Altering the mag for 9mm

[Gencom]

i bought the conversion barrel from pistol gear and i THOGHT i had bent the mag tight enough, went to the range to shoot my cheap ammo and pow, first shot no eject, i manually eject the cartidge and it does it again.. how to you know exactly how far to bend the lips??

[dbfxdm]

I was told that the lips needed to be .35" at the forward contact point (right where they curve out away from the cartridge) and .33" at the rear contact point (at the base of the brass).

Scott at Springer has modded one for me. He checked it out and says that it feeds reliably - I should have it by the end of the week.

I will let you know how it works as soon as I get an opportunity to shoot it...

[Gencom]

Did you order it from him or didyou have to send it in? Basically i'd like to buy a premodded one or get it done, cant say i really trust myself lol.

[dbfxdm]

I was in the same dilemma. I have a couple of extra mags but really didn't want to mod one myself and risk destroying it. So I actually ordered a mag from Scott along with some other work I had him do. He modded the mag for me and shipped it. He would have modded one of mine but it was easier just to buy another one from him.

[bruce21b]

this might be a dumb question, but why would you have to bend the mag for a conversion barrel to work?????

[Gencom]

Originally Posted by bruce21b

this might be a dumb question, but why would you have to bend the mag for a conversion barrel to work?????

Because the 9mm sits a bit to high in the .40 magazine causing jams

[gdkeys]

I would think an incorrectly configured magazine could cause failure to feed, and lock back problems - but don't understand why it would cause failure to eject. Could someone enlighten me please?

Thanks!

[dbfxdm]

The width of the lips on the mag along with the diameter and length of the cartridge determine the vertical position and angle of the cartridge. There is an optimum location and angle for the cartridge as it sits at the top of the mag awaiting its turn to be chambered.

If it sits too low, it may not get stripped out of the mag reliably and/or it may hit too low on the feed ramp and jam. An incorrect angle and an extreme high position can cause the same sort of Fail To Feed problems.

If it sits too high, it can interfere with the ejection of the spent brass. It may block the empty cartridge from being extracted reliably from the chamber and will usually cause it to either pull loose from the extractor and stove pipe or be re-chambered - Fail To Eject.

Since the .40 cal cartridge is larger in diameter than the 9mm, the 9 will sit higher in the top of the .40 mag - high enough to cause Fail To Eject problems but in most cases not too high to cause Fail To Feed problems.

Ideally, you want the CENTERLINE of the 9mm cartridge to be in exactly the same position as the centerline of the .40 for optimum reliability. The new XDm 9mm mag is designed this way, it may be both a few thousanths shorter and narrower at the lips.

The alternative, if you want to accomplish the same thing with a .40 mag, is to close up the lips just enough to lower the cartridge to the same optimum position. The trick is to squeeze or bend it consistently on both sides from front to back in order to preserve the angle of the cartridge as well.

It is probably not near as complicated as it sounds because there is quite a bit of tolerance there. However, I can always use another mag and since Scott was familiar with the procedure and was doing other work for me as well, it made sense to just buy one from him and get him to do it for me.

[Gencom]

Originally Posted by dbfxdm

It is probably not near as complicated as it sounds because there is quite a bit of tolerance there. However, I can always use another mag and since Scott was familiar with the procedure and was doing other work for me as well, it made sense to just buy one from him and get him to do it for me.

yeai didn't see that option to have him do it on his site, did you change out your recoil spring as well?

if i can get a 2 mags done from him id also buy some other stuff but alas like i said i dont see mag mod as a option on his site

[dbfxdm]

Give Scott a call. I'm pretty sure that his phone # is on his web site (Springer Precision). He's also pretty active on the forum. I think his ID is Loves2Shoot - you could send him a PM.

I did put a Don's Guide Rod (stainless) in but I have not changed the spring. Scott told me that the factory spring should be fine for anything but light hand loads. Any 9mm factory ammo shoot work fine.

I figure that when I get the barrel and mag, I will try out a few different brands and see. If I have a problem, I'll change the spring.