S&W model 41 magazine problem #2

After I got the magazines my new S&W model 41 pistol  to stay in the gun when shooting (with help from this forum) they worked perfectly.  So I decided to buy 4 more factory magazines.  That way I wont have to reload during a match.  When I tried the new ones I found they caused stove pipes, usually when feeding the 2nd round.  I took the worst of the 4 new mags and stoned the lips smooth.  Then I then adjusted the lip spacings to match the two original magazines.  I went to the range today and tried the two original mags again (5 rounds each) and they still worked perfectly.  Then I tried the new one with the adjusted the lips.  Of course it had a stove pipe when feeding the 2nd round.  Then I put 100 rounds thru the original mags (5 at a time) and they both worked flawlessly.  Then I tried the new one again and it had a stove pipe on the 2nd round again.  AT least it is consistent.

 I noticed the front lips on the new magazines don't line up perfectly with the rounds like the old ones do.  Is there anything else I should be looking for?  Lip height? Lip angle?

DJW1CAV

When you say you have a stove pipe, is the live round sticking up out of the slide, or the spent case?

If it is the live round I would close the lips up slightly toward the front to contain the live round better as it is trying to feed with too much of a nose up attitude.

And if it's the spent round look at your mag tension

jglenn21 wrote:And if it's the spent round look at your mag tension

Its the spent round.  The spent round is wedged on top of the round being fed into the chamber.  The round being fed has the lead bullet 1/2 way in the chamber.  The back side of that round is still in the mag.  The spent round is wedged so tight that it dents the case of the new round.
DJW1CAV

could be a large difference in magazine spring pressure between old and new.. or simply the extractor needs tuning or replacement. The
Volquartzsen extractor for the 41 is a great replacement.. almost every 41 at our matches has one in it.. solves a lot of extraction/ejection issues.

easy enough to swap out.

jglenn21 wrote:could be a large difference in magazine spring pressure between old and new.. or simply the extractor needs tuning or replacement. The
Volquartzsen extractor for the 41 is a great replacement.. almost every 41 at our matches has one in it.. solves a lot of extraction/ejection issues.

easy enough to swap out.

I will look into magazine spring pressure.  I have used a  trigger gauge in the past to check my model 52 magazines.  I will see if I can do the same here.

As far as the extractor.  I saw them at Brownells for $15 and was thinking about getting one.  Now I will for sure.  
Thanks,
DJW1CAV

Maybe this is obvious, but new mags often need to break in before functioning reliably. One way to do this is to manually cycle the follower about one zillion times by  sliding the mag button by hand. I know one guy who swears by slathering the mag with polishing clay before doing this (and obviously cleaning it afterward!). Also, load the mags and let them sit that way, to relax those new springs.

My guess it's because the new mags are a bit tight internally and their springs are new and stiff. The spring is tightest when the second round is rising, and it's pressing up hard under the slide. This slows the slide and means the fired brass has less energy to eject, and the slide doesn't get all the way behind the rising round properly either. Therefore, that round gets dragged forward by friction, while the fired brass gets in the way from above.

As far as the extractor.  I saw them at Brownells for $15 and was thinking about getting one.

Rimfire Sports and Custom

& free shipping....

test for magazine spring tension (based on TT's suggestion)

slinghot first round into chamber
drop mag
add one more round into mag
reinsert mag
fire 
Stovepipe?
clear and fire again
Stovepipe?

If you think it is the spring, drop the mag floorplate and put the old spring in the new body and retest.

Aprilian wrote:test for magazine spring tension (based on TT's suggestion)

slinghot first round into chamber
drop mag
add one more round into mag
reinsert mag
fire 
Stovepipe?
clear and fire again
Stovepipe?

If you think it is the spring, drop the mag floorplate and put the old spring in the new body and retest.

I did a comparison spring force test using a trigger pull gage connected to the bad magazine.  It repeated the test with a good magazine.  The two were identical.  That tells me the springs are not the problem.  Next I plan to sway the internal components between a good and bad magazines.  and do the fire test as you suggested.   This wont tell me what is wrong but it should give me an idea of where to look.  I have been looking at the geometry of the magazines.  While I see slight differences I have no idea of what to change.  
DJW1CAV

Long shot but I have seen the button on the magazine that you place thumb and push down to load can be too long. I bought a bunch of new magazines that work in the new 41 but not the old one. It caused FTF problems because the button hit/rubbed inside mag well and drug enough to change timing. It was a small thing but a little trim/polish there made all the difference.

Len

LenV wrote:Long shot but I have seen the button on the magazine that you place thumb and push down to load can be too long. I bought a bunch of new magazines that work in the new 41 but not the old one. It caused FTF problems because the button hit/rubbed inside mag well and drug enough to change timing. It was a small thing but a little trim/polish there made all the difference.

Len

Thanks Len,
I will check it out.
DJW1CAV

LenV wrote:Long shot but I have seen the button on the magazine that you place thumb and push down to load can be too long. I bought a bunch of new magazines that work in the new 41 but not the old one. It caused FTF problems because the button hit/rubbed inside mag well and drug enough to change timing. It was a small thing but a little trim/polish there made all the difference.

Len

Len,

I checked for interference with the magazine button and the frame.  There is plenty of clearance.    

What I did find today is that on all of my magazines, the left rear lips are VERY close to the slide ramp.  (What I am calling the slide ramp is the part that strips the round from the magazine and the back of the ramp cocks the hammer).  On the bad magazine there is zero clearance between the lip and ramp.  My plan is to swap internal components between good and bad magazine housings, shoot the gun and see if the problem lies with the internal components or the magazine housing.  If the magazine housing is the culprit, I will bend the lip that is touching the slide ramp to give it a couple of thousands clearance.  Then back to the range to test.
It sure is tough to be retired .

DJW1CAV

djw1cav wrote:What I did find today is that on all of my magazines, the left rear lips are VERY close to the slide ramp.

Are your mags "riding high" due to the level where the mag catch hooks the top edge of the slots? Bending the lips might not fix that, and could introduce other issues.

The problems with my magazines are completely solved.  To summarize,  I had one magazine that failed to feed the 2nd round all of the time and another that was intermittent when feeding the 2nd round.  Both of the magazines had one lip that was too close to the slide ramp.   I removed just enough material from the mag lip to give .002' clearance.  Now both magazines function 100% of the time.    
Thanks for all of the suggestions and guidance on this problem.
DJW1CAV