POF vs Sig556

[Jig Stick]

Can anybody tell me the difference between the gas systems in these two rifles? I have a 556 and was under the impression that it operates the same way as the POF system, but Im not sure if that is true or not. Im contemplating buying a POF in 308 and/or 223

 

[oneshot onekill]

Re: POF vs Sig556

Well, Basically any piston driven rifle works via a piston being driven by gas pressure behind the exiting projectile which generally, for timing reasons, happens forward of the receiver. The gas exits the barrel thru a small hole, into a chamber, pressurizes the chamber and that pressure moves the piston. The piston mechanically forces the bolt backward. A spring pushes the bolt forward, stripping the next round from the magazine and into the chamber...
So... Functionally, they work the same. However, the design is completely different.

In the Sig, the piston and rod are all one unit and I believe they are fastened to the bolt carrier (but can be removed from the bolt carrier). Someone correct me if I'm wrong. The spring that pushes the bolt forward is located around the piston rod. The Sig was designed from the ground up to be a Piston Gun.

POF makes a "modified" AR type of rifle. The Piston System replaces the Direct Impingement system normally found on an AR type rifle. The piston, piston rod and bolt carrier are seperate parts. The piston pushes a seperate rod that is driven through the upper receiver and impacts the Carrier-key portion on top of the Bolt Carrier Group. That's what drives the BCG backward. The buffer and spring in the buffer tube which is in the buttstock are what drives the BCG forward and strips the next round from the magazine and chambers it.

Clear as mud... Right?

FWIW, I prefer POF over Sig.

 

[Anchor Zero Six]

Re: POF vs Sig556

Sig is distant kin to the AK the POF is an AR.

IMO you can honestly say the POF was designed as a piston every bit as much as the SIG.

Unlike AR piston conversions the POF was engineered to function as a piston and there are things incorporated into it that adress the shortfalls of the conversion kits such as gas port and location, BCG design and the "Heat Sink" barrel nut that also supports the piston thus reducing flex allowing less deflection and a more linier piston travel.

While I'm a fan of the 556 I feel the POF is a better value with the rock 5R barrel and a trigger that dosnt suck unlike the 556. Also you can have a matching pair if you decide on a 308 later.

 

[oneshot onekill]

Re: POF vs Sig556

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Anchor Zero Six</div><div class="ubbcode-body">Sig is distant kin to the AK the POF is an AR.

IMO you can honestly say the POF was designed as a piston every bit as much as the SIG.

Unlike AR piston conversions the POF was engineered to function as a piston and there are things incorporated into it that adress the shortfalls of the conversion kits such as gas port and location, BCG design and the "Heat Sink" barrel nut that also supports the piston thus reducing flex allowing less deflection and a more linier piston travel.

While I'm a fan of the 556 I feel the POF is a better value with the rock 5R barrel and a trigger that dosnt suck unlike the 556. Also you can have a matching pair if you decide on a 308 later. </div></div>

Yes... I would Definitely have to agree that POF did NOT just take an AR an throw a Piston Kit in it. I'm anxiously awaiting the day that I can afford a POF in .308! I have on in 5.56 now and it's by far the best and most accurate AR type rifle I've ever owned!

 

[Jig Stick]

Re: POF vs Sig556

very interesting indeed. Im not sure what to do. Im thinking maybe keep my 556 and get a POF in 308. I watched the video intro on the POF site. Correct me if Im wrong but in order to adjust the gas system you have to drill out the plug at the end of the gas chamber to allow more / less pressure based on what you are trying to accomplish? My 556 has a knob that you turn on the gas system to allow more or less gas to be fed into the system. I like this much better than having to drill a $3000 rifle

 

[oneshot onekill]

Re: POF vs Sig556

No, No... There's no drilling involved! The gas plug on the front of the gas block has 2 positions for normal operation or suppressed.

 

[terrygood]

Re: POF vs Sig556

The sig operating system is nothing like the POF. POF is a custom piston AR. Sig is a refinement of the AK.

 

[oneshot onekill]

Re: POF vs Sig556

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: terryg</div><div class="ubbcode-body">The sig operating system is nothing like the POF. POF is a custom piston AR. Sig is a refinement of the AK. </div></div>

Uh... Not to be an ass, but did you even read the other responses? Isn't this basically what they said???

 

[damit]

Re: POF vs Sig556

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">No, No... There's no drilling involved! The gas plug on the front of the gas block has 2 positions for normal operation or suppressed. </div></div>

+1, its very easy to change, just twist the plug out of the front, remove the piston and install it 180 degrees ( flip it over) and put it back together, takes less than 30 seconds.

Dave

 

[KillShot]

Re: POF vs Sig556

There's no comparison between the POF and the Sig. Get the POF and you'll be glad you did!

 

[cyrekzz]

Re: POF vs Sig556

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: damitboy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">No, No... There's no drilling involved! The gas plug on the front of the gas block has 2 positions for normal operation or suppressed. </div></div>

+1, its very easy to change, just twist the plug out of the front, remove the piston and install it 180 degrees ( flip it over) and put it back together, takes less than 30 seconds.

Dave </div></div>

On the older POF models it believe you install it either backwards or 180 degrees, i can't remember... but on the newer POF models - there's an N or S on the gas plug itself, no need to remove the piston. At least that's the way it's on my 308 POF. I thought 223's from there were this way too.

 

[Shooter McGavin]

Re: POF vs Sig556

The Sig is close to a Robinson XCR in design, which is designed off of the AK. The POF is awesome. I have a POF 308 and a POF 415. Also, I have a Robinson XCR. I will not be getting rid of any of them.

Jamie

 

[barehander54]

Re: POF vs Sig556

I'm a sig 556 owner, I just bought one 8 months ago I see alot of negative input about this rifle, I was never a solider of police officer or anything like that I do enjoy shooting though I got a AR type rife for protecting for the in case scenario it was a little pricey, I could of choose bushmaster,colt,rockriver.I think the gun dealer I bought it from might of mislead me I told what I was looking for he convinced me this was it and I personally like the way it felt look like a nice rifle, but only beejesus it was hard to sight I had to put a sign 15 foot away just to see where it was hitting on paper, called sig I was ready to give it back to them they gave me a bs story so i tried it again I did get to hit at 50m with pretty tight groups but it need take alot of rounds and I found that the 62gr shot better but every round has cycle through it has anyone else have problems should I trade it dose it even had resale value on this rifle or did I get scammed.

 

[Jig Stick]

Re: POF vs Sig556

see...Ive had the opposite experience with the sig556. It outshoots my bushmaster easily. And it has never failed to extract or jammed on me. My Bushy has numerous times. And my 556 seems to be a good shooter as well. To be honest I never measured to see if it shoots MOA or better. Maybe Ill do that tomorrow at the range.

Im just wondering why one would pick the POF system over the 556 system, all other things being equal.

 

[leadbullet]

Re: POF vs Sig556

as much as i like my 11 AR's I like my Sig 556 even more because it isn't another freaking AR.
they are both good rifles, pick one up shoot it, save your coin and get the other, life is too short to limit yourself with gun choices.

 

[cyrekzz]

Re: POF vs Sig556

I have both myself - i liked the sig for the fact that it had the side cocking handle - that's just nice i think. The trigger is definitely not made for accuracy - more for reliability. My upper and lower don't fit tight like new - i guess it's hit and miss. I was at a gun shop about 6 months ago and was looking at some new sig556's and some of them had a tight upper/lower fit, and some of them were somewhat looser. My personal one is the latter, but i bought it used with a few hundred rounds though it already too... I also have to change my stock out to at least a metal buffer tube - can't stand that plastic one as i have to keep tightening it.

my $.02

 

[leadbullet]

Re: POF vs Sig556

I bought my sig556 at the shot show when they first released it, so I have one of the first 300 made and those are very good all around. the next production run was "terrible" as far as fit, canted optic rails, finish two tone upper and lower etc. those are really bad examples of the 556 unfortunately. the newer one are much better manufactured.
hope this helps debunking the 556 problems. some do and some don't.

 

[samnev]

Re: POF vs Sig556

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KillShot</div><div class="ubbcode-body">There's no comparison between the POF and the Sig. Get the POF and you'll be glad you did! </div></div>
+1