I know this is working backward but I have a lot of IMI 55 grain 5.56 ammo that I have acquired.  Now I want a very accurate barrel to shoot the lighter grain bullets.  I bought a 1:9 20" Varmint barrel that I am not happy with.  I am sure someone out there has found an accurate shooting barrel for the IMI brand 55 grain bullet.  I am looking for accuracy period, weight is not a consideration.

Any insight would be appreciated.

Thanks

My 1:9 rock river loves American eagle 55gr.

You are wasting your time and money if your trying to chase sub moa with 55gr fmjs doesn't matter what brand.

Use it for its intended purpose plinking to hit a man sized target.

If you want accuracy buy match ammo or debate diving in to the wonderful world of reloading.

No point in buying an expensive barrel when it comes to chucking 9 cent projectiles.

This is working backwards. You're asking for a barrel to shoot 2.5-3MOA ammo better than 2.5-3MOA, which is not going to happen. Sure, you may get a cherry picked 5-shot group under that, but it's bulk Ball ammo. 

If you want "accuracy", or rather "precision", find a load your 20" RRA Varmint barrel likes, as I'm sure that thing will shoot well with the right load. IMI M193 is great ammo, but to expect much more than 2.5-3MOA is asking more than the ammo can deliver. 

That all said, I HIGHLY recommend you look at Austrialian Outback Ammunition's 55gr Sierra Blitzking load. It's affordable (usually around $.50/round or so), and it files VERY well. 

Good luck.

Crappy bullets make crappy groups, period.

Your only hope is to keep the RPM low as possible while still stabilizing the bullet.

Find a 16" with a 11 twist. Low RPM, but stable.

The IMI 55 grain ammo is equivalent to M193 5.56 in power and accuracy.  That means it is 2.5-3.0 MOA ammo. Nothing wrong with it for its intended purpose.

However, a better barrel will not reduce its group size.

Example.  I have a match grade heavier profile 1:8 stainless .223 Wylde chambered hand lapped precision 16" barrel from a custom barrel maker.  With match ammo, expecially my Berger 52/Lapua match case handloads, it is capable of less than 1/2 MOA.

But, when I shoot M193 or M855 ammo from it, it shoots the same 2.5 MOA groups that my lowly mass produced 1:9 gov't profile carbine barrel does.

If you want a more accurate barrel, get one.  But, it will still be no more accurate than the ammo you feed it.   Get a better barrel, but feed it more accurate ammo if you want smaller groups.

All good points.  I guess I am asking for a good barrel to shoot lighter weight bullets.  Currently I am getting the same group with Hornady 55 gr varmint loads as I am with the IMI 55gr.  I want to upgrade my barrel to shoot lighter weight bullets accurately, at least to have the potential to do so.  I am not expecting extreme accuracy when shooting IMI FMJ.  But I would like a barrel that has the potential to shoot very accurate groups with good ammo.  What is a good length, good twist and of course brand.  I am looking for something in the $500-$1000 range.  Or should I forget lightweight bullets and go heavier if I can't get accuracy from 55gr bullets?

I should have been clearer on my original request.

If you are willing to spend $500-$1000 for a barrel, then you can clearly afford the best.  That would mean Kreiger, Lilja, Bartlein, Shilen, and such.  My choice was the M4 Navy "Recon" or Recce 16" barrel from Lilja.   It is a custom barrel. It is the same profile that Lilja made under contract for Navy SEAL rifles as spec'd by Navy Crane.  416 stainless, 1:8 twist, Wylde chamber, pull button rifled, hand lapped.  Tolerances in bore and rifling permit only .0002" maximum variation from straight over the course of the entire barrel length.  It is a special profile that is heavy under the handguard out to the gas port, and then a bit thinner to the muzzle.  It is a 16" (actually 17' counting the barrel extension) and is a carbine gas port location.  They also make models with a mid length port location, if you prefer or need that.  About $500.  While it was designed to shoot 77 grain SMK bullets out to 600 yards or so, you can see below how it does with match grade 52 grain flat base target Bergers at 100.

Others here will recommend Kreiger, and it is also excellent.  Either will provide better accuracy that 99.9% of us, myself included, are capable.  With proper break in, a free float rail, a good trigger, proper optics and technique the limiting factor will be you.

Generally speaking lighter, shorter flat based bullets are best for 100 yard groups, and longer, boat tailed bullets tend to work better at longer distances, especially beyond 300 yards, assuming that the bullets are match grade.  A 1:8 twist match grade barrel will permit you to easily stabilize the full range of bullets that will reliably cycle through an AR15 magazine.

As important as the barrel is, you must have really good ammo, a lighter, smooth trigger, optics up to the task, and good technique shooting from proper support -- bench rest front and rear rests or bags, or quality bipod and rear bag.

I am 66 years old, wear bifocals and my technique is not as good as it was when I was younger.  The limitation is me or this barrel would probably shoot down in the "3s" (.3 MOA).



Compared to a Gov't profile 16" carbine barrel:



With my Berger 52 grain handloads:

As already covered a fantastic barrel will never make up for military grade FMJ bullets. I think you'll be happy with your current barrel if you give it a really good cleaning and feed it premium bullets.

Federal makes 69 grain Gold Medal Match ammo and so does Black Hills and Australian Outback. Their 52/53 grain bullets will hammer from any twist rate barrel, even 1/7 or 1/8 chromed lined rack rifles. I have a 16" Colt H-bar with a 1/9 twist that shoots 52 grain SMK bullets into 3/4" groups at 100 yards.

Use the IMI ammo for blasting, self-defense and 3-Gun style shooting and save every piece of brass that hits the ground. You may not think reloading is in your future at the moment, but once you have couple thousand empty once fired cases you may change your mind. You can always sell it for around $70.00 per thousand if you decide not to.

I suggest White Oak Armament 1/7 or 1/8 twist SPR barrels for great accuracy that aren't too heavy. Their DMR rifle barrels work great too. You're looking at $300 for the SPR and $400 for the DMR. Pay the extra $10.00 and have them blast the barrel to a matte finish or it will show up shiny.

it seems like it would make more sense to spend the $500-$1000 on better ammo. 

if you want to stick with ball, MEN M193 is crazy accurate

We are about the same age so suffer from the same eye issues.  I just added a "Zeiss Conquest HD5 Rifle Scope 5-25x 50mm Side Focus" Scope to help with that issue.

The barrel I am shooting is a new "Olympic Arms Barrel AR-15 5.56mm NATO .920" Muzzle Diameter 1 in 9" Twist 20" Chrome Moly".  I also swapped out the trigger for a 3.5 lb trigger recommended by a gun smith.  Trigger is great.  I also upgraded to a SavageArms NOS bolt carrier group.  

As you can tell from my posts this is my first and only AR15 so I am a real newbie.  I looked at a bunch of high end barrels but eliminated them one by one for one reason or the other mainly I wanted a drop in barrel that would shoot 55 gr. that maintained the 5.56 ability.  I don't plan on shooting in meets, at least at this point, but I am a little anal about accuracy.

I will have to take another look at my original list of barrels.

I do have one really basic question.  Are heavier bullets inherently more accurate than faster lighter bullets?  My newbie logic was that faster flying bullets would have less drop and thus be more accurate.  If this premise is false then I need to revisit the whole bullet weight and barrel issue.

Try better ammo in that barrel.  Get some match grade ammo and see how it does.  Lighter flat based bullets tend to be a little better at 100 yards.  Longer, higher ballistic coefficient bullets tend to do better beyond 300 yards.  They tend to be heavier.

But, this assumes match bullets from match barrels.  The most accurate .224" bullets I have tried at 100 yards are the flat base Berger 52s.  My most accurate longer range .224" bullets are 77 grain Sierra Match Kings and  Berger 77 OTM.  These bullets are not more accurate at distance because they are heavier.  It is because they are more streamlined and less affected by wind.  Think arrow versus baseball.

Generalizing here, no, short lighter, quality bullets will probably make better shorter range groups. The short flat based bullets are easier to make balanced plus there is also the benefit on being able to use a slower twist barrel which minimizes imbalance effects.

Long boat tail bullets are harder to manufacture perfectly balanced so they tend to not make as tight close range groups. They require a faster twist which will magnify imbalance effects.
Once you start to get out there in distance the longer higher BC bullet start doing better because they lose velocity at a slower rate and are less effected by wind.


In terms of a basic ARs ability, you probably wouldn't notice a huge benefit shooting a short flat based bullet.


I like to go with tighter twists so I  can use high BC bullets. I  have no practical use for sub moa groups at 100yds, long range is where I want the best performance. Those sub moa groups do me no good when the wind drift is 5 feet.

There isn't anyway to predict what weight bullets any given barrel will shoot well, other than the obvious fact that slow twist barrels won't stabilize long bullets. OP, it sounds like your barrel just doesn't like 55 grain bullets. This could be true of any individual barrel made by any manufacturer in any length or twist configuration.

As others have said, if you're getting 2.5-3 moa out of that IMI ammo, that's pretty much as good as any other barrel will do with it. If you want a new barrel, just buy whatever quality barrel you want the most, as there's nothing anyone can point you to that's more likely to shoot IMI 55 grain FMJ better than anything else.

All other things being equal, a faster bullet will drop more slowly than a slower bullet. At longer ranges, having a faster bullet can mean that it's easier to shoot accurately at targets of varying distances because it's easier to account for bullet drop.

I find that for shooting at fixed targets of known distance, lower and mid-velocity loads are more precise than maximum velocity loads. When you have plenty of time to dial or hold for your drop, it doesn't matter much if you have a lot of drop.

OP, as you noted in your first post, you're doing this backwards. As long as you're doing it backwards, you're not going to get to where you want to go. Find the ammo that works in your barrel. Don't look for a barrel that works for your ammo, even if you already have a lot of it. If you're picky about accuracy, that bulk FMJ is never going to do anything for you no matter what barrel you run it out of.

IMI is not super accurate ammo. It's plinking stuff. You are looking at the wrong part of the equation.

Thanks to all of you for your input.  I just ordered $200 of various match grade cartridges in an attempt to find a good flying bullet for my barrel.  It also looks like reloading is in my future.  I am now thinking of building up a second upper using my old barrel to shoot up the IMI stuff and then use the brass for reloading.  I put a brass catcher on my AR so I won't have to chase down the casings in the mud... I live in Oregon ;-).

Thanks again...for all the help.

Sounds like a solid plan. What ammo did you go with? 

The reloading element may allow you to achieve much better results, sometimes even to a surprising degree.  I've been putzing with bullets from 55g to 75g for my 5.56/.223 guns for a bit now with various powders and amounts while using a chrono and target comparison.  For my guns I came upon a 68g HPBT using a given amount of Varget that shoots extremely well across all my 5.56/.223 semiautos in 9.25, 10.5, 11.5, 14.5, 16, 18, 20, and 24 inch barrels.  Frankly I'm a little shocked that this particular load does as well as it does across so many varied weapons.  Now, that's not to say I haven't found a bullet/load to perform in one of these specific guns to a higher level.  As an example, my 5.56 Tavor likes the 75g bullet/load a little better for 100 yard accuracy even though I'm sure the gun was more optimized for 55-62g stuff as designed.  Still...it's pretty neat that when you reload you can come up with a darned good all-around bullet that will work across a wide range of weapons...but it takes a fair amount of testing to get there most of the time...but that can be half the fun.

On the high dollar barrel pursuit?...nothing wrong with that.  However, while doing this reloading effort with 5.56/.223 ammo, I found some amazing results with some pretty cheap barrels.  As some others here have already stated, you'll probably get ahead better with good ammo than with a very expensive barrel...at least a cheap barrel that's within some level of reason, of course.  My 20" AR15 that I use as my test mule for chrono and target testing most of the time is a $140 416R SS 1:8 barrel setup.  It's a 1 MOA gun with the right ammo.  I was highly disappointed with this barrel when I first sighted in the gun with 55g XM193 Federal American Eagle.  I got 2-4 MOA with no real consistency in 5-shot groups.  As soon as I started using it for chrono/target testing for my reloads...20" barrels are usually the standard length for AR15 reloading data...it was very apparent that it liked higher quality, heavier bullets.  I was almost ready to chuck this barrel for nothing other than chrono comparisons to reloading manual data.  The lesson learned...don't toss your barrel because of 55g FMJ bulk ammo performance...unless...that's all you will ever shoot.