting since most handloaders use 124gr or heavier bullets and keep them below 1100, but if you're shooting a 115gr bullet, the common minor power factor range is going to put you right in that transonic range.  

To be clear, I'm not saying this is going to make your 115gr loads outright inaccurate.  They most likely are still suitably accurate for action pistol if used in the transonic range.  Like so many other loading considerations, something having a negative impact does not always mean having a significantly negative impact, and you should always accept measurable results over theory, but if you're looking to improve precision, this is one easy avenue to pursue.  I personally keep my pistol loads under 1100 or over 1200.  It's not a difficult restriction to work with.   And if you prefer to use fast burn rate pistol powders to keep down recoil, your best course of action may in fact be to go with that 125gr Hornady HAP and find the most accurate load near but under 1100 feet/sec.  I wish you luck.    

[himurax13]

I didn't know they made match barrels for the CZ, where can I find one? Thanks, Dave.

CZ customs makes their own.

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