I am curious what folks' impressions are. I am more curious about the non-takedown version. One nitpicky thing I want to know is if all the gas system venting is done at the block; I don't want it done anywhere under the handguard.

My experience with their DI guns is that they're not TDP. Trigger and hammer pin visually loose in the lowers from the few I looked at.

For the price of the SR556, I'd personally buy a PWS product which is a gem of a rifle that most don't know about.

I am familiar with PWS. The same criteria would apply. Is the gas venting done outside the confines of the handguard? It doesn't appear so.

The SR556 gas system isn’t remotely like a DI system, so TDP doesn’t apply. Although I have the takedown, I believe the front end is the same as the non-takedown. It’s a short piston system with the piston staying completely inside of the gas block, which is in front of the handguard. Inside the top of the handguard is a transfer rod that runs the full length of the handguard and transfers the force from the piston to the carrier. You can see the exploded view of the parts in the manual.

https://ruger-docs.s3.amazonaw...m/_manuals/sr556.pdf

The PWS, at least the Mk111 upper I have, is a long stroke piston where the piston is connected directly to the carrier. Also, on my PWS, the handguard goes nearly the length of the barrel, and the gas regulator is accessed through a cutout in the top of the handguard, so it has to vent under the handguard.

quote:

Originally posted by Dwill104:
The SR556 gas system isn’t remotely like a DI system, so TDP doesn’t apply.

ORLY? TDP still matters for the lower, which is what I referred to. Trigger and hammer pins were visibly loose in the lower.

There's no gas under the handguard.
Which is good as it's not exactly simple to remove it.


I have only heard of one instance of a broken piston on an SR556.
That was before they stopped making them.

I have an SR762, almost 1,000 rounds through it so far with no issues.
If something happens to the gas system I'll probably just convert it over to DI rather than sending it in to be repaired.

Most piston guns designed around the AR15 have this issue: "that was before they stopped making them."

There are a lot of proprietary designs in firearms, few decide not to purchase a Win 94 or Remington pump .308 because they can't find parts in a clamshell at a gun store. It's simply not expected. For some reason tho, AR15's are - even tho they don't wear out parts any quicker than the others. On the other hand, they get shot a lot more, cheaper ammo and less recoil make that opportunity which a lot of shooters take advantage of. Competitors run 10k rounds annually keeping up their skills, few do that with a lever gun - SASS maybe.

All the different piston guns over the past ten or more years share that distinction - they were introduced, sold and then the market died down and they were taken out of production. Nothing inherently "wrong" with that, plenty of handguns and hunting rifles have short sales histories. In over 45 years of the Army using DI tho, there is only one piston system that remains - HK's 416.

Like Ruger, HK doesn't sell parts much. It was a significant issue when I had a HK91, and those parts/accessories were expensive, too. But, there wasn't much to swap or improve, either - which is something AR owners as a group would be loathe to admit.

I have had a sort of touch-and-go thing with the SR series for years. Almost ten years ago, I was in the market for an AR10; I pretty well had my mind made up on a SR762. I couldn't find one in my area, and ended up with a Colt 901 instead; I am glad that happened, as the 901 has been awesome. I then considered the SR again, in the takedown variety, for the 5.56 and .300 switchability; that interest waned. I am back again, in my pursuit of suppressed perfection. In my experience, an adjustable piston system doesn't guarantee a cleaner or less gassy gun; especially when there isn't an opportunity for gas venting as far forward on the gun as possible. It seems that gas vented beneath handguards tends to get trapped/deflected in an unfavorable way. The 416, Colt 6940P, and SR556 all vent in their gas blocks, which are exposed to the open atmosphere. The 416 and Colt are spendy, and I don't want to invest that kind of cash in an experiment. If I had a time machine, I'd go back to when/where an LE surplus 6940P could have been had, but that's not an option. So the SR556 is where my head is at, in my specific application; though I am no longer fond of the takedown idea.

Thanks to all, for your responses. Powermad and Dwill confirmed my hunch.

Ya down with TDP? (yeah you know m... no actually)

Thermal design power?

Sounds like TTBS to me.

i had one years ago, when they first came out, had a lot of problems with it running right, sent it back to ruger, they "fixed" it (they didnt lol) and so I sold it
LWRC now is what I have , could not be happier

What kind of problems were you having with the gun? I appreciate the LWRCs, but I am looking for something that vents out the exposed block, for the reason mentioned above.

quote:

Originally posted by cas:
Ya down with TDP? (yeah you know m... no actually)

Thermal design power?

Sounds like TTBS to me.

Technical Data Pkg? That's the first result from Google "AR15 TDP"

Take down pin(s)?