So there's a thread on SH with one guy claiming that his BA50 (formerly Cobb 50, now Bushmaster) can shoot 0.8 MOA, and "1.035 MOA" consistently using military surplus M33 Ball ammo.  While Bushmaster does advertise the rifle as capable of "1MOA Accuracy with M33 Ball", I'm still calling BS.  Isn't the M33 cartridge itself, inherently, not capable of >2 MOA accuracy regardless of the rifle used?

http://snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2714361&page=2

It doesn’t seem worth getting into a pissing contest with someone over the Internet by attempting to discount their claim.  The truth is that some rifles “like” certain ammo and maybe this rifle is one that works with it.

I make this statement from the perspective of my M1A.  Back when I bought it, many people were claiming that the South African surplus was a solid 2 MOA and under performer.  My M1A never managed better than about 6 – 8 MOA on SA surp.  Did those other M1A owners lie?  Probably not.  After I switched over to shooting Malaysian surplus, I was shooting 3 – 4 MOA with no other changes.  The people whose guns liked the SA ammo thought it odd that my rifle shot so much better with Malaysian surp.

After I started reloading for my M1A, I was able to shoot 2 – 3 MOA consistently and I expect to stay under 2 MOA once I put a scope on the rifle.

In summary, I have no doubt that some people stretch the truth about their shooting and the results they get.  Most are probably like me and don’t – because that would defeat the whole point and validity of discussing these issues on forums.  I’m a decent shot, but I have no illusions that I’m some uber-sniper or anything like that.  It would seem silly to me to try and lie to people that I’ve never (and probably won’t) ever meet.

I'm looking for a bit more reliable input.  If his (and Bushmaster's for that matter) claims are true, I'll dump by Barrett and buy a BA50 in a heartbeat if it can shoot <1MOA with M33 Ball.

However, if that were the case, wouldn't everyone in FCSA be using a BA50?

Now while what Snot-Rocket says is true about some rifles like certain ammo better than others. Called harmonics, or barrel whip. I used to shoot 22 LR with a barrel that is about .9" in dia, but yet I had a weight that I could adjust that would change the harmonics and lessen the barrel whip. Could actually see the group shrink.

With that said. My own experience is that one day I took to the range I think it was 30 rounds of SA M33 and the group was about 36" with 20 shots at 600 yrds. Then I shot 10 rounds of AMax bullets. Group came down to about 12". And I had not jacked around with tuning the powder charge or the seating depth. Knowing how a M33 is made with the mild steel insert. I really have a problem with anyones claim of less than 2 MOA for this round in any rifle. The M33 is the Ma Duce spray and pray round.

And using M33.   Yeah, right!

I would have to see it to believe it.

I was the Match Director for 1000 yard matches for several years. Back around 2006 or so I had a person calling me a couple times a week for a couple months asking about the match that was upcoming. He kept bragging about how he shoots 3 inch groups all day long with his AR50 consistently. He wanted to know what size groups needed to be shot to win an award. I told him that if he could shoot under a 12 inch agg at this range, then he would be in the top shooters. He laughed and said he was sure to win if that was all he had to do. I was getting tired of hearing his exploits and registered him for the match. He showed up looking like a RAMBO wannabe bragging to everyone how good he was. Well after the match when all the stats were complete and we handed out the awards this braggart ended up coming in LAST PLACE. He was also the biggest pain in the ass I ever wittnessed in 12 years of match shooting.

I have never been able to achieve better than about 3 MOA with surplus ball in my Cobb BA50, and only slightly better with new factory loads from Barrett and AE. I am sure that most of that is me, but I feel safe in saying that the BA50 is not a sub 1 MOA rig.

I popped 30 rounds of milsupr Singapore M33 equivalent in my BA and it held around 2-3 MOA; tried 10 rounds of USA Ammo API and it held under one MOA, 5 high and 5 inches left of zero at 100 yards.  Several rounds cloverleafed.  Go figure (but I ain't complaining!!)