OAL issue

[Rich406]

I recently purchased an aftermarket barrel for my P320 x5. I sent the manufacturer a dummy round to that they could Ream the chamber to fit my ammo. This is my carry optics gun and when I went to zero it in, I was getting a 6-7” group at 15 yards from a rest. I put the OEM barrel back in, and the group size went back to 1-2”. 

 

Speaking to the manufacturer, they had me check the fit, and everything looked good. However one thing I did notice is, they must have reamed it slightly too short. My ammo ranges from 1.130-1.135 and the 1.135 rounds don’t pass the plunk test. The ammo is slightly too long, maybe .002-.003, could this be the cause of the blown out groups?

 

I’ll add that I have another barrel from the same manufacturer on my 2nd x5, and it groups beautifully with the same ammo. 

 

[Hi-Power Jack]

12 hours ago, Rich406 said:

 My ammo ranges from 1.130-1.135 and the 1.135 rounds don’t pass the plunk test. 

 

I'd shorten the ammo to 1.125 - 1.130" and see if that solves the entire problem.     

[Rich406]

6 hours ago, Hi-Power Jack said:

I'd shorten the ammo to 1.125 - 1.130" and see if that solves the entire problem.     

I tried that today, made no difference. 

[Sarge]

2 hours ago, Rich406 said:

I tried that today, made no difference. 

Just as a test, shorten it even more until it drops in.

[Rich406]

9 minutes ago, Sarge said:

Just as a test, shorten it even more until it drops in.

 

I made up some 1.120 ammo and that made no difference. I’ve come to find that it’s something in the gun itself. I switched barrels with my x5 that was running good, and the problem went away. When I put the barrel from the good x5 into the problem gun, I had the same blown out groups. 

 

I spoke with he manufacturer, and they really had no ideas on what else to check. I’ll probably end up sending the complete gun into them to check out. 

[Hi-Power Jack]

53 minutes ago, Rich406 said:

 

I made up some 1.120 ammo and that  made no difference.  

 

From your initial post, it seems like there are two different problems:

  1.  Your rounds won't plunk

  2.  Your rounds are not accurate

 

When you say the 1.12 ammo "made no difference", do you mean :

 

  1.  they still do Not plunk ?

or

  2.  the rounds plunk, but they're still Not accurate ?

[Rich406]

23 minutes ago, Hi-Power Jack said:

 

From your initial post, it seems like there are two different problems:

  1.  Your rounds won't plunk

  2.  Your rounds are not accurate

 

When you say the 1.12 ammo "made no difference", do you mean :

 

  1.  they still do Not plunk ?

or

  2.  the rounds plunk, but they're still Not accurate ?

 

The rounds still didn’t shoot accurately in that barrel. 

[Sarge]

7 minutes ago, Rich406 said:

 

The rounds still didn’t shoot accurately in that barrel. 

Oh, that barrel just wants a different load probably. Shorten, lengthen, drop charge, add charge, reduce crimp, increase crimp, etc. No two barrels are the same.

[Rich406]

6 minutes ago, Sarge said:

Oh, that barrel just wants a different load probably. Shorten, lengthen, drop charge, add charge, reduce crimp, increase crimp, etc. No two barrels are the same.

 

The barrel shoots perfectly in one gun, and has 7” groups in another gun. Something off with how it locks up. I asked the initial question last night when I was still speculating what the problem was. 

[Hi-Power Jack]

31 minutes ago, Rich406 said:

 

  Something off with how it locks up. 

 

Right, that new barrel has to be fitted better.   

 

But, what length bullets are you now using ?   1.125" ?

[Rich406]

1 hour ago, Hi-Power Jack said:

 

Right, that new barrel has to be fitted better.   

 

But, what length bullets are you now using ?   1.125" ?

 

I’ll have to work up a shorter load. For now, I have 5-6k of my 1.135 oal to use up. 

Edited December 12, 2018 by Rich406