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OK guys, be easy on me here........

I have a RRA LAR-15 (CAR-A4) that I have not even shot yet! It was bought used from a respected Forum Member here back in 2007.

It is my understanding that these rifles have a gas blow back design that is something different than a gas piston system.
The gas piston conversion system helps eliminate powder residue from your face/eyes thru the rear of the charging handle and additionally, the conversion makes the rifle more reliable.

The questions are:
1. Am I correct on the 3 assumptions above?

2. Is it worth it and what is the approximate cost of good quality parts to do this gas conversion?

3. If I was to send the upper off to someone for a gas block/piston conversion I believe that I can send it out myself (upper only) by USPS without going thru an FFL. Is this correct, including out of State?

4. Who does this conversion (Wilson, RRA, etc.....) or someone who is experienced and has the correct tools willing to do this for me locally and also test the rifle after the work?

Thanks!

As far as my AR goes, the gas blowback works fine. I haven't had a malfunction since I've had it, for about 500 rounds (true, that's not a lot) you personally really don't get dirty as a shooter, other than just range dust from being outside, your hands get dirty from loading magazines though like every other gun.

So you probably are correct in the last 2 assumptions, and yes I'm fairly certain it is a blow back design, with that said, if you're gonna burn triple digits of dollars to perform what I would consider a minor upgrade at best, which you would probably have to do with every new upper you get, it would be more cost-efficient to spend that money on practice ammo, or a free float barrel, or fluted, or a longer barrel, or a higher quality bolt assembly, etc.

But, I have not looked into the gas system really, all I know is from shooting experience, no research. The AR does get fairly dirty, and since it's all black it can be easy to miss spots, which if done over and over can lead to jams and what-not, but I'd rather take the time and clean the weapon properly then spend good cash on a system that's not broken.

Alan,

You are correct, sir. The standard Stoner design is DI, or direct impingement system which results in residue being blown back into the bolt and chamber.

Bushmaster makes a pretty good piston kit, form what I hear. Personally I have gone to the LMT system because the barrels and calibers are interchangeable. LMT's aren't inexpensive, however. The advantages are that the chamber and bolt are much cleaner, and because hot gases are not blown back into the chamber, the rifle runs much cooler, resulting in a more reliable, longer lasting rifle. Depending on the system, recoil may also be slightly reduced.

As far as whether or not it's worth it, that is up to you. I HATE cleaning AR's, and I like the technology behind the piston system, so it works for me. If you are just shooting the rifle occasionally then it may not be worth the expense. If you like have the best system available, then go for it. I know your taste in 1911's and an LMT for instance would fit right in .

Edited: Based on the fact that you haven't fired that rifle yet, it would be hard to justify the cost, unles you just want to have it.

Oh, and you can ship the upper yourself, but the BM system is made to be installed easily.

Thanks Pinkycatcher and SSG for the replies and info.

Both of you indicated that if I do not actually shoot the rifle much, the expense would probably not be justified. I have not shot it since I got it almost 2 years ago. All I did was remove the carry handle and install a Aimpoint CompM4 site on it. That was quite a bit of an expense in itself......

I have 1000 rounds of ammo that I got when I got the rifle and planned on shooting it, but never got around to it with no place to go and no one to go with.....

SSG thanks for the info on BM and LMT options. I will have a look at both.

But, until I actually start shooting this thing, I may go ahead and leave it the way it is.

Thanks again for the info!

Here is a writeup from one of the forums I belong to

http://www.tacticalunderground.us/forum ... 9&p=217060" onclick="window.open(this.href);return false;

Apparently...carrier tilt is a BIG issue with these types of systems!

Thanks!

I believe that one of the advantages of the gas piston systems is that they are tunable, more or less on the fly, for different loads. That being said, I've fired 45, 55, 62, 68, 69, and 75 grain cartridges through one of my ARs with the standard gas system, and I would say that most of the deviations in accuracy are due to barrel twist, than due to the gas system.

The Annoyed Man wrote:I believe that one of the advantages of the gas piston systems is that they are tunable, more or less on the fly, for different loads. That being said, I've fired 45, 55, 62, 68, 69, and 75 grain cartridges through one of my ARs with the standard gas system, and I would say that most of the deviations in accuracy are due to barrel twist, than due to the gas system.

It is not the piston system that affects the accuracy, it is the heat. The piston system has more moving parts and in my eyes more to break or go wrong. Yes they stay cleaner and cooler, but unless it is a work gun for you I would not spend the money on a piston conversion. I have always heard keep em clean, keep em clean, and then get serious about keeping em clean. I have never had issues with my rifles as long as they were relatively clean. Any of the twist rates of the barrels are accurate if you find the ammo they like.

Also if you are set on a piston conversion, there is a newer set up out there that connects the piston to the bolt carrier and the contact is made it the gas tube. Instead of the piston being connected to the lever in the gas block and the contact being made outside of the gas tube and smacking the bolt carrier. This design supports the impact of the piston more and is less likely to wear from what I understand. I am unsure of the brand name though...

John Farnam's take

http://www.defense-training.com/quips/14Apr09.html

Very interesting.......

I have decided to leave mine stock. If I think I need a Gas Piston Rifle, I will buy a SIG .556 in the future.

Heck, I might even keep the stock AR and get this Sig Pistol. Looks like the closest thing to a Legal SBR (without the cost & registration).

RECIT wrote:

The Annoyed Man wrote:I believe that one of the advantages of the gas piston systems is that they are tunable, more or less on the fly, for different loads. That being said, I've fired 45, 55, 62, 68, 69, and 75 grain cartridges through one of my ARs with the standard gas system, and I would say that most of the deviations in accuracy are due to barrel twist, than due to the gas system.

It is not the piston system that affects the accuracy, it is the heat. The piston system has more moving parts and in my eyes more to break or go wrong. Yes they stay cleaner and cooler, but unless it is a work gun for you I would not spend the money on a piston conversion. I have always heard keep em clean, keep em clean, and then get serious about keeping em clean. I have never had issues with my rifles as long as they were relatively clean. Any of the twist rates of the barrels are accurate if you find the ammo they like.

Also if you are set on a piston conversion, there is a newer set up out there that connects the piston to the bolt carrier and the contact is made it the gas tube. Instead of the piston being connected to the lever in the gas block and the contact being made outside of the gas tube and smacking the bolt carrier. This design supports the impact of the piston more and is less likely to wear from what I understand. I am unsure of the brand name though...

By deviations due to barrel twist, I simply meant that some twist rates tend to be better for some bullet weight ranges than other twist rates. BTW, I clean my firearms anyway, regardless of firing mechanism.

By deviations due to barrel twist, I simply meant that some twist rates tend to be better for some bullet weight ranges than other twist rates. BTW, I clean my firearms anyway, regardless of firing mechanism.[/quote]

Oh I hear ya about cleaning them, I did not intend to imply that you didn't clean your firearms. I was just stressing that the AR platform must be kept clean in order to maintain reliability. The piston systems to keep them a lot cleaner, but if it is clean to begin with you should not have tons of problems.

Brother has the Sig 556 and loves it. I have shot it side by side with my conventional stag AR. The 556 is noticeably heavier towards the front of the gun, and the iron sights are not really up to par. My complaints with the sights are that the rear flip up is very small and seems fragile, and the front sight is just a big wide square peg that makes accurate shooting difficult. Other than that, MAN IS THE ACTION SMOOTH! I particularly like the charging handle, which makes for easier loading/you dont have to take the rifle off your shoulder to chamber a round. His gun has funtioned flawlessly and boy does it have some ejection force, about 10-15ft at 2 o-clock! Very smooth, accurate, and reliable gun that is piston operated which he picked up at a gun show for $1400.

Edit: I forgot to mention the original point for my post. The 556 does have slighter LESS recoil than my stag. I attribute it to the small amount of extra weight and the piston operating sytem.

Well, if I do get a different .223 it will either be the Sig 556 or the HK MR223 (if it ever gets to the US).

The Sig will take AR15 Mags and I already have a bunch of those

Not sure if the HK MR223 will take them or not. Probably not.......