Well, never let it be said there are no contentious posts on this forum. These days I keep everything at 4.5 lbs because after years of service rifle matches and trips to Gunsite, I just don’t want to re-educate my trigger finger and acquire new “muscle memory”.
That said, I did start out as a Bullseye shooter and did play around with light triggers for quite awhile. Like most of the other guys here, I chewed up a number of parts getting there, but did finally learn how to get a consistently crisp trigger. I will mention the 3.5 lb. bull’s eye limit was pretty near the safe limit in my old Series ‘70 Goldcup. Its big heavy steel trigger stirrup had a lot of inertia, and without Colt’s little spring-loaded sear depressor to absorb shock, the closing slide would drop its hammer, even at that weight.
The bull’s eye shooters at the time all cultivated the habit of depressing the trigger while releasing the slide stop. This keeps the disconnector from coupling the trigger and sear. I never liked relying on that maneuver, though it works. Instead, I devised the following test:
Put a heavy rubber band around the grip safety to depress it. With the slide back and no magazine adding weight, hold the gun between the thumb and index finger; thumb pad over the lower grip panel screw on one side, index finger pad over the opposite screw, and no other part of the hand touching. Point the muzzle up to add the trigger’s weight to what bears back against the leaf spring. With the other hand touching the gun as minimally as possible, depress the slide stop. If several repetitions of letting the slide slam into battery this way causes no hammer following, then that just isn’t an issue in this gun. It doesn’t matter what the trigger pull is, because no matter how loosely held or at what angle or with how little ammunition weight, it won’t cause the hammer to follow the slide. If your gun can’t pass this test, it is marginalized at that extreme and you might be vulnerable to a civil suit should it discharge on closing. To take Jeff Cooper only slightly out of context, at that point it wouldn’t be an accidental discharge, but rather a negligent one.
If you find you must increase the trigger weight for safety, don’t despair. This two-stage trigger allows the stages to be controlled independently. You will find most any trigger whose first stage is roughly 2/3 to 3/4 of the total trigger weight will feel reasonably light, regardless of whether it is two pounds or five. To tolerate a wide range of different pressures without pain, fingertip nerves, like those in your ears, have logarithmic sensitivity, and aren’t very sensitive to small pressure changes. About 10% is the limit of detection under most conditions. Press down on a kitchen scale with your finger until it reads 10 ounces, then vary it up and down an ounce. Your finger can barely detect the pressure difference. If you make the first stage of a trigger 90% of its total pull weight, you will keep setting it off accidentally because the difference between take up and let off would be too small to discern reliably. Aim for 2/3 of the trigger weight in the first stage and I think you’ll like the feel, whatever weight you settle on.
As to the trigger pull itself, I also own the Power Custom jig and like it. However, the one I use for the 1911 is my own design, made before the Power Custom was available. Something Mr. Hunter mentioned is the reason I made it originally. You do see frames with hammer and sear pin holes slightly out of parallel. This means an ideally dimensioned hammer will NOT mate evenly with an ideally dimensioned sear in that frame. The sear will pick up more weight on one hammer hook than the other. I designed my jig with a series of interchangeable, reversible rollers that range from cylindrical through several thousandths of taper in half thousandth increments. Were I to do it over today, I would make a spring-loaded tilting adjustment. Still, the tapers allow me to obtain even engagement in a frame with poor pin hole parallelism (my old Goldcup being one of them). The conventional approach to fixing this is to lean on your stone more to one side of the sear than the other until high spot blue or smoke shows your engagement marking evenly. A jig can actually prevent this from working, which is why so many good triggers come from craftsmen who have learned the feel of the stones. You could make tapered rollers to replace the hardened dowel pin in the Power Custom fixture, but loosening the vertical slide and shimming its channel at the top or bottom to tilt left or right makes more sense to try first.
Now to the crisp trigger. I may contradict some other thinking here, but let me argue for the principle I have used successfully for 20-odd years. As an engineer I see the engagement working at two different extremes, with creepy behavior in between: At the soft extreme, the sear nose and hammer hooks are radiused to match. The radius is centered on the sear pin axis and matches the arc it describes. This sounds difficult to achieve, but is actually simple to get by lapping. The result is an engagement in which so much area is in contact that minimal microscopic deformation of the contours occurs under mainspring pressure, so the static and kinetic coefficients of friction are nearly the same. The result is what is called a roll-over trigger. You feel the engagement slip, but it doesn’t hesitate, so you get no creep. You simply feel it slide forward until it lets go. I’ve met shooters who prefer this to a crisp trigger. One commented that as long as he felt the sear sliding, he knew he wasn’t jerking the trigger.
The hard extreme is a trigger in which the static coefficient of friction is significantly greater than the kinetic one. In this arrangement the pressure needed to break the static starting position and start the engagement sliding is greater than that needed to keep it sliding. To the extent the trigger finger is tensioned like a compressed spring, once it overcomes static friction, it springs through the rest of the engagement against the lower kinetic friction. This is called an avalanche mechanism. The perception is that you pressed back to a point, then the trigger suddenly popped rearward to the over-travel limit. This is the breaking glass rod. To get the static friction greater than the kinetic friction, you want a thinner line of contact in the engagement so it deforms microscopically and the compressed metal parts are made more intimate. In school, my physics professor offered the theory that in static conditions microscopic pressure welds formed that had to be broken to initiate sliding. This would seem to argue for a razor edge sear nose, but doesn’t, because you don’t want there to be any tendency to scrape or roughen the metal. It must be blunt. So you want the sear nose very slightly rounded and the hammer hooks polished flat. The radius on the sear nose causes the static contact line to be small. As the sear moves it is constantly presenting new surface to the hammer hook flats, which prevents new static bonding, and presents an ever-so-slightly diminishing radius, decreasing contact angle as it slides. So, even if static friction were to re-establish itself, it would be at a lower resistance. All this contributes to the avalanche being unstoppable once it starts, and this gives you “crisp”. You don’t want a high pressure lubricant in this situation as it may reduce the static bonding. Light gun oil only.
This may sound like heresy to the polished flat advocate, but it works. I got the idea from Russ Carniak. Back when the Ohio Gun Collectors Association still held its meetings and gun shows in Columbus (before the idiot City Council banned ersatz assault weapons and the Association withdrew), he had a booth at all the shows. He was very generous with his knowledge of 1911’s and walked me through my first one, checking my progress at every show and offering feedback and corrections. Philosophically he said there was no point in being secretive. Too few people would invest enough effort developing the skills to create real competition. It was better to spread the interest.
Anyway, it was on one of these check-my-work visits that I showed up with a perfectly flat and mirror-polished engagement that had a little irregular creep I couldn’t get rid of. Russ pulled the gun apart and took a medium India stone, and made about three light rounding passes over the sear nose and reassembled it. No creep. The pull weight might have inched up because of the rougher surface, but “boosting” the hammer took care of that. He said the medium stone was better than a fine stone because almost no engagement is dead perfect, and the slight surface texture allowed the sear nose to burnish itself to its own best fit.
So, the last item is a test to find out whether your trigger is really crisp, or just kinda-sorta? With the gun on empty, cock the hammer. Put your trigger finger in the guard and take up the first stage slack. Stick your free hand’s thumb inside the trigger guard and press the pad against the inside front of the guard, bending the thumb until the knuckle presses back against your trigger finger. Relax the trigger finger and let the thumb take over. This gives you good control, because the thumb is anchored to the trigger guard and won’t spring through the release. Slowly bend the thumb knuckle until the hammer drops. If you really have a crispy critter, the compressed pad of your trigger finger will be enough spring to follow the trigger and you will feel no creep. If the trigger isn’t quite there, you were probably going to get intermittent creep down the road anyway. A little more rounding should clear it, but don’t overdo it if the job is to have longevity.
Have fun, and good luck!
Nick
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I don't have a forge. I quess I will just have to continue to buy them and then fit them to the gun using files, jigs, and stones.
