9mm to .40 conversion?

[DocSunShine]

Good info Rob. Sounds like I can use my CORE after all, just run irons on it and cut a .40 barrel a little. Kinda convoluted, but if it works, who cares....

 

[robkarrob]

One other thing I have not mentioned. The 9mm to 40 swap is a better swap, than the 40 to 9mm. The reason is by grinding the barrel to fit in the 9mm slide, you are making it a perfect fit, no extra side to side clearance. You end up with the same clearance as with the original 9mm barrel.

With the 40 to 9mm swap, the barrel is drop in, as the 9mm tang width is .025 inch more narrow than the 40 barrel tang width. The normal tang width to slide slot clearance is .004 inch per side. Since the 9mm barrel has extra side to side clearance of .012 per side, the total side to side clearance for the 9mm barrel in the 40 slide would be around .016 inch, as opposed to the stock clearance of .004 inch per side. Those of us that have made the 40 to 9mm swap have found no problems with that extra side to side clearance. No effect to any function of the gun, including accuracy.

Bob

 

[Smitty357]

One other thing I have not mentioned. The 9mm to 40 swap is a better swap, than the 40 to 9mm. The reason is by grinding the barrel to fit in the 9mm slide, you are making it a perfect fit, no extra side to side clearance. You end up with the same clearance as with the original 9mm barrel.

With the 40 to 9mm swap, the barrel is drop in, as the 9mm tang width is .025 inch more narrow than the 40 barrel tang width. The normal tang width to slide slot clearance is .004 inch per side. Since the 9mm barrel has extra side to side clearance of .012 per side, the total side to side clearance for the 9mm barrel in the 40 slide would be around .016 inch, as opposed to the stock clearance of .004 inch per side. Those of us that have made the 40 to 9mm swap have found no problems with that extra side to side clearance. No effect to any function of the gun, including accuracy.

Bob

Yep, accuracy from the 40 converted to 9mm surely hasnt been a problem. Me and the ole lady both seem to shoot our converted .40 to 9mm better than we actually shot the factory 9mm. Weird how that works, but I guess the guns differ in trigger pull slightly and thats probably the main reason.

 

[Kogashuko]

After shooting my C in 357, 40, and 9 I can say I favor the 9mm. After looking at some ballistic tests on modern hollow points, I really like the critical duty but thats me, I will stick with the 9.

I also own a fs 40/9 and both size 45s. I really like the 9. After I finish some work on my house I will be going with a core 9.

 

[Lpryer]

9mm to 40 and vice versa

I Have a M&P 2.0 in 9mm I has seen the 40 to 9 conversion done as just the barrel and as a slide and barrel with no issues. I contacted S&W customer service directly and posed the question of can it go the other way (9mm to 40 with a 9mm frame) if you are using a slide a barrel combination. They stated that you can with no issues and no modification to the slide, but you do have to keep the frame styles together compact to compact for example. You can on the other hand run a longer slide than was originally purchased for example you can run a 5" 40 on a 9mm that had a 4.25" from the factory.

 

[Well Armed]

I Have a M&P 2.0 in 9mm I has seen the 40 to 9 conversion done as just the barrel and as a slide and barrel with no issues. I contacted S&W customer service directly and posed the question of can it go the other way (9mm to 40 with a 9mm frame) if you are using a slide a barrel combination. They stated that you can with no issues and no modification to the slide, but you do have to keep the frame styles together compact to compact for example. You can on the other hand run a longer slide than was originally purchased for example you can run a 5" 40 on a 9mm that had a 4.25" from the factory.

The thread is about 6 years old . Welcome to the forum though!