Generally whenever I buy a used pistol the first thing I do is change the recoil spring. But now I have the grips off my new to me 4006 to change them out for a new one and I noticed that the mainspring is very easily accessed, much more easily than on Sig pistols for instance. Should I change it out while I’ve got the grips off? I don’t know the round count interval for a mainspring and I haven’t been able to find it anywhere.
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3rd Gen mainspring change interval?
- Thread starter MattB
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I have never changed one, ever. No problems. That said, if some idiot had it before you and was cutting off coils, etc., then replace it. The more important spring to look at is the recoil spring. That one may need changing. Maybe not, but I would think it would be the first to need replacing.
Rock185
US Veteran
FWIW, Since shortly after they were introduced, I've owned various 3rd. Gen pistols in .45 ACP, 9MM, 10MM, etc. I don't think I've ever changed a mainspring, and don't recall ever having light primer strikes, etc. IMHO, certainly couldn't hurt to install a new mainspring if you have one though.
I've never changed ANY spring in my 3rd gen 9/40/10/45. If they act up years in the future I will attend to it then.
mrmike7189
Member
Its cheap insurance ...Ive changed every recoil spring and magazine spring in every used pistol I've bought. never bothered with the mainsprings however/
I am not aware of a change interval for the mainspring, but I would say that it might not be a bad idea if you strip the pistol to the point that you have to remove the spring. I would think this would be especially true of a pistol that is purchased as a used firearm.
JohnHL
SWCA Member
As most here already know, the mainspring does more than just power the hammer.
It aids the recoil spring during the firing cycle.
A 40 caliber cartridge is harder on pistols than a 9mm or 45, so it would be a good idea to replace it if uncertain of its age.
Be aware, a new mainspring will likely increase the weight of the double action trigger pull, but if it does, it means it is protecting the pistol better than the old one was.
John
It aids the recoil spring during the firing cycle.
A 40 caliber cartridge is harder on pistols than a 9mm or 45, so it would be a good idea to replace it if uncertain of its age.
Be aware, a new mainspring will likely increase the weight of the double action trigger pull, but if it does, it means it is protecting the pistol better than the old one was.
John
Good point about .40. Even though the 4006 is stainless steel it still will take more of a beating than other mainstream calibers short of something like .357Sig (I do wish S&W had made a .357 3rd Gen though).
JohnHL
SWCA Member
Stainless steel frames are why I converted a 4006 and a 4006TSW to 357 Sig!
Too much stress for the alloy framed pistols.
And yes, I upgraded the recoil and main springs.
John
Stainless steel frames are why I converted a 4006 and a 4006TSW to 357 Sig!
Too much stress for the alloy framed pistols.
And yes, I upgraded the recoil and main springs.
John
Where were you able to find a .357Sig barrel for a 4006? My only .357 is a Glock 32 but I really like the cartridge.
kbm6893
SWCA Member
Me too. But I also change the firing pin spring since it comes in the pack with the recoil spring. A friend of mine inherited his cousin’s early 4506. Gun was very beat up. I got the spring pack and changed most of them, including the main spring.
JohnHL
SWCA Member
I didn't.
I used 5906TSW barrels and reamed the chambers to .357 Sig.
I also had to change the angle of the barrel camming lugs on the 5906TSW barrel to work in the 4006 non-TSW.
I like the cartridge, too!
John
Every used 3rd Gen I've purchased got a thorough cleaning & a fresh set of all the common springs: recoil, firing pin, mainspring & magazine springs.
They're 25-30 year old guns that have been who knows where with who knows who & I want to start my relation with them from a known good starting point & that begins with new springs, always.
.
They're 25-30 year old guns that have been who knows where with who knows who & I want to start my relation with them from a known good starting point & that begins with new springs, always.
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Truth has been spoken!
A lighter weight or worn mainspring will make for a lighter trigger, but at the expense of faster breech unlocking and higher slide velocity during the extraction phase. A heavier mainspring will increase the trigger pull, but also applies more forward pressure on the slide at the moment of firing, thus delaying the unlocking of the breech, which means the bullet is further along or completely clear of the barrel, resulting in less gas pressure forcing the slide backwards and less slide velocity during extraction.
A heavier mainspring is far better than a heavier recoil spring when trying to balance the forces in a semi-automatic pistol.
In a high round count 40 pistol? Yeah, I might change ALL the springs. But not in a 9mm or a 45. In those I only keep up with the recoil springs and mag springs. I have cleaned firing pin springs and the firing pin channel too, but saw no reason to replace the springs.
Member Dave Nash addressed this once before here. In a well used pistol, everything "settles in". And as long as the pistol functions properly, leave it alone. In many thousands of rounds - 9K through a value line 457 / 19K through a value line 910 - I never changed the mainsprings. Just the recoil and mag springs. The 457 still runs great. The 910, I cracked the frame at 19K rounds. Its a parts gun now.
IIRC, member CALREB discussed this topic as well. Telling us that the recoil springs in the 4566 and 4506-1 did not necessarily need the factory suggested "3K round" change interval. Only change them when the recoil spring takes a 1/4 inch set or the gun starts to experience malfunctions. No mention of having to change mainsprings.
In an aluminum framed pistol, I would change recoil springs sooner, usually at the factory recommended interval, unless it was a small 9mm or 45, like a Chief Special. Those I change at around 1500 rounds. But I see no need to touch the mainspring on those guns either. If it ain't broke.... Regards 18DAI
Member Dave Nash addressed this once before here. In a well used pistol, everything "settles in". And as long as the pistol functions properly, leave it alone. In many thousands of rounds - 9K through a value line 457 / 19K through a value line 910 - I never changed the mainsprings. Just the recoil and mag springs. The 457 still runs great. The 910, I cracked the frame at 19K rounds. Its a parts gun now.
IIRC, member CALREB discussed this topic as well. Telling us that the recoil springs in the 4566 and 4506-1 did not necessarily need the factory suggested "3K round" change interval. Only change them when the recoil spring takes a 1/4 inch set or the gun starts to experience malfunctions. No mention of having to change mainsprings.
In an aluminum framed pistol, I would change recoil springs sooner, usually at the factory recommended interval, unless it was a small 9mm or 45, like a Chief Special. Those I change at around 1500 rounds. But I see no need to touch the mainspring on those guns either. If it ain't broke.... Regards 18DAI
I went ahead and changed out the mainspring on my 4006. Both the new and old spring were the same length with the same only notable difference being the new spring is shinier than the old one. No noticeable change to the trigger pull after the change. May not have been necessary but changing both recoil and main springs is cheap preventative maintenance on a .40 pistol. And one of the nice things about the 3rd gen design is how easy it is to change the springs. Changing a mainspring on a Sig is a massive pain by comparison.
