So its time to get a new rifle and I'm trying to decide on a short stroke piston (Sig 556 or rock river pds) or a regular (DI) AR 15. This is going to be an SBR which is why I'm looking at the piston driven with the folding stock. I'm wanting to make an informed decision rather than an emotional one. Is there anyone who can speak intelligently on this subject?
I have a SCAR 16 and am in the boat of SBR as well. From my perspective the standard benefits of the piston still stand. You still have to make sure that you have the correct gas port size and on the piston guns (such as the scar) all I have to do is swap out small set-screw like ports until I get the best operation. It is also nice when I put a can on the end of the rifle that all I have to do is flip the selector on the gas block and voila no gas in the face (well, it still wouldn't hit my face because of a much better design but w/e).
This is not to discredit the DI guns in any way as they can be made to be reliable and function just find as SBR's..obviously. There are just the slight advantages of the purpose built piston guns. It's really up to you to determine if the cost is worth it.
To further assist you I offer these emotional pulls as well.....Standard size SBR, DI rifle? That's nice. Folding stock, side charging, SBR that fits in your pocket? Well duh.
This is not to discredit the DI guns in any way as they can be made to be reliable and function just find as SBR's..obviously. There are just the slight advantages of the purpose built piston guns. It's really up to you to determine if the cost is worth it.
To further assist you I offer these emotional pulls as well.....Standard size SBR, DI rifle? That's nice. Folding stock, side charging, SBR that fits in your pocket? Well duh.
Mini-14 - Short Stroke Piston
AR-15 - DI
I'll take DI.
AR-15 - DI
I'll take DI.
Um, I don't think a Mini-14 is a short stroke piston system, matter of fact I'm quite sure it isn't, but a good example would be a M1 carbine, AR-18, or a M-14 without the mini, which is probably what you ment. Now we could debate the merrits of a 5.56x45mm carbine to the merrits of a 7.62x51mm battle rifle for the next gazillion years, but mini-14,s (which is also a 5.56x45mm cartridge shooter) will still not be a short stroke piston system. 
The M1 Carbine works very similarly to the Mini-14?
Heavier, more moving parts, non standard parts, parts not readily available, louder suppressed, oh you were looking for benefits. My bad.
No M1 carbine and Mini-14,s don't work similarly. The M1 carbine IS a short stroke piston system. The Mini-14 is a full stroke gas impingment system. Not the same at all, although I will agree that they are both semi autos
Ok well I'm only interested in AR 15 style rifles, and Sig 556 (unless someone has a suggestion other wise) but thanks for that lesson.
Weight is not an issue, I jumped a saw around Iraq for a year and it is still my favorite man portable weapon.
As for the parts issue if neither Sig or rock river can't make a product that can take a beating, and honor their warranty if something breaks that's a big problem.
As for the sound issue: if I have to go loud with it it won't be from a sniper hide?
Thanks though dustingaunder I'm trying to see if someone cam talk me out of it.
Next try. Anyone have a suggestion for one of the two, or one I haven't thought of?
Weight is not an issue, I jumped a saw around Iraq for a year and it is still my favorite man portable weapon.
As for the parts issue if neither Sig or rock river can't make a product that can take a beating, and honor their warranty if something breaks that's a big problem.
As for the sound issue: if I have to go loud with it it won't be from a sniper hide?
Thanks though dustingaunder I'm trying to see if someone cam talk me out of it.
Next try. Anyone have a suggestion for one of the two, or one I haven't thought of?
I always enjoy a good back and forth banter as it typically increases my knowledge on a subject.
American Rifleman
http://www.americanrifleman.org/ArticlePage.aspx?id=1572&cid=4
"The Minis barrel is threaded into the receivera seemingly unconventional method of attachment in modern military-style rifles. Its short-stroke gas system uses a fixed piston mounted to the bottom half of a split gas block clamped around the barrel with four Allen-head machine screws. When the operating slide is at rest and the bolt in battery, a cylindrical cavity in the front face of the slides forward section encloses the piston. During firing, powder gases pass through a port in the barrel before entering the piston and expanding into the cylinder, driving the operating slide rearward. Unburned powder particles vent along a steel liner in the stocks fore-end. Partly because the Minis gas system is self-cleaning, it has a reputation for running reliably even with minimal maintenance."
Brownells
http://www.brownells.com/.aspx/lid=...pgrading-the-Ruger-Mini-14-The-Brownells-Way-
"It has an investment cast heat-treated receiver and a Garand breech bolt locking system with a short-stroke fixed-piston gas system."
Both websites have people much smarter than myself and both refer to the Mini 14 as having a short stroke piston gas system.
American Rifleman
http://www.americanrifleman.org/ArticlePage.aspx?id=1572&cid=4
"The Minis barrel is threaded into the receivera seemingly unconventional method of attachment in modern military-style rifles. Its short-stroke gas system uses a fixed piston mounted to the bottom half of a split gas block clamped around the barrel with four Allen-head machine screws. When the operating slide is at rest and the bolt in battery, a cylindrical cavity in the front face of the slides forward section encloses the piston. During firing, powder gases pass through a port in the barrel before entering the piston and expanding into the cylinder, driving the operating slide rearward. Unburned powder particles vent along a steel liner in the stocks fore-end. Partly because the Minis gas system is self-cleaning, it has a reputation for running reliably even with minimal maintenance."
Brownells
http://www.brownells.com/.aspx/lid=...pgrading-the-Ruger-Mini-14-The-Brownells-Way-
"It has an investment cast heat-treated receiver and a Garand breech bolt locking system with a short-stroke fixed-piston gas system."
Both websites have people much smarter than myself and both refer to the Mini 14 as having a short stroke piston gas system.
