Storm lake or KKM for 40>9mm conv barrel?

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taseal

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I had a 9mm on layaway at one place, but found a much cheaper 40 pro, and they threw in 2 9mm mags to help with the conversion. so I saved 50 bucks, and got 2 extra 9mm mags (along with the 2 40 mags)....

I got that and now I'm looking at a conversion barrel, so I can shoot 9mm (my preferred caliber) I'll also have the 40 barrel, so 2 calibers one gun. I'm happy....

that being said, I was sure I would go with storm lake. Their rifling twist is 1:16 and that's better than KKM's 1:24 which I'm not sure how it will handle 147gr loads. I will shoot both, but probably 115 for comp work, and 147 for other stuff.

so which do I go with?

ps - FWIW, i shot the .40 and the 9 side by side... the 40 at first didn't feel like it was kicking so hard. then I shot a 9mm pro and wow, that thing barely jumped. back to 40 and it was kicking pretty hard lol. (115 vs 165)

I'm a 9 guy, what can I say :D

I shot it right after I bought it, and my groups weren't that respectful. I would say maybe like 5" groups at 25 yards. but that's with no practice. I hope to get it down to like 2-3 with the right ammo (this is offhand)

oh, and the trigger compared to apex sear, ram and usb; it was rather creepy and heavier. reset felt the same. I would still rather take the apex kit I have on my MP9c
 
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taseal said:
I had a 9mm on layaway at one place, but found a much cheaper 40 pro, and they threw in 2 9mm mags to help with the conversion. so I saved 50 bucks, and got 2 extra 9mm mags (along with the 2 40 mags)....

I got that and now I'm looking at a conversion barrel, so I can shoot 9mm (my preferred caliber) I'll also have the 40 barrel, so 2 calibers one gun. I'm happy....

that being said, I was sure I would go with storm lake. Their rifling twist is 1:16 and that's better than KKM's 1:24 which I'm not sure how it will handle 147gr loads. I will shoot both, but probably 115 for comp work, and 147 for other stuff.

so which do I go with?

ps - FWIW, i shot the .40 and the 9 side by side... the 40 at first didn't feel like it was kicking so hard. then I shot a 9mm pro and wow, that thing barely jumped. back to 40 and it was kicking pretty hard lol. (115 vs 165)

I'm a 9 guy, what can I say :D

I shot it right after I bought it, and my groups weren't that respectful. I would say maybe like 5" groups at 25 yards. but that's with no practice. I hope to get it down to like 2-3 with the right ammo (this is offhand)

oh, and the trigger compared to apex sear, ram and usb; it was rather creepy and heavier. reset felt the same. I would still rather take the apex kit I have on my MP9c
Click to expand...

Would be interested in a response about the 9mm barrels in the 40c too....
 
Broil said:
Would be interested in a response about the 9mm barrels in the 40c too....
Click to expand...

I did more research on the storm lake so far, and it seems like a great conversion kit. the youtubers seem to be very happy with reliability and it looks neat with the SS colors (or cerakote/isonite it black)

haven't look at the KKM, but the 1:24 twist is scaring me, seems great for 115gr, and that's about it. maybe 124.
 
The only time I ever shoot 147 gr 9mm is suppressed. You just like having the heavier bullet? I have one of the storm lake thredded barrels and seems fine. I have never even looked into twist rate for 9mm handguns.
 
I read that. according to them, kkm is more accurate, but storm lake will shoot better with more variety of ammo
 
SGT_Kramer said:
Seems like he was just about as happy with the new production barrel from smith and wesson. I'd probably go that route as I bet it's cheaper. I notice no difference in accuracy through my threaded storm lake barrel and my factory barrel.
Click to expand...

right, but I can't use a stock 9mm barrel for a 40..

I need a conversion barrel :)

if i was buying a 9FS, i would make sure to get the new barrel.

the mp40 looks like the regular 9 barrel, but that's probably because it works. and copying the 40 barrel to a 9mm didn't work out so well
 
Dunno about the fullsize, but my M&P 40 barrel is the same diameter as the 9mm, so I just bought a factory 9mm barrel from Midway for $69.00. Less money, and a factory barrel. Can't beat that.
 
scattershot said:
Dunno about the fullsize, but my M&P 40 barrel is the same diameter as the 9mm, so I just bought a factory 9mm barrel from Midway for $69.00. Less money, and a factory barrel. Can't beat that.
Click to expand...

have you verified with a micrometer?

I have a 9c i will chekc dimensions tonigt.

i know 9mm to 40 does't work, because the barrel doesn't fit. that says something... (the 40 is too big, which means the 9 is too small. even though it might fit, the tolerances might be too great (not visible to the eye)
 
I think it's other part of the barrel that the size if different and the 9mm does not have clearance for the 40 but the 40 does have clearence for the 9. It's iaround the breach and not the dia of the barrel itself ...... I think. Could be wrong not first time not last.
 
SGT_Kramer said:
I think it's other part of the barrel that the size if different and the 9mm does not have clearance for the 40 but the 40 does have clearence for the 9. It's iaround the breach and not the dia of the barrel itself ...... I think. Could be wrong not first time not last.
Click to expand...

here is an interesting post.

almost worth a shot. if it doesn't work, maybe you can sell the barrel

http://smith-wessonforum.com/smith-wesson-m-p-pistols/170963-test-9mm-factory-barrel-m-p-40-a.html
 
Use the search function.

Almost 2 billion (seems like at least) people have dropped factory 9mm barrels in their 40 and have no problems. One guys even posted on here that S&W more or less confirmed the 9mm will work just fine in a 40.

The search will also show you that there have been a lot of problems with the Storm 'conversion' barrels. Many get sent back and many needed gunsmithing to work.

This is really a well discussed subject you will find. ;)

And Bud's sells the M&P pro for $475 with night sights and three mags, you didn't say what you paid.
 
For what its worth, the KKM bbl is THE one for converting the M9 Beretta for hardball match use. This is, of course, designed to be optimum for the military 115 gr ammo that is mandatory for National Match Service Pistol.
 
Lost Lake said:
Use the search function.

Almost 2 billion (seems like at least) people have dropped factory 9mm barrels in their 40 and have no problems. One guys even posted on here that S&W more or less confirmed the 9mm will work just fine in a 40.

The search will also show you that there have been a lot of problems with the Storm 'conversion' barrels. Many get sent back and many needed gunsmithing to work.

This is really a well discussed subject you will find. ;)

And Bud's sells the M&P pro for $475 with night sights and three mags, you didn't say what you paid.
Click to expand...

I see that. afaik, he talked to a cust service rep, not an engineer who designed the barrels, chambers breeches etc. we all know how much the cust service reps know.

that being said, it does seem possible... and been done.

I paid 579 with 1 extra 40 mag, and 3 extra 9mm mags to help me with the 'conversion'

I would have gotten it off buds, but I usually get it from budspolicesupply and they have been out of stock for a while now
 
About rifling twist: The standard is that when one goes to a longer, heavier and slower bullet for caliber, the twist rate may have to increase to stabilize the bullet.

Example: in .223 a 1-12 (1 turn in 12 inches) twist stabilizes up to around 60 grain bullets, 1-8 twist will stabilize up to 77 grain bullets. A 1-10 inch twist will cause 75 grain bullets to go through 50 yard targets sideways.

Colt used 1-16 for everything except the Python, which used a 1-14 inch twist. S&W seems to use 1-18.75 on everything under .44 (possibly .41).

Since S&W never had accuracy issues with the rifling twist on previous models of various caliber pistols, I doubt that any non-operator caused issues are due to rifling twist. Certainly, going from 1-18+ to 1-24 rifling with 147 gr bullets isn't going to help things.
 
WR Moore said:
About rifling twist: The standard is that when one goes to a longer, heavier and slower bullet for caliber, the twist rate may have to increase to stabilize the bullet.

Example: in .223 a 1-12 (1 turn in 12 inches) twist stabilizes up to around 60 grain bullets, 1-8 twist will stabilize up to 77 grain bullets. A 1-10 inch twist will cause 75 grain bullets to go through 50 yard targets sideways.

Colt used 1-16 for everything except the Python, which used a 1-14 inch twist. S&W seems to use 1-18.75 on everything under .44 (possibly .41).

Since S&W never had accuracy issues with the rifling twist on previous models of various caliber pistols, I doubt that any non-operator caused issues are due to rifling twist. Certainly, going from 1-18+ to 1-24 rifling with 147 gr bullets isn't going to help things.
Click to expand...

which is why I think the 1:16 is ideal for 9mm and storm lake offers this.

18.75 should be just fine with 115gr i would say... i've had 2 MP9s and they were excellent. my mp9c i just can't seem to shoot it as good as i shoot my full sizes.

look at glock, isn't their 9mms like 1:10 or something?
 
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