I've been using inexpensive target ammo, from Walmart in the 55 grain FMJ  Remington/Winchester White Box, or the Fed 50 grain JHP.  I'll get a 3 shot group into 1/2", but then it'll open up 1 1/2" to 3".  Some are even worse.  Very inconsistant.

I've been shooting this ammo in my Sabre Competition and in my Rock River Arms AR 15s.  

The flyers don't string.  It's more like a shotgun blast.  I know this ammo can shoot, but I'm at a loss why they open up.  The barrels are free floated.

One friend of mine suggested that I stretch my recoil spring out so that I get a better seat on the bolt??? Anyone ever done this?  Any suggestions for tightening up these groups with this ammo would be greatly appreciated?  Or is there a problem with the ammo.  (BTW, the rifle is 'sandbagged-in' during the 5 shot testing).  

Thanks

Quoted: I know this ammo can shoot, but I'm at a loss why they open up.  The barrels are free floated.

I don't think you really understand the difference between "cheap" ammo and "match" ammo.

Match ammo is held to MUCH tighter manufacturing tolerances. This means each round is as close as possible ballistically to the last. This is what gives you tighter groups.

With "cheap" ammo the tolerances are very large and the consistency is poor. Hence your "flyers".

Cheap ammo in the most accurate rifle in the world will still give you "shotgun" groups. If you are shooting to test the accuracy of the rifle you need match ammo suited to your rifles barrel.

BTW, I can get Sub MOA groups from a non-free floated Bushmaster Heavy Barrel with Federal Match 55gr.

One friend of mine suggested that I stretch my recoil spring out so that I get a better seat on the bolt???

He's a buckethead... don't listen to anything technical he has to say about AR's. That will do nothing.

Your shooting ammo that has a certain amount of Bias due to the fact it is mass produced on high speed lines.
It's a fact of life, if your looking for Sub MOA on a consistent basis, then reload or buy the more expensive match grade ammo.

A lot of variables here, barrels,triggers. This is a case were your expectations are well exceeding what the ammo your using will do consistently. Sounds like the ammo is shooting pretty darn good, you may need to lower your accuracy expectations.

Oh, and you answered your own question when you metioned "inexpensive target ammo"....

Quoted: One friend of mine suggested that I stretch my recoil spring out so that I get a better seat on the bolt??? He's a buckethead... don't listen to anything technical he has to say about AR's. That will do nothing. Your shooting ammo that has a certain amount of Bias due to the fact it is mass produced on high speed lines. It's a fact of life, if your looking for Sub MOA on a consistent basis, then reload or buy the more expensive match grade ammo. A lot of variables here, barrels,triggers. This is a case were your expectations are well exceeding what the ammo your using will do consistently. Sounds like the ammo is shooting pretty darn good, you may need to lower your accuracy expectations. Oh, and you answered your own question when you metioned "inexpensive target ammo"....

You'd be wise to take everything this man just said to heart.  Not only because he knows what he's talking about but because he knows what he's talking about.

The groups you just listed are pretty decent for 100 yards. The other thing you have to keep in mind and I can't say it enough is that every barrel is prejudiced.  Some like certain types of bullets or combination of bullets, powder and OAL.  This is a very in depth thing but if you're not going to reload, just find out what load your rifle likes in the cost you like.  But typically, the better the ammo, the more consistenty, the better groups you'll get.  Unless your barrel doesn't like that certain ammo for some reason.  It's a journey and there is no one answer that covers every rifle.  Sorry.

Try different kinds. Black Hills, Hornady TAP, and anything else that has the right bullet for what you are wanting to do. If you post your barrel length, twist and even make then I am sure someone will have somthing like yours and can suggest some ammo to try.

Quoted: I'll add in 3 shot groups don't mean squat.  All they are good for is the course adjustments for sighting in. If you want to measure group size you need at a minium 10 round groups.  Anything less is not going to be a true representation of the what the ammo+rifle can do. Great thread from Molon on this subject  <Click Me>

Exactly.

3-shot groups are meaningless, and even 5-shot groups can be deceptive.

Quoted: 3-shot groups are meaningless, and even 5-shot groups can be deceptive.

There's a few things the "article" leaves out. Many shooters change their cheek weld and other interfaces with the gun between groups. I feel like these inconsistencies account for many of the roving groups talked about. Personally, while I have fired three shot groups on occassion, my norm is an average of five, 5 shot groups. Even an average of five, 3 shot groups is meaningful though.

Two other things need to be taken into account. First is shooter fatigue when firing extended strings. This is especially apparent when using iron sights for extended group shooting. The second pertains mostly to bolt guns. With the possible exception of varmit rifles, most bolt gun owners are concerned with what the rifle does from a cold barrel. Anyone here ever tried to fire a 10 round group out of their lightweight hunting rifles (lotsa powder) on a hot summer day???

Just a few thoughts on the subject from someone who has fired many groups over the years...

Quoted: 3-shot groups are meaningless, and even 5-shot groups can be deceptive.

I disagree
I've been getting pretty good info and have zeroed many a scope with 3 shot groups.

The U.S.Army has used 3 shot groups in everything from M16/M4 Zeroing to screening 120MM Main Gun Rounds for as long as I can remember.

For all the Gee wizz, slide rule,benchrest shooter, chronograph, caliper, hey look at this incredibly tight-group , scientific Minutia, it may be just fine, but on the whole, the 3 shot group can pretty much tell the average shooter where he's at and where he needs to be.

Believe it or not...Most of us do not use the "Werner Von Braun" Approach to shooting......

Someone hinted above about barrel heat, but I'm surprised nobody has chimed in.

Your first 3 shot group has a 'fairly' consistent barrel temperature, but every subsequent shot will have a different barrel temp.  Unless you set up a cadence (time between shot strings), your POI will vary quite a bit.  

I have noticed some AR's actually get more accurate as they raise to a consistent barrel temp.  The trick is, keeping the barrel in a that 'heat zone'.  

IMHO/YMMV

To get the thread back on track, you spent a lot of money on your rifle, why go cheap on the ammo.

That being said, if it wasn't for the shear volume of ammunition that I shoot in practice and competition, I would just buy a case or two of Black Hills per year (I find them to be MUCH better than Federal Gold Match) and call it good.  Since (pre-Army and again in about a year when I get back from deploymen) I shoot on average about 1k rounds per month of .223 it just makes sense to reload (especially since Sierra has bulk packed 69gr. SMK's now).

So, like others have said, step up and buy better ammo or start reloading.  I doubt that you want to lower the expectations of your ammo.  Again, I prefer Black Hills.  I find them to be more consistent lot to lot than anyone else.  Price-wise they're tough to beat too.  In a pinch (i.e. slept in and didn't feel like firing up the press), 3-4 boxes of Black Hills fixes everything (good thing for keeping good load data for sight adjustments).

Rich

Quoted: Quoted: Quoted: 3-shot groups are meaningless, and even 5-shot groups can be deceptive. I disagree I've been getting pretty good info and have zeroed many a scope with 3 shot groups. The U.S.Army has used 3 shot groups in everything from M16/M4 Zeroing to screening 120MM Main Gun Rounds for as long as I can remember. For all the Gee wizz, slide rule,benchrest shooter, chronograph, caliper, hey look at this incredibly tight-group , scientific Minutia, it may be just fine, but on the whole, the 3 shot group can pretty much tell the average shooter where he's at and where he needs to be. Believe it or not...Most of us do not use the "Werner Von Braun" Approach to shooting...... I've used 3-shot groups for many years. If you don't know your gun or ammo, then maybe you need 20 shots. With my gun and ammo, the next 17 will go right where the first 3 went. Military grade ammo is inconsistent, and that's why these large spreads show up inconsistently, and is also why with mil-grade ammo you can get better group representation from a larger sampling number.

It's a matter of statistics, not preference or opinion.  

Molon covers it extremely well in his thread. www.jobrelatedstuff.com/forums/topic.html?b=3&f=118&t=279218



(Absolutely, if you are zeroing a rifle, 3-shot groups are FINE - but if you are trying to determine the accuracy of a particular barrel, then you cannot use 3-shot groups).

10 shot groups are the only type that are statistically meanigful.  There is a thread tacked on this very subject.  Quite a good read.  Ideally a full mag would be the best measure of the weapon/ammo combination's practical accuracy.

Quoted: Quoted: 3-shot groups are meaningless, and even 5-shot groups can be deceptive. I disagree I've been getting pretty good info and have zeroed many a scope with 3 shot groups. The U.S.Army has used 3 shot groups in everything from M16/M4 Zeroing to screening 120MM Main Gun Rounds for as long as I can remember. For all the Gee wizz, slide rule,benchrest shooter, chronograph, caliper, hey look at this incredibly tight-group , scientific Minutia, it may be just fine, but on the whole, the 3 shot group can pretty much tell the average shooter where he's at and where he needs to be. Believe it or not...Most of us do not use the "Werner Von Braun" Approach to shooting......

Thats because the M16 and 120mm are consistant systems.  Three shot groups generally pattern the same where a 10 shot group would.  For other sytems that are not consistant the small three shot group is not indicative where the next three shot group will be.  AK or Mini-14 for example.

Quoted: shot 20 consecutive shots inside 30 minutes

We're talking about accuracy with AR15s at realistic ranges with realistic rates of fire.  Firing 1 round every 90 seconds at 1000 yards is well outside the scope of what we're talking about in this thread.

Holy shit............

Quoted: Quoted: Quoted: shot 20 consecutive shots inside 30 minutes We're talking about accuracy with AR15s at realistic ranges with realistic rates of fire.  Firing 1 round every 90 seconds at 1000 yards is well outside the scope of what we're talking about in this thread. Sorry. I removed my egregious post, in order to leave room for your definitive answers, which surely will be appearing shortly to solve this issue for us.

Forest already provided a link to a thread that covers the issue far better than I possibly could.