Barrels

jasons said:
I believe Green Mountain also makes and sells blanks, which anyone could buy and chamber / profile to their own specifications. They may also do contract work when the orders are big enough.
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Yeah I just called them back, and they said exactly that. They said they make barrels for some big name companies, but that these companies don't want people knowing it came from Green Mountain.

They also sell blanks, and then people do what they want from there.

Either way, they had some 10.5" barrels left over from a contract, so he sold me one for an awesome price. I hope these barrels are good to go.

I got a 10.5" 5.56 1:7 chrome lined barrel for $113. I don't know if it's a heavy barrel or not. I forgot to ask what profile it was. So I got one after all. I am very excited. He said it will ship tomorrow. I didn't even know they were based in NH. [laugh]
 
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ntomsw said:
Yeah I just called them back, and they said exactly that. They said they make barrels for some big name companies, but that these companies don't want people knowing it came from Green Mountain.

They also sell blanks, and then people do what they want from there.

Either way, they had some 10.5" barrels left over from a contract, so he sold me one for an awesome price. I hope these barrels are good to go.

I got a 10.5" 5.56 1:7 chrome lined barrel for $113. I don't know if it's a heavy barrel or not. I forgot to ask what profile it was. So I got one after all. I am very excited. He said it will ship tomorrow. I didn't even know they were based in NH. [laugh]
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IIRC, Nighthawk does the same thing to 1911 barrel blanks. They buy them from X and say it's Nighthawk Custom. Smooth.

Are you making it piston or DI?

And yeah GM rules. Got my barrel a day and a half after ordering. Will buy from them again without hesitation.
 
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I might be inclined to get a lothar walther very light profile barrel in stainless for $199, then have it wacked off to 10" by a local smith. Then you get a very nice quality, accurate barrel for not a lot of dough.

I'd suggest because there is so little barrel ahead of the gas port that you open up the port before assembly and fit it with an adjustable gas block. Then you can tune it to run properly without much headache.

Don

p.s. I own a LMT 10.5" SBR upper and have it on a registered SBR, pre-ban lower. Its 100% reliable as you'd expect a military style upper from LMT to be. But it is not terribly accurate. Lets face it, 99.99999% of the time all we are shooting is paper or steel. If a gun isn't accurate, its not satisfying to shoot. But thats me.



In contrast, I recently built this standard 16" rifle with a Lothar Walther barrel. The adjustable JP gas block allowed me to tune it to run reliably but recoil softly. It is a FANTASTIC shooting gun. I find that I reach for this 99% of the time when I want to shoot an AR. No, its not really cool looking. But it runs perfectly. And it weighs only 6.2 lbs with the optic.

 
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dcmdon said:
I might be inclined to get a lothar walther very light profile barrel in stainless for $199, then have it wacked off to 10" by a local smith. Then you get a very nice quality, accurate barrel for not a lot of dough.
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Sorry it this seems likes a silly question but as I said I'm just a CMP/NRA 200/300/600 Yard Service Rifle (20") Competitor.

These cool looking rifles you guys are building with 10" barrels are obviously / probably not meant to be 100 yard benchrest guns or 200 yards or beyond slung up tight position shooting guns.

How do you test and what do you use as criteria to determine if one barrel is more accurate than another?
What do you consider good or acceptable accuracy out of these 10" barrel setups?
Distance / MOA ?

Thanks,
George
 
G Smith said:
Sorry it this seems likes a silly question but as I said I'm just a CMP/NRA 200/300/600 Yard Service Rifle (20") Competitor.

These cool looking rifles you guys are building with 10" barrels are obviously / probably not meant to be 100 yard benchrest guns or 200 yards or beyond slung up tight position shooting guns.

How do you test and what do you use as criteria to determine if one barrel is more accurate than another?
What do you consider good or acceptable accuracy out of these 10" barrel setups?
Distance / MOA ?

Thanks,
George
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It doesn't key hole...
 
G Smith said:
Sorry it this seems likes a silly question but as I said I'm just a CMP/NRA 200/300/600 Yard Service Rifle (20") Competitor.

These cool looking rifles you guys are building with 10" barrels are obviously / probably not meant to be 100 yard benchrest guns or 200 yards or beyond slung up tight position shooting guns.

How do you test and what do you use as criteria to determine if one barrel is more accurate than another?
What do you consider good or acceptable accuracy out of these 10" barrel setups?
Distance / MOA ?

Thanks,
George
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I always shoot with a tight sling when I can. Which is why I built the 16 inch gun above. It has a carbon fiber free float tube.

As I'm guessing you know there are an infinite combination of choices you can make with respect to barrel length, barrel thickness, sight radius, and accuracy.

But here are some general truisms.

Assuming no wind, assuming the use of optics, a short barrel will be more accurate than a long barrel for a given diameter. It will be stiffer and therefore more precise.

Tweaking these assumptions, things get more complex. For example, holding barrel diameter constant, a long barrel on an iron sighted rifle will decrease mechanical accuracy just like above, but will increase practical accuracy as a result of the longer sight radius. You see tricks areound thses compromises when people use things like bloop tubes. This allows the user of a shorter and stiffer barrel with the longer sight radius of a longer barrel.

If you add wind into the equation it gets even more complicated. A longer barrel pushes a bullet faster so there is less wind drift at longer distances. So a scoped rifle with a longer barrel may be more accurate than a shorter barrel on a windy day despite its lower mechanical accuracy.

I hope this all makes sense. Its all a balancing act, a set of choices and compromises.

With all that said, a reasonably heavy 10" barrel can give outstanding accuracy if the rifle is scoped. Noveske, who makes some of the more accurate non-match grade barrels for ARs, sells a stainless 10" barreled upper that is easily a 1 moa shooter. But you need a scope. The sight radius is simply too short for really precise shooting.

The fact that most of these 10" barreled guns aren't really very accurate comes from 3 factors.

1) Military specification chambers - Loose chambers and long freebore are all conducive to reliability, not accuracy. (The lothar walthers use Wylde chambers, which are a great compromise between accuracy and safety if someone uses a 5.56x45 round in it rather than .223.
2) Chrome plated chamber and bore. All else being equal, a chrome lined bbl won't be as accurate as a non-chrome lined bbl.
3) Short sight radius - A gun with a carbine gas system has a lot less sight radius than a gun with a rifle length gas system.

I hope this helps.

As an aside. I've set some minimums for any AR upper that I will ever build or buy.
1) Barrel will be stainless with a Wylde chamber
2) It will have a free floated barrel.
3) it will have a sling attach point on the FF tube.

The 10.5" LMT upper is worth too much for me to bastardize. I'll probably sell it at some point and build a SBR upper myself that meets my criteria. Again, I'm no Creedmoor cup champion, but I do prefer to shoot accurate guns.

As for my definition of accuracy, it varies by gun. If I can AVERAGE 2 moa benched with cheap ammo I'm happy. I don't believe all of the people who claim 1 moa groups actually get them. Either that or they shoot 5 - 3 shot groups, pick the best one and claim thats what their rifle is capable of.

Sometimes things are much less quantitative. If I shoot my Glock 34 slowly at 25 ft, I get a decent group. If I shoot my Les Baer slowly at 25 ft, I get one ragged hole. The baer is more satisfying to shoot.
 
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dcmdon said:
With all that said, a reasonably heavy 10" barrel can give outstanding accuracy if the rifle is scoped. Noveske, who makes some of the more accurate non-match grade barrels for ARs, sells a stainless 10" barreled upper that is easily a 1 moa shooter. But you need a scope. The sight radius is simply too short for really precise shooting.
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dcmdon,
Thank you for posting all that.

At what distances is the 10" gun with a scope on it good for 1 moa?

Thanks again,
George
 
Well, in theory, if its 1 moa at 100 yards, it will be 1 moa at 400 yards, with no wind.

Maybe some of the really long distance guys can chime in. But wind accelerates the bullet laterally. So as the bullet flies through the air wind drift increases at a greater than linear rate. I don't think its exponential, but its more than linear.

Based on this chart, a .223 will drift in the wind this chart represents 5" in at 200 yards, 15" at 400, and 50" at 600.

picture3-new.jpg



The other thing barrel length affects is terminal ballistics. If you're hunting, the extra energy the longer barrel gives you means something. If you're just punching paper, its not relevant.

Here are some numbers for the .308 at varying bbl lengths.

Handload with IMR4320
Load......24"......22".....20".....18".....16"
180HL..2700...2660...2620...2550...2480
 
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dcmdon said:
Well, in theory, if its 1 moa at 100 yards, it will be 1 moa at 400 yards, with no wind.
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Sorry, I should have clarified. I wasn't inquiring about theory.

I'm interested in hearing about actual moa accuracy at 100 yards and longer (if applicable) that you and others that are building these quality uppers with 10" barrels are actually getting on paper.

Are you seeing 10 shot MOA groups on paper at 100 yards?

Further than 100?

How far?

Thanks again,
George
 
I think the confusion here is this thread is in the competition rifle forum, and is about shooting service rifle, yet there are a lot of posts about AR barrels that are probably not going to be used in any service rifle competition.

Hey, maybe I'm wrong, but I was pretty confused when I started reading a thread about service rifle competition barrels and all of a sudden people are talking about ar pistol barrels.
 
Almostelmo said:
I think the confusion here is this thread is in the competition rifle forum, and is about shooting service rifle, yet there are a lot of posts about AR barrels that are probably not going to be used in any service rifle competition.

Hey, maybe I'm wrong, but I was pretty confused when I started reading a thread about service rifle competition barrels and all of a sudden people are talking about ar pistol barrels.
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That's what we call "Thread Drift".
Probably caused by the Coriolus Effect.
 
I apologized for hijacking the thread.

I just wanted to know about the quality of Green Mountain Barrels, because I am also getting a 20" barrel for a future build as well.
 
It seemed like we were all talked out regarding Pat's original question on Service Rifle barrels.

Figured maybe we could learn something from the 10" barrel shooters.
I don't know if our 20" barrels should be twice as accurate as a 10" or 1/2 as accurate.

Plus where this thread is in the Rifle Competition Folder I figured the shorty AR's were used for some type of Competition.
 
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G Smith said:
It seemed like we were all talked out regarding Pat's original question on Service Rifle barrels.

Figured maybe we could learn something from the 10" barrel shooters.
I don't know if our 20" barrels should be twice as accurate as a 10" or 1/2 as accurate.
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The 20" should be 2x as accurate but only 1/2 the time
 
One thing you didn't bring up with barrel length and fps of the bullet. If you take two ar barrels the same length but different length gas system. The one with the longer gas system will be moving faster.
 
When someone says they are happy with 2 MOA barrel/ammo combo...that's a zombie gun. In competition for High Power, we need 1/2-3/4MOA...barrel/ammo combo, this combined with a persons "hold" will shoot 10's and x's.
If we shoot with a 2MOA gun...combined with "hold" we'd be lucky to shoot 8's and 9's.
There is a whole new world beyond 50-100yds shooting. It takes time, skill and to a point tenacity to learn the game.
 
I agree. i would never shoot a cmp match with my 10.5" chrome lined LMT upper. even if they allowed me to.

However, you are wrong about the 2 moa. 2 moa is about what you can expect out of a 20" A2. I don't know how old you are, but 1 MOA used to be something.

Now, every schmuck with an AR and a chinese optic claims 1 moa. But what does 2 moa mean?

Is it a best of 10 - 3 round groups?

Is it an average of 10 - 5 round groups?

Those two methods will give wildly different results. A 1 moa gun measured the first way may be a 2 moa gun measured the second way.


Almost any gun can shoot a 1" 3 round group at 100 yards if you shoot 10 groups and pick the best one.

5 - 5 shot groups with my reloads, my 10.5" LMT will AVERAGE 2 inches at 100, benched, with a 12x optic.

Using the same methodology my stock CMP Bushmaster from the mid 90s will average a bit under 1" with my hand loads.
 
charliet said:
When someone says they are happy with 2 MOA barrel/ammo combo...that's a zombie gun. In competition for High Power, we need 1/2-3/4MOA...barrel/ammo combo, this combined with a persons "hold" will shoot 10's and x's.
If we shoot with a 2MOA gun...combined with "hold" we'd be lucky to shoot 8's and 9's.
There is a whole new world beyond 50-100yds shooting. It takes time, skill and to a point tenacity to learn the game.
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Aww come on Charlie, what do you know about Highpower, you only have a 107 posts! [wink]
Dan
 
dcmdon said:
I agree. i would never shoot a cmp match with my 10.5" chrome lined LMT upper. even if they allowed me to.

However, you are wrong about the 2 moa. 2 moa is about what you can expect out of a 20" A2. I don't know how old you are, but 1 MOA used to be something.

Now, every schmuck with an AR and a chinese optic claims 1 moa. But what does 2 moa mean?

Is it a best of 10 - 3 round groups?

Is it an average of 10 - 5 round groups?

Those two methods will give wildly different results. A 1 moa gun measured the first way may be a 2 moa gun measured the second way.


Almost any gun can shoot a 1" 3 round group at 100 yards if you shoot 10 groups and pick the best one.

5 - 5 shot groups with my reloads, my 10.5" LMT will AVERAGE 2 inches at 100, benched, with a 12x optic.

Using the same methodology my stock CMP Bushmaster from the mid 90s will average a bit under 1" with my hand loads.
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To me it's across an 80 shot course match (especially at 300 and 600.) If I have more than a few shots that are way off call I swap the barrel. (For example if I call a wide 9 at 3 and it comes up a 10 at 6 I start to wonder. If that happens more than 3 or 4 times in a match something is wrong.) Of course you need to be able to call shots fairly accurately for that method to work.

EDIT: I'm just a service rifle shooter so if my calls are within a minute or so if impact I'm happy. Charlie's a match rifle shooter (an OK one for a match rifle shooter, I guess [thinking]) so for him being 1/2 minute off call is a much bigger deal than it is for me. (That's the difference between a center X and a wide X / tight 10 to put it in context.)
 
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jasons said:
To me it's across an 80 shot course match (especially at 300 and 600.) If I have more than a few shots that are way off call I swap the barrel. (For example if I call a wide 9 at 3 and it comes up a 10 at 6 I start to wonder. If that happens more than 3 or 4 times in a match something is wrong.) Of course you need to be able to call shots fairly accurately for that method to work.
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Also if your new like me all shots in the black i am excited, all rounds with in the 5 ring and I am relieved.
I have only shot reading XTC 80 3 times and each time I shoot better.... 670,690,720 cant wait for 2014 might get to reading 2 or 3 times again
 
dcmdon said:
I agree. i would never shoot a cmp match with my 10.5" chrome lined LMT upper. even if they allowed me to.

However, you are wrong about the 2 moa. 2 moa is about what you can expect out of a 20" A2. I don't know how old you are, but 1 MOA used to be something.

Now, every schmuck with an AR and a chinese optic claims 1 moa. But what does 2 moa mean?

Is it a best of 10 - 3 round groups?

Is it an average of 10 - 5 round groups?

Those two methods will give wildly different results. A 1 moa gun measured the first way may be a 2 moa gun measured the second way.


Almost any gun can shoot a 1" 3 round group at 100 yards if you shoot 10 groups and pick the best one.

5 - 5 shot groups with my reloads, my 10.5" LMT will AVERAGE 2 inches at 100, benched, with a 12x optic.

Using the same methodology my stock CMP Bushmaster from the mid 90s will average a bit under 1" with my hand loads.
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Everybody's measuring stick is different, but nobody should use 3-shot groups as a basis for accuracy. Also "best 3 (or 5) of 10" is not going to tell you anything.

Personally, I shoot 5, 5-shot groups and take an average. You must count "fliers".
Realistically, we can get by with a 1MOA rifle, but 1/2MOA-3/4MOA makes me feel a lot better.

I don't run with anybody shooting 10" barrels, so I can't comment on their accuracy. Still, for accuracy, I'd put any of the top-tier 20" barrels against a 10", 14", 16" barrel any day of the week.
 
I'm with Pat, I shoot 3 groups...I use 10 shots each. I'm looking for 1" group at 200yds. this is bench rested with match sights, not scoped. This is with a pretty serious AR match rifle. I wouldn't expect that with a rack grade gun, carbine or rifle.
I know that FN, the builder of the Army's standard rifle it has to shoot 4" at 100yds to make acceptance....My point is what are you shooting at and why? If its combat rifle vs. a competition rifle there is world of differences, yet the military over the last 10yrs or so has been instituting the Squad Designated Marksman program...which they have issued basically a competition grade rifle to certain trained soldiers within a unit, so that targets (bad guys) can be engaged at 500yd with a high degree of accuracy.

I can guarantee my rifles all shoot 1/2 moa or less
 
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