Any loss of Accuracy when using a Conversion barrel?

[kmanick]

I have a storm lake .40 to 9mm Conversion barrel incoming and I wonder if
anyone that has used these in their .40 noticed any change in accuracy?
I'm going to use 9mm magazines as well. I'm hoping all works smoothly

 

[Sprocket]

Accuracy is based on 3 things:
gun
ammo
shooter

Change any one of those things and you can expect a learning curve.

Let me guess - you're hits are grouped well but high and off center...

 

[kmanick]

Well I haven't gotten it yet but my current groups are a little off to the right and sometimes a little low (I'm left handed)
with my .40

I actually shoot my 9mm Shield more accurately, which prompted me to try this (scored a basically brand new Storm lake for under a $100.00) I figured I'd give it a try.

Accuracy is based on 3 things:
gun
ammo
shooter

Change any one of those things and you can expect a learning curve.

Let me guess - you're hits are grouped well but high and off center...

 

[Sprocket]

Well I haven't gotten it yet but my current groups are a little off to the right and sometimes a little low (I'm left handed) with my .40

Big surprise - It's not the gun, it's you. How tight are the groups? what diameter at what distance? Both play in here...

You're flinching with the 40 - it's a matter of how much now.

Be honest - we don't care but if you want to improve - be honest and we'll all help.

 

[Gammon]

Tough to predict what will happen. Changing the barrel can change the point of impact as the new barrel may not fit like the old one.

 

[MachineHead]

I'm a lefty and I have the same barrel conversion. It's not a bad learning curve. It's pretty cool to have and it's nice to be able to keep shooting in case you run out of one type of ammo.

 

[mac1911]

Your gun has a design flaw.... Rightyitis.
See US lefties have to deal with guns designed and built by righties

I shoot lefty. When shooting pistol (i don't shoot often ) I tend to over grip this pushed the barrel off to the right...I have been working with my hands for 30 years and over the past 10 have definitely lost a little sense of "grip" .
I don't know anything about the conversions. I shoot a 4013tsw and few years back I ran a CMP service pistol match for fun with it. I kept all but 7 shots in the black.

 

[greencobra]

i've never been too sure with those .40 to 9 conversions, however i own a storm lake .40 to .357 sig barrel for a smith 40c. it shoots real well with no point of impact difference i can tell. when i got my barrel, the machining was defective and the thing wouldn't drop in, i had to send it back. but all is well now.

 

[briz]

Comparing apples to apples. In my experience, I felt as though the Storm Lake conversion barrel was more accurate than the stock 9mm.

My wife has the FS M&P 9MM and I have the 40. Both have the same APEX trigger kit.

I ended up selling the barrel though and picking up a complete 9MM slide for mine.

 

[Sprocket]

I too am a lefty and I put a storm lake bbl into my 9. I'm definitely having a grip problem as mentioned above. My groups are tight but off to the right a bit. I put the barrel in trying to eliminate any problems with the gun, the ammo is all the same too - must be the loose nut behind the grip...

Over all I think the OP will have a better time shooting the 9. Good luck and keep ups posted. Pics of your targets too!

 

[kmanick]

I am aware of the "pull" or "flinch" with the .40, I don't do it any where near as much with my Shield, I shoot the 9mm shield pretty well,
also do you guys see any difference cycling with 115 gr vs 124gr? I'm guessing 124 may work better?
my shield

my .40

as you can see once I dial in with the 9 I'm pretty much on target, the .40? not so much LOL!

 

[drgrant]

Shoot it off a rest and see what happens. Thatll take most of the flinching etc out of it.

 

[dcmdon]

Storm lake barrels are good.

As long as you don't end up with tolerances stacking to make a sloppy fit, then I'd venture that you will be more accurate for 2 reasons.

1) Aftermarket barrels tend to have tighter chambers and shorter leade. All good for mechanical accuracy.
2) A 9mm recoils less than a .40. Less recoil means less inclination to flinch or push = more practical accuracy.

I have a G35 with a KKM 9mm conversion barrel and its the most accurate Glock I own.

Don

 

[dcmdon]

I am aware of the "pull" or "flinch" with the .40, I don't do it any where near as much with my Shield, I shoot the 9mm shield pretty well,

You don't know this until you either get a misfire or do a ball and dummy drill. I've done this trick with new shooters many times. Typically I'm there to help solve a problem with bad groups or the gun shooting low.

I'll take a few shots to confirm that the gun is sighted properly. With the mag in the gun I'll secretly empty the chamber. (pop the mag out a half inch, gently and quietly rack the slide, then gently push the mag back in)

Then I'll put the gun down and suggest to the student that he give it "one more try". 90% of the time when the gun goes click there is a huge flinch or push. The light bulb goes on over their head and we continue with a number of ball and dummy drills.

Strangely, when the shooter expects that there may be a dummy in the chamber, he settles right down.

Don

p.s. One nice thing about 9mm Glocks with factory barrels is that they will feed and chamber an empty piece of brass. So you don't need to bring dummies to the range.

 

[kmanick]

You don't know this until you either get a misfire or do a ball and dummy drill. I've done this trick with new shooters many times. Typically I'm there to help solve a problem with bad groups or the gun shooting low.

I'll take a few shots to confirm that the gun is sighted properly. With the mag in the gun I'll secretly empty the chamber. (pop the mag out a half inch, gently and quietly rack the slide, then gently push the mag back in)

Then I'll put the gun down and suggest to the student that he give it "one more try". 90% of the time when the gun goes click there is a huge flinch or push. The light bulb goes on over their head and we continue with a number of ball and dummy drills.

Strangely, when the shooter expects that there may be a dummy in the chamber, he settles right down.

Don

p.s. One nice thing about 9mm Glocks with factory barrels is that they will feed and chamber an empty piece of brass. So you don't need to bring dummies to the range.

at the last CCW class I took at MFS he had us load other students mags and mix real bullets with snap caps to do just this type of exercise.
it was quite eye opening to see how many people were milking their pulls.
I need to to this with my .40.

 

[kmanick]

I finally got a chance to use this today. Shot 50 rounds of 180gr .40 first. Meh...not terrible, but no where near as good as I could be.
Swapped out the barrel and mags and alternated shooting 115gr and 124 grain. Surprisingly I shot the 115 grain better. I shoot the 124
grain better with my shield. (that surprised me). 124 almost felt like a .22 through this thing. I don't know if I'll ever shoot it as a .40 again.
I loved it! zero malfunctions. At massapoag with 115gr I hit the gong 4 of 5
with 124 2 of 5. that surprised me as well, I figured at distance the heavier grain would be more accurate.
the .40 haters may have a point LOL!

 

[92G]

the 9mm conversion barrels lock up quite nicely in the glock slide at least in my G32 gen 4. given the snug lockup, I would imagine they should be plenty accurate assuming the barrel itself is correct.

on the topic of "accuracy" of glock .40's, my experience w glocks chambered in .40 is that's they're undersprung as they utilize the same recoil spring weights at the 9mm models (w exception of the gen 4 G19 vs 23). once I bump up the recoil spring strength such as 20-22lb RSA, both the G22 and G23 shoot much more comfortably for me.

the caveat here is if shooters is a limp wrister, then the heavier spring might be an issue. for this reason I make my wife shoot any gun where i'm adjusting the recoil spring strength to be sure it doesn't under cycle in her little lady wrists.

kmanick- what gen of G23 are you shooting? if gen 2 or 3, very easy to adjust the RSA. w gen 4 it's not too difficult either just requires an adapter. just something to consider.

Comparing apples to apples. In my experience, I felt as though the Storm Lake conversion barrel was more accurate than the stock 9mm.

My wife has the FS M&P 9MM and I have the 40. Both have the same APEX trigger kit.

I ended up selling the barrel though and picking up a complete 9MM slide for mine.

I have noticed the same. however I'm not sure it's the barrel itself or rather the lockup to the slide. the OEM M&P barrels are loose fitting at the breech face. the wiggle left-right. i'm not sure if this was intentional to favor reliability over accuracy, or typical S&W mediocrity. in contrast, the storm lake barrels fit much more snugly which seems to keep the POI more consistent. in some cases the aftermarket barrels fit a little too snug, and need to be cut down to fit.

 

[kmanick]

I don't have a G23. I did this with my M&P FS .40

 

[dcmdon]

SQUIB - my Gen 4 G34 and G35 had different recoil spring assemblies. I think its across the board on the Gen 4s.

For what its worth, I would not rely on a conversion gun for defensive purposes unless I also swapped out the ejector, extractor, and recoil spring assembly(gen4 only).

They are all different. While my G35 with a KKM conversion barrel has run 100%. Its a toy. So I have only swapped out the barrel.

 

[92G]

SQUIB - my Gen 4 G34 and G35 had different recoil spring assemblies. I think its across the board on the Gen 4s.

For what its worth, I would not rely on a conversion gun for defensive purposes unless I also swapped out the ejector, extractor, and recoil spring assembly(gen4 only).

They are all different. While my G35 with a KKM conversion barrel has run 100%. Its a toy. So I have only swapped out the barrel.

Yes w gen 4's the .40 cal RSA is slightly heavier, but only a bit like 1-2 lbs.
w the gen 3 glocks the .40 and 9mm RSA is the same, which puts the .40 models at way undersprung.

same w the glock 20 and 21. They use the same RSA in all generations. which is ridiculous for full power 10mm loads pushing over 600 ft-lbs the slide smacks the shit out of the frame.

Its really my only beef w glocks in general is their shitty spring tension selection for anything other than 9mm. In fact I believe half the reason why .40S&W has a reputation for being "snappy" and unpleasant is because so many folks shot a stock gen3 G22/23 and hated it. With weak 180gr not too bad but with some hot 165 gr pushing over 450 ft-lbs ouch!

 

[dcmdon]

. In fact I believe half the reason why .40S&W has a reputation for being "snappy" and unpleasant is because so many folks shot a stock gen3 G22/23 and hated it. With weak 180gr not too bad but with some hot 165 gr pushing over 450 ft-lbs ouch!

I disagree with your conclusion. I took a .40 cal USP in in trade and it shot horribly.

I do agree with your data points. The difference between a Gen 3 and Gen 4 G23 is NIGHT AND DAY. Huge improvement.

Don

 

[drgrant]

I disagree with your conclusion. I took a .40 cal USP in in trade and it shot horribly.

I do agree with your data points. The difference between a Gen 3 and Gen 4 G23 is NIGHT AND DAY. Huge improvement.

Don

That's funny considering a USP .40 full is one of the .40s i hate tge least... because the recoil system sucks most of the snap out of the cartridge.

 

[92G]

That's funny considering a USP .40 full is one of the .40s i hate tge least... because the recoil system sucks most of the snap out of the cartridge.

^this I also found the USP 40 to shoot like a kitty cat. in fact it shot so nice I found it boring and sold it. the USP dual RSA system soaks up all the punch. even the 480 ft-lb 40 shot great.

that USP 40 got me dreaming about a USP in 10mm. too bad HK didn't go that route. would have been a sick pistol.

 

[dcmdon]

I hated it.

I found it much more difficult to hit with than a Gen 4 22. Although easier than a Gen 3 23.

I wanted to love it. I had taken it in trade very cheaply and it was a beautiful gun. I have large hands so it fit me really well.
I must have dry fired it 1000 times before I finally took it to the range. It had the LEM trigger, which I liked very much.

Don