Looking For Documentation Of Min. Distance Of Acceptable Trigger Pre-travel

[Jim Bellino]

Have seen references lately to what the minimum amount of trigger pre-travel should be. They range from .025 to .045.....these appear to be peoples opinions as I cannot find any documentation anywhere. Spent hours going thru K's vol 1 & 2 page by page and still no documentation. Never gave it much thought as my two 1911's do have some pre travel but never measured it till yesterday and find that one has .018" and the other .022" take up/pre-travel. So I am somewhat concerned but both pistols(one a high end the other a factory production) pass all safety tests and have been 100% reliable for over four years now. I do realize the need for some pre-travel but never knew there was/is a specified minimum.
Can anyone point me to documentation as to what proper pre travel minimum should be?
Thanks,

[dawsti]

Bill Wilson states a minium of .030 is needed . He has built a few 1911's.

[Jim Bellino]

Bill Wilson states a minium of .030 is needed . He has built a few 1911's.
dawsti...thanks but I know what Bill Willson states and many other knowledgable 1911 pistolsmiths state otherwise....that is why I am looking for documentation of specifications....not what people state.

[Hawkmoon]

People are people. When a specific "people" is the founder, owner, and proprietor of the company making one of the most respected brands of the pistol in question, what he says ceases to be "what people state" and becomes a manufacturer's specification. Bill Wilson represents Wilson Combat. If you know he says that, then you have documentation. The fact that other sources may differ doesn't change that.

Back in the 60s my brother managed a Firestone tire store that was right across the street from a Ford dealership. People would occasionally buy a new Ford, drive it across the street to Firestone, and have a new set of fancy tires and wheels installed. The mechanics had all been trained to "upsell" whenever possible, so even though these were brand new cars, they checked the front end. Typically, the ball joints were (according to Moog specifications) too sloppy and needed to be replaced.

So much for specifications.

[Jim Bellino]

Hawk...prerhaps I should have asked if JMB or the US Govt. had a specification as to what min. pre-travel should be. Sorry for the confusion.

[niemi24s]

The info you're looking for (if it exists at all) is probably buried in the Colt or U.S. Army Ordnance Dept. archives. If can't get it from Colt, perhaps a request to the Government under the Freedom Of Information Act might get it for you. Or, it might be in one of the U.S. Army Technical Manuals as part of an acceptance inspection.

Other than those three sources, you could use the blueprints in our Technical Issues section to calculate what the pre-travel would be in a gov't issue gun.

Probably only take you about 3 full days to arrive at it.

Regards

[Frank]

I suppose it's possible that no one has ever determined an absolute minimum for proper function. It could be that as long as there is some noticeable pre-travel the gun will function properly, and no one has bothered trying to find out how little is too little to function right.

DVC

[berkbw]

I think you're looking for a sick mule to whip here. And, yes, you could come up with some #s from the JMB dwgs, - - but considering the stiff trigger pull, and soft trigger spring, do you REALLY think it matters?

The ans. is reset + some. Unless you're building a race gun, why do you ask?

b-

[John]

Remember that there was no adjustment for pre-travel in the original parts, no pre-travel setting tabs in the JMB trigger. So I have to assume that the pre-travel was not exactly specified in the original specs, and that it was what it was, when all the parts were installed in the pistol.

Of course, John Moses had designed and dimensioned those parts, so that there is some pre-travel.

[mikeydio]

http://www.brazoscustom.com/Home.htm

Here is a link to an article published by custom pistolsmith Bob Londrigan from Brazos Custom where he said that the minimum pretravel is at least .025 and as much as .040, depending on the gun. His method to test it is to slowly lower the hammer to half cock and then pull the trigger. If the pretravel is sufficient, the hammer should not fall.

Brazos Cutom builds a lot of pistols for USPSA competitors whose guns get hard use, so this sounds like a very good source for this information.

Mike

[Jim Bellino]

Thanks to all...got my answer...just headed off in the wrong direction as many had posted min. pre-travel in many other threads and posts so I "assumed" there was a written spec for it. Min pre-travel for proper functioning would be unique to each individual pistol due to parts variations and tolerance stacking.....this is the basic answer I received from three different custom pistol builders.
Mods....go ahead and lock this thread....no need to waste anyones time.
Thanks,

[Frank]

Okay, Jim, I'll close the thread. It looks like we have a definitive answer, and it make sense to me.

DVC