CM9 bbl. in a PM9 [Archive]

JimC

11-30-2011, 08:05 AM

I sent Kahr customer service an e-mail yesterday asking if the CM9 bbl. would drop into the PM9 pistol and work.

Their answer was "unfortunately they are not interchangeable." :(

I was going to buy a CM9 bbl. to chronograph loads and compare the readings between the conventional rifling of the CM9 bbl and the polygonal rifling of the PM9 bbl. in order to settle the never ending question as to which of the two produces the higher velocities.

I also have about 600 rds. of lead bullet 9mm loads that I wanted to shoot up and the CM9 bbl. w/it's rifling would have worked well for this.

I guess it ain't going to happen.

rwblue01

11-30-2011, 09:08 AM

Based on my experience with Glocks.....you should not have a problem shooting some lead in the polygonal barrel. My suggestion is to run 100 rounds (or less) lead, then 20 rounds FMJ.

Thunder71

11-30-2011, 09:28 AM

If they are not interchangeable I guess the internals aren't as exact as one might think.

I wonder what else is different?

HeyGuysWatchThis

11-30-2011, 10:04 AM

OldLincoln

11-30-2011, 10:09 AM

Based on my experience with Glocks.....you should not have a problem shooting some lead in the polygonal barrel. My suggestion is to run 100 rounds (or less) lead, then 20 rounds FMJ.
I have no experience so bow to others knowledge.... I read that the poly rifling gathers lead and lead bullets will deform to allow for that while FMJ will not (why they clean the lead out). The danger is to get the FMJ through a leaded barrel drives pressure way up. The recommendation I read was to clean the lead out before shooting FMJ.

Don't know anything other than what I read so it's certainly not gospel but wanted it out there for discussion before someone does it.

JimC

11-30-2011, 10:10 AM

Based on my experience with Glocks.....you should not have a problem shooting some lead in the polygonal barrel. My suggestion is to run 100 rounds (or less) lead, then 20 rounds FMJ.

Thanks but I'm familiar with shooting lead thru polygonal barrels, I've been doing it for many years and I'm also aware that there could be negative consequences doing so.

Contrary to what you may believe, it's NOT a good practice to shoot jacketed bullets thru a barrel or any rifling configuration after shooting lead, especially if the lead is on the soft side and you get some build up. The jacketed bullets will actually cause the lead already on the bore to bond to the bore.

Shooting lead was only a secondary thought. As I said initially...I wanted the CM9 bbl. to do some chronograph testing and compare the two.

JimC

11-30-2011, 10:16 AM

I think you may have been just talking to one of their CSR reps, not a gunsmith. Don't we have several members on here with both guns? Seems to me this question should be pretty easy to answer. If the barrels can be swapped and then they feed rounds, that should answer the question.

I don't know in what capacity Jay at Kahr Arms serves but he said " unfortunately they are not interchangeable" so his word is good enough for me before I lay out $140.80 for the barrel. ;)

Send them an e-mail of your own and ask for a response from a gunsmith... service@kahr.com

JimC

11-30-2011, 10:18 AM

I have no experience so bow to others knowledge.... I read that the poly rifling gathers lead and lead bullets will deform to allow for that while FMJ will not (why they clean the lead out). The danger is to get the FMJ through a leaded barrel drives pressure way up. The recommendation I read was to clean the lead out before shooting FMJ.

Don't know anything other than what I read so it's certainly not gospel but wanted it out there for discussion before someone does it.

Your are correct and this is what causes the "KABOOMS" as they are referred to in Glocks.

Plus the lack of support for the case head in the .40 S&W caliber models.

jlottmc

11-30-2011, 10:50 AM

I dunno, that sounds a bit fishy about the bbls not being interchangeable. My wife has a CW45, and I have an older P45, all the parts I have messed with are interchangeable. I took the top end off, and swapped frames, and slide stops to prove a point to her. All good in my book. The cm9 bbl may need a little tweaking to be on a different gun, but most guns are like that to get that final fit.

rwblue01

11-30-2011, 10:58 AM

Your are correct and this is what causes the "KABOOMS" as they are referred to in Glocks.

Plus the lack of support for the case head in the .40 S&W caliber models.

The 40 is a different animal. It is loaded with less margin for error.

The 9mm has a greater margin of error as you can see in the commercial loading with include +P and ++P loads.

I have done it with no ill effects. If you don't feel safe doing it, then don't.

Ikeo74

11-30-2011, 01:40 PM

JimC

11-30-2011, 01:44 PM

Jim, to settle this once and for all, just buy a CM9 to add to your collection and go shoot and test them side by side. :D

Yup, just what I had in mind...NOT! :D

BEARDOG

11-30-2011, 02:05 PM

Yup, just what I had in mind...NOT! :D

Oh come on Jim, they are practically giving away CM9's at Bud's...only $386 shipped!
http://www.budsgunshop.com/catalog/product_info.php?products_id=76031

Then you can sling lead in one hand, and jacketed in the other!!! ;)

jocko

11-30-2011, 02:14 PM

Jim, to settle this once and for all, just buy a CM9 to add to your collection and go shoot and test them side by side. :D

I find that hard to believe. I would sur elike to know what tyhe diffrerence is EXTERNALLY..

kayl

11-30-2011, 03:55 PM

Oh come on Jim, they are practically giving away CM9's at Bud's...only $386 shipped!
http://www.budsgunshop.com/catalog/product_info.php?products_id=76031

Then you can sling lead in one hand, and jacketed in the other!!! ;)

Even cheaper at Cheaper Than Dirt (Can't link, at work) - I think they're at about $340-$350 shipped!

Thunder71

11-30-2011, 03:57 PM

At that price... hmmm...

MK9/PM9/CM9 ... gotta have one of each flavor, right?

Bawanna

11-30-2011, 04:18 PM

I tried to find the source I heard it from regarding lead and polygonal barrels. I saved it for just such an occasion and put it someplace where I knew I wouldn't lose it. You know how that goes.

Based on what I recall it really isn't a buildup even far as the lead goes its a pressure situation. The article and it was from a viable source although I can't recall that either said you could shoot a 1000 rounds of lead through a poly barrel but it could blow up on 1001 or 597 or #1. Many get away with it without issue so I don't think there's any way to really foresee it coming.

Jay @ Kahr is a respected source (I don't know him personally) but if he says the sky is falling you better grab your hard hat.

JimC

11-30-2011, 04:25 PM

I find that hard to believe. I would sur elike to know what tyhe diffrerence is EXTERNALLY..

Here ya go... jay.dandrea@kahr.com ask him for yourself. ;)

JimC

11-30-2011, 04:28 PM

Jay @ Kahr is a respected source (I don't know him personally) but if he says the sky is falling you better grab your hard hat.

My opinion also. I have dealt with him via e-mail several times since I purchased my PM9 in July and I have always trusted his advice/opinions on Kahr related issues.

I trust him more than I do Internet supposition or conjecture.

Bawanna

11-30-2011, 04:35 PM

My opinion also. I have dealt with him via e-mail several times since I purchased my PM9 in July and I have always trusted his advice/opinions on Kahr related issues.

I trust him more than I do Internet supposition or conjecture.

I trust him too but where do I fit in? You think I'm a supposition or a conjecture. I'm gonna have to look them up, both kind of sound like they might me wild arse guess?

I guess if I get to choose I'd pick conjecture, a little more macho sounding, now I'm sure if Dietrich was to choose he'd pick supposition on account of his fondness for similar sounding words and such. Maybe I'll ask him, this will make his day.

JimC

12-01-2011, 07:07 AM

Thunder71

12-01-2011, 07:12 AM

BS

LMAO :)

Thanks for the follow up!

jocko

12-01-2011, 07:12 AM

huymm very interesting indeed. thanks. Jim C, ur on the ball. would have made for a nice test to..

I wonder if anyone is on our fourm who has both and who could post a photdo of each barrel so we can see what changes kahr made... I think I will now pull my abouve thread to. not trying toargue here with anyone, just trying to understand why they made this change..

kahrlover123

12-01-2011, 08:53 AM

I have the PM9. Some of my buddies have CM9. Would I want to change the barrel to find out? Hellllllllll Noooooooooooo.
My PM9 is shooting perfectly. Why do I want to screw things up? Specially Jay from Kahr (I've dealt with him lots of times too) already says NO :D

CJB

12-01-2011, 09:13 AM

On the lead - polygonal - pressures thing... I dunno.

Here's what goes thru my mind, with some considerable first hand "guy behind the counter at the range" experience - about ten years worth.

If you're shooting lead thru a poly barrel, and it starts to lead up, the #1 thing thats gonna happen is you're accuracy is gonna go to poo. You're gonna keyhole, and get whing-ding fliers. You're gonna experience other problems - as lead will build up at the front of the chamber, as also will lube used, no matter if its "dry" or not.

Good sense says - hey clean the damn thing out!

Practical sense says, if you're shooting lead, lots of lead... pop a brush thru that puppy every so often! I wont go into de-leading procedures, but higher speed lead bullets will lead more than the same bullet at lower speeds. Same with lead hardness, harder being less likely to leave deposits.

Just sayin... its a problem that can managed

~~~

Also... I've followed the Glock KABOOM events pretty closely. To the best of my knowledge, there's been a big deal about frame problems, some barrel problems, some slide issues... but not seeing much on lead-in-the-bore issue as being a source of KABOOM. Not saying some idiot didn't have an issue. Not saying the issue was really lead either, because something like a lead squib might be attributed to lead in the bore "after all everyone knows you're not supposed to shoot lead in a Glock". I'm sure someone someplace sometime may have shot enough lead thru a Glock to cause an issue.... statistically its possible.

~~~

Funny thing too, when you really lead up a gun... you get this tube of lead... irregularly shaped on the end, that protrudes from the end of the barrel. Quite literally, if a customer was shooting lead, and noticed the "tube", and complained, we'd just take a pocket knife and cut it off, and hand him back the gun (usually our rental).

In cases at the range - we loaded everything fairly soft (lead was cheap, tin/antimony more expensive). We had to load the 9's and 45's enough to cycle the guns. The 357's were really dirty though. We had NO control of what folks shot in guns before, after, or during the shooting of our El-cheapo reloads. Not once in ten years did I see a barrel go south due to leading of the bore, and subsequent shooting of high power ammo through a dirty bore. I did see my share of squibs, a few egg'd barrels from squibs, and one blown .45 barrel that the "gun smith" blew up with his own reloads.
And I saw a terrible accident at another range (Markham Park) where a 44 Super Blackhawk went to pieces with the owners reloads. That accident didn't hurt the shooter, but the cylinder pieces caught the hand of the guy next to him, and did some serious (maybe permanent) damage.

dirtengineer

12-01-2011, 11:06 PM

...And I saw a terrible accident at another range (Markham Park) where a 44 Super Blackhawk went to pieces with the owners reloads. That accident didn't hurt the shooter, but the cylinder pieces caught the hand of the guy next to him, and did some serious (maybe permanent) damage.

Wow, what kind of loads do you need to blow up a blackhawk!? They are pretty strong guns.

HeyGuysWatchThis

12-02-2011, 08:35 AM

Ok sports fans, here is the answer I received from Jay just minutes ago in regard to why the CM9 barrel will NOT work in the PM9 pistol.

Good morning. The barrels are completely different shapes and are not made to lock with the slide in the same way. I hope this information helps and apologize for any inconvenience.
sincerely,

Jay
Kahr Customer Service
508-795- 3919

You guys can debate it all you want but, it looks as if one can not use the CM9 bbl. in the PM9. ;)

Very interesting. I can only assume it has to do with the differences in how the slides are machined between the CM and PM models. Oh well, thanks for being willing to try it out and answer the question, JimC! It would have been interesting to find out once and for all.

JFootin

12-02-2011, 09:37 AM

Very interesting. I can only assume it has to do with the differences in how the slides are machined between the CM and PM models. Oh well, thanks for being willing to try it out and answer the question, JimC! It would have been interesting to find out once and for all.

Agreed. The whole idea was to reduce production costs by lessening and simplifying the machining processes on the slides, and apparently that was the case on the inside, too.

JimC

12-02-2011, 12:48 PM

I received some information earlier today, NOT from Kahr Arms, that what I was told by Jay at Kahr Arms customer service about the CM9 barrel not being compatible with the PM9 was incorrect.

I have no way to substantiate what I was told, I don’t even know the original source for this information and I have not received any further information.

In light of this, I will have to believe what Kahr Arms has told me about the two models and their barrels unless they, Kahr Arms, tells me directly that their first response was incorrect.

I'm done with this issue and no longer have a need to know about the difference in velocity between the two barrels.

Bawanna

12-02-2011, 01:14 PM

Jimc your right to believe what your told from a manufacturer but when doubt rears it's ugly head it sometimes pays to research if you can.

I can't say this "officially" but I have it on high trusted authority that if your PM and CM are both new models the barrels will in fact interchange.
If your PM is the old style or what we call the blunt nose it would be shorter and would not work.

BEARDOG

12-02-2011, 02:02 PM

Just another point to this, I remember a few months ago we went through this same thing over slide stops, Kahr said the MIM was different then the machined and would NOT interchange....Then a few members chimmed in and said that was B.S. They have done it and it worked fine.

That said I wouldn't drop $140 on a barrel either that the manufacturer flat out tells me won't work. But if i had a PM9 and a CM9 available I would bet they would swap just fine

Jim C.
Here is a interesting ammo velocity comparison from Jeff Quinn with a CW45 and a P45 as you can see he found that the standard rifling in the CW45 was slightly FASTER! ??? Go about half way down to the chart.
http://www.gunblast.com/Kahr-45s.htm

JFootin

12-02-2011, 02:16 PM

Jim C.
Here is a interesting ammo velocity comparison from Jeff Quinn with a CW45 and a P45 as you can see he found that the standard rifling in the CW45 was slightly FASTER! ??? Go about half way down to the chart.
http://www.gunblast.com/Kahr-45s.htm

OK. That's the second actual test report that we've had on the forum saying the conventionally rifled barrels shoot bullets faster than the polygonal barrels in these Kahrs. :rolleyes:

JimC

12-03-2011, 02:27 AM

I can't say this "officially" but I have it on high trusted authority that if your PM and CM are both new models the barrels will in fact interchange.
If your PM is the old style or what we call the blunt nose it would be shorter and would not work.

Bawanna;

Possibly your "high trusted authority" can "officially" contact Jay @ Kahr Arms and explain to him why the CM9 bbl. will interchange with the new model PM9, which I have. ;)

CJB

12-11-2011, 09:53 PM

Any follow up on this?

Can two users, one CM, one PM post some shot of barrels? This isn't making sense to me, unless its the part upper inside corners of the slide that are different radii perhaps?

OldLincoln

12-11-2011, 10:41 PM

OK. That's the second actual test report that we've had on the forum saying the conventionally rifled barrels shoot bullets faster than the polygonal barrels in these Kahrs. :rolleyes:
If they do it isn't much. 10ft/sec = 6.8mph. You can run faster than the difference. Doesn't really matter in a SD gun. You point it, pull the trigger, it goes bang and the BG is slowed down. He won't care much if it's 7mph faster or slower.

JimC

12-12-2011, 05:42 AM

Any follow up on this?

Can two users, one CM, one PM post some shot of barrels? This isn't making sense to me, unless its the part upper inside corners of the slide that are different radii perhaps?

I had forgotten all about this one, thanks for reminding me. ;)

I haven't been contacted by Jay or anyone else at Kahr Arms advising me that a "high trusted authority" has told them that the two barrels will safely interchange.

:behindsofa:

JFootin

12-17-2011, 12:05 PM

Here's the link, Jocko: http://www.youtube.com/watch?v=o28W4mf7Gn4

End of dicussion! The only diff between the PM9 and CM9 is cosmetic and accessory options. The CM9 is not some cheapened product, like a Kel-Tec posing as a Kahr. It is a bargain PM9!

jocko

12-17-2011, 12:14 PM

thank you, I knew u were good for something. I need tomake note of that in case I need ur help again. Thank u.

CJB

12-17-2011, 12:22 PM

thank you, I knew u were good for something. I need tomake note of that in case I need ur help again. Thank u.

Nuff said... and nuff seen. You can get enough views of the inside of the CM9 slide to observe the shape, and the quality with which the metal was cut.

Good job

jocko

12-17-2011, 12:28 PM

yes indeed JFOOTIN has found his nich in life, he gets my vote for THE MAN OF THE MINUTE REWARD"

bot any longer thanb that though, .This was a heavy debated topic awhile back with nobody believing anybody,but I think this video puts that topoic to a nice resting place.

Micha2u

12-18-2011, 01:31 PM

There are actually 2 videos on this out on YouTube. Pretty interesting...

He wants to sell his unused CM9 barrel for $75 (a couple of weeks ago) becuse the PM9 barrel in the CM9 was working great for him.

Here are the Youtube links:

www.youtube.com/watch?v=FjXN6U_xDek

w (http://www.google.com/url?url=http://www.youtube.com/watch%3Fv%3Do28W4mf7Gn4&rct=j&sa=X&ei=sT7uTsm-LsTL0QGi15zeCQ&ved=0CB8QuAIwAA&q=pm9+barrel+in+cm9&usg=AFQjCNF0sEQyb_soZmpvftcreUxtpt62rQ)ww.youtube. com/watch?v=o28W4mf7Gn4