Piston or DGI..Which is more accurate?

timoram

timoram

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Well I'm planning on picking up an AR or similar platform (blackrifle of sorts).

I'm one that will always seek out the best possible accuracy out of my firearms that I can. That being said which is a better performance platform for accuracy.

I was under the impression that a DGI system was better for accuracy as there is no mechanical linkage to the gas piston. I do not know if this is true or if it is just myth. I have heard this a few years ago when the piston AR's were slowly entering the market.

If you can give you opinion/facts about this matter and possibly suggest a blackrifle that will fit the bill that would be great.

Tim
 
The gun with the best barrel and bullets (+Trigger) will be the most accurate. Piston or DI doesn't matter too much. The bullet is out of the barrel before the bolt unlocks.
Both types of guns can be very accurate.

Most of the time it is the skill of the shooter that plays a big part. Some of the match and DCM built guns are best (match barrels) although my HK MR223 is very accurate (I got about 2 MOA at 500 meters off the mag in my last Service Rifle match).

Rich
 
Gunnerlove said:
So what do you want to do with this rifle?

Competitions? Ranges?
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It will be something geared for all purpose.
I'm slowly getting into some shooting sports but most of my time would be at the range.
I do want the best accuracy I can get from the rifle but at the same time I do not want something that will sacrifice reliability and durability to do so.
 
Rich LPS said:
The gun with the best barrel and bullets (+Trigger) will be the most accurate. Piston or DI doesn't matter too much. The bullet is out of the barrel before the bolt unlocks.
Both types of guns can be very accurate.

Most of the time it is the skill of the shooter that plays a big part. Some of the match and DCM built guns are best (match barrels) although my HK MR223 is very accurate (I got about 2 MOA at 500 meters off the mag in my last Service Rifle match).

Rich
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Here is your answer. Stop worrying about the gear and shoot.

TDC
 
timoram said:
It will be something geared for all purpose.
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At least with the Ares system, there is no difference:
fen0jd6clo.jpg

I would start with a DI. The only real difference with piston is easier to clean, more expensive, and heavier. If you want moderately accurate, go HBAR. If you want really accurate, have a look at JP Enterprises.
 
Keep in mind that with a piston system there is hardware hung on the barrel which could affect the vibration pattern of the barrel while the bullet is in transit. This is nothing to do with movement of the piston after the bullet has cleared the port.
The whole point of a floated barrel is to keep the barrel free of anything pressing on it or any tensions. That is why float tubes are used on some AR rifles - to keep the barrel free the influences of forend tension or pressure.
Is a ducted gas system inherently more accurate than a gas piston system? I don't know.
Incidentally, references are often made to the AR system being DGI - Direct Gas Impingement. The AG42B, Hakim, and MAS 49 use DGI. The AR does duct gas through a tube, but it is not DGI in the sense that these rifles are. The gas is ducted into an expansion chamber within the boltcarrier, and the expanding gas forces the carrier back from the bolthead. This drives the carrier to the rear, as well as rotating the bolthead to unlock. That is why there are piston rings on the bolthead, and gas ports on the side of the carrier. If the passageway through the bolt carrier key were blocked, would the rifle function by DGI?
 
What would be the optimal barrel length for a .223.
I want to keep it as short as possible but still have it be reliable and accurate. I seem to see a lot of 16" setups, would this be similar to what I should be looking at?

Any recommendations would be great. I'm looking for something that is a flat top with heavy barrel and DGI.
As for price in and around the $2000 range would be what I'm shooting for.

Tim
 
Contact Questar to see if they can put together an 18" Stainless Bull barreled Varmit Rifle together for you. It's a tack driver for well under $2K

Stag (arms East) has their 6R, it's 24" but for the price and the accuracy.... Great Rifle.
 
rivetc78 said:
Contact Questar to see if they can put together an 18" Stainless Bull barreled Varmit Rifle together for you. It's a tack driver for well under $2K

Stag (arms East) has their 6R, it's 24" but for the price and the accuracy.... Great Rifle.
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Thanks for that information.
I will look into both of these.

Any other suggestions?

Tim
 
Since you are in POCO you should contact Joe at Dlask Arms. He has exactly what you need for your price. You will not be dissapointed. The others mentioned are good choices though.
 
The common thought that bull barrels are more accurate than thinner profiles in an AR is a myth, so don't get sucked into buying a barrel with a 1 1/2" tube thinking it's going to blow everthing else out of the water....

Generally speaking, DI guns have a better chance at providing superior accuracy than one with a piston. The same can be said when comparing a DI gun with a float tube to one with regular handguards; there is less 'stuff' to impart potential inconsistancy.
Can a specific gas gun 'A' perform as well as the next DI gun 'B' on the line? You bet - some perform as good or better.

The same can be said with 'match' barrels.
You have a better than good chance of having a 'match' barrel perform really well from one of the custom shops than you do a regular 'rack grade' barrel from one of the common manufacturers. But make no mistake, there are 'rack grade' guns that shoot as well or better than some 'match' barrels out there.
 
Accurate custom AR's is what we specialize in. We can build any length or profile barrel you want. We use Rock Creek stainless match barrel blanks that are as good as any barrel you could find on a bolt action target rifle.

This is an 18" barreled SPR clone that printed a 1/4 inch group the first time we tried it.

ARSpartan.JPG
 
I think you need to assess what you want this rifle to do. There is no question, as Rick at ATRS has shown, that you can build an extremely accurate AR. If all you ever see yourself doing is punching holes in paper off a bench or bipod, then weight isn't really a factor and you can go the heavy barrel/PRS stock/big glass route. However, if you also see yourself doing IPSC rifle or 3-gun, you'll find that rifle is pretty heavy and awkward. I've tried numerous configs over the years, and have settled on a 16.1" middy (mid-length gas/mid-weight Noveske barrel) config with a UBR stock. Switch between an Aimpoint H1 and a Falcon 1.5-5, both in Larue mounts, depending on what I'm doing with the rifle. Not perfect, but handy enough for 3-gun, and accurate enough for Service Rifle. The UBR is a bit heavier than a VLTOR, but balances the rifle nicely and is comfy enough to use prone for longer periods. Also long enough to get into the USA. Lots of options with black rifles, and very easy to spend lots of $$$. Figure out realistically what you're going to want the rifle to do for you before you start building.
 
Theoretically the DI system should give better consistancy. In all practicality though the gas system is a minor consideration.

The care and workmanship that goes into a rifle will make it a better shooter, regardless of system.

Experimentation and patience with various hand loads will make the rifle a better shooter.

Time and dedication will make you a better shooter, which is the most important of all.
 
rhs said:
I think you need to assess what you want this rifle to do. There is no question, as Rick at ATRS has shown, that you can build an extremely accurate AR. If all you ever see yourself doing is punching holes in paper off a bench or bipod, then weight isn't really a factor and you can go the heavy barrel/PRS stock/big glass route. However, if you also see yourself doing IPSC rifle or 3-gun, you'll find that rifle is pretty heavy and awkward. I've tried numerous configs over the years, and have settled on a 16.1" middy (mid-length gas/mid-weight Noveske barrel) config with a UBR stock. Switch between an Aimpoint H1 and a Falcon 1.5-5, both in Larue mounts, depending on what I'm doing with the rifle. Not perfect, but handy enough for 3-gun, and accurate enough for Service Rifle. The UBR is a bit heavier than a VLTOR, but balances the rifle nicely and is comfy enough to use prone for longer periods. Also long enough to get into the USA. Lots of options with black rifles, and very easy to spend lots of $$$. Figure out realistically what you're going to want the rifle to do for you before you start building.
Click to expand...

Excellent post.. You have to have a goal before you can execute a plan of attack.:cool:

TDC
 
rhs said:
I've tried numerous configs over the years, and have settled on a 16.1" middy (mid-length gas/mid-weight Noveske barrel) config with a UBR stock.
Click to expand...

Get a 16" midlength basic Noveske upper and find a decent lower from somewhere. You can spend as much money on it afterwards and add whatever fits your needs.
 
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