Model 41 Recoil Spring Strength

I have a 1978 Model 41 that I have owned for about 4 years.  I've shot only standard velocity ammo through it, mainly CCI SV and it seemed to run great for hundreds of rounds, then have extraction/ejection issues.  Didn't matter if the gun was clean or dirty and its always lubed appropriately.    I never sorted it out as I got a 1911 Nelson conversion and have been happily shooting that gun.  I decided to get the 41 out and see how it ran.  Same issues - intermittent problems with  CCI SV.  I happen to have a lot of SK+ on hand and tried that - it was worse and that ammo seems to be less powerful than CCI.  So, I field stripped it and then stripped the slide.  The extractor looked ok, but the extractor spring was very soft.  So, I put in a new extractor spring and a VQ extractor expecting improvement.  No better.  Next I got a Wolff recoil spring calibration kit.  I'm almost out of CCI SV so want this gun to run on SK+.  The 7 pound spring was no better than the factory spring and the 6.5 pound spring was a little better, but still had ejection issues - kept getting empty cartridges stuck in the gun in various positions.  The 6 pound spring seems to have done the trick!  Had time to run 60 rounds through the gun with no issues.  I even shot three magazines with 10 rounds in them as I feel the gun should be able to function as it was designed.  My question is, have others had to go down to the 6 pound spring to get their gun to work?  I feel that CCI SV will probably run with the 6.5 pound spring, but have little left for testing.   I like the feel and balance of a 41, but I never truly warmed up to this gun because of the reliability issues.
Thanks,
Jeff

I use 6 pound springs in both of my Model 41s. With CCI SV and TAC-22, I have to put a drop of oil on the first round in the magazine. I do not have to do that with the CMP Eley bulk pack .22.

Be careful with the lighter weight springs in the model 41.  Sometimes the lighter weight springs do not have the strength to fully seat the bolt back on the breach and the gun will not fire.  You can identify this by when the gun goes click with no bang, instead of immediately racking the slide, push the slide forward and see if it will move forward a quarter inch or a eighth of an inch.  If it does, that is a indication that your recoil spring is too light.  

Frankly, I would take a good hard look at your extractor (which you replaced with a volksquarzen which is good), your ejector (it is attached to the slide stop on the left side of the pistol under the grip), and also see if your hammer bushing needs cleaning.  I have had a couple of model 41's where the hammer was so hard to cock that it fouled up the functioning of the pistol and once cleaned, ran flawlessly.  

Your ejector, once you field strip the pistol, should have minimal play side to side.  if there is more then a barely perceptible amount of slop in the ejector, it is not hitting the empty brass good and should be replaced.  

If you need detailed instructions on dissasembly and reassembly of the model 41, I have some good ones with pictures.  Be forewarned, the  hammer removal and replacement, especially with a empty chamber indicator, required a highly trained octopus with eight hands and you gotta hold your tongue just right while you slide the hammer in with all the springs held back.  

Regards, 
Crankster

Both of my 41's eat a steady diet of CCI SV with no issues and factory spring which I change after a couple of cases.

Thanks for the comments.  I'm going to keep shooting the 41 with the 6 pound spring in it and see how the next few hundred rounds go.
Jeff

I gave up on SK in my 41.  I tried the lightest recoil spring and still the SK could not cycle the slide.  Often the empty case would still be in the chamber.  I believe it is the hammer spring that remains the force that SK cannot handle.  NSK said the pressure curve was different.
SK is also weak cycling in other guns.  Oddly enough though SK produces similar velocity as does ammo that cycles. 

Here are chronographed velocities from a Marvel (velocity sd)

900B 958 7, 961 7
SK Std Plus 930 8, 934 10, 922 4
Wolf MT 972 26, 980 10, 972 28
Wolf again 981 20
CCI SV^ 927 8, 929 22
CCI SV^^ 932 17, 942 19
Eley P Std 959 12, 962 11 (aqua)
Eley Tgt P 950 10, 944 2 (yellow)
Eley P Xtra 929 18, 931 9 (lt blue)
Here too, the SK weak cycled in the Marvel, but not as bad as in the 41.

All but the SK and Wolf cycled fine when in the 41.  Wolf was not quite as bad.

The 900B BTW was very accurate.  I had some groups well under 1" in the 41

Jack H wrote:I gave up on SK in my 41.  I tried the lightest recoil spring and still the SK could not cycle the slide.  Often the empty case would still be in the chamber.  I believe it is the hammer spring that remains the force that SK cannot handle.  NSK said the pressure curve was different.
SK is also weak cycling in other guns.  Oddly enough though SK produces similar velocity as does ammo that cycles. 

Good data. It is my opinion, based on all the malfunctions I have had firing SK STD Plus Rifle Match in my M41's, is that rifle match ammunition is not appropriate for pistols.

I highly recommend everyone read The Machine Gun Vol IV by Chinn. It is free at the link.  Read the blowback section. Pressure curve, the correct pressure curve, is critical for blow back operation. These mechanisms are timed so they open just below 650 psia (centerfire, don't know the rimfire value) so the residual breech pressure in the barrel will accelerate the case and pop it out of the chamber. If pressures are too high, the worst case is sidewall rupture. If pressures are too low, then failures to extract, eject, stove pipes, etc. We have all had one of the other, and if you shoot rifle match, you will probably experience lots of stove piping and failures to eject, and failures to feed. The manufacturer expect you to shoot rifle match in a rifle, therefore it makes sense that the manufacturer is not controlling pressure curve timing, only peak pressure and velocity.  Of course with serendipity, someone out there has rifle match that functions their semi auto thunderstick perfectly. And those shooters ought to go out and buy a lottery ticket because they are lucky guys. However, I do not recommend buying $1000, $1500 dollars of rifle match ammunition for use in a pistol, as you may get stuck with an expensive case of ammunition that will not function your semi auto pistol.


I copied this from Chinn, and it might not be in the blow back section, and it is probably for a 20mm machine cannon, but overall, the principal is, the breech block starts to move before pressure is zero. If pressures are too low, the mechanism will malfunction. If pressures are too high, the mechanism will malfunction. Semi auto and full auto mechanisms need ammunition held to much tighter pressure curve standards than bolt guns.

Got to the range again today. I put 60 rounds of SK through it and it ran great. Only issue was I had one FTF and the slide was fully forward. There was an indentation on the rim. Put it back in the magazine and it fired. No idea if it was a gun or cartridge issue.
I also shot really well today. Amazing how confidence in equipment makes it easier to shoot well.
Had a weird thing happen at the end. I had some Federal Auto Match in my bag and thought I’d just see if it functioned. First round went bang but when I pulled the trigger a second time it went click but no shot. The first case was still in the chamber and I had to pry it out. Also, the bolt pin came out about 1/3 of the way. Never had that happen before!
I put the bolt pin back in place and loaded another round of Auto Match. It also fired and the case was stuck in the chamber. I stopped shooting at that point.
I think I have my gun set up for SK now, but don’t understand what happened with the Auto Match.
Jeff

Okay, here's my 2¢ worth. Remember, it's worth exactly what you paid for it.

I shot my 41 for years with a large supply of Winchester white box SV. Not just that I had a bunch of it, it was also sooooo soft in recoil, I loved it in Sustained. AND my 41 shot 0.30" or less (not C-to-C, but the WHOLE group) for most 5-shot groups with it at 50' off a rest. One little hole. I had a Wolff reduced spring in it, but I don't remember what weight (it was 30 years go!).

Everyone else shot CCI SV. The ones who tried my Win WB had function problems. Fine, guns have preferences.

When my WinWB supply started diminishing, I bought a brick of CCI SV from another shooter.

My first club match (just a single NMC), I thought my 41 was busted OR I had had a stroke or something. I shot a group the size of my hand at 50' in Slow, Timed and Rapid. After the match was done, I went back in the range and benched it. Same group, about 4" wide and 5" tall. OFF A REST WITH A RED-DOT AT 50'!

I was ready to ship my 41 off to my smith to ask,"Wha hoppen??'

Then, in a moment of brilliance, I scrounged through my gunbox and found the remnants of a box of Win WB and tried 5 rounds off the rest.

They went in a .28" group.

Tried CCI SV again RIGHT AWAY. 

4" x 5" group.

I started a long and intense research project with .22 ammo. The problem with my 41 and CCI SV turned out to be headspace of the cartridges (a different discussion), but for function, it was about pressures. Not the amount but the TIMING.

First, I chrono-ed CCI SV and my WinWB. They were within 20-40 fps of each other, so the high end of the pressures had to be similar. Yet the CCI felt MUCH MORE SNAPPY, while my Win WB was sooooo soft. A Win ballistician I got on the phone called it "recoil-pulse development." That meant how the pressure builds over the time the bullet takes to leave the barrel.

Apparently, the powder in CCI makes most of its pressure early, while the WinWB powder takes some time to built. Hence, I surmised, why my WinWB had functioning problems in some shooters' 41s. In Slamfire's post, look at the graph; I think it would be the spike in the curve occurring more toward the beginning for CCI and the spike being broader and maybe later for Win WB.

So it is not JUST the strength of the spring that dictates function reliability, but also the recoil pulse. 

So, like our old saying goes, try different ammos in your .22. When you find one it likes (is accurate and functions reliably), stop overthinking. Buy a pallet of it and GO PRACTICE.

This 2¢ probably didn't help much, but hope it sheds a little light.

PS: I had to run a bent brush into the chamber between targets to make sure there was NO fouling in there or there was a chance I'd have a failure to go into battery with the reduced-power spring. If I did the brush thingy, I could shoot all day with no problems.

JNW1 wrote:Had a weird thing happen at the end.  I had some Federal Auto Match in my bag and thought I’d just see if it functioned.  First round went bang but when I pulled the trigger a second time it went click but no shot.  The first case was still in the chamber and I had to pry it out.  Also, the bolt pin came out about 1/3 of the way.  Never had that happen before!
I put the bolt pin back in place and loaded another round of Auto Match.  It also fired and the case was stuck in the chamber.  I stopped shooting at that point.
I think I have my gun set up for SK now, but don’t understand what happened with the Auto Match.
Jeff

First off, I'm new to pistol shooting, so all I have to offer is a very shallow pool of anecdotal observation. My new (to me) 41 will not shoot Auto Match (target 722b). I had the same experience as yours: stuck cases were more common than not, and stovepipes were common for the cases that tried to eject. Tried some CCI SV, et voila! fully reliable. Eley Target seems ok as well.

FWIW: the gun has a Clark barrel, and Clark action work, no idea about spring details.

I shot up the last of my "last ammo shortage" Fed AutoMatch with no intention of buying it again. Same problem: cycling far enough back to cock the hammer but frequent cases stuck in the chamber at the same time.

Sharpened the extractor, lightly polished the chamber, made sure the extractor spring was strong enough. No joy. CCI *Blazer* was cycling fine.

Finally took a close look at the fired cases and concluded from the skid marks that the Fed ammo brass was staying more expanded and/or not "springing back" after peak chamber pressure. That could explain why some faster and presumably higher-pressure ammo can be less reliably. 

The short barrels of pistols vent gas as the muzzle so soon after ignition, I doubt that bolt opening at the higher part of the pressure curve discussed above is a factor in making cases stick. The bolt opening at the low part of a rapidly falling pressure curve could result in inadequate blowback IMO.

AND, a little trick for stuck cases transferrable from the M41 to most anything with an external extractor: Press in on the extractor for more firm engagement and you often can get the case out with regular slide retraction. STICKY when doing that is led me to my soft brass theory for AutoMatch.

I don’t think CCI SV is as hot as it once was. I had some white box SV that was at least 20 years old that ran fine in my 41. The newer blue box was OK in warm weather but stovepiped when it turned cooler. Never have used SK so cannot comment on it. I have gone to Eley CMP bulk exclusively and have had no failures at any temperature. The Eley shoots as accurately as CCI in my pistols, two 41’s and two Nelsons.

6.5Lb recoil spring in my 41. Volquartzen extractor. I bought it used a few years ago and date it to 1984. When I bought it I replaced all the springs and it has run flawlessly with just about every SV ammo there is.

I saw this post earlier, but did not want to share until I had fixed my problem. 

I've had a similar problem with cases getting stuck in the ejection port on both of my 41s. At the recommendation of a good, and very experienced, friend; I fixed the problem on gun #1 by  replacing the bolt with a NEW S&W mdl 41 bolt from Brownells, a new extractor spring and 6lb recoil spring.

Since the fix, I have shot > 200 rounds of Aguila Super Match with 0 alibis  vs 2 - 4 FTE per practice match (30) shots.

Will do pistol #2 when the new 41 bolt from Brownells arrives.

I suspect that the bolt was worn on my 1970 vintage pistols that were passed down from my father. The worn bolt was not holding the case securely enough to complete the extraction process.

My experience suggests that if changing the springs does not solve the problem, then try replacing the bolt with a new one. Costs will be about $70 for a NEW bolt from Brownells.

Just my 2 cents.

IME with more than one firearm, when the bolt is has a loose grip on the fired case (which causes exactly the problems patch175 describes, and more), another place to look is relieving the "inside" stopping point of contact on the extractor. No extractor spring in the world (including 1911 ones which are their own spring) can help if it is not free to move that last little bit tighter on the case rim.

Which reminds me, I *think* that is good on the 41 but I will need to check again.