Generally, 9mm pistols aren't converted into .40 (and vice versa) because the breech face is part of the slide, and as the diameter of rear of the case is different between the calibers, so you'd need a new slide. Add in new barrel, spring, and mags to the cost of a slide, and you're essentially in for the cost of a new gun. About all the .40 is usually convertible to is .357 SIG, and that because the rear of the case is essentially .40 cal, which means you use the same slide, and usually the same mags and same recoil spring.
URBAN LEGEND - .40 to 9mm Conversion?
1 - 19 of 19 Posts
Please report your findings. I'd be interested in hearing what they have to say. In my case, I've been shooting primarily 147 gr. handloads, with some factory 115 gr. ammo - primarily WWB. But then these conversions have worked well for me.
I started thinking about your comments regarding those who have reported failures with conversion barrels. For the most part, the complaints I have read from others had to do specifically with those who were running silencers on their guns. Many reported that the barrels required a couple hundred rounds unsuppressed to break in before they were reliable with a can. In these instances, they reported that the barrels ran just fine without the suppressor attached.
Your comments piqued my curiousity, so I thought I'd go see just what discernible difference I could find. As it turns out, it appears the extractor has full purchase on the extractor groove in the case. One detail that may be overlooked is that the extractoris pushed inward by spring pressure. The extractor on the .40 slide appears to be able to move inward far enough to still fully engage the groove on the 9mm case head.
Hopefully, this picture shows the extractors well enough to see what I mean. The top slide is a 9mm slide with a factory 9mm barrel, and in the lower one has the LW conversion barrel in a .40 slide. I was going to try to take the picture with the barrels fully locked in the slide, but you couldn't see the extractors well enough. I've got the barrels pulled slightly forward in the picture.
You have a barrel that supports the case - often more fully than the factory barrel. As shown above, the extractor fully engages the case (although that's a reliability issue, not a safety issue). Please explain why these are any more "dangerous" than a factory barrel.
I've never seen a "home made" conversion barrel. The only ones I've seen were commercially produced.
To everyone, do whatever your personal comfort level allows. No one is forcing you to use anything you don't want to.
What are you trying to say about me, Kost?!?
Seriously, it isn't that big of a deal. One of the reason I got into HKs in the first place was because of the multi-caliber platform potential of the USP. I've done every possible conversion I'm aware of, except for .40 Super. For whatever reason this topic creates a lot of controversy, but I guess it needs to happen every so often.I don't know about .40 to 9mm conversion barrels for P30s, but they DO work in a USP. People have been doing this in Glocks, HKs and SIGs for years with good results. Even though the breech face is larger, most extractors and ejectors can still make contact with a 9mm case. I used an EFK 9mm conversion barrel in one of my .40 USPs for several years and I was very happy with it. I did have a few feeding issues when I first started using it, but they went away when I replaced the old magazine springs. Back then I was mainly shooting WWB, and the accuracy was above my expectations. I eventually sold my .40 to 9mm conversion barrel when I acquired a complete 9mm top end.
I DO NOT endorse using a conversion barrel for anything other than training. But for training purposes, they can be better than an OEM barrel. They are about 1/3 the price of a complete upper (if you can find one), 9mm ammo is much cheaper, and reduced recoil helps in eliminating flinch reflexes and improving trigger control. Also, even if the reliability is less than 100%, that can be an advantage for practicing malfunction drills. I actually wish I had a setup that would "reliably fail" once in a while for that purpose...
I don't see how the chances for a catastrophic failure would be any greater with a conversion barrel than with an OEM barrel. In my experience they are safe and effective, but should be confined to the roles of plinking and training. I don't believe that any firearm is 100% reliable (if you think so, you need to shoot more), but I wouldn't risk adding any unnecessary variables with a gun that your life may depend on.
1 - 19 of 19 Posts
