Kahr Tight Tolerences?

[King Rat]

I was reading on another forum and some poster made comments that Kahr having tight tolerances was marketing BS. Rather than argue this, I am more interested to see if anyone has any data, specifications etc that can in fact show that Kahr does in fact engineer their fire arms to tighter tolerances.

[Canine Dave]

Tighter than what?

I suppose you can engineer a product with "tighter tolerances", but manufacturing has to be able to build it, QA all the while must monitor the control limits set by engineering and the bean counters have to set a price that we all can afford and Mr. Moon can make a profit.

To know for sure, just ask Kahr Co. what their scrap rate is.

[guido4198]

I have a minute this morning, and ZERO "inside information" on Kahr's tolerances, scrap rate, or anything else directly related to facts that would answer the OP's question.
With that disclaimer out of the way, I'm going to posit, based upon personal experience that Kahr's small 9mm handguns are built to tighter tolerances than most others on the market. I'm only basing that upon my personal experience and observations made while going through the FACTORY RECOMMENDED break-in period that I, like most here experienced when we brought our brand new 9mm CM/PM handguns home.
Many have decried that break-in requirement. Some have made statements to the effect of "I'm not gonna trust my life to a weapon that doesn't run perfectly from the very first round". Interestingly enough..I get that. Building a handgun, or assault rifle ( for example) that runs perfectly from round one, that runs under any possible adverse conditions is not hard to do...you simply loosen the manufacturing tolerances and allow "slop" to be built in. The AK47 is a good example of a very dependable, excellent weapon with a lot of tolerance built in. The compromise is loss of precision. Custom built .45 acp 1911 Clark longslide NRA bullseye pistols are at the other end of that spectrum. 100% reliability wasn't MANDATORY because we got to put our hand up for an "alibi" in an NRA match. There aren't any "alibi"s" in defensive shooting.
I've often described my CM9 as being analogous to a Lamboughini of defensive handguns. When the CM/PM9 series was introduced...it was the hottest setup on the market. Mr. Moon created a genuine hi-performance sidearm and I'm convinced tight tolerances were part of his formula.
Your opinion may vary.

[Canine Dave]

Precisely 200 rounds, not 199 nor 201, because at 201 wear-in stops and wear-out begins. At what round count do you stop trusting your CM/PM9?

I trust your opinion, loved your "alibi" analogy!

I didn't have to drive my new car under 50mph for 500 miles and change the "break-in oil at a thousand miles, either. What's going on here?

[King Rat]

Precisely 200 rounds, not 199 nor 201, because at 201 wear-in stops and wear-out begins. At what round count do you stop trusting your CM/PM9?

I trust your opinion, loved your "alibi" analogy!

I didn't have to drive my new car under 50mph for 500 miles and change the "break-in oil at a thousand miles, either. What's going on here?

I think Kahr simply placing a number to assure a break-in. As we know many do not require any rounds other simple racking slide etc. And any gun I have ever had and I have owned many, I put more than 500 rds of mixed ammo including defense ammo before I carry. And that is NO BIG DEAL. I am simply trying to find some engineering facts about the gun. I am sure there are folks on this forum that enough knowledge to help out with this question.

[skiflydive]

I'd like to see us stop confusing "tolerance" with "clearance." Tolerance is the allowed variance of a machined dimension to it's designed dimension. In other words, .500" +/- .002 is a tolerance reference where +/- .002" is the tolerance. The part can be anywhere from .498" to .502" and be within tolerance. Clearance is the space between 2 mating surfaces. so while Kahr may make parts that are .500" that mate with a part that's .498" that's .002" clearance not .002 tolerance. Other manufacturers than Kahr make their firearms with looser clearances, Kahr makes theirs with tighter clearances. If you say something is built to tight tolerances (a VERY, VERY good thing in machining) it means nothing in terms of how loose or tight the fitment of the parts is. Some will design and manufacture to loose clearances because they can't/don't/won't machine to tight tolerances (the tighter the tolerance the more expensive the machining is) and so must design in more clearance to make up for it. Ever held a gun that seems to rattle? That gun has wider clearances than the one that doesn't rattle. It may be made from parts with tolerances in the +/- .0002's but the clearances are much more open. My $.02 as a manufacturer, although I think people who don't understand the difference will always refer to tight "clearances" as tight "tolerances". My semantics rant over...carry on.

[zamboni]

I'd like to see us stop confusing "tolerance" with "clearance." Tolerance is the allowed variance of a machined dimension to it's designed dimension. In other words, .500" +/- .002 is a tolerance reference where +/- .002" is the tolerance. The part can be anywhere from .498" to .502" and be within tolerance. Clearance is the space between 2 mating surfaces. so while Kahr may make parts that are .500" that mate with a part that's .498" that's .002" clearance not .002 tolerance. Other manufacturers than Kahr make their firearms with looser clearances, Kahr makes theirs with tighter clearances. If you say something is built to tight tolerances (a VERY, VERY good thing in machining) it means nothing in terms of how loose or tight the fitment of the parts is. Some will design and manufacture to loose clearances because they can't/don't/won't machine to tight tolerances (the tighter the tolerance the more expensive the machining is) and so must design in more clearance to make up for it. Ever held a gun that seems to rattle? That gun has wider clearances than the one that doesn't rattle. It may be made from parts with tolerances in the +/- .0002's but the clearances are much more open. My $.02 as a manufacturer, although I think people who don't understand the difference will always refer to tight "clearances" as tight "tolerances". My semantics rant over...carry on.

very good, informative post. I was thinking the same thing while reading this thread.

[King Rat]

very good, informative post. I was thinking the same thing while reading this thread.

Great Reply. very informative. I wonder if Kahr actually provides any data to their design? What are the benefits to a tighter gun? I would think longevity would be one. (I confess to being about as knowledgeable to engineering design as I am Neurosurgery.) But am trying to follow along as much as possible.

[Canine Dave]

This is why I like KahrTalk. Smart, knowledgeable folks here.* Great thread.

So, when a break-in is mandated, does that imply that the pistol is designed and built with light interferance fit between parts of the pistol? That would make sense. As the pistol wears in, the light interferace would become a tight clearance fit.


*excluding me.

[guido4198]

Precisely 200 rounds, not 199 nor 201, because at 201 wear-in stops and wear-out begins. At what round count do you stop trusting your CM/PM9?

I trust your opinion, loved your "alibi" analogy!

I didn't have to drive my new car under 50mph for 500 miles and change the "break-in oil at a thousand miles, either. What's going on here?

You may not treat your new car to a break-in, but I have followed a factory recommended break-in procedure for my motorcycles over the years. Non-high performance Cars aren't likely built to the same standards.

I'd like to see us stop confusing "tolerance" with "clearance." Tolerance is the allowed variance of a machined dimension to it's designed dimension. In other words, .500" +/- .002 is a tolerance reference where +/- .002" is the tolerance. The part can be anywhere from .498" to .502" and be within tolerance. Clearance is the space between 2 mating surfaces. so while Kahr may make parts that are .500" that mate with a part that's .498" that's .002" clearance not .002 tolerance. Other manufacturers than Kahr make their firearms with looser clearances, Kahr makes theirs with tighter clearances. If you say something is built to tight tolerances (a VERY, VERY good thing in machining) it means nothing in terms of how loose or tight the fitment of the parts is. Some will design and manufacture to loose clearances because they can't/don't/won't machine to tight tolerances (the tighter the tolerance the more expensive the machining is) and so must design in more clearance to make up for it. Ever held a gun that seems to rattle? That gun has wider clearances than the one that doesn't rattle. It may be made from parts with tolerances in the +/- .0002's but the clearances are much more open. My $.02 as a manufacturer, although I think people who don't understand the difference will always refer to tight "clearances" as tight "tolerances". My semantics rant over...carry on.

Excellent point. Thank you for taking the time to provide this information.