PM9 chronograph results

[JimC]

I got in a short but productive range session today after some early morning rain.
I’ve wanted to see for myself what the MV of the Speer 124 gr. +P short barrel load is out of my PM9. This is my current SD load.
I was also curious about the Win. 127 gr. +P+ load thru the short 3” PM9 bbl.

Here are my results:

Speer Gold Dot # 23611 124 gr. +P short barrel.

Avg. 6 rds. – 1116.6 fps
ES – 15.1 fps

Avg. 6 rds. – 1121.2 fps
ES – 31.7 fps

Winchester Ranger # RA9TA 127 gr. +P+

Avg. 6 rds. – 1117.4 fps
ES – 21.6 fps

Winchester NATO # Q4318 124 gr. FMJ

Avg. 6 rds. – 1045.1 fps
ES – 73.4 fps

Avg. 6 rds. – 1056.2 fps
ES – 58.3 fps

As one can see, the 127 gr. Ranger +P+ load is just about the same as the +P 124 gr. Speer load. I actually believe that the +P+ load looses velocity out of the 3” Kahr barrel.

After 1,114 rds, thru my PM9 since July, I decided to swap out the recoil assembly. I used one of the new units direct from Kahr that is reported to have 15 coils on the outer spring but mine can barely come up to 14.5 coils and that’s giving it the benefit of the doubt.
I ran 78 rds. thru the PM9 with the new unit with only 1 FTF and I don’t know why. It was not a “nose dive” but rather just a failure to feed from the mag. I've never experienced a "nose dive" with my PM9 or even a FTF.
Other than that, it’s GTG with a new recoil assembly. Included in the 78 rds. were 20 rds. of my SD load, the Speer 124 gr. +P short barrel, they ran 100%.

[94zcar]

Good results for a 3 inch barrel. Gold dots always seem to be loaded pretty hot.

[green02crew]

Have you ran any 147gr rounds through? I would be interested to see a +P 124gr vs a 147gr same brand/type ammo and see the differences in speed from this short a barrel.

[JimC]

That's on my list of thing to do. ;)
I just bought 500 rds. of the Win. Ranger Bonded 147 gr. JHP ammo (RA9B) that I want to test.

[guido4198]

What was the reason for swapping out the recoil assembly...???

[JimC]

What was the reason for swapping out the recoil assembly...???

I did so because Kahr recommends that the assembly be changed in a carry weapon every 1,200 to 1,500 rds. or every couple of years, which ever comes first.

1,114 rds. was close enough to 1,200 and I was there with the new assembly on hand plus I intend to carry my PM9 on regular basis more than shoot it so I changed it out and test fired it...it's GTG. ;)

[guido4198]

Thanks Jim.
I've seen this recommendation to replace the recoil assembly @ 1500 rds. I understand the wisdom of following the manufacturer's recommendation for your carry weapon. I'm sure I'll do the same. My CM9 is nowhere close to that point yet, although at a couple of hundred rounds every week-end...it won't be long..!!
On that topic though...I'm glad you mentioned it. I'm curious to know what functional manifestations might occur at that level of use to signal that it's time to swap.
Is the 1500 rd. swap universally observed, or has someone run their's well over 1500 and can share their experience..??

One can imagine any number of "issues" which might arise from continuing to fire SD rounds with a recoil assembly that has "aged"(weakened..?) from use. Of course, simple failure to function might be an immediately observable signal that one has pushed the envelope a bit too far. A more insidious issue might be that continuing to fire hot SD rounds with a weakened recoil system could begin to allow FRAME DAMAGE.
Anyone...????

[jocko]

that new recoil spring will take a pre designed set soon and it wil funciton perfeclty., save the old assembly. nice report

changing recoil springs is usually in the eyes of the beholder. Alot of times the gun itself will let you know when it is time to change springs, failure to lock open is usualy a good indication that it might be time, FTRB is also another sigh. Different guns will tell you different things. Kahr used to sell us the outter recoil spring for the pM series guns but now they I guess want to rip us off to buy the entire $25 system which is just not needed. A shame IMO. Eventually wolffs will get some springs out for the cm9 and new slide style PM9 and PM40.

For some owners also 1500 rounds is alot of time shooting. My guess is that most gun owners don't shoot a 1000 rounds out of their guns. But we also know in these new cm9 and new slide style PM9, that when onj e replaces his recoil springs that sometimes he has one hell of a time getting that new set even on, do to the over all strength and length of the outter spring. This will for a few rounds give failure to lock open and possably feed issues. once the spring takes its designed set, all will be well. Some as u know to have clipped off a quarter coil and had zero issues after that to, so travel at ur own speed, remember when u clip u also lesson some spring strength to and IMO a quarter coil off is more than likely NADDA loss..

[WMD]

Interesting results! Just thought I would mention...., the Kahr pistols are not rated for +P+ ammo. Be careful! :)

[JimC]

Here is the e-mail response from Kahr that I based my decision on to replace my assembly when I did. I figure the cost of the replacement is a small price to pay for peace of mind with my EDC.

You may feel differently and that is by all means you choice.

Good afternoon. Thank you for the question. If the firearm is used as
a carry weapon, we would recommend changing the recoil spring every
1200-1500 rounds or every couple of years (whichever comes first) as
preventative maintenance. If this firearm is just used for range use, we
would recommend changing it whenever you start to see failure to feed or
return to battery issues. I hope this information helps.
sincerely,
Jay
Kahr Customer Service
508-795- 3919

[JimC]

Interesting results! Just thought I would mention...., the Kahr pistols are not rated for +P+ ammo. Be careful! :)

I'm well aware of that but thanks for reminding me.
I'm of the mindset that a few +P+ rounds now and again will not damage the pistol.

[jocko]

IMO if one needs to

shoot that +P+ stuff in a 9mm , why not just buy a 40 cal and be done with it. I trust that my PM9 would shoot +P+ ammo, but if I have zero intentions of ever carrying it or what ever, then why push the envelope

[OldLincoln]

I may be wrong, but wasn't Kahr originally rated for +P+? Seems like it was then the advertising was changed but I do not recall a warning not to shoot it. I suspect it was the Buffalo stuff that made a lot of folks rightly shy away from +P+ and I won't shoot it in mine for sure. And as you saw the +P+ tested doesn't make a hair's difference to the bad guy.

I do carry +P mainly because it's pushing a 147gn HST and didn't cost any more than the standard when I bought it. I've been rightly accused of trying to mimic a 45, but if I had one I'd be carrying it with a +P HST also. So would I then be mimicing a .50? I sure won't carry one of those around.

[jocko]

I have never read it. Many shy away from saying it is OK for as u know +P+ really has no indfustry accepted standards. I think from the legal standpoint they are not ging to tell one to shoot +P+ like u stole it.. I have no doubt kahrs can take +P+ ammo, how long is another story. I don't know of to many who shoot +P+ for range fodder either, so for ccw carry more than likely it is gonna go bang every time. It seems some (not u of course) want to always push the envelope with things, not just firearms either..

[Bill K]

Thanks for the interesting data.

The spring issue is one reason I have two Kel-Tec .380s, one with a laser for mostly training/practice and a second for mostly carry. Hate to discover in a SD situation that I should have replaced the guide rod springs. Using the same reasoning maybe buy a CM9 as a mate for my PM9?

I don't get the part about replacing based on a time interval, can someone explain that to me? Thanks...

[TriggerMan]

Thanks Jim.
I've seen this recommendation to replace the recoil assembly @ 1500 rds. I understand the wisdom of following the manufacturer's recommendation for your carry weapon. I'm sure I'll do the same. My CM9 is nowhere close to that point yet, although at a couple of hundred rounds every week-end...it won't be long..!!
On that topic though...I'm glad you mentioned it. I'm curious to know what functional manifestations might occur at that level of use to signal that it's time to swap.
Is the 1500 rd. swap universally observed, or has someone run their's well over 1500 and can share their experience..??

One can imagine any number of "issues" which might arise from continuing to fire SD rounds with a recoil assembly that has "aged"(weakened..?) from use. Of course, simple failure to function might be an immediately observable signal that one has pushed the envelope a bit too far. A more insidious issue might be that continuing to fire hot SD rounds with a weakened recoil system could begin to allow FRAME DAMAGE.
Anyone...????Would watching for changes in how far and what direction your shell casings eject be another easy way to time the replacement of the spring assembly?

[jocko]

forgot that, absolutey, especialy if u can remember how it was when new springs were in the gun..

[JimC]

FYI, just because I chose to chronograph the +P+ ammo thru MY PM9 doesn't mean that:

1. I shoot a lot of it thru my PM9.
2. I'm saying it is 100% OK to shoot it thru your PM9.
3. I'm saying it's any better than a good +P round or even a good standard pressure loading.

I shot it to have the data for my use if needed in the future.

As was already pointed out, the 127 gr. +P+ didn't show all that much improvement over the 124 gr. +P Gold Dot for the short barrel pistols.

[jocko]

I nderstand ur point and it looks like from some of ur chrono work that the +P + round is highly over rated to entice the buyer to pay alittle more for what is actually no gain.

without a chrono to do what u did we have no way of knowing what the hell is going on.. nice job by the way.

[OldLincoln]

Jocko, I read that in an early introductory article in a magazine that was on-line. I'll try to find it as I know it was a rabbit trail off a Kahr search.

[OldLincoln]

Okay, I re-ran the trails and found my statement in the Interview of Moon by Massad (http://kahrauction.com/PA-1B/review_ahg_1001.html):.

I was wrong in my assumption that non-gun reasons led Kahr to drop the +P+ okay. See the bold below.

---------------------
Ayoob: You built your first 9mm, the K9, to take 9mm +P and +P+ ammo, and one complaint was that the springs were strong enough to make the gun's slide hard to draw back. Tell us where you went with that.
Moon: The recoil springs in the first K9s were 24 pounds. Based on the feed-back from customers who experienced difficulty in manipulation of the slide, we changed the recoil spring to the current design of 18 to 20 pounds. At this time we only offer one strength of recoil spring in the Kahr K9 models - 18 to 20 pounds.
Ayoob: Did this impact the company's policy of warranting the guns to handle +P and +P+ 9mm, and full power of .40 S&W?
Moon: According to our instruction manual we recommend only high-quality factory ammunition of the proper caliber. The Kahr 9mm can handle +P loads and in the Kahr .40 S&W we recommend regular pressure, high-quality factory ammunition.

[mightymouse]

Is the short barrel GD more than just low flash fast burning powder? Its not about improved velocity.
What about the bullet design that's supposed to expand at lower velocities from a short barrel?

Personally I'm not as worried about using any of the top grade SD ammo in a 3" barrel in 9mm or .40 as they were designed for shorter barrel than the .45, ... big hole regardless, but not as its intended from 5"
I'm sticking to 124 +p SBGD until another better magic bullet comes out.

[MO_Soldier]

Keep in mind, +P+ means more PRESSURE, not more VELOCITY. The 2 don't always equate, as these test results prove!

[jimsea]

....and not that it matters, all things being equal and given identical ammunition, the CM9 barrel has a higher velocity than the PM barrel.

[MO_Soldier]

....and not that it matters, all things being equal and given identical ammunition, the CM9 barrel has a higher velocity than the PM barrel.

What's your source?

[jimsea]

What's your source?

there's a velocity test comparison floating around here somewhere. one of the veterans probably has it handy. sorry, but it would take me forever to find it again.

........the long and the short of it is that the special rifling in the PM matched grade barrel creates more friction with the projectile than the standard rifling in the CM barrel. while the round may be slower out of the PM barrel, the projectile is spinning faster and is technically more stable/accurate.

[MO_Soldier]

there's a velocity test comparison floating around here somewhere. one of the veterans probably has it handy. sorry, but it would take me forever to find it again.

........the long and the short of it is that the special rifling in the PM matched grade barrel creates more friction with the projectile than the standard rifling in the CM barrel. while the round may be slower out of the PM barrel, the projectile is spinning faster and is technically more stable/accurate.

Very well. I like to know the sources of things before acting on them, especially when the life of myself or my family is on the line.
I just uncovered some new information leaning towards 124gr +P rounds in 9mm as being the best 9mm rounds besides +P+, but I don't endorse those anyway because of a lack of standardization/regulation.

I want some Federal Tactical LE HST 124gr +P's now!

[OldLincoln]

Right on, MO! You can find it at Kyles (http://www.kylesgunshop.com/store.php?seller=KylesGunshop&navt1=50216).

[JimC]

....and not that it matters, all things being equal and given identical ammunition, the CM9 barrel has a higher velocity than the PM barrel.

And you base this statement on...?

Traditionally, the conventional rifled barrels produce less velocity than polygonal barrels.

I have found this to be true using a G17 w/the standard barrel and then firing the same ammunition in the same G17 but with a Bar-Sto barrel with conventional rifling.

HK has always made the claim that their polygonal barrels in the USP line produce higher velocities that conventional barrels.

I guess the only way that we will know for sure is for one of us :rolleyes: to buy a CM9 barrel and do some chrono testing with the PM9 with CM9 barrel installed. Let's see...$140.80 for a CM9 barrel for testing?????

I don't think so.

[JimC]

This discussion reminds me of the old days, late '70's into the mid '80's, when many of us in LE were carrying the S&W "J" frame 5 shot revolvers off-duty and all the new hyper velocity .38 Spl. ammo was hitting the market.

The one round that everyone wanted was the US Secret Service 110 gr. +P+ load that they had made specifically for them by Win. and later Fed. as I recall. That stuff was hot in those little 1 7/8" "J" frame barrels and they were like flame throwers!!! :eek:

S&W came out with a don't use notice for these little guns and this hot ammo. I recall being at S&W for an LE Armorers course for their revolvers back in '85 (yea, I had to dig out the cert. for the date) and the instructors told us that the steady use of this +P+ ammo would stretch the frames on these little guns and render them useless due to misfires because the firing pin could no longer reach the primer sufficiently.

And outside locked in my vehicle was my 2" M36 loaded with that exact US SS 110 gr. load! ;)

Ok I know, I digress here but this came to mind with all of this talk about +P+ ammo.

BTW, the one load that was popular at the time in those little guns was the Rem. 125 gr. JHP load. I don't know if it's even made any longer.

[jimsea]

And you base this statement on...?



I don't think so.

http://kahrtalk.com/showthread.php?t=7094&highlight=cm9+chronograph+results post #9

FWIW while doing some CM9 research prior to purchase, I found the test results mentioned in this thread.........feel free to do your own search.

[JFootin]

Here is a post that shows chrono results between a K40 and a CW40. Now what do you think? :)

http://kahrtalk.com/showpost.php?p=76975&postcount=6

[Thunder71]

Nobody to my knowledge has compared apples to apples as of yet. Close but different doesn't prove anything at all to me.

[JFootin]

Nobody to my knowledge has compared apples to apples as of yet. Close but different doesn't prove anything at all to me.

What do you mean? A K40 with polygonal barrel against a CW40 with conventional rifling. Isn't that what we are talking about here?

[Thunder71]

Those are different, though similar. I'm waiting for a CM9/PM9 comparison done at the same time with the same ammo before I agree one way or the other about the barrel differences.

Equal guns, same shooter, different barrels.

[jocko]

also gotta remember every barrel is potentially different to. take 4 PM9 barrlels all polygonal rifled and thenthe same box of ammo and I bet the chrono reports will be different. Now can it ba the barrel, or the ammo or the chrono. we will just have to accept what we read and then decide ourselves. hAD MY pm9 HAD the convential rifled barrel in itk I could have cared less.

[MO_Soldier]

also gotta remember every barrel is potentially different to. take 4 PM9 barrlels all polygonal rifled and thenthe same box of ammo and I bet the chrono reports will be different. Now can it ba the barrel, or the ammo or the chrono. we will just have to accept what we read and then decide ourselves. hAD MY pm9 HAD the convential rifled barrel in itk I could have cared less.

Very true...but if there is ANY significance in the variation of muzzle velocities, the averages of the firings should reflect that.
Ie. 4 different PM9's might AVERAGE 1000fps, and then 4 CM9's might average 1020fps...etc. Thus establishing a consistent difference in muzzle velocity with the same rounds.

I HOPE my PM9 doesn't lack muzzle velocity. However, it seems to me that the extra friction required to spin my bullet faster for extra accuracy, will only yield a slightly slower bullet that is well worth the added accuracy.

[jocko]

good point and for me is their was 50ft difference in either, it would mean nadda to me. Pros and cons on the accuracy differene to. In a 3" bbl, I serioulsy doubt if polygonal rifled will do jack sh-t for accuracy. but again some people are just good shooters where as then there are people loike me that well ain't worth sh-t...

[MO_Soldier]

good point and for me is their was 50ft difference in either, it would mean nadda to me. Pros and cons on the accuracy differene to. In a 3" bbl, I serioulsy doubt if polygonal rifled will do jack sh-t for accuracy. but again some people are just good shooters where as then there are people loike me that well ain't worth sh-t...

Well think about a difference of 100fps for a moment.
With the typical self defense scenario being WITHIN 15ft, we will base it off just that.
A difference of 100fps divided by 15 is roughly 7. That means a difference of 100fps in your bullet's velocity only means .143 seconds behind the faster bullet upon impact. I don't know about you, but I can't move that fast! Maybe Bawanna can downhill(is that in bad taste?) ;) I certainly don't mean any insult and have seen him joke about it.

Other than the effects velocity has on terminal ballistic behavior, it means nothing.

[MO_Soldier]

good point and for me is their was 50ft difference in either, it would mean nadda to me. Pros and cons on the accuracy differene to. In a 3" bbl, I serioulsy doubt if polygonal rifled will do jack sh-t for accuracy. but again some people are just good shooters where as then there are people loike me that well ain't worth sh-t...

Also, I've put several rounds in very close proximity to each other from 21 feet with my PM9. I can't objectify because I haven't shot the CM9...but I'd say that's pretty darn accurate for a 3" barrel!

[OldLincoln]

When I first got interested in Self Defense (about 4 years ago), I read everything I could find and researched it all to find just the right gun and ammo and studied the laws and watched the videos. I was sure I had all the answers but then over time I began to realize you can overthink this stuff. I now believe if you were to rank all guns in all calibers, all ammo, all shooting positions, all clothes, all holsters,, and all everything else, you could draw line under the least acceptable and about anything above that will do the self defense job.

Even the FBI says 12" of penetration in their controlled testing is a benchmark for ammo. They also have requirements for going through glass, etc. but they don't say you have to have n% expansion or maintain n% weight to qualify.

It has taken me a long time but I now say good is good enough.

[jocko]

sure makes alot of sense to me. We tend to over think on alof of things. I bet a BG can't tell the differenc in a 124 grain and a 147 grain hp going through him either!!!

[dirtengineer]

I know that my dad and I both have Taurus Model 44 .44 magnum with the 6.5" barrel. His is blue and mine is stainless. I get consistently 100 fps better. I have no idea why.