What's an average life span for an m1a, Round count before something major breaks or the barrel is done?

I have heard 15,000 rounds on a barrel, 150,000 rounds on a reciever.

However I am not sure about that.

Quoted: What's an average life span for an m1a, Round count before something major breaks or the barrel is done?

The different parts have different life spans and that depends on how used or new the parts are when you start counting. Pretty much all the usgi parts you see out there are used parts and the wear can vary. A good receiver should last about 400,000 to 450,000 rounds, barrels last depending on how much accuracy you want and what they gave in the first place. A chromelined barrel can give you it's best accuracy longer than a non chromelined, but a nonchromelined will be more accurate on average than a chromelined will. General numbers would be around 12,000 to 15,000 for a chromelined barrel and 7000 to 10,000 for a non. Alot of that depends on the shooter too and how he/she maintained it and cared for it.
You can read some of the best information on the M14 around on Different's website and in the book he wrote.

Different's history of the M14

Replacing your op rod spring every so often will help as well

Quoted: Replacing your op rod spring every so often will help as well

I bought a few extra oprod springs when I got my M1A last year.  What would you call "every so often"?  Will there be a noticable decline in their strength?

Quoted: Replacing your op rod spring every so often will help as well

Try Tubb's chrome silicon springs out and you won't need to change them as often or maybe not at all for as long as you own the rifle. I love the set I bought a while back that already have a couple thousand rounds on them. They make my rifle run great and from the lack of compression I've seen on them from that time gone by, should last a very long time.

Superior Shooting springs

maybe about every 3000 rds or so. If you look at a op rod spring that has been in for a a lot of rounds ( thousands ) you'll notice that the sides are worn flat. This will reduce the weight of the spring. In 1911 circles for comparison: Look at a 8lb recoil spring next to a 18.5lb recoil spring notice the diameter of the spring wire. Some say don't change springs that often but they'll cheap when you really look at it. Better than buying a new gun

Quoted: Try Tubb's chrome silicon springs out and you won't need to change them as often or maybe not at all for as long as you own the rifle. I love the set I bought a while back that already have a couple thousand rounds on them. They make my rifle run great and from the lack of compression I've seen on them from that time gone by, should last a very long time.

+1

I have Tubb's CS springs in my MK14. The op rod spring fits nicely over my SADLAK NM spring guide.
This combo should provide excellent performance for thousands of rounds.

Spare parts for the bolt and trigger group should be all you need for a long service life.

Some older M-1A receivers are reportedly pushing a qtr million rds. Rebarreled and rebuilt many times over.

I think a lot depends on what accuracy you expect from the rifle.  A true match shooter might change out the barrel every 3000-4000 rounds because he can see the accuracy difference.  But for someone who is shooting an un-accurized rifle with milsurp ammo, the accuracy dropoff of that same worn barrel may not be as apparent.  

Quoted: Some older M-1A receivers are reportedly pushing a qtr million rds. Rebarreled and rebuilt many times over.

If you just think about that, about how long these rifles will be there running strong, that's what makes them so great, that's what makes them better than others.
Yeah, you'll change out parts and barrels, but that rifle will be here long after your gone.
Ah that beautiful steel receiver, how I love it.

I have a little over 18K rounds in my M1A, with a TRW barrel, that I used for HP matches before I retired it and used my newly built M1A.. even after 18K rounds.. it will still hold the 10ring on a SR target offhand... the difference I saw was at 600yds...  :( with that many rounds through it...