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Beyond mil-spec?
- Thread starter keens
- Start date
Achilles11B
New member
"Beyond mil-spec"? He must be knowledgeable in the AR manufacturing processes of Colt and FN.
Sounds like a sales thing to me.
Sounds like a sales thing to me.
LMT does nothing more than any other top brands. Honestly just ask him to define "beyond milspec"
Funny you mention loose tolerance Tirod, i was just reading the other day about several custom actions failing in the field along with jewel triggers due to tolerances being too tight. Makes sense why the 700 and AI action, which don't get me wrong the AI is in it's own league, are extremely reliable.
Funny you mention loose tolerance Tirod, i was just reading the other day about several custom actions failing in the field along with jewel triggers due to tolerances being too tight. Makes sense why the 700 and AI action, which don't get me wrong the AI is in it's own league, are extremely reliable.
OK Tirod, I have to ask a few questions here because I honestly do not understand a few things that were said. Let me start by saying that I didn't choose to misuse the meaning or the difference in the meaning of the words tolerance and clearance. I simply failed to use them in their proper context. It wasn't intentional, I made a mistake. Now hopefully we can move on. You made this statement:
And then you followed it up with this:A part with tighter tolerances is exactly what Winchester began making in 1964, taking less effort to hand fit them. It then cost less labor to complete a firearm.
I understand that +/- .015" means an allowable tolerance (or diffference in size) of .030" from one part to the next. How does tightening that tolerance up to say +/- .010" or a range of .020" allowable from the specified measurement cause the process to be cheaper, or cause them to be less reliable. You are still withing that original .030", you just are machining parts closer to the desired size. If you are allowed .030" tolerance in other words, it seems to me that tightening that up to .020" would be more expensive and I don't see how that could adversely effect reliability since you are still within the same tolerances. You just have less room to play with. Let me try and make my question clear. If the specs say a dimension needs to be 1.185" +/- .015 that means the part could be anywhere from 1.170" to 1.20" in size. If you tightened up those tolerances to +/- .010" the part would be anywhere from 1.175" to 1.195". How does that adversely effect reliability or make it cheaper to manufacture because "it requires less hand fitting"?Tolerances are based on what can be controlled in reproducing parts in mass quantities. They are listed on the blueprints within a range of measurements, such as +/-.015". That's a range of .030 allowable from one part to the next. It's what is actually specified on AR blueprints downloadable on the net.
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Remember "mil spec" = minimum qualified low bid. Do you want something equal to the governement's low bid item, or a "non-spec"/"beyond spec" upgrade?
I am going to call you on that.
In this context, it is not necessarily a cost issue, its an approach to what is desired result, though you can argue the approach and the merits of the desired result. You appear to be mixing up a cheap bid with mil spec. The cheap bid still has to meet the spec. That’s why the bids are so competitive . As you are on a level field, its who want the contract not who makes the better gun (though huge efforts made to have production costs as low as possible and meet the spec, you sure are not going to exceed it as you get nothing for it, you may exceed it enough so that your failures are minimal or non existent as a cost saving measure)
A non mil spec part can be better or worse. A true Mil Spec part meets certain standards and specifications.
example: In the case of RRA Bolts, they have chosen not to go Mill Spec. Mil spec does not call for a chrome bolt group (which they offer) so they are off mil spec there period.
Mil spec also calls for a proof shot on the bolt and a Magnetic Particle (if I have that right) NDT check to ensure the bolt did not reveal flaws.
RRA chose to use an mfg that does random testing (or RRA does the random testing)
RRA bolts may or may not pass the military test (not all mil spec bolts do either, but all that do not are rejected). ANY RRA bolt that would fail is not going to be revealed.
Keep in mind that the company that makes those bolts for RRA may only fire test a certain number, but they can and do have a quality process to ensure the stock meets or exceeds the requirements.
Is that good or bad? Military thinks its bad, RRA thinks that it works just fine for civilian use. They are doing just fine.
RRA could also use pure crap metal and put out pure crap bolts and it would definitely be inferior. They do not do so as their bussiness model is the mid level AR quality gun.
Mil spec will ensure a level of quality. Whether or not its any good is up to the standards, not Mil spec.
Non mil spec an be better or it can be worse. It depends on gather mfg.
Technosavant
New member
Mil spec will ensure a level of quality. Whether or not its any good is up to the standards, not Mil spec.
Non mil spec an be better or it can be worse. It depends on gather mfg.
Exactly. The "mil spec" is essentially a given specification for the rifles for military use. That is what they have decided is needed- they won't accept any less, they aren't wanting anything more. As far as ARs go, for the parts that are relevant (as stated, lowers and LPKs for our purchase, by definition, are NOT milspec due to the full auto or burst capability in the TDP), the milspec is not a bad guide, but not everybody needs it. Furthermore, there may be places where we have better options available to us. It's all the user's needs and budget.
The only real problem is when people misunderstand this- you have some people claiming if it isn't milspec it's junk. You also have people claiming something that's not even close to milspec is every bit as good for every purpose. Both are wrong. As stated, that non-milspec bolt might be every bit as good. There might be microscopic flaws that weren't found. You don't KNOW. If you're going for absolute reliability, the TDP is not a bad place to start. If you're going for something else, it's probably irrelevant (a varminting AR is going to have a barrel that is decidedly non-milspec... a slower twist stainless heavy barrel with a .223 chamber just isn't ever going to be purchased by the military).
I'm no pre-64 Winchester expert, the problem they were getting into was that the tolerances were much wider - to the point parts wouldn't even fit together properly. It took a more highly qualified assembler more time to hand file or fit parts to get them to function together as an assembly. Not as bad as trimming the wrong pieces of a jigsaw puzzle together, but bad enough to spend a lot of time in labor assembling a gun that would work as one.
The pre-64 lovers fail to mention that if you need work on the gun, a gunsmith will likey order that part and then spend hours matching it to keep the gun working - they aren't "drop in."
So, Winchester changed the design on some labor intensive bits and was able to get ones that worked right the first time, no fitting required. They made the parts conform to specification as needed for the dynamic operation - a drop-in fit. For some reasons the collectors think they are "cheap," when in reality, they were made right the first time, and less expensively.
Winchester survived by making more profit, and was able to increase production by less time in labor spent on the gun.
In contrast, the average old hillbilly (me) can assemble an AR with vice grips on the dining room table, take it out to the range within an hour, and zero it with little concern it will malfunction. Pretty incredible considering that multiple vendors literally hundreds of miles apart did the work with only the military blueprint as a guide. The better ones can and do keep tolerances in check - but I still had to assist the pins into the lugs with a small deadblow the first time, suckers were real tight. The centerlines of the two axes were off just about the limit of fitting together.
That's an issue of "tolerance stack," where all the parts together as an assembly add up the plus and minus they are off and an overall dimension becomes the issue. Other AR builders have reported uppers either too big or tight when fitting the barrel extension. Both parts can be in spec, but not work well together.
Assembling in quantity, a factory would batch complementary dimensions and get optimum fits. If they make both parts, they bias the target dimension to get them more toward that. When bending roofs for yard dog truck cabs, it was usually better to keep them on the small side, the welders could deal with a tight fit, but could do nothing with a larger gap. Those would be scrapped at the value of its complete work in process cost - not at the cheaper value of something scrapped while getting fabricated.
That brings in the accounting, which is a major concern in production. It's always better for the machine operator to junk the parts than pass them on and have the next department in assembly do it for them. In Winchester's case, they couldn't even do that - it was make them work or nothing could be built at all.
Ironic they refined their parts making process by tightening the tolerance down to "drop-in" superiority but get excoriated by collectors for making cheap trash. I guess those guys liked the idea of underpriced handfitted guns and the maker going out of business. Funny when they also complain about not being able to find parts for their exclusive low production cars and having to pay expensive mechanics to fix them.
Are those expensive cars built to tighter tolerances, yes in some areas. Door fits on bodies have decreased 50% over the years. Does it make much difference the Escalade has smaller gaps than my 90 Cherokee? No, and for that, I didn't see many Escalades out in the 19" snow we had last Feb 2011. Both use all four wheels with drive, but one can and will be out there getting me to work.
"Fit and finish," "tighter tolerances," and that stuff can be just aesthetic, not functional. In and of themselves, saying one maker does it better doesn't mean his product is.
The pre-64 lovers fail to mention that if you need work on the gun, a gunsmith will likey order that part and then spend hours matching it to keep the gun working - they aren't "drop in."
So, Winchester changed the design on some labor intensive bits and was able to get ones that worked right the first time, no fitting required. They made the parts conform to specification as needed for the dynamic operation - a drop-in fit. For some reasons the collectors think they are "cheap," when in reality, they were made right the first time, and less expensively.
Winchester survived by making more profit, and was able to increase production by less time in labor spent on the gun.
In contrast, the average old hillbilly (me) can assemble an AR with vice grips on the dining room table, take it out to the range within an hour, and zero it with little concern it will malfunction. Pretty incredible considering that multiple vendors literally hundreds of miles apart did the work with only the military blueprint as a guide. The better ones can and do keep tolerances in check - but I still had to assist the pins into the lugs with a small deadblow the first time, suckers were real tight. The centerlines of the two axes were off just about the limit of fitting together.
That's an issue of "tolerance stack," where all the parts together as an assembly add up the plus and minus they are off and an overall dimension becomes the issue. Other AR builders have reported uppers either too big or tight when fitting the barrel extension. Both parts can be in spec, but not work well together.
Assembling in quantity, a factory would batch complementary dimensions and get optimum fits. If they make both parts, they bias the target dimension to get them more toward that. When bending roofs for yard dog truck cabs, it was usually better to keep them on the small side, the welders could deal with a tight fit, but could do nothing with a larger gap. Those would be scrapped at the value of its complete work in process cost - not at the cheaper value of something scrapped while getting fabricated.
That brings in the accounting, which is a major concern in production. It's always better for the machine operator to junk the parts than pass them on and have the next department in assembly do it for them. In Winchester's case, they couldn't even do that - it was make them work or nothing could be built at all.
Ironic they refined their parts making process by tightening the tolerance down to "drop-in" superiority but get excoriated by collectors for making cheap trash. I guess those guys liked the idea of underpriced handfitted guns and the maker going out of business. Funny when they also complain about not being able to find parts for their exclusive low production cars and having to pay expensive mechanics to fix them.
Are those expensive cars built to tighter tolerances, yes in some areas. Door fits on bodies have decreased 50% over the years. Does it make much difference the Escalade has smaller gaps than my 90 Cherokee? No, and for that, I didn't see many Escalades out in the 19" snow we had last Feb 2011. Both use all four wheels with drive, but one can and will be out there getting me to work.
"Fit and finish," "tighter tolerances," and that stuff can be just aesthetic, not functional. In and of themselves, saying one maker does it better doesn't mean his product is.
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@Tirod, it still sounds to me like we were on the same page all along (other than my misuse of the word tolerance). Do you agree or disagree with this statement or not?
Tighter tolerances mean less reliability.
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