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1911 cyclic rate vs. ext/mag tension
hijumperrs2
Member Posts: 70 ✭✭
wondering how and how much cyclic rate of fire,dwell and slide recovery after ejection is effected by increased extractor tension and increased mag tension.just opening a forum on the subject,i can make a loose gun sing and a tight gun rock but can i break the rules and use extractor /mag tension to control the dwell and recovery?i am not out to argue or compare intellect just wondering. thanks
Comments
edit in the type of shooting you are doing IMHO 100% function is the most important factor . #1 extractor tension if too tight will cause some cases to be hard to slide up the breach face of slide this can cause mis-feeding problems #2 if the extractor tension is too loose then the case can fall out from under the extractor hook and thus cause ejection problems. Now as to Magazine spring #3 the spring must have enough power to push the next cartridge up against the Magazine lips during the time the breach face of the slide clears the case head on the way back under recoil and the time it moves forward again after it's full cycle.A heavy spring MAY cause the slide to drag on the way back and MAY even very slightly slow down the slide in stripping the cartridge out of the magazine. However to decrease Cyclic time you can relate to a race engine and reciprocating weight.In a car it is pistons and connecting rods and valves.In a pistol it is mainly the slide and a few other
small parts. In My opinion it is a tossup between felt recoil and speed. If you seek speed then you need to lighten slide and increase recoil spring.If you want to use red dot sights DON'T mount it on the slide like most Bull-Eye Shooters do but rather use a frame or grip mount. Cal Grip is the only grip mount I know ofthat will stand up to your type of shooting. If you can find a post WW II and Pre series 70 Gold Cup slide these came from the factory with lighting cuts in the slide so they would function with light loads and standard recoil spring you can use this slide and heavy recoil spring to help you reach faster cyclic times . However the felt recoil may negate this advantage because it COULD
increase your recovery time between shots. . You pose an interesting question.You can with a milling machine cut down on weight of slide. just be careful you don't want to EAT a part of a slide.
As a practical matter, there is only so much spring tension you can have on a magazine spring before the thing becomes impossible to load and/or compromises reliability. Too little tension and you also compromise reliability.
Meanwhile, the only part of the slide cycle where mag tension affects anything anyway is the about 3/4" return travel when the slide is in rebound actually stripping a new round. At that point, the slide is already moving at good velocity.
With extractor tension, not only does this affect slide resistance less, but you have even less leeway to adjust it.
If you WANT to affect rate of fire (and I'm not even sure why you would. . .see below), these are probably one of the LAST places you'd look to tune things.
Believe it or not, one of the biggest factors in 1911 cycling time is the MAINSPRING (not recoil spring) tension, since more resistance there means slower rearward travel of the slide during recoil when it cocks the hammer. I think that's probably where most of the "money" is if you wanted to tune this.
While you'd think that a heavier recoil spring would make the gun cycle slower, its a little more complicated than that. The slower slide recoil you get with a heavy spring is mostly offset by the faster rebound. And there is only so much you can play with this and still get the gun to a. work reliably and b. not batter itself to pieces.
Also note that true cyclic rate of fire on a stock 1911 (eg if you illegally made it go full auto by monkeying with the sear) is somewhere around 1000 rpm.
Sure you could tune this rate up or down, to some extent by playing with spring weights and such, but no matter what you do to it, you're probably not going to INCREASE [edit, sorry] the cycle time much above 0.1 of a second and get the gun to work right. That's still about as fast (if not faster) than a human being can repeatedly pull the trigger on any semi-auto gun, even using bump fire.
In other words, no matter what the theoretical cycle time is on any given 1911 pistol, its probably not going to be the limiting factor in rate of fire in any sort of real world shooting.
So unless you have a burning need to convert a 1911 (illegally) into a submachine gun, its not even clear to me why you'd want to mess with this.
EDIT: Perry is onto something here that I omitted from this post because its sort of getting away from the original question. Yes, you can increase cyclic rate of fire by decreasing the slide weight (which itself you can do in different ways). In addition to a lower-weight main (hammer) spring, you can also probably try lowering the mass of the hammer itself.
All of these things have to be done in a smart way to make sure that the gun is still reliable and you don't increase wear and tear on the gun.
But again, if you're talking about any kind of real-world shooting (pins, plates, bullseyes, defensive, hunting whatever) the limiting factor is NOT going to be cyclic rate of fire of the pistol.
In some of these disciplines (eg bullseye, hunting) rate of fire is effectively irrelevant. Only when you get into the fastest of the fast (eg race gun shooting) does rate of fire matter, and even there the limiting factor is probably going to be your ability to control recoil on the gun, get the sights back on target, and squeeze the trigger, not the intrinsic cycle time. If you really need to shoot faster, take a look at compensators and/or lighter loads.
So far as I can tell, to the extent that things like dwell time and such matter, its only to ensure that the gun functions reliably and smoothly. The idea is to get the gun to be 100% reliable with your given load, yet at the same time minimize slide/frame impact since it both contributes to wear and tear, and (more importantly) can affect the recoil feel.
thanks for the input.i have been using a lightened slide and keeping the spring weight so that the ejected brass is within a meter and a half.i also use a flat profile firng pin retainer (no curve at bottom).also i polsih and tune the mainspring with 17-19 lb springs.additionally i reangle the base of the hammer to gradually let the slide do its job but retain the initial angle stock at the bottom to keep dwell at its most when the round is first leaving the chamber.i am not into full auto.what i am into is accuracy and speed.and all these things i speak of effect accuracy greatly.as for increased tension i am talking about an additional 4 oz on the extractor and a small shim at the bottom of the mag.cyclic rate, perceived ,changes if i take it back to stock or add the above mentioned changes or should i say accuracy and sight aquisition during high speed drills.thanks for your input.
OK, I got it now. As you say, less slide/frame impact should translate into less recoil jolt, which may translate into faster/more accurate followup shooting.
This might be described as "practical rate of fire" and its a little bit of a different thing than absolute gun cycle time (which in theory has little to nothing to do with the shooter at all).
My understanding on this (and Perryshooter can correct/amplify) is that the goal in tuning your gun is to have the slide come back just hard enough to just barely make it all the way back to cock the hammer and hit the end of its travel, but no harder than that. Its not really a question of how long in milliseconds this takes, but rather how hard the slide hits the frame.
I don't think you should have to tweak magazine spring tension, let alone extractor tension to get there.
If you want a "thought" experiment think about this.
If magazine spring tension were REALLY a meaningful factor in affecting your recoil or accuracy, then you should notice differences in both just by switching brands of magazine. Do you? (I'm guessing "no").
Further, since spring tension goes up as you load the magazine if this were really a factor, you should even notice differences in accuracy/recoil between different shots from the SAME magazine!
Note that to some extent you will anyway, as the emptier your magazine, the lighter the gun, and therefore the more recoil you'll have. In my experience, this effect actually IS noticeable when you have heavy double-stack magazines in relatively light polymer framed guns. In that case, there is a noticeable difference in recoil between a "full" gun with a loaded mag and an empty one on the last shot. With big heavy single-stack guns like full sized steel 1911s. . .not so much.
But if you want to know for sure what this does, you can simply test this empirically, by swapping out magazine springs with different tensions into the same body to see what happens. I doubt you'll notice any difference.
On ejectors, since ejecting brass all by itself creates its own sideways "recoil", there is some merit to trying to reduce the overall ejection force. In theory, the less far the gun tosses your brass, the less sideways recoil you'll have and the faster you'll be able to get back on target.
In practice, I think there is only so much you can do to tweak this and still keep your gun functioning reliably.