Accuracy Differences

[Sinplicity]

So I took 2 of my K9’s to the range today. The accuracy difference between the two was shocking to me. My EDC (Aug 2014 build) K9 will put 5 rounds in one hole at 7yds. My new to me older K9 (not sure the build date, but serial number starts with ARxxx) had a significantly larger spread along with shooting high. I switched barrels and the differences tracked with the barrel change. There were also consistent first-round flyers with EITHER pistol. NO, those weren't operator error, although I admit that is typically the first thing to look for. Those were the FIRST rounds of five round strings, it occurred across both pistols and I can make it happen (or not) depending on how I chamber a round from a fresh mag. Using the slide stop resulted in the first round always going left. Pulling the slide ALL the way back and letting it fall consistently resulted in the first rounds going where they were intended.

Interesting results to say the least. I’ve ran my EDC K9 through countless IDPA matches as well as through a few 2 or 3 day training courses. It’s always preformed great. The first round flyer was a new discovery and interesting in and of itself. I was pretty disappointed with this older one. Bought it because it had the old dovetails and was thinking of milling the slide for a RDS. Now it looks like I need to put a new barrel in it first. I've got 3 K9's, a T9, MK9 and a PM9. All shoot one hole groups except for this old K9. She may just be wore out...

I took photos of the target, intending to post them to this thread, but apparently I don't have permission to post attachments... Bummer...

[gb6491]

At 30 posts you will be able to attach images. However, you can upload images to an off sight host and link them here. I use postimages.org
After you upload an image there, a page will open with links on it. Copy the link for "Hotlink for forums:" and paste it here in your message:
https://s22.postimg.cc/5lrdxnhv5/DSC2103.jpg (https://postimages.org/)
Alternatively, you can copy from the "Link" and paste it here using BB code put link here


As to your K9s:
First round fliers - you might try a plunk test by pulling the barrels then dropping a live round into the chambers to how they seat.
http://i58.tinypic.com/15d53ic.png
As you write "Using the slide stop resulted in the first round always going left. Pulling the slide ALL the way back and letting it fall consistently resulted in the first rounds going where they were intended.", I wonder if you will see the case sitting a little proud of the barrel hood when you just drop a round into the chamber.

Old K9 accuracy - I've found lead fouling can sometimes be hard to see, perhaps that's the case here. You might try some lead cleaning patches or a real hard scrubbing to see if there's any improvement.

That's all that comes to my mind at the moment.:confused:

Regards,
Greg

[Sinplicity]

Thanks for the feedback, Greg, all the way around. I’ve been lurking this forum for a LONG time gleaning information from a lot of quality people. Noted on the post count for images. I’ll work on getting my count up!

Great thought on chamber fit and barrel lead. I hadn’t thought about lead buildup. I’ll check both those things when I get them tore down later this evening.

[Sinplicity]

So I ran a couple tests tonight. I checked the bullet headspace with the rounds I was using today (factory PMC 115 bulk ammo.) Took two rounds out of the box and measured their Over All Length (OAL) with a set of calipers. Both were 1.154" +/- 0.0005 (calipers.) I then used one of the rounds to check headspace. Using a depth mic, I was surprised to see the round fit just under 0.0005" below the barrel "hood" (not sure what that part of the barrel is called.) That measurement was consistent across all three K9's.

I then took that one round and chambered it using the slide stop lever. Pulling it back out showed it still measured 1.154". Re-chambering it using the "sling shot" method yielded the same results: no discernible change in OAL of the round.

I didn't see any lead in the suspect barrel, but it's soaking now and I'll be cleaning the snot out of it when I finish this post. As far as the flier round based on chambering method, I'm still scratching my head... I was hoping you were onto something with that.

[Sinplicity]

BTW, Greg. Just saw where you were located. Both sides of my family hail from that neck of the woods. My grandfather was a Graham County Deputy for a few years. My dad tells stories of being thown in the Graham County jail when he misbehaved as a toddler. I think we still have kin in the Safford/Thatcher area. It's a small world!

[Sinplicity]

So the first photo shows a 5-Spot target. Range was 7yds. Top target was my EDC K9. I think there were 10 rounds there (I was loading 5 rounds in the mag and shooting groups.) Next one down was the older K9, first 5 rounds. That was when I noted the 1st-round flyer. Also note how the group shot high. Lower target was 2 mags of 5 through that old K9 with me doing everything I could to manage sights and trigger. Note the 2ea. first round flyers.

https://s20.postimg.cc/8bj18vw5l/image1.jpg (https://postimg.cc/image/8bj18vw5l/)

This was me duplicating the 1st round flyer with my EDC K9. Like I said, I can make that happen or not, based on how I chamber the round.
https://s20.postimg.cc/potbnqz6h/image2.jpg (https://postimg.cc/image/potbnqz6h/)

[gb6491]

That's pretty darn good shooting with your EDC K9. I see why you carry it!

Some other thoughts:
Have you checked the primer hits, looking for any differences between the flier cases and the others? I'm thinking along the lines that some offset of the hit on the flier cases from where it is on the other cases might suggest something about how the gun is locking up.

Is there any burr/peening/other damage or wear to the area where the slide and barrel lock up? Same question in regards to the bottom barrel lug and where it contacts the slide stop pin. Anything on the barrel hood or breech face?

I'm a little further west (near Yuma), but is good to see Arizona being further represented on the board:)
Darn inconvenient having two Gila Mountain ranges in the same state:bump2:

Regards,
Greg

[Bawanna]

Nice knife Greg, one of my favorite things next to guns. Great for cleaning the nails after a day in the dirt.

That's a nice one.

[gb6491]

Nice knife Greg, one of my favorite things next to guns. Great for cleaning the nails after a day in the dirt.

That's a nice one.
Thanks boss. It has seen a lot of use and held up well. I guess that should expected from a blade made by the Royal Kami!
Regards,
Greg

[Bawanna]

And a Bura to boot. Makes it twice as nice.

[Barth]

Barrels are unique friend.
Same manufacturer, same caliber and same length.
Different accuracy and/or velocity.
One may favor a particular weight and/or manufacture ammunition.
That's just the way it is...

Barth Six Barrels

[Sinplicity]

I could definitely see that making a difference in group location (shooting high like it did.)
I cleaned that old K9 to make sure it was free of lead. Next time I get it out I’ll take your suggestion and bring several types of ammo. We’ll see if it was lead buildup, finicky about ammo type or operator error.

[Bawanna]

Never ever admit operator error, that's unmanly. Blame it on the gun, the ammo, the weather, be creative.

[Barth]

I could definitely see that making a difference in group location (shooting high like it did.)
I cleaned that old K9 to make sure it was free of lead. Next time I get it out I’ll take your suggestion and bring several types of ammo. We’ll see if it was lead buildup, finicky about ammo type or operator error.

My MK40 40 S&W likes anything 180 gr.
All my 9 mm guns favor 147 gr from any manufacturer.
Try some 147/150 Federal HST or 147 Winchester Ranger T-Series.
I'm running Federal Micro 150s in my micro 9mm guns...

Ammo Matters