View Full Version : AR parts replacement
After reading the troglodyte maintenance thread, it got me wondering what the military/armorer/Colt manufacturer recommendation on replacing parts based on round count is. I read in one of Patrick Sweeney's books that the military life cycle of an M4 barrel is 7500 rounds. You guys know any other recommendations based on round count or where I might find out? The search didnt turn up much.
7500 is maybe a mean number, but by no means definitive. The only wat to tell is to gage the weapon which is done at least annually by DS/GS maintenance. That consists of barrel straightness and bore erosion.
After reading the troglodyte maintenance thread, it got me wondering what the military/armorer/Colt manufacturer recommendation on replacing parts based on round count is. I read in one of Patrick Sweeney's books that the military life cycle of an M4 barrel is 7500 rounds. You guys know any other recommendations based on round count or where I might find out? The search didnt turn up much.
7500 is maybe a mean number, but by no means definitive. The only wat to tell is to gage the weapon which is done at least annually by DS/GS maintenance. That consists of barrel straightness and bore erosion.
Do armorers mike the parts based on round count or just once/twice a year? Is there mean numbers for various parts, if so what are they?
They are gauged on an annual basis for most units and between cycles for training units.
They are gauged on an annual basis for most units and between cycles for training units.
Interesting. I sat through a FN presentation on SCAR some time ago and the selling points was that so and so part would last X many rounds which is X many rounds more than the same part on a M16/M4. Didnt know what the recommended X number of rounds were.
Belmont31R
09-14-10, 16:50
Interesting. I sat through a FN presentation on SCAR some time ago and the selling points was that so and so part would last X many rounds which is X many rounds more than the same part on a M16/M4. Didnt know what the recommended X number of rounds were.
With a unit arms rooms theres no way to keep track of individual round counts. Its easier to do it based on some time of time/event schedule than round count.
Essentially what happens is that the unit armorer will schedule with the DS/GS personnel to have the unit's weapons inspected.
The personnel will then perform the inspections and gagings as per the TM. Included in the inspections is protocol to conduct an test of the bolt using "dye penetrant".
Generally speaking personnel wait until their weapon(s) malfunction or break before they are repaired. This doesn't include something like a stock or handguard that is cracked or damaged. It would be replaced fairly quick.
Things like springs are replaced when they fail.
Essentially what happens is that the unit armorer will schedule with the DS/GS personnel to have the unit's weapons inspected.
The personnel will then perform the inspections and gagings as per the TM. Included in the inspections is protocol to conduct an test of the bolt using "dye penetrant".
Generally speaking personnel wait until their weapon(s) malfunction or break before they are repaired. This doesn't include something like a stock or handguard that is cracked or damaged. It would be replaced fairly quick.
Things like springs are replaced when they fail.
This does not seem smart to me at all. Even in the automobile industry people do "preventative maintenance." Why would you not do that when your life depends on something? Springs, gas rings, and the like doesn't cost hardly anything.
Thanks for the interesting reply by the way, the dye penetrant process was new to me. Wish I knew more about stuff like that.
The problem in my opinion is the system of maintenance that. At the unit level the armorers have very little training and aren't allowed to make any repairs. Also, many military personnel still do not know how to check gas rings, how to check extractor tension, etc...
For example. Let's say that you get assigned to a unit and are issued an M4. You have no idea what has been done to it. Everything is based upon inspections and gagings. Nowhere in the TM (unless I missed it) does it tell personnel what they are looking at. It simply focuses on obvious stuff (cracks in stocks, damaged rails, etc...)
In my opinion if a unit is getting ready to deploy then all the M4's should get new gas tubes, new springs (buffer, hammer and trigger and extractor) at a minimum.
Unit level armorers should get more training and or they need to get more small arms repairman at the lower levels. I would go so far as to assign a couple of small arms repairmen to every combat type unit that deploys and they would have tool kits and parts that accompany them.
An aggressive maintenance program will cost more money. Think about all the people on the boards who balk at spending xxxx amount for small parts. Now imagine that a typical Infantry battalion will have around 700 M4's and the cost associated with replacing those items. We haven't even started talking about magazines, and other weapons. The cost adds up quick and it would be hard to justify.
This does not seem smart to me at all. Even in the automobile industry people do "preventative maintenance." Why would you not do that when your life depends on something? Springs, gas rings, and the like doesn't cost hardly anything.
Thanks for the interesting reply by the way, the dye penetrant process was new to me. Wish I knew more about stuff like that.
This does not seem smart to me at all. Even in the automobile industry people do "preventative maintenance." Why would you not do that when your life depends on something? Springs, gas rings, and the like doesn't cost hardly anything.
Thanks for the interesting reply by the way, the dye penetrant process was new to me. Wish I knew more about stuff like that.
One of the differences between automobiles and firearms is that automobiles have odometers. Intervals for automobiles are based on time and/or mileage. Often times, in the military, the end user or unit armorer (who in the Army normally has a supply MOS and has not been to Small Arms Repair School at Aberdeen Play Ground) does not have any idea how long the rifle has been in service or what the round count is through that particular weapon. Most repairs are based on when the weapon "breaks" they will send it in for repair.
I know individuals and companies are trying to change this with maintenance schedules and even round counters for weapons. We will see where it goes. I do believe preventive maintenance is a better solution.
nicholst55
10-03-10, 01:11
One of the differences between automobiles and firearms is that automobiles have odometers. Intervals for automobiles are based on time and/or mileage. Often times, in the military, the end user or unit armorer (who in the Army normally has a supply MOS and has not been to Small Arms Repair School at Aberdeen Play Ground) does not have any idea how long the rifle has been in service or what the round count is through that particular weapon. Most repairs are based on when the weapon "breaks" they will send it in for repair.
I know individuals and companies are trying to change this with maintenance schedules and even round counters for weapons. We will see where it goes. I do believe preventive maintenance is a better solution.
Mostly true, except that in my 35 years experience, the unit armorer holds whatever MOS he holds - usually whatever the unit has an excess of. The MTOE calls for a 92Y (Unit Supply), but the unit armorer hardly ever holds that MOS, which means he has essentially no training in weapons repair. On top of that, it's frequently just an additional duty for whoever is assigned to the position. Combat arms units also like to rotate people out of the arms room every six months, so that they don't lose all proficiency in their real MOS.
Are you beginning to see a problem?
familyman357
10-03-10, 19:15
After reading the troglodyte maintenance thread, it got me wondering what the military/armorer/Colt manufacturer recommendation on replacing parts based on round count is. ......
At the Colt M16 armorer's course (put on by Colt) that I took this summer, the instructor was loathe to be pinned down to any maintenance/replacement schedule based on round count.
wolf_walker
10-03-10, 20:10
They will save a fortune in the long run if they get a round counter in there(and use the data correctly). The rest of the machine fixing world has been watching distance/hours since the dawn of mechanical time for just that reason.
Look at aircraft maintenance, hour based inspections, etc. Takes time for the results to trickle down, but it's the way to do it.
The problem in my opinion is the system of maintenance that. At the unit level the armorers have very little training and aren't allowed to make any repairs. Also, many military personnel still do not know how to check gas rings, how to check extractor tension, etc...
For example. Let's say that you get assigned to a unit and are issued an M4. You have no idea what has been done to it. Everything is based upon inspections and gagings. Nowhere in the TM (unless I missed it) does it tell personnel what they are looking at. It simply focuses on obvious stuff (cracks in stocks, damaged rails, etc...)
In my opinion if a unit is getting ready to deploy then all the M4's should get new gas tubes, new springs (buffer, hammer and trigger and extractor) at a minimum.
Unit level armorers should get more training and or they need to get more small arms repairman at the lower levels. I would go so far as to assign a couple of small arms repairmen to every combat type unit that deploys and they would have tool kits and parts that accompany them.
An aggressive maintenance program will cost more money. Think about all the people on the boards who balk at spending xxxx amount for small parts. Now imagine that a typical Infantry battalion will have around 700 M4's and the cost associated with replacing those items. We haven't even started talking about magazines, and other weapons. The cost adds up quick and it would be hard to justify.
For what it's worth, I recall during our pre-deployment training in 2004 at Ft. Bliss, we had one week where everyone's weapon was rotated through a contract run weapon inspection/repair program. I have no idea what they checked or did, but I seem to remember it was one of the big name contractors like Raytheon.
More that likely this was a pre-embarkation inspection. They would have probably done gaging(s) and a basic inspection looking for damage. But, there really is no way to gage an extractor spring or gas tube.
It also comes down to the person doing the inspection. If it were me I would replace the tube and spring almost w/o question. I won't knock whoever did the work, but I do know that the requirements aren't very high.
My number one philosophy has always been and will always be this; "If you wouldn't carry the weapon into combat after you inspect or work on it, why should someone else? In other words have confidence in the work that you have done and that it was done right.
For what it's worth, I recall during our pre-deployment training in 2004 at Ft. Bliss, we had one week where everyone's weapon was rotated through a contract run weapon inspection/repair program. I have no idea what they checked or did, but I seem to remember it was one of the big name contractors like Raytheon.
A problem I see with relying on round count for PM would be the rate and conditions that the weapon was fired under.
1,000 rounds fired semi-auto over a period of several months during marksmanship training is going to put a lot less strain on a weapon than 1,000 rounds fired full auto in a couple of days time under desert combat conditions.
familyman357
10-05-10, 16:45
A problem I see with relying on round count for PM would be the rate and conditions that the weapon was fired under.
1,000 rounds fired semi-auto over a period of several months during marksmanship training is going to put a lot less strain on a weapon than 1,000 rounds fired full auto in a couple of days time under desert combat conditions.
Absolutely. It wouldn't be perfect, but I believe that even a simple round count system would be a step in the right direction from the run-it-'til-it-breaks "schedule" that is so prevalent.
Of course, then the debate will be what should be done at what round count. I wouldn't expect much guidance from the manufacturers. At the Colt M16 armorer's course I attended, the instructor basically stated that Colt would probably never publish hard numbers for the expected service lives of various parts. The rationale was that (as has been already stated), how hard a weapon is used/run can make a material difference in part longevity. If a hard-used/maybe-abused part fails at a round count lower than the published figure, Colt doesn't want to take a hit for putting out a "defective" part. They don't want to open up that can of worms.
I have heard that in the previous courses as well. I am sure that there is a common sense way of approaching it, though it would require a little testing. Having said that when in doubt, replace it.
Absolutely. It wouldn't be perfect, but I believe that even a simple round count system would be a step in the right direction from the run-it-'til-it-breaks "schedule" that is so prevalent.
Of course, then the debate will be what should be done at what round count. I wouldn't expect much guidance from the manufacturers. At the Colt M16 armorer's course I attended, the instructor basically stated that Colt would probably never publish hard numbers for the expected service lives of various parts. The rationale was that (as has been already stated), how hard a weapon is used/run can make a material difference in part longevity. If a hard-used/maybe-abused part fails at a round count lower than the published figure, Colt doesn't want to take a hit for putting out a "defective" part. They don't want to open up that can of worms.
With a unit arms rooms theres no way to keep track of individual round counts. Its easier to do it based on some time of time/event schedule than round count.
And that is why brand new condition unfired rifles have been destroyed as they outlived their chronological paper life.
I don't know if that is still going on but it was in the 70's.
And that is why brand new condition unfired rifles have been destroyed as they outlived their chronological paper life.
I don't know if that is still going on but it was in the 70's.
Ugh! :sad:
And that is why brand new condition unfired rifles have been destroyed as they outlived their chronological paper life.
I don't know if that is still going on but it was in the 70's.
What :confused:
What :confused:
Everything had/has(?) a shelf life. Even hard items like a weapon.
You and I may not agree with the assessment but that is the way it was, at least. May still be. But that was at the time of the Viet Nam fracas winding down or over and there were apparently excess stores of weapons and it was explained to me when I questioned it that everything has a shelf life. Plus storage was expensive, etc, etc.
Different time, different world.
Not much different from M14's being chopped up.
I'll admit this is a rather bizarre statement considering I have fired M16's from Vietnam. Not to mention many weapons like M14's were sent to depots, overhauled and then sold to foreign countries or mothballed.
Weapons are usually re-used until they fail gaging or some other dimensionally problems arise. I fixed weapons in Iraq that were damaged in combat and during IED attacks, they weren't scrapped out.
Everything had/has(?) a shelf life. Even hard items like a weapon.
You and I may not agree with the assessment but that is the way it was, at least. May still be. But that was at the time of the Viet Nam fracas winding down or over and there were apparently excess stores of weapons and it was explained to me when I questioned it that everything has a shelf life. Plus storage was expensive, etc, etc.
Different time, different world.
Not much different from M14's being chopped up.
I thought the whole thing was bizarre.
But it was a long time ago and was truly a different time.
Nobody needs to put much stock in it, but, going along with the thread it just says that at least at one time supposedly good weapons were destroyed on a 'time in service' basis.
Odd, too.
Especially when you think of WWII era BIG gun barrels still being used for other purposes.
Incidentally the destruction of perfectly good M14's is well documented. Lee Emerson's book is one documentation. 750,000 destroyed between Crane and Anniston. ( Page 97, second edition).
The NRA used to write about it also.
I'm not trying to be argumentative here, just relaying a weird thing I supposedly learned about and the well documented M14 info.
At the Colt M16 armorer's course (put on by Colt) that I took this summer, the instructor was loathe to be pinned down to any maintenance/replacement schedule based on round count.
Armorer courses vary depending upon whose course it is and who is teaching it. When I and our staff teach armorers courses we see a vast array of weapons, which allows all students in the class to see the differences in the weapons as well from an internal perspective of how the weapon was made. In courses we do make suggestions as to the minimal lifespan of parts based on several decades of studying parts. We see variances in the life of the parts and assemblies depending upon how the rifle is handled in the field, maintained for cleanliness to greatly include lubrication (where/how/which lubricants), quality of the parts, how well they are machined, quality of the original assembly of the rifle, what materials the parts are made from and how they are machined (huge differences here sometimes), variances in semi-auto -vs- full auto fired weapons, and ammunition selection. In the armorers class and manuals we provide a lot of numbers of the minimal lifespan of parts which is based on an average. We show examples of rifles that were worn out to the point of being locked at 2500rds from brand new, due to improper maintenance though bad cleaning and lubricating with the not so AR15/M15 lubricants like wheel bearing grease. We do see rifles that go greatly longer than their minimal round count of which we attribute to maintenance and operation, example is that we have several rifles that are running on the original bolt assemblies at 95k rounds. My suggestion is to first make sure your rifle is properly assembled, maintain your rifle with regular and thorough cleaning using good tools/cleaners/lubricants, and inspect things to make sure they are not being worn (like a action spring that can show wear at about 12K, and if continued use will cause the action of the rifle to be more violent which can cause problems with wear and stress). Regular maintenance is a must with a good thorough cleaning and lubrication, heavy carbon deposits on guns that are run dry will show wear, as compared to a wet lubricated gun. I recommend doing a full inspection of the rifle on a regular basis and always do so if the rifle has been used hard or been exposed to harsh conditions to include being dropped in sand/dirt and something similar, you should include gaging, and if you have access to a bore scope then use it as well.
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