Kkm For G17

[nphd2000]

I'm wondering if anyone else noticed this on their KKM barrel. I bought a comped 9mm KKM barrel to build a sudo SJC G17 steel gun (Can't swing the $ for a real 1). The gun wouldn't cycle reliably with factory ammo (even wolf). A friend of mine noticed the right side barrel hood (where "KKM Precision" is written) had wear or rub marks on it like it was rubbing the slide. We took the barrel out and noticed that the barrel foot where it contacts the locking block had a distinct contact line on it but only on the right side, about 1/2 way across the foot, then it stopped. It seems the barrel foot is contacting the right side of the locking block first and cocking the barrel in the slide. The stock barrel doesn't have the 1/2 wear mark. Anyone else notice this? I have about 300 rounds through the barrel. I contacted KKM, just wondering what other people thought.

Thanks.

[Kimberkid]

This is why they are called "semi" drop in. Some dont.

Also, you might not wanna use Wolf as your gold standard for test ammo.

You might take a stone and gently take off a very small amount where you see rub marks, or find a gunsmith and get him to final fit it.

[SRT Driver]

My G34 has a KKM installed.

I noticed the same thing and contacted Kevin in Oct of last year. He basically said he had never heard of this but offered to replace the barrel.

I never sent the old one back.. it still shoots fine.

[Kevin Kline]

Some drop ins fit fine, other require a little bit of work. My fit perfectly and hasnt malfunctioned yet, shoots great. Im sure it is only a very small amount of fitting.

[coltgov]

If you cycle it by hand and it feels fine, then it may be too heavy a recoil spring. Try 13 lbs, then 11lbs. If that doesn't work, then you need to handload for a higher PF using slower burning powders. Also see if you are limp wristing.

[D. Manley]

I'm wondering if anyone else noticed this on their KKM barrel. I bought a comped 9mm KKM barrel to build a sudo SJC G17 steel gun (Can't swing the $ for a real 1). The gun wouldn't cycle reliably with factory ammo (even wolf). A friend of mine noticed the right side barrel hood (where "KKM Precision" is written) had wear or rub marks on it like it was rubbing the slide. We took the barrel out and noticed that the barrel foot where it contacts the locking block had a distinct contact line on it but only on the right side, about 1/2 way across the foot, then it stopped. It seems the barrel foot is contacting the right side of the locking block first and cocking the barrel in the slide. The stock barrel doesn't have the 1/2 wear mark. Anyone else notice this? I have about 300 rounds through the barrel. I contacted KKM, just wondering what other people thought.

Thanks.

I use a comped (new 3-port version) KKM on my G34 so the situation is very similar to yours. When I ordered, I asked about recoil springs and they said I would likely have to go to 13 LBs. I had a 15 in the gun and tried it using factory 115 GR loads and it would FTE every few loads. The 13 LB spring helped quite a bit but it required removing about 4 1/2 coils to solve the problem. I might note that 147 GR loads cycle the 15 LB spring reliably...the "snap" of ejected brass is noticeably better with the heavier load. I did not have a production 11 LB spring with me the day I did the springs test but have one now and intend to try on next opportunity.

[SA Friday]

I'm wondering if anyone else noticed this on their KKM barrel. I bought a comped 9mm KKM barrel to build a sudo SJC G17 steel gun (Can't swing the $ for a real 1). The gun wouldn't cycle reliably with factory ammo (even wolf). A friend of mine noticed the right side barrel hood (where "KKM Precision" is written) had wear or rub marks on it like it was rubbing the slide. We took the barrel out and noticed that the barrel foot where it contacts the locking block had a distinct contact line on it but only on the right side, about 1/2 way across the foot, then it stopped. It seems the barrel foot is contacting the right side of the locking block first and cocking the barrel in the slide. The stock barrel doesn't have the 1/2 wear mark. Anyone else notice this? I have about 300 rounds through the barrel. I contacted KKM, just wondering what other people thought.

Thanks.

I use a comped (new 3-port version) KKM on my G34 so the situation is very similar to yours. When I ordered, I asked about recoil springs and they said I would likely have to go to 13 LBs. I had a 15 in the gun and tried it using factory 115 GR loads and it would FTE every few loads. The 13 LB spring helped quite a bit but it required removing about 4 1/2 coils to solve the problem. I might note that 147 GR loads cycle the 15 LB spring reliably...the "snap" of ejected brass is noticeably better with the heavier load. I did not have a production 11 LB spring with me the day I did the springs test but have one now and intend to try on next opportunity.

So, is it the comp is 'bleeding' (ignorance on my part as to the best way to identify this) energy from the fired round and the heaver spring is stopping the slide from fully cycling? The heavier round causes more pressure so it cycles more reliably? Or... is it the extra weight at the end of the barrel is causing the cycle of firing to be out of sinc? Also... the barrel and foot markings are not the cause of the malfunctions and it would cycle fine without the comp? Or are the barrel and foot markings something to potentially look at as the cause (or separate issue but should still be addressed by fitting)?

Also, doesn't cutting coils off of the recoil spring make the spring heavier? I don't understand the concept behind cutting coils off, but am very curious about this.

Sorry bout all the questions, but this string caused more questions than answers for this layman.

Edited April 19, 2006 by SA Friday

[nphd2000]

Sorry for the confusion this thread may have caused. I was realy just wondering if anyone else that had a KKM barrel noticed any kind of wear marks on the barrel. This is the first 1 I have owned and the groups are tight but I had difficulty getting the gun to cycle with store bought 9mm ammo (wanted 9mm for static steel). The comp does bleed of pressure (suppose to, thats why it's there) but I understood that other people use factory ammo and the gun cycles. I put an 11 pound spring in the gun and it helped but sometimes the gun would not go all the way into battery. A friend of mine said "polish the inside of the slide, it may be rubbing slightly on the barrel hood" when I took the gun apart I noticed the side of the barrel had rub marks on one side only. I took it to my friend and he looked at the barrel foot and noticed the 1/2 wear mark also. The real confusing part was the foot mark and the rub mark are on the same side, it they were on opposite sides I would say the barrel is cocking to the side when contacting the locking block, but thats a whole different thread. I contacted KKM and he pretty much told me "Thats normal, if it groups good don't worry about it" but he also said "Send it to me and I will look at it if you would like". Some fellow shooters say "send it back" others say "shoot the darn thing it ain't broken in yet" I was just wondering what the broad spectrum of people on here thought, and if anyone else experienced this.

Let me add that I do have a hand load using HS-6 and 115 JHP's that cycles the gun and shoots flat but the wear marks are still on the barrel and I am concerned that they will get worse and start effecting the accuracy, or, is it like slide peening? (Oh no, now I'm thinking 2 much)

Edited April 19, 2006 by nphd2000

[coltgov]

From what I noticed on my KKM, it wears the matt finish off and leaves it shiny. I think the tennifer surface hardening Glock does on the slide may polish the KKM barrel where it contacts. My wear marks is right on the right side and above the KKM PRECISION engraving.

[SA Friday]

Sorry for the confusion this thread may have caused. I was realy just wondering if anyone else that had a KKM barrel noticed any kind of wear marks on the barrel. This is the first 1 I have owned and the groups are tight but I had difficulty getting the gun to cycle with store bought 9mm ammo (wanted 9mm for static steel). The comp does bleed of pressure (suppose to, thats why it's there) but I understood that other people use factory ammo and the gun cycles. I put an 11 pound spring in the gun and it helped but sometimes the gun would not go all the way into battery. A friend of mine said "polish the inside of the slide, it may be rubbing slightly on the barrel hood" when I took the gun apart I noticed the side of the barrel had rub marks on one side only. I took it to my friend and he looked at the barrel foot and noticed the 1/2 wear mark also. The real confusing part was the foot mark and the rub mark are on the same side, it they were on opposite sides I would say the barrel is cocking to the side when contacting the locking block, but thats a whole different thread. I contacted KKM and he pretty much told me "Thats normal, if it groups good don't worry about it" but he also said "Send it to me and I will look at it if you would like". Some fellow shooters say "send it back" others say "shoot the darn thing it ain't broken in yet" I was just wondering what the broad spectrum of people on here thought, and if anyone else experienced this.

Let me add that I do have a hand load using HS-6 and 115 JHP's that cycles the gun and shoots flat but the wear marks are still on the barrel and I am concerned that they will get worse and start effecting the accuracy, or, is it like slide peening? (Oh no, now I'm thinking 2 much)

nphd2000, please don't read into my post as you were unclear. That wasn't my intention with the questions. I am very curious about this and some of the subsequent posts, so I asked a bunch of questions in an attempt to gather more info from some of the other more experienced members. Sorry if I made it sound like there was confusion from your initial post. I have been parusing the older posts about barrel fittings and recoil springs because I wanted to learn more about these two subjects. This post was generating the questions I had been wanting info on too, so I asked here. Once again sorry about the misunderstanding.

[nphd2000]

No harm done Friday, thats why we are here to ask questions and learn.

I felt that the barrel rub was causing the gun not to cycle properly and thats what started this post. Of course , before I noticed the rub marks I was messing with loads and spring weights. One thing I learned is you may have to go above "mouse fart" loads to get the gun reliable. I think I'm going to shoot the gun more and see what happens with the barrel "rub".

Turns out all the stuff I did during my slow standing practice (Range rules you know) went out the window during an actual USPSA match. The "feel" of recoil and muzzle blast while "practicing" at the indoor range is amplified. Shooting the same set-up at a match feels completely different.

Nick

Edited April 21, 2006 by nphd2000