How significant is free floating the barrel of an AR to accuracy? How significant is 'play' between the upper and lower to accuracy?
Free floating an AR
- Thread starter Stinkyshoe
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According to gunsmiths who work on ARs used in long-range competition, the "play" between an upper and lower receiver has no effect on the accuracy of the rifle. If a little wiggle is going to bother you, get one of those little thingies you put in the lower to keep it tight with the upper for peace of mind.
As for a float tube, if you are shooting using a sling to aid in stability, the torque on the barrel will change the point of impact of your rounds fired. This matters in a match rifle, but is not really a factor in a battle rifle. On an AR used for varmint hunting, a float tube is nice, as it allows you to add a bipod or sling swivel to the tube without affecting the barrel. Basically, with free-floating an AR, it is pretty dependent on what you will use the rifle for. IMO, floating an M4rgery that is going to be an uber-tactical urban warfare rifle wouldn't really make sense, as the accuracy difference at the ranges in question is not worth the extra weight. If you want to shoot groundhogs at 300 yards using a bipod, a tube makes sense. If you want to shoot HighPower matches, a float tube under the handguards is a necessity.
As for a float tube, if you are shooting using a sling to aid in stability, the torque on the barrel will change the point of impact of your rounds fired. This matters in a match rifle, but is not really a factor in a battle rifle. On an AR used for varmint hunting, a float tube is nice, as it allows you to add a bipod or sling swivel to the tube without affecting the barrel. Basically, with free-floating an AR, it is pretty dependent on what you will use the rifle for. IMO, floating an M4rgery that is going to be an uber-tactical urban warfare rifle wouldn't really make sense, as the accuracy difference at the ranges in question is not worth the extra weight. If you want to shoot groundhogs at 300 yards using a bipod, a tube makes sense. If you want to shoot HighPower matches, a float tube under the handguards is a necessity.
Goalie's answers were good. As far as the slop between upper and lower, it won't truly affect accuracy, but it can be annoying. Some lowers don't have the room below the safety for the rubber insert. For those, the fix is a little more dramatic. I used JB Weld to bed my uppers to their lowers and that lasts for about a year of hard use before you have to do it again.
Goalie,
Thanks for the response. What you are saying definitely makes sense. So in other words if the rifle would have a scope on it, then free floating the barrel would probably be a good idea? Is there any difference bewteen free floating with the National match handguard compared to the nifty looking aluminum?
Steve,
Would you mind elaborating on the process of using JB weld between the uppers? I must say I have used JB weld for a lot of other things(that it probably wasn't designed for
, its almost like duct tape and bailing wire ) but I have never thought to put it between the uppers. I was having a discussion today with a gun smith at a gun show selling Vulcan Arms ARs. The lower reciever on these are a molded plastic and the upper is some composite material. The barrel is a free floated, A4 style. There was no play at all between the upper and lower, which is impressive for a $625 dollar rifle. He claimed that he was shooting 7/8 groups (5 shots) with cheap ammo. With my Bushy I was shooting anywhere from penny sized to 1.5 Moa. My scope has a 3 Moa dot as the point of impact. Would you think that this is the reason why I am getting less than desireable groups(because of the large point of impact? Do you have any suggestions for a scope that would be a good varmit or target scope? The funny thing is that I can shoot as good of groups with irons on this rifle as I can with the 3 moa point of impact under 9x magnification.
Thanks
Ss
Thanks for the response. What you are saying definitely makes sense. So in other words if the rifle would have a scope on it, then free floating the barrel would probably be a good idea? Is there any difference bewteen free floating with the National match handguard compared to the nifty looking aluminum?
Steve,
Would you mind elaborating on the process of using JB weld between the uppers? I must say I have used JB weld for a lot of other things(that it probably wasn't designed for
, its almost like duct tape and bailing wire ) but I have never thought to put it between the uppers. I was having a discussion today with a gun smith at a gun show selling Vulcan Arms ARs. The lower reciever on these are a molded plastic and the upper is some composite material. The barrel is a free floated, A4 style. There was no play at all between the upper and lower, which is impressive for a $625 dollar rifle. He claimed that he was shooting 7/8 groups (5 shots) with cheap ammo. With my Bushy I was shooting anywhere from penny sized to 1.5 Moa. My scope has a 3 Moa dot as the point of impact. Would you think that this is the reason why I am getting less than desireable groups(because of the large point of impact? Do you have any suggestions for a scope that would be a good varmit or target scope? The funny thing is that I can shoot as good of groups with irons on this rifle as I can with the 3 moa point of impact under 9x magnification.Thanks
Ss
The national match float tube under the handguards was developed to provide a free floating barrel while still fufilling the competition rule that states that the rifle must be cosmetically and dimensionally the same as the issued M16 to be CMP legal as a service rifle. People who shoot matches with tricked out AR15's and match rifle sights (designated as match rifles, not service rifles) often use the cool looking aluminum tube, as well as adjustable stocks. As a benefit, you can always buy an aluminum tube that has a rail built into the bottom for swivels and accessories.
As for optics, I am the wrong guy to ask. It is my belief that the glass should cost more than the gun.
As for optics, I am the wrong guy to ask. It is my belief that the glass should cost more than the gun.
Goalie
Thanks for the info. So basically it is personal preference. Please do comment on scopes...no guarantee I'll listen though:? (to me $300 seems like a lot for a scope.)
Could anyone comment on chrome-lined barrels vs. non chrome lined, in terms of accuracy, barrel life and reliability? Which would you prefer? Does it really matter?
Thanks
Ss
Thanks for the info. So basically it is personal preference. Please do comment on scopes...no guarantee I'll listen though:? (to me $300 seems like a lot for a scope.)
Could anyone comment on chrome-lined barrels vs. non chrome lined, in terms of accuracy, barrel life and reliability? Which would you prefer? Does it really matter?
Thanks
Ss
Chrome lined is great if you are going to build a rifle for battle use. Chrome lined is easier to maintain, but less accurate that comparable stainless or chrome-moly barrels. As for optics, Trijicon makes some seriously sweet balistically calibrated optics for ARs that come highly reccomended for use on a battle rifle. For target or varment use, Leupold, Zeiss, Swarovski or any other good glass would be desireable. With optics, you get what you pay for.
On the free floating, I agree with most of what goalie has stated. I free-floated my AR in September and since then I've seen groups tighten up (from the bench @ 100yds) from about 1.5"-2" to 1"-1.5" with the stock Bushmaster barrel. However, without a bench or a very tight sling, I don't notice any difference between my non-free floated groups and my free-floated groups - so it just goes to show that the gun is already more capable than the shooter in my scenario.
Another thing to keep in mind when considering free-floating is anticipated usage. If you plan on doing a lot of firing (say an Urban Rifle course at Thunder Ranch or more local equivalent), those solid aluminium tubes can get awful hot pretty fast. If you are target shooting, probably not an issue; but I like tubes that have good ventilation just to be on the safe side.
Vulcan Arms was formerly known as Hesse Arms. I've seen quite a bit of negative commentary on those rifles but have never used one myself. You probably should research this some before committing.
My 16" HBAR with chrome bore and chamber regularly produces 1"-1.5" 5-shot groups at 100yds. It has produced a 4-shot 0.25" group in the past but that was more of a freak incident. Theoretically, chrome-lined barrels may be less accurate than non-chrome-lined (assuming both are good barrels to start with); but in practical use, I think the difference will be smaller than 90% of shooters can appreciate. If you are shooting High Power matches, you may be in the area where that 10% are present.
Concerning barrel life and reliability, Denny Hansen mentions in SWAT Magazine that he has an Olympic Arms rifle with about 80,000 rounds through it (Oly uses a non-chrome lined barrel though I don't know if that is a single barrel or several barrels since the article discussed only the rifle itself). So the non-chrome-lined can certainly last a long time in reliable use if you aren't looking for match accuracy from them. If you are shooting High Power or other formal matches, then your requirements from a barrel are going to be a lot different.
The major factor in barrel life is heat - so it will not only be how many rounds you fired them; but how they were fired. Rapid firing builds up heat worse than slow fire and a handguard that traps heat builds up heat worse than a well-ventilated one.
Unless you envision a lot of full-auto or poor maintenance, I don't really see chrome-lining as a major factor one way or the other. I'd guess that the carbine of the editor of SWAT magazine sees its fair share of hard use, so it seems like either one will serve the purposes of most of us in both accuracy and useful lifespan.
Another thing to keep in mind when considering free-floating is anticipated usage. If you plan on doing a lot of firing (say an Urban Rifle course at Thunder Ranch or more local equivalent), those solid aluminium tubes can get awful hot pretty fast. If you are target shooting, probably not an issue; but I like tubes that have good ventilation just to be on the safe side.
Vulcan Arms was formerly known as Hesse Arms. I've seen quite a bit of negative commentary on those rifles but have never used one myself. You probably should research this some before committing.
My 16" HBAR with chrome bore and chamber regularly produces 1"-1.5" 5-shot groups at 100yds. It has produced a 4-shot 0.25" group in the past but that was more of a freak incident. Theoretically, chrome-lined barrels may be less accurate than non-chrome-lined (assuming both are good barrels to start with); but in practical use, I think the difference will be smaller than 90% of shooters can appreciate. If you are shooting High Power matches, you may be in the area where that 10% are present.
Concerning barrel life and reliability, Denny Hansen mentions in SWAT Magazine that he has an Olympic Arms rifle with about 80,000 rounds through it (Oly uses a non-chrome lined barrel though I don't know if that is a single barrel or several barrels since the article discussed only the rifle itself). So the non-chrome-lined can certainly last a long time in reliable use if you aren't looking for match accuracy from them. If you are shooting High Power or other formal matches, then your requirements from a barrel are going to be a lot different.
The major factor in barrel life is heat - so it will not only be how many rounds you fired them; but how they were fired. Rapid firing builds up heat worse than slow fire and a handguard that traps heat builds up heat worse than a well-ventilated one.
Unless you envision a lot of full-auto or poor maintenance, I don't really see chrome-lining as a major factor one way or the other. I'd guess that the carbine of the editor of SWAT magazine sees its fair share of hard use, so it seems like either one will serve the purposes of most of us in both accuracy and useful lifespan.
What can I say? I like everyone's answer. If you're only shooting at 100 yards, and you don't care about cutting the 6" x ring out of a target at 600 yards, then a flot tube may not be necessary at all. Of course, the good thing is that the HP style tube doesn't get too hot at all (NTIT practices will prove that). Aluminum without a covering would get hot mighty quick I'd bet. Also, on this topic, round count. I don't use a barrel for more than about 4K rounds. After that they can start getting flyers at distance at any time.
A plastic lower? Hmm... No thanks.
FWIW, I've handled a hell of a lot of ARs and they do tend to loosen up over time. I would expect the plastic lower to stretch or wear in odd ways over time.
To bed an AR, (remember this doesn't add to the real accuracy of the gun) first apply a release agent to the rearmost part of the lower, in, out, EVERYWHERE. Also put it on the rear pin and inside the rear lug hole on the upper.
Now, degrease the upper and apply JB to the rearmost mating faces and the sides of the rear lug. Close the action and insert the pin. Place the rifle upside down (carry handle down) and hang some weight from it and leave it overnight. The next morning, say a prayer that you got release agent every where you should have, and open it up. All done.
I am not responsible for you screwing this up.
I would say you're lucky to get 1.5" groups with a 3 MOA dot. If you want an optic that will allow for one-hole groups, use a scope.
A plastic lower? Hmm... No thanks.
FWIW, I've handled a hell of a lot of ARs and they do tend to loosen up over time. I would expect the plastic lower to stretch or wear in odd ways over time.
To bed an AR, (remember this doesn't add to the real accuracy of the gun) first apply a release agent to the rearmost part of the lower, in, out, EVERYWHERE. Also put it on the rear pin and inside the rear lug hole on the upper.
Now, degrease the upper and apply JB to the rearmost mating faces and the sides of the rear lug. Close the action and insert the pin. Place the rifle upside down (carry handle down) and hang some weight from it and leave it overnight. The next morning, say a prayer that you got release agent every where you should have, and open it up. All done.
I am not responsible for you screwing this up.
I would say you're lucky to get 1.5" groups with a 3 MOA dot. If you want an optic that will allow for one-hole groups, use a scope.
Zak Smith
Member
One aspect not mentioned yet is that it's easy to free-float an AR15 yourself. You'll need the upper receiver vice block kit and an armorers wrench (about $100 total from Brownells) and a modicum of mechanical competence -- my own electrical engineering / computer geek self was able to do it no problem.
This is made more difficult if your barrel already has a permanently attached brake. To remove the front sight tower, you just need a good steel punch and a small hammer. Full instructions can be found on AR15.com.
The entire switch can be done in a half-hour, easy.
-z
This is made more difficult if your barrel already has a permanently attached brake. To remove the front sight tower, you just need a good steel punch and a small hammer. Full instructions can be found on AR15.com.
The entire switch can be done in a half-hour, easy.
-z
DMK
Member
Are there freefloat tubes out there that would let you keep your original handguards? Say for example on a midlength carbine?
DMK
Member
Thanks Steve. I've seen the NM floating setups like referred to above. I just always have to be different.
I wish you would of told me about the release agent earlier in the post before I used the jb weld.
But its ok I guess as I practiced on frontsights rifle first.
But its ok I guess as I practiced on frontsights rifle first.
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