Assuming 100 rounds a day, how long would it take to wear parts

>>34178645
100 days before you would probably have to replace the bolt, so 10000 rounds. Depends on how fast you burn those hundred rounds each day though.

>>34178645
it depends.

Replacing worn springs routinely will probably be the determining factor. The lower can last forever in theory (the tube only breaks if the bolt slams back enough from a weak spring)

The upper could last just as long.

Springs should be replaced every 10k rounds.

Ive never seen a buffertube, buffer, or magazine, or gas tube wear out.

Barrel will need replaced depending on what you're shooting. Light loads could probably last more than 100k, hot loads can burn a barrel un less than 500. (Assuming no full retard burnout)

No idea how long a bolt carrier will last. The bolt head itself will depend largely on how well its made, but they tend to go early at the cam pin

What about the same senario but replace the ar with a new condition military rifle (mosin nagant, mauser) what would likely be the first thing to break on a simple bolt action.

>>34179161
My dick your mother's ass. Also, an extractor

>>34179161
I can't say that I've ever seen an old world military rifle fail under normal use, only through user error due to reloading or improper ammunition. Likewise with early model 70's and ruger m77s.

>>34179475
I haven't seen much but parts breakage is for sure , anything small or any spring is going to break alot faster then the action

What could you make a barrel out of if you wanted the longest lasting thing possible? Assume you're still shooting FMJ

>>34178645
really depends on the quality of the moving parts like bolt, bolt carrier group, trigger, hammer, firring pin, barrel. if you have excellent parts, you will have a long-lasting excellent rifle.

>>34179161

Extractor, small springs like the extractor spring, trigger system springs, main spring.

Barrel, depending on caliber and what loss of accuracy you find acceptable. Some rifle rounds are rough on barrels.

>>34178645
It takes a long time. we run an M4 as our primary for pest destruction and most times it gets taken out to do that- tend to run 150 to 400 or so rounds per day through it. Over the last 2 years its had roughly around 4500 rounds through it and hasn't ever had a stoppage or fail to feed.
About the most intense maintenance was taking a dremel to the feeds and polishing them up, bit of de-gunking on the bolt and carrier as well as making sure the gas system is squeaky clean. Lube it up and its all good to go.
Some stuff like the hand guards can get a bit rattly, that just means loctite and a tighten up.

Magazines if they're metal will typically last for ages, provided you don't dent them, throw them around and mistreat them, plastic mags tended to suffer a bit over time around the lips and if they crack you may as well chuck them