Absurd accuracy problem with a P80

[zaitcev]

I'm having a very strange accuracy problem with a 9mm P80 with a Faxon barrel. It sounds unbelievable, but please hear me out.

Here's a target at 10 yards:



Looks like nothing special - it's what happens when someone jerks the trigger, right? But nope. Here's what really happens:

The shots are taken from a rest, slow fire. First shots are very close to the POA. Ignore the windage being off, it's the rear sight. However, as the magazine is getting drained, the center of the hits starts creeping down, towards the area marked with "15". Total size of the drift appears to be about 3.5".

If I let the gun "rest", then it returns to hitting the POA. Seems like something heat related, then.

Anyone has any idea what is going on? I know that an M16 barrel can do something like this as it heats up, but it does the same drift amount at 100 yards, not 10 yards. This drift is much too large for uneven stress bending the barrel. So, what is it?

 

[Coal Dragger]

It doesn’t appear that you are capable of shooting groups at 10 yards and want to blame the equipment.

Jerking the trigger from a rest still has an effect on your results.

Can you shoot an 80% or higher score on a B8 bullseye target at 25 yards standing off hand with any handgun you have ever fired?

If the answer is no, find someone who can and have them shoot your pistol for you to determine if it’s a gun problem or a you problem.

 

[Slamfire]

Jerking the trigger from a rest still has an effect on your results.

Handguns are hard. I have been shooting Bullseye Pistol for five years and I am slowly getting to the point that all shots are on target. But not on the repair center.

Guys who shot like this, with a 45ACP, are Gods!

 

[jhb]

wouldnt it take a whole lot of rounds to have enough heat to have any effect? few mags couldn't have much if any effect....could it?

 

[edwardware]

Yup. I've learned to never blame a pistol for accuracy issues, no matter how well-rested, until another skilled pistol shooter duplicates the problem.

No offense intended, but I bet it's you. Get a friend to shoot it from a rest.

 

[murf]

put the stock barrel back in and make sure it is not the weapon.

luck,

murf

 

[JohnKSa]

If it were just a nice straight line moving downwards, I would be more confident of something changing in the gun although that much "walk" on the POI at only 10yards is hard to explain.

The separate groups off to the left worry me though. I can't think of what would move things over and then suddenly move back after a few shots. That makes me wonder about some kind of shooter error or a problem with technique while shooting from the rest.

 

[Kano383]

Check the dustcover/slide gap when cold, and when hot. Any difference?

As for the "Gun is fine, you just can't hit a barn shooting from inside" theories... The gentleman has tried more than once, has seen that when the gun is cold POA/POI are close, has questioned himself already... What makes you think that he would be jerking/flinching/messing around in a consistent pattern, and would be too dumb to notice?

He did not specify, but I infer that he has shot handguns before, and has a pretty good idea of his own shooting capabilities...

 

[Zaydok Allen]

Check the dustcover/slide gap when cold, and when hot. Any difference?

As for the "Gun is fine, you just can't hit a barn shooting from inside" theories... The gentleman has tried more than once, has seen that when the gun is cold POA/POI are close, has questioned himself already... What makes you think that he would be jerking/flinching/messing around in a consistent pattern, and would be too dumb to notice?

He did not specify, but I infer that he has shot handguns before, and has a pretty good idea of his own shooting capabilities...

Because it’s a classic low left hit pattern that comes with flinching or trigger jerk. So it’s not out of line to tell the shooter he needs another opinion.

Another shooter or a Ransom rest is needed to confirm mechanical or shooter error.