Originally Posted By: bubbatime
Blown, what is your issue with lubrication? If you lube an AR generously with lube, it is less likely to jam. The design is such that it is practically impossible to over lube the AR as it will throw off any excess lube that it doesn't need. No one is saying the Vickers lube way is the way of the future. He was just proving a point. If any excess lube puts pressure on the bolt, it will QUICKLY dissipate as the excess lube is thrown off the bolt.
My point comes from documented research. The Army put together an engineering team to figure out why M249's where failing in combat. They found out it was excessive lubrication getting into the chambers and decreasing the friction that results as the cartridge case obturates and seals against the chamber. This friction and "locking" action places a lot of the rearward force upon the chamber instead of the weaker bolt. You get lubrication in there and that friction goes away and DOUBLES the force seen by the bolt face. Upwards of 6000+ lbf on M855A1 ammunition currently fielded whereas the bolt should see only about 3000 lbf in a properly lubricated gun. That excessive force may not break the bolt on the first round, or several mags worth if the bolt is in good shape. But these bolts develop weakness at the cam pin hole and lugs adjacent to the extractor and you have no idea how marginal a bolt is once you are issued a rifle. Marginal bolt + double the force = something bad. Why you think that's a good risk to take for the sake of wasting a bunch of lubricant is beyond me. The Army issued guidance about using more lube than specified in the TM's under very specific conditions. But like many things that guidance was quickly taken out of context. I dragged my rifle all over Ft. Benning and we almost never had enough CLP to go around. My rifle didn't jam and it was filthy with coarse grit that really locks up actions compared to that talc stuff overseas. My issue is that IT IS A BOLD FACED LIE to state that you cannot over lubricate an AR. Do you think Vickers knows more than US Army Technical Center for Explosives which published the safety bulletin? Do you think Vickers even knows the bulletin exists?
Originally Posted By: bubbatime
Military bolts are subjected to a high pressure test round (one shot of M197) of 70000 PSI (+ or - 3500 PSI) I highly doubt that any excess lube comes anywhere close to the pressure of firing a M197 round. And even if it did, the pressures would drop substantially after only 2-3 rounds as the lube gets thrown out of the bolt/carrier.
This is were a shallow understanding of the operating principals in play works against you. First, that 70 ksi test round is only a bit higher than M855A1. Second, that higher pressure means the case locks to the chamber that much harder which is why the bolt face doesn't not see much of an increase in force as you would expect. This shows in the data between M855 and M855A1, M855A1 operates about 8000 psi higher than M855 but only results in a very small increase in force against bolt face. Second, military CLP has additives that make it very persistent, it simply doesn't go away in only "2-3 rounds" (if it did do you think the M249 would have issues too?) and the fact that the excess lube gets thrown onto the rounds loaded in the magazine which in turn carry it right back into the chamber.
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Not to mention that the M16/M4 bolts have a lifespan of about 5K to 8K rounds on average and are replaced during weapon maintenance.
That's great, next time I'm in the arms vault I'll be sure to look around and see where it's documented on the rifles how many rounds have been fired. Seriously, do you think we keep track how many bullets a given rifle has fired? Do you know when bolts are replaced in our rifles? When they break. That's why I kept a spare bolt, firing pin, pack of gas rings, and extractor kit in my gear. Every once in a while we get a by-serial-number list of which weapons to send up for higher level inspection and maintenance, that list has nothing to do with round counts as we often send up rifles than may have seen only a few hundred rounds through them in years.
Blown, what is your issue with lubrication? If you lube an AR generously with lube, it is less likely to jam. The design is such that it is practically impossible to over lube the AR as it will throw off any excess lube that it doesn't need. No one is saying the Vickers lube way is the way of the future. He was just proving a point. If any excess lube puts pressure on the bolt, it will QUICKLY dissipate as the excess lube is thrown off the bolt.
My point comes from documented research. The Army put together an engineering team to figure out why M249's where failing in combat. They found out it was excessive lubrication getting into the chambers and decreasing the friction that results as the cartridge case obturates and seals against the chamber. This friction and "locking" action places a lot of the rearward force upon the chamber instead of the weaker bolt. You get lubrication in there and that friction goes away and DOUBLES the force seen by the bolt face. Upwards of 6000+ lbf on M855A1 ammunition currently fielded whereas the bolt should see only about 3000 lbf in a properly lubricated gun. That excessive force may not break the bolt on the first round, or several mags worth if the bolt is in good shape. But these bolts develop weakness at the cam pin hole and lugs adjacent to the extractor and you have no idea how marginal a bolt is once you are issued a rifle. Marginal bolt + double the force = something bad. Why you think that's a good risk to take for the sake of wasting a bunch of lubricant is beyond me. The Army issued guidance about using more lube than specified in the TM's under very specific conditions. But like many things that guidance was quickly taken out of context. I dragged my rifle all over Ft. Benning and we almost never had enough CLP to go around. My rifle didn't jam and it was filthy with coarse grit that really locks up actions compared to that talc stuff overseas. My issue is that IT IS A BOLD FACED LIE to state that you cannot over lubricate an AR. Do you think Vickers knows more than US Army Technical Center for Explosives which published the safety bulletin? Do you think Vickers even knows the bulletin exists?
Originally Posted By: bubbatime
Military bolts are subjected to a high pressure test round (one shot of M197) of 70000 PSI (+ or - 3500 PSI) I highly doubt that any excess lube comes anywhere close to the pressure of firing a M197 round. And even if it did, the pressures would drop substantially after only 2-3 rounds as the lube gets thrown out of the bolt/carrier.
This is were a shallow understanding of the operating principals in play works against you. First, that 70 ksi test round is only a bit higher than M855A1. Second, that higher pressure means the case locks to the chamber that much harder which is why the bolt face doesn't not see much of an increase in force as you would expect. This shows in the data between M855 and M855A1, M855A1 operates about 8000 psi higher than M855 but only results in a very small increase in force against bolt face. Second, military CLP has additives that make it very persistent, it simply doesn't go away in only "2-3 rounds" (if it did do you think the M249 would have issues too?) and the fact that the excess lube gets thrown onto the rounds loaded in the magazine which in turn carry it right back into the chamber.
Quote:
Not to mention that the M16/M4 bolts have a lifespan of about 5K to 8K rounds on average and are replaced during weapon maintenance.
That's great, next time I'm in the arms vault I'll be sure to look around and see where it's documented on the rifles how many rounds have been fired. Seriously, do you think we keep track how many bullets a given rifle has fired? Do you know when bolts are replaced in our rifles? When they break. That's why I kept a spare bolt, firing pin, pack of gas rings, and extractor kit in my gear. Every once in a while we get a by-serial-number list of which weapons to send up for higher level inspection and maintenance, that list has nothing to do with round counts as we often send up rifles than may have seen only a few hundred rounds through them in years.
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