Feeding Problem

[JPro45]

First, Thanks to all for the great topics and discussion here on the forums.

I recently put new ISMI srpings and SV comp followers in two of my 140mm SV mags. Both have Dawson basepads. Today was my first outting with the new components. In 200 rounds I had three FTF. All were the same. The slide stopped on the round which was nose up in the ejection port. Always on the last round in the magazine. All other rounds in the mag fed without incident.

I purchased the gun used and it came with the magazines. They were running fine before I cahnged the springs. I know, I should have left it alone, but I thought new springs and followers would be a good thing. The gun was manufactured in 1997.

What could be causing this problem? Do I have to send the magazines out to be tuned?

The gun is a short dust cover SV. I am running a 12.5 lb ISMI recoil spring with a blue Wilson buff, FL stainless guide rod. The hammer spring is factory.

Thanks in advance.

[Guest Larry Cazes]

had a similiar problem with my SV mags after running about 500 rounds through them. I had been using dawson +1 pads, SV comp followers and Wolf standard springs. After the first 500 rounds and the springs took a bit of a set, the last round in the mag would jam between the breechface and barrel hood. I switched to Grahams extended springs. These are 2 coils longer and were originally intended for 140mm extended or 170mm tubes. I clip 1 coil off and they have quite a bit more tension and feed 100%. I can fit 19 in the mag without overstressing the springs with this setup.

[Duane Thomas]

A good pistolsmith once told me, "Whenever a previously reliable gun starts puking on you, the first thing you should ask yourself is, 'What did I change?'" In this case, you know what you changed. If the gun worked before you made these changes, put the magazines back the way they were.

[schmitz]

I'm with Duane here,

changed my genuine springs in SV mags, replaced them by Arredondo's (because I thought they were better quality) and got the same problem (nose-diving). Changed back to my genuine SV springs and the problem was gone.

One lesson learned

DVC, Henny.

[Detlef]

one note of caution here: Sooner or later (maybe later, true...) you will have to replace the mag springs. I have often found with Wolff and Grams springs that they need a *break-in* period of a few 10 or so load-unload cycles, then the puking stops. Since you're probably (Murphy's law) going to see the first signs of weakening mag springs a few days before *the big match*, you might just as well deal now with the procedure of replacing them and tuning/breaking them in... Start by changing one thing (the SV mag spring against a new one)...

--Detlef

[Singlestack]

When I replace mag springs with Wolf springs, I load the mags full and let them sit overnight. Helps speed up the *break-in* period.

[Detlef]

Beven Grams, a while ago, posted a few good arguments that it is the number of load-unload cycles, not the duration of compression, that weakens springs and determines their life time.

[JPro45]

Thanks for the advise. I know if it wasn't broke I should not have fixed it. I am glad I tried it now because, as posted above, eventually the springs would have to be changed. I am going to put the original followers back in and just go with the springs to try and narrow down the problem.

Thanks again for the assistance.

[Guest Larry Cazes]

Detlef, I believe that your right......I have also noticed that with the Grahams extended springs and +1 Dawson bases, my mags will take 20 rounds but that the column made by the compressed spring is collapsed and overstressed. Should a coil in the column be pushed completely down to or passed the coil below it (im calling this collapsed) then you might as well just throw that spring away because in my experience it is overstressed and will soon fail.

[benny hill]

It's the followers, not the mag spring's.