It is VERY easy to increase the spring tension if you know how to work on a 1911, all you have to do is put a bit more bend in the leaf for the grip safety on the sear spring. However, if you don't know what you are doing it's quite possible that you may end up taking a box of loose parts to a local gunsmith and you know he will have something to say about that.
Process is quite simple. Step one, make sure the pistol is unloaded and cock the hammer. Start by removing the thumb safety. If you don't have an ambi safety that is done by flipping it on and off while lifting it up. If you do have an ambi safety I would [B[STRONGLY[/B] recomend taking your pistol to a gunsmith, ambi safeties can be a huge PITA to remove and they vary in how it's done. Next, pull the trigger and let the hammer down. Now look at the lower rear of your grip and you'll see a cross pin that retains the mainspring housing. Remove that pin with a pin punch and the mainspring housing will slide out the bottom. At this point the grip safety will be loose and you can lift it free. Under that you will find the Sear Spring, note the tab on the bottom of the Sear Spring and the notch it fits in the rear face of the grip frame. You can then lift the sear spring free. The spring leaf for the grip safety is the one on the right that poke OUT of the recess in the grip. Bend it a touch more so that it pokes a bit further out of the grip frame. Now lift up the hammer strut and place the Sear Spring back in position. Note that it should lay flat and square at the lower edge by the tab and the leaf on the left side must me resting ON TOP of the Sear Lever. The center leaf also must be ON TOP of the trigger bow. Once you have the Sear Spring in position you can then slide the mainspring housing up so that it covers the locating tab and part of the lower surface of the sear spring. Note, it's critical that when positioning the mainspring housing you position the tip of the hammer strut in the dimple in the center of the mainspring plug. With the hammer in the down position you should be able to slide the mainspring housing most of the way home but you'll need to stop a bit short so you can put the grip safety in position. Note, I've found it helpful to pull the hammer back just a touch if I need to get a bit more learance to slide in the grip safety, doing this will keep the tip of the hammer strut in position in the mainspring plug. Once you have the grip safety in place take the thumb safety and insert the pin with the thumb safety rotated about 180 away from it's normal position, and this point you are simply using the pin of the thumb safety to hold the grip safety in position. You can then push the mainspring housing into position and insert it's cross pin to hold it in location. Now pull the hammer back to full cock. Then lift up the thumb safety and rotate it so that it is at the ON position but sitting high. At this point you'll need to push on the plunger for the thumb safety to compress it into the plunger tube so that the thumb safety will drop fully into place.
That all there is to it and with some practice you can do the whole job in perhaps 2 or 3 minutes.
Final step anytime you do anything with the Sear Spring is a full set of Function tests. Test one is to check that the sear is catching the hammer at half and full cock. Test to is to check for "hammer follow" bu uncocking the pistol and racking the slide as fast as you can by hand, in this test the hammer must remain at full cock to pass. Usually a failure of either of these tests is due to getting the leaf for the Sear UNDER the sear lever instead of ON TOP of it. The final test must be done in live fire with a magazine that has been "short loaded". Start with one round loaded, chamber it, drop the magazine, and fire the gun. After this test make sure that the hammer remained at full cock, anything else indicates "hammer follow" and this is unsafe for any further testing. Next, load 2 rounds in a magazine and fire one shot, then observe the position of the hammer. If it's at full cock fire the second round and observe if the slide locked back. If all of these tests pass with flying colors you are good to go.
Now, the reason why function testing is so critical. I mentioned "hammer follow" and had you test for it for a very good reason. That is when you start tinkering with the Sear Spring on a 1911 you can end up with a Machine Pistol if you get it "just wrong". Normally the half cock notch will catch the hammer if the sear doesn't have enough tension but nothing in life is 100% certain. If you have hammer follow and that hammer doesn't get caught at the half cock notch it's quite possible the pistol could "chain fire" and empty the magazine. In a 38 ounce handgun loaded with 45ACP you'll have enough muzzle climb to put some rounds straight up. Get your chin in the way when that happens are you'll be taking the long dirt nap.
Bottomline, YOU NEVER EVER fool with the Sear Spring on a 1911 without doing a full and complete Function Test after you have the pistol back together.
