• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Piston Rifles Accuracy

Re: Piston Rifles Accuracy

Two happiest days in my life were the day I bought my REPR and the day I sold my REPR.
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hk dave</div><div class="ubbcode-body">

Sure sure, know piston ARs don't crap where they eat, but a dirty bolt has never kept my DI ARs from running.

They build piston ARs for one reason, because suckers will buy them and pay extra for it. </div></div>

Hi Dave- While it is certainly your choice to believe that piston rifles have no benefit, that's not the case for everyone. I have some arthritis issues (bad) on my right arm (some of this due to my potassium levels are always low = weaker bones and other issues, but that's another story)For me, having a piston rifle is exceptionally easier to clean. I simply can't hold a bolt carrier group and all it's parts to clean them, it's just too painful.

I'm a good shooter, but not nearly good enough that I need the most accurate rifle - most likely because I will probably never be able to shoot as well as a .5MOA gun (or less) could do. The piston rifles have their benefit for sure, but not for everyone.
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hk dave</div><div class="ubbcode-body">...A Piston AR15 has a rod slapping the TOP of a converted bolt, exerting pressure and stress on the LOW REAR of the carrier... </div></div>

If you look at the design of some most piston systems, there isn't any "slapping" going on. The rod is already touching the BCG and the piston is pushed by the gas which pushes the rod just as smoothly as DI system. Also carrier tilt has been eliminated on most piston systems.

I agree that with all else the same the DI should be more accurate, but NOT because of parts "slapping" together or BCG's not going straight back. Its more likely to be because there more moving parts. However these accuracy differences are negligible as demonstrated by many and the benefits of the Piston system out weighs the negligible accuracy differences by far IMO.

FYI I own 3 DI AR's and one Piston AR. Love them all
 
Re: Piston Rifles Accuracy

I have never had a malfunction on my ARs, but I would usually have multiple malfunctions on my ak. I got rid of one, guess which one.
 
Re: Piston Rifles Accuracy

Maybe a good question would be, "How accurate does it need to be for your style of shooting?" If you're a flat ranger, bagged up with reloads and killing paper all day...then yeah, maybe you want a JP, etc. If you beat your rifle around in the truck, nearly never clean, shoot suppressed in the dust at moving targets and braced over trees and jeep hoods with decent quality ammo...then you might be interested in a POF or LWRC or PWS. That's not to say that the DI rifles aren't capable of that kind of shooting, but my REPR just eats that type of activity up. Get what you like, not many of us shoot enough to tell the difference. The side charging handle of the REPR sealed the deal for me after years of gas face from suppressors. I still want a PredatOBR and a PWS though...
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chainring</div><div class="ubbcode-body">Maybe a good question would be, "How accurate does it need to be for your style of shooting?" If you're a flat ranger, bagged up with reloads and killing paper all day...then yeah, maybe you want a JP, etc. If you beat your rifle around in the truck, nearly never clean, shoot suppressed in the dust at moving targets and braced over trees and jeep hoods with decent quality ammo...then you might be interested in a POF or LWRC or PWS. That's not to say that the DI rifles aren't capable of that kind of shooting, but my REPR just eats that type of activity up. Get what you like, not many of us shoot enough to tell the difference. The side charging handle of the REPR sealed the deal for me after years of gas face from suppressors. I still want a PredatOBR and a PWS though... </div></div>

Well put.

Again, I think most people are missing the point. The difference in accuracy between DI and piston is NEGLIGIBLE. Pick what you like and shoot it.
 
Re: Piston Rifles Accuracy

Sunday, I shot some 77-gr SMK loads (2650-fps). Rifle is an LMT MRP Gas Piston. I have a S&B 4-16x42 mounted via ADM Recon-SW QD mount. Trigger is the stock (Heavy) single stage military. Rifle has an Atlas bipod mounted on the bottom rail, and I used a rear bag shooting prone off of my buddies covered deck.

Wind was left to right at 7-mph, 84-deg F, 7200-ft elev. pressure at 30.35 inHg.

I wanted to check the loads and compare them to what JBM says.

at 100-yards it shoots sub-moa (on 4x4 and 4x8 steel plates)
at 200 yards it shoots moa (on 5x10 and 10x10 steel plates)
at 300 yards it's still around 1-moa, but the wind is moving my
bullets causing hits to shift (on 10x10 and 18x24 steel plates)
Between 400 and 800-yards (in 100-yard steps) I'm having solid hits (on full size IPSC steel targets), except when I'm not agressive with my wind holds.
Also notice bullets are flying flatter at around 0.2-mils higher between 200 and 800-yards.
A little bit higher at 900-yards, still have solid hits.
At 1K the bullets are flying almost 1-mil higher then what JBM says it should, dial correction, and more solid hits.
Wind shifts to a head wind, and I have three rounds remaining in the rifle/magazine.
JBM says my bullets transition to sub-sonic flight just past 1K, but I want to see what I can do at 1100-yards (24X30 Steel Plate). First round overshoots the target by 1-mil, azimuth wise I was still on target. dial correction, and second shot was just under the target, and azimuth wise I'm still good. I hold half-mil and the third round impacts target.

So with that being said, a gas-piston 16" barreled AR is doing very well, and much more then anyone would expect from any 5.56 at these extented ranges.
 
Re: Piston Rifles Accuracy

I'm not a fan of the op-rod driven AR's, but the LMT system is one of the lightest on the market, and is difficult to distinguish in weight/balance between a DI gun.

To me, the biggest issues are reliability and handling before accuracy, so those need to be addressed first for me.

So far, the properly-built DI guns have a reliability AND accuracy record that op-rod guns fall short of, but it's great when you get results like this with your LMT.

As far as cleaning goes, every op-rod driven weapon I've been issued or have used needed cleaning in the gas block and piston areas, in <span style="font-style: italic">addition to </span>the internals of the receiver.

With a DI gun, I don't really clean them, other than brush off the brass residue on the bolt face, and add more Slip2000 EWL. At certain round counts, I'll break down the bolt and clean out debris from the ejector channel, as well as the extractor, and replace the ejector spring.

The claim that op-rod driven guns don't require cleaning is a marketing ploy, in my experience. They are usually MORE maintenance-intensive, like the FAL, M14, M60, M240, SAW, etc.

Neglecting the piston head and gas block on an exposed op-rod design is a recipe for malfs when enough carbon or carbon+rust build up in that area. What I like about the DI design is that you basically have a closed system that, if kept wet with a thick oil, doesn't allow rust to form, and carbon fouling only increases the gas seal of the system.
 
Re: Piston Rifles Accuracy

Did you guys see the article in the 2013 Black Guns magazine about the Sig Sauer AR10?? (Sig 716)

The article was impressive! Not only is the price cheaper ($2,132) than most piston rifles, but it's a shooter!

It shot six shot groups of 7 types of ammo from 147gr to 180gr....
0.42
0.29
0.37
0.33
0.46
0.33
0.55
 
Re: Piston Rifles Accuracy

At what distance were the groups shot?
wink.gif
j/k

I take it they used a Precision Marksman model? If those numbers are real, that is extremely impressive.
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hk dave</div><div class="ubbcode-body">At what distance were the groups shot?
wink.gif
j/k

I take it they used a Precision Marksman model? If those numbers are real, that is extremely impressive. </div></div>

Dave - as you know they mostly shoot at 100 yrds, but it the article doesn't say.....now that I re-looked at it the author sighted in at 25 yrds. I'm thinking these groups are based on this distance?? before I get "yelled at" (oops), I now realize these groups are not impressive if only at 25 yrds. (at 100 yrds it would be impressive.

I bow my head with tail between my leggs...
 
Re: Piston Rifles Accuracy

Anybody that does an article on a rifle with groups at 25 yards ought to be beaten with a rubber hose.
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chainring</div><div class="ubbcode-body">Anybody that does an article on a rifle with groups at 25 yards ought to be beaten with a rubber hose. </div></div>

Ranger that!
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Blackrifle1</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hk dave</div><div class="ubbcode-body">At what distance were the groups shot?
wink.gif
j/k

I take it they used a Precision Marksman model? If those numbers are real, that is extremely impressive. </div></div>

Dave - as you know they mostly shoot at 100 yrds, but it the article doesn't say.....now that I re-looked at it the author sighted in at 25 yrds. I'm thinking these groups are based on this distance?? before I get "yelled at" (oops), I now realize these groups are not impressive if only at 25 yrds. (at 100 yrds it would be impressive.

I bow my head with tail between my leggs...</div></div>

ROFL It's all good.

I was just sitting here thinking, "Holy moses... I need to get me one of these laser beams! Six shot groups all 1/3rd moa with 7 different types of ammo?! This is the holy grail of all rifles PERIOD."
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hk dave</div><div class="ubbcode-body">
ROFL It's all good.

I was just sitting here thinking, "Holy moses... I need to get me one of these laser beams! Six shot groups all 1/3rd moa with 7 different types of ammo?! This is the holy grail of all rifles PERIOD." </div></div>

HA! I agree....maybe someday we'll have that
 
Re: Piston Rifles Accuracy

Anytime I see the headings on glossy gun rags, saying...

"It's a 1000yd Sure-shot!"

or...

"It's Sub-MOA Sure-shot!"

I have to check to see that I didn't zone out in the toilet paper aisle. They just can't leave that "sure-shot" out of there for some reason, and it's usually the same author. He must get a healthy fringe benefit package to keep writing up rifles like he does. It's shameless really.

Did they really post those numbers for 25yd groups?
 
Re: Piston Rifles Accuracy

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LRRPF52</div><div class="ubbcode-body">Anytime I see the headings on glossy gun rags, saying...

"It's a 1000yd Sure-shot!"

or...

"It's Sub-MOA Sure-shot!"

I have to check to see that I didn't zone out in the toilet paper aisle. They just can't leave that "sure-shot" out of there for some reason, and it's usually the same author. He must get a healthy fringe benefit package to keep writing up rifles like he does. It's shameless really.

Did they really post those numbers for 25yd groups?</div></div>

People eat that stuff up... its awesome.

People will say "My gun can do .27" groupings" and all the friends go "WOW THATS AMAZING!"

Of course nobody thinks to ask how far the group was shot at... nor do they care. Those are the same folks that think bullets travel straight.
smile.gif


I used to be one of those.
wink.gif
 
Re: Piston Rifles Accuracy

I think this is where I discovered that Slip2000 EWL is the lube to use on DI guns. I use it exclusively on my MWS, and it's so easy to clean up. I'm now using it on my other AR's.

I did a torture test with my LMT DI carbine. No cleaning or lube, and zero malfunctions until around 750-rounds when I had a round that wouldn't allow the bolt to fully close. Hit the forward assist, and it kept on running. That was before I started using Slip2000 EWL.

Yes, the DI guns do run dirty, but the 5.56 rifles aren't that bad compared to the 308 variants.