Re: 2 stage trigger, Why is it better?or not...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dukedurham</div><div class="ubbcode-body">I see that a lot of AR style guns are getting the 2stage upgrade, but what about the bolt runner? Does this style control not do as well here? Goin'Hot, that's what I was thinking as well, maybe 3 lbs. </div></div>
As Sterling Shooter explains above, the ARm being a semi (or in some cases, a fully) automatic rifle,requires a trigger design that ensures uou will only fire one round per trigger pull, if that is what it is set for. I should think that it is probably very disconcerting to have the rifle double or even go full auto when you thought only one round would come out. The other big issue with the AR-15 is the incredibly long lock time, due to the design of the hammer and floating firing pin interaction. It's not quite as long as a flint lock, but it is much longer than the lock time of a bolt rifle.
For a bolt action rifle, the trigger only needs to release the firing pin or striker, which is under spring pressure. You can get it to go even faster with a stouter spring and a titanium firing pin. This provides for a lock time under 4 milliseconds, closer to 2 milliseconds. The trigger can get quite light and there is no danger of doubling or going full auto. The trigger does not have to capture and retain the striker after it releases it.
The AR-15 trigger has a lock time in the 12-15 millisecond range. It is heavy because of many factors, not the least of which is the fact it must capture and hold the hammer back when this object gets pushed back by the rearward action of the bolt carrier group. The hammer must positively capture and hold this hammer, or else you get doubling or worse. So the hammer design on an AR is more complex than on a bolt rifle because of the fact it has to do several things. A two-stage trigger is a great way to overcome the weight inherent to the AR trigger but that complicates it further as the trigger must be able to reset itself back to the starting position if the shooter changes his or her mind after pulling through the first stage. Also, an improvement of the stock AR trigger would be a faster lock time. Most after market AR triggers do not address this; the Geissele is the only trigger I am aware of that actually cuts this time down somewhat, in this case to about 8 milliseconds, which is still much longer than on a stock bolt rifle.
On my match AR rifle, I have installed a Geissele trigger and I have set the overall weight to just a shade under three pounds. I have set the first stage to 2 1/2 pounds, pretty much the standard setting as supplied, but the second stage if only ounces. So, when I get ready to shoot, I aim at the target and I take up the first stage (there is a definite stop); 2 1/2 pounds is very light and easy to maintain. Let me just say here, that I do not subscribe to the notion that one should squeeze the trigger and that the gun firing should come as a surprise; I want my rifle to fire exactly when I want it to. So, while holding the first stage, I refine my aim, and exactly when I want the shot to go, I just slightly increase the pressure on the trigger and hold the position on follow through being mindful of that long lock time. In competition, I stay glued to the target and in position until the target goes down.
When I shoot my target bolt rifle, I have to remind myself that it does not have a two-stage trigger, this one has a Timney and it is set very light, less than a pound. I actually do not like mixing trigger types and I much prefer a two-stage to a single stage design.