Free float necessary for sub-moa accuracy??? UPDATE 3/22/14

[WB300]

Please be patient with me as this bolt guy takes his first venture into the AR arena. Search-fu continues, but is taking longer than expected.

My mil-spec DPMS 5.56 served me well on the SWAT team, but now she sits in the safe. Minute of basketball was sufficient for the team, but now I want to upgrade her for some coyote hunting and longer range plinking. I've tried different match factory ammo and even tried handloading, but can't get better than 2 moa. My lower is a separate project, so I am concentrating on the upper for now.

I was thinking of putting a match grade 1-8 twist .223 wylde barrel on it, but want to keep the weight and profile of the rifle similar to what I already have burned into memory just in case I can't stay away from the team and decide to go back. Dropping $1K into it is not a luxury I have right now.

Current outside diameter of the DPMS barrel is .75", so something like a JP medium contour should be an easy replacement. The front sight post is that big ugly fixed hunk of metal that came with the gun. Just before it is where the handguards are held into place. Now in the bolt world, a quality barrel that is properly free floated is desired. But people have been able to do some amazing things with AR uppers to get great consistent accuracy. I would like to just replace the barrel (and BCG if I go JP), and not have to get into replacing gas block, handguards, etc. if I can avoid it. Is this possible??? I understand all of the variables that go into consistent sub-moa shooting, but all things being equal, has this / can this be done without free floating?

Let me hear your thoughts and experiences on this. I am seeking knowledge as well as a solution.

Thanks in advance.

Bill

 

[lte82]

Free float is essential for *consistent* sub-moa shooting.

You can get moa / sub-moa barrel and free float tube for cheap:

16" SS air-guaged barrel & low pro gas block:
Rock River Arms: 16 / 18 / 20 Inch Stainless Steel Heavy Barrels

Free float tube:
DPMS Free Float Tube Handguard AR-15 Aluminum Black

$300 and a little elbow grease and you are done.

Drop in a nice trigger and you will have a shooter. I could recommend better components, but if you are on a budget that's probably the cheapest way to do it.

 

[MarkCO]

The problem with the AR is the same as with the bolt guns. You have a contact point on the hand guard that results in differential loading and in fact some shot to shot mechanical return issues. The heavier and stiffer you get the barrel, the less the effect. It is possible that purely switching the hg will eliminate the need for a new barrel, but DPMS chrome lined barrels (assuming that is what you have) are not going to get you under 1 MOA no matter what you do.

If you are under 5K rounds on your upper, you should be able to re barrel it plus a new hand guard for about $400 or so depending on barrel and HG choices. What are your requirements for a barrel and what would you need in a HG?

 

[diggler1833]

^ Agreed. You might be able to get some sub-MOA groups out of a non-free floated barrel every once in a while. However, even if you have an accurate rifle that is not free-floated you can change the harmonics of the barrel simply by accidently putting more pressure on the handguard. That is why lte82 mentioned "consistent". When I got to spend a bit more of my time shooting service rifle matches I always had my web sling precisely marked for each shooting position. That way I exerted the same force on the sling swivel and barrel each time I went back to whichever position I had to. consistency, consistency, consistency.

My .02 would be to either get the new barrel and a free floated handguard. Or RRA, DPMS and a whole lot of others make complete "quality" varminting uppers that are well under $1K. You could have two uppers for your one rifle, or you could sell off your old upper to recoup some of the cost.

Good luck to you.

 

[Cobracutter]

Yea man, FF is pretty much requried anytime the words accuracy or precision come into play.

If you are mechanicaly inclinded, you can do the work yourself. Get something like a Gieselle reaction rod and a set of reciever blocks and you can do the work yourself.

There are a bunch of quality, budget priced FF rails out there. Fortis is a very popular, Sub $200 rail that has keymod points.

As far as barrels go, you have to pay to play. You may get lucky with a cheaper one, but you also may get a dud. For budget priced, high quality barrels, WOA is what you want. WOA just plain shoot, and that is why they have been a mainstay on highpower rigs for over 10 years.

There aren't many factory uppers I would trust if you want to shoot ragged holes. They are are dependent on the barrel they use as that is where practicaly all the accuracy of an AR is derived.

 

[redneckbmxer24]

I've had non FF AR's that shot great but consistently free floated AR's shoot better. For what you're doing I'd sell the DPMS upper and buy a complete rock river predator pursuit upper for about $600. You'll be money ahead doing that vs. replacing the barrel and handguard.

 

[sinister]

Precision ARs start with a superior barrel, a good trigger, and precision ammo. Your definition of precision and range distance (i.e., coyotes and plinking) will determine whether or not you need to free-float.

Your solution (if your barrel is still in good condition) could be as simple as a basic, no-frills free-float tube and a good trigger -- well under your targeted spending limit.

 

[Little gator]

Like cobra said, get a white oak barrel. great for the money.

As long as the hand guard is free floated it doesn't much matter (more or less IMHO) I got a el-cheap-o you can have for 30 bucks. Comes with barrel nut. Then you can take that 200 and drop it on a trigger.

Or buy a $150 rail and spend 25 bucks on a jp spring set. They don't lighten the pull buy much but it's waaaayy cleaner than stock ones.

 

[Greg Langelius *]

L-W AR Match Varmint barrel and matched bolt. You will need a .936 diameter gas block, a rifle length gas tube, and a rifle length free float forend.

You might find a complete Varmint Upper to be far simpler, and maybe even cheaper. My Stag Model 6 Super Varminter comes with a free float 24" stainless bull barrel, 1/2MOA accuracy guarantee, and has never disappointed me.

For something similarly configured, but with a 16" barrel length, try this.

I have the complete Stag 6 rifle and the latter upper. The Stag is impeccable, but I have to wait for Spring to try out the 16" upper. We woke to 6 degrees on the beck deck thermometer this morning.

Greg

 

[tipper]

WB300, this is not a hard answer, take the upper you have off put it away, an build or buy a new upper that is not spray & pray.

 

[WB300]

Thanks folks. Free float it is.

Now I just need to decide on buying a complete upper or piecing this one. Problem is, I've never tinkered with an AR before. And I don't know anyone in the area to trust with doing the work for me, so I'd probably have to send it out. I will keep researching.

As far as my accuracy requirements... I handload for my bolt rifles, and I try to achieve as close to 1/2 moa as possible (I blame 2 sniper schools and the Hide for this. lol). I don't expect this from my AR, but would be absolutely thrilled if I could get close.

Greg... Many thanks for the links.

tipper... I hear ya. Keep it simple.

Keep the suggestions and links coming.

Bill

 

[ORD]

Thanks folks. Free float it is.

Now I just need to decide on buying a complete upper or piecing this one. Problem is, I've never tinkered with an AR before. And I don't know anyone in the area to trust with doing the work for me, so I'd probably have to send it out. I will keep researching.

As far as my accuracy requirements... I handload for my bolt rifles, and I try to achieve as close to 1/2 moa as possible (I blame 2 sniper schools and the Hide for this. lol). I don't expect this from my AR, but would be absolutely thrilled if I could get close.

It isn't outside the realm of possible to get a consistent 1/2MOA AR provided you are a consistent, 1/2MOA shooter. The biggest impediments I see when people are trying to wring every last bit of potential out of any AR is that they don't tailor their rifle to those ends to the extent necessary (i.e. - to have a REALLY accurate AR, you need a high quality, free-floated, match barrel, a quality trigger be it a Geissele, JP, etc., a decent optic/mount or irons suited for precision levels of accuracy, and quality ammo, preferably ammo that is tuned/loaded for the particular rifle in question). You can build or buy, but as with all things, your mileage will vary depending on the direction you take.

For example, you can buy an off-the-rack upper like the RRA Varmint A4, as one example, and be done with it. They are one of the best bangs for the buck in the industry right out of the box, capable of pretty easy and consistent sub-MOA accuracy with decent ammo (commercial or reloads) and a competent shooter doing his/her part. While I have considerably less experience with them, the Stag Varmint uppers/rifles I have used and seen used are similarly capable and at a fairly comparable price point to the RRA.

Building...well...building opens up a whole can of worms that more or less lets you have precisely what you want/need, but as with all things, you can add up expenses in a hurry if you aren't already setup for assembling ARs just in terms of tools such as a decent vise, vise blocks, a torque wrench, etc. If you want to build on the upper receiver/setup you have now, there are highly competent AR smiths out there that will disassemble your existing upper and reassemble it with any number of different parts (barrels, FF handguards, gas blocks, etc.) of your choosing for ~$50 plus S&H both ways. Steve and the guys at ADCO come to mind for a service like that. They are extremely good at what they do and they also have some of the best turnaround times in the industry with most work taking ~2wks from receipt to return to you. See here: https://www.adcofirearms.com/shopservices/

Good luck with your project!

 

[ddavis]

Assemble your own LOWER, UPPER, FREE FLOAT, TRIGGER, GAS BLOCK - Step by step instructions! - AR15.COM

All you will need to know about upper/lower assembly, with pictures!

Get yourself an upper and lower action block/clamp, an armorers wrench, and a set of punches and you can do anything you need. Well worth the initial investment and you can help your friends with their rifles as well. I'd say put together another upper then you can just swap out the crappy M4 upper with your accurate one depending on what you want to do with it.

 

[WB300]

OK folks here is the update...

After careful consideration, I decided to have the upper re-built. I almost took redneck's advice and purchased a RRA, but I couldn't get the advice out of the back of my head that an old wise gunsmith once told me... "You can buy a factory one with a great reputation and hope you don't get something that meets their specs, but not yours, or have it built by a reputable smith who won't let it go until it meets your specs."

Big thanks to Mark at Carbon Arms (MarkCO in above post). Through many PM's and phone calls, he worked his magic. He even took the time to educate me on the importance of having the gas tube, buffer, spring, and bolt all work together to make a smooth easy shooting rifle. Nordic 18" threaded match stainless barrel. Nordic NC-1 rifle length handguards, Barnes Precision NiB BGC (because I screwed mine up), Carbon Arms Gas Block, and he even installed a TBAC brake for my can. As I wait for parts for my lower to arrive, I couldn't help but put the new upper on my bone stock lower with the adjustable Tupperware stock and go to the range. Threw some cheap walmart aluminum rings on top to hold a fixed 4X scope I had laying around. Of course I get to the range and realized I forgot my ammo. Duh! A search of my range bag turned up 4 Factory Federal .223 Balistic Tips laying in the bottom. Front rest with a t-shirt for a rear rest. Nice little 1" group! I know it's nothing to write home about, but given the circumstances, I'm happy, so don't go pissing in my lemonade! Eventually I will put a PRS on it and drop a Geissle in. The NF 2.5-10 awaits also. Recoil was smooth.

As soon as I get the lower done, I'll take some factory match ammo as well as some reloads and see what she can really do. I'll post pics then also.

Thanks again to all who contributed to this thread.

And yes... It is now free floated.

Bill

 

[tickled pink]

I ordered a White Oak Armament complete 18" varmint upper with a 1 in 7" twist and having it fluted to save some weight. I reload and am hoping for it to shoot 1/2 MOA or less. I am putting it on top of my Colt LE6920 M4 lower that I installed a Giessele SSA-E trigger myself.

White Oak Armament | Complete Uppers | Varmint Uppers

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