Springfield Armory Mainspring Housing

[Andis2068]

I own a Springfield Armory 9mm Range Officer and it came with Springfield's proprietery "key-lock" mainspring housing. I wanted a magwell so I replaced that with a Smith and Alexander mainspring housing. Knowing that my 1911 didn't come with a mainspring cap pin, I also purchased one of those. When I function checked it, the hammer wouldn't strike the firing pin. I stripped it down and ruled out braking any parts. I was dumbfounded; the only cause I could think of was the mainspring cap pin, so I removed it and now it functions flawlessly. Could someone tell me why this solved the problem? The cap pin was used every time I've seen a 1911 assembled or disassembled.

[mont1120]

I just had the same question you have after buying a Range Officer last week. It is in .45 and it too did not come with a pin. I will be very interested in finding out why this is the arrangement.

[technetium-99m]

The housing internals are different. You need a minimum of a new spring and cap, you may need a new pin retainer too.

[open17]

Spring, mainspring cap, mainspring cap pin. Had the same problem----those parts fixed it.

[Andis2068]

I had already put an after market mainspring and recoil spring in it to flatten out the recoil, but I reused the the mainspring cap and and pin. As I said, I also purchased a new cap pin, as the Springfield doesn't come with one.

[BeerBaron]

Hmm. Do you mean the little bent pin used to hold down the mainspring when taking off the msh?

Or the pin that holds the msh into the grip?

I just bought a loaded 9mm and it came with both.

Cocked hammer. Put in pin. Remove the bottom pin, slide out msh. Take out the bottom piece and the spring and the cap and put those into the new msh (egw in my case). Push down on spring, insert holding pin, insert new msh, put in retaining pin, remove holding pin and bobs your uncle.

It's possible the ro is different but I'd be surprised.

[Bob DuBois]

Purchase a pin kit, it's always nice to have spares replace the plunger and pin. Be a good time to put in a new 17 lb mainspring.

Have a vice put a punch in the vice and compress the spring with the mainspring housing.

[Bidah]

I replaced mine a while ago. The cap is different, so you need one of those. A spare pin is a good idea, although I did use my old one (and kept the spare).

[greyhounder]

Had the same problem I almost sure Springfield uses a shorter hammer extension to the spring,that is why I think the hammer flops when it is cocked.

[Sandbagger123]

Check to see if the hammer struts are the same length as standard one

[HOGRIDER]

Hammer strut is stock 1911......only the MS housing internals are different....

[louu]

On 9/22/2014 at 8:40 PM, Andis2068 said:

I own a Springfield Armory 9mm Range Officer and it came with Springfield's proprietery "key-lock" mainspring housing. I wanted a magwell so I replaced that with a Smith and Alexander mainspring housing. Knowing that my 1911 didn't come with a mainspring cap pin, I also purchased one of those. When I function checked it, the hammer wouldn't strike the firing pin. I stripped it down and ruled out braking any parts. I was dumbfounded; the only cause I could think of was the mainspring cap pin, so I removed it and now it functions flawlessly. Could someone tell me why this solved the problem? The cap pin was used every time I've seen a 1911 assembled or disassembled.

Have you or anyone else here figured out why this gun is like this? I was just pulling my hair out thinking I did something wrong putting a new ignition kit in.

Edited February 8, 2018 by louu

[DsWright]

On 2/7/2018 at 7:50 PM, louu said:

Have you or anyone else here figured out why this gun is like this? I was just pulling my hair out thinking I did something wrong putting a new ignition kit in.

 

I have an RO in .45.  I went with the Dawson ICE magwell ans MSH.  Took old parts out of stock MSH, put them in new MSH, and off to the races.  That was thousands of rounds ago and no issues.

[zzt]

louu, SA does this because they use a 70 Series system instead of an 80 Series.  They do this to minimize the possibility of a discharge if the gun is dropped on its nose.  So the use a Ti firing pin to reduce mass and a heavy firing pin spring.  Then they beef up the mainspring to get the thing to fire.  That's why the trigger pull is so lousy.  Replacing the three parts listed above cures the problem.  With an 18lb mainspring, you end up with a 3.5lb trigger.  You cannot go lighter than 18lb or you risk FTFs.  I swapped by buddy's stuff out.  I would have switched to a SS firing pin and normal strength spring, but he wanted to keep the Ti pin.  It works.

[Beef15]

Springfield on top, normal on the bottom:

The hammer strut is the same. The mainspring cap is substantially different, the hammer strut sits down in it probably 3/16 of an inch, the extra height of the cap is stopping it prematurely. The spring is also substantially shorter, using a normal spring with those parts is not optimal. I forget if there is any difference in plunger, I couldn't find the SA one.

[anbrumm]

So glad I saw this. Fought with putting a longer spring into my 1911 for a while the other day. Ordered the correct cap and retaining pin this morning. 

[louu]

On 2/12/2018 at 9:18 AM, zzt said:

louu, SA does this because they use a 70 Series system instead of an 80 Series.  They do this to minimize the possibility of a discharge if the gun is dropped on its nose.  So the use a Ti firing pin to reduce mass and a heavy firing pin spring.  Then they beef up the mainspring to get the thing to fire.  That's why the trigger pull is so lousy.  Replacing the three parts listed above cures the problem.  With an 18lb mainspring, you end up with a 3.5lb trigger.  You cannot go lighter than 18lb or you risk FTFs.  I swapped by buddy's stuff out.  I would have switched to a SS firing pin and normal strength spring, but he wanted to keep the Ti pin.  It works.

Thanks ZZT wish I would have read this earlier. I got a regular cap, spring and pined it in like it's supposed to be. Problem is I used a 17# spring because that's what everyone on here says to use in a .45. I finally got around to shooting it today after the winter rebuild and out of 48 rounds I had 1 FTF, light strike. All of the other primers barley had a dent in them. I'm debating weather to just put the stock stuff back in or getting an 18# spring. With the current 17 you can tell by dryfiring it that it's not hitting hard enough. 

[zzt]

Wolff makes an 18lb spring.  Personally, I use an ISMI 19lb mainspring.  The goal is to ensure everything goes bang, even CCI primers.  Anyone who claims to be able to tell the difference in trigger pull between 17, 18 or 19 lb springs once the system is set to the same pull weight is really just imagining it.  Fire control works as a system.  When you adjust one thing, you readjust another to compensate.  I can achieve a 100% reliable 1.5 lb trigger using a 19 lb mainspring and an ISMI standard weight firing pin spring and a SS firing pin.

[pk47]

I know this is an old thread, but it provided invaluable information.  I recently started moving into 1911 pistols and I had bought a used SA 1911-A1 a few years ago.  When I got into the lower I did not understand why it was made in this kludge sort of way.  Thanks to ZZT for explaining this.  I have some new parts on order now.