Can New Mag Springs Cause

[carinab]

If this belongs in the technical questions section, please move it....and yes, I did a search first before posting yet another magazine spring question, Erik

I just put new mag springs (ISMI) in all my STI tuned magazines. Each hold 19 rounds of .40 but the last three rounds are tight/hard to get in. At the range today I had a plethora of feed failures where the round was stopping right on the ramp. My OAL for the round that encountered the stoppage is 1.190. I've previously run this OAL before without an issue. I've also previously run shorter rounds at 1.175 without any issues. The bullet style etc, etc, are all the same. The stoppages only occured after I changed to new mag springs which seems opposite of what should happen.

Anyone else had this happen?

Tomorrow I will try some 1.175 OAL rounds and if I still get stoppages, I may try changing my recoil spring. It could just be coincedince that the recoil spring gave out at the same time as I put in new mag springs.

[XRe]

Try the old springs??? In theory, strong mag springs could cause this problem if you've got something rough going on or not enough recoil spring.

When was the last time to changed your mag springs or your recoil spring?

[EricW]

Don't ask me how to tune an ISMI, but most mag springs need to be trimmed, I believe. I had to cut a couple coils off my Grams spring/followers. If they're that tight, I don't see the harm in cutting a coil and seeing if that fixes the problem.

[carinab]

Try the old springs??? In theory, strong mag springs could cause this problem if you've got something rough going on or not enough recoil spring.

When was the last time to changed your mag springs or your recoil spring?

<{POST_SNAPBACK}>

Unfortunately, I'm too efficient and the old springs are headed for the landfill.

I assume you mean when did I change them last before just now? Last season for the mag springs but I was running a different gun then. This gun has less than 3500 rounds through it so the answer is never on the recoil spring.

[XRe]

Unfortunately, I'm too efficient and the old springs are headed for the landfill.

D'oh. Hang on to what works just in case the new stuff don't

I assume you mean when did I change them last before just now?  Last season for the mag springs but I was running a different gun then.  This gun has less than 3500 rounds through it so the answer is never on the recoil spring.

<{POST_SNAPBACK}>

First time w/ ISMI, or not?? If not the first, do they seem tighter than the last time you changed 'em??

You may have already worn out your recoil spring, so that's worth a shot.

In my experience, in the past, ISMI springs were pretty tough - as Eric says, you can probably trim a coil or two and not have a problem. However, I'd probably look at my recoil spring, first, and try a new one of the same weight/make just to make sure.... YMMV

[Jasonub]

change recoil springs. but first clean your mags there may be some dirt

[ErikW]

I've found nose/ramp jams to be caused by weak recoil springs or foo-foo recoil systems (buffers, sprung guide rods).

[carinab]

The mags and gun were completely clean...and I have no foo-foo recoil systems in my gun!!! No buffers and my guide rod is a two piece.

I have packed the mags full and am letting them sit that way until tomorrow. I recall reading in one of the threads (perhaps Beven posted it) the recommendation to "pre-set" the springs. If that doesn't do the trick then tomorrow I will replace the recoil spring with one of the same weight and see if that does the job.

[bulm540]

invest in a grams spring and follower kit. One of my SVI mags would nose dive with ISMI springs and arredondo followers. Bought a spring kit from Chris Patty 2 weeks ago and FTFs are gone.

[TeamGE]

carinab,

My recomendation for "pre-setting the mag" has nothing to do with letting a full mag sit over night to relieve spring pressure. Pre-setting the mag is where you put your thumb over the top round in a full mag, and beat the base pad into the palm of your other hand, to make the rounds sink into the mag, thus making the rounds set, for as if the mag was inserted into the gun. This practice will releive some pressure and friction on the bottom of the slide, to make sure the slide speed is not reduced too much for a malfunction.

If the last 3 rounds are hard to load into your 19 round mags, you have a mag tube that needs tuning.

My Follower Kits come pretuned with 11 or 13 coil springs. A Limited legal mag will use an 11 coil, and an Open 140 tube with an extended base pad will use a 13 coil spring, same for a 170 tube.

[carinab]

My apologies for attributing the practice to you Bevan. I just remember reading it in one of the threads you were active on. You may have even been recommending against it! I don't recall...but I couldn't find the thread when I searched. It's possible the about the mag bodies. I'm not certain if when they were "tuned," it was the whole mag or only the lips.

The good news is I tested this morning and the problem is gone. This is the first time I've used ISMI springs and they are pretty stiff. I got them as payment from someone as a favor and thought I would try them out since my old springs were very old. After I get back from ladies camp, two mags are coming your way for you to work your magic!!

[jrguar]

Carinab,

I had the same probem several years ago...... I started using brandy new ISMI springs with either Bevens para follower or stock para followers....

The last few rounds were very tight going into the mags....The only way I could get them to run was ... not to fill the mags....

I should note I was shooting a P-14 with stock mags using Grams Base Pads and ISMI 140 MM mag springs.....

After thinking about this for a while...I shortened the mag springs ... maybe 2 coils and all of a sudden 100% functioning with full mags (18rounds in 45acp) ......

My best guess is try trimming one or 2 coils and see how they work...

Good Luck,

Joe