Piston or DI for a Grendel Build?

[rabiddawg]

Holy 4.5 year old thread resurrection

I got a laugh out of it because dwalters66 directed his comment to the post from 3/12.

[Mike Wood]

I got a laugh out of it because dwalters66 directed his comment to the post from 3/12.

Same here!! Lol

[LRRPF52]

Well...FYI...I think the accuracy debate is more scholastic than real. Most modern gun makers making piston guns have compensated for the issues concerning this. But moreover, the Marines adopted the H&K417 and M27 which are piston stroke rifles.

Can you elaborate more on that? This is the first I've heard of them adopting the HK417 7.62 NATO rifle.

I know they augmented the SAW with the M27, but nothing on the 417.

[Capt. Morgan]

I went with the piston for much the same reasons - easy to clean and reliable if it has to run dirty (SHTF scenario). I used to own a FAL and frequented their forum and was amazed at the Tale of Ol' Dirty - a lengthy thread by a FAL owner who purposely ran thousands of rounds with not only with no cleaning (aside from assuring a safe bore), but sometimes submerging the rifle in whatever form of mud happened to be handy. And it just ran and ran and ran.

As for accuracy, I haven't pushed out beyond 100 yards yet (range limitation where I shoot) but at that distance my Precision Arms rifle with an Adams piston can cloverleaf fairly regularly. The biggest wildcard in accuracy is definitely me.

The primary advantage I see in DI is weight and cost. And that has some merit and appeal to me, I may yet pick up a DI Grendel. I might even like it better (except for the cleaning part).

But when I hear people say "DI works, why change it?" I sometimes feel it should be said "Gas pistons are clean, rugged, reliable and still accurate, why change it?"

If I bought the argument that I should go DI just because Stoner did, I would still be using a telephone with a cord.

[Mike Wood]

I went with the piston for much the same reasons - easy to clean and reliable if it has to run dirty (SHTF scenario). I used to own a FAL and frequented their forum and was amazed at the Tale of Ol' Dirty - a lengthy thread by a FAL owner who purposely ran thousands of rounds with not only with no cleaning (aside from assuring a safe bore), but sometimes submerging the rifle in whatever form of mud happened to be handy. And it just ran and ran and ran.

As for accuracy, I haven't pushed out beyond 100 yards yet (range limitation where I shoot) but at that distance my Precision Arms rifle with an Adams piston can cloverleaf fairly regularly. The biggest wildcard in accuracy is definitely me.

The primary advantage I see in DI is weight and cost. And that has some merit and appeal to me, I may yet pick up a DI Grendel. I might even like it better (except for the cleaning part).

But when I hear people say "DI works, why change it?" I sometimes feel it should be said "Gas pistons are clean, rugged, reliable and still accurate, why change it?"

If I bought the argument that I should go DI just because Stoner did, I would still be using a telephone with a cord.

Links to piston vs. DI accuracy test? Thanks

[LRRPF52]

The main reasons for going to op-rod driven ARs in a select few units in the military was for SBR suppressed use, a lot of full auto, and the ability to adapt to different ammunition types in 5.56 NATO.

I'm unaware of similar testing and conclusions for 6.5 Grendel. You really need to engineer the system around the operating mechanism if you're going to go that route, which is what HK did with the HK416, which now has an adjustable gas regulator with the HK416A5 version.

[ahillock]

Everything I have read or seen has DI AR15s as being more accurate than piston AR15s. Not to mention cheaper and lighter.

[LRRPF52]

Free-floating and using quality barrels are a bigger factor than the operating system.

A lot of the slap-on op-rod kits aren't well engineered, so accuracy issues may be a result of other problems with the designs.

I personally haven't had reliability issues with real M4s, M4A1s, M16A1s, M16A2s, or the AR15s I have built over the years.

[Klem]

Everything I have read or seen has DI AR15s as being more accurate than piston AR15s. Not to mention cheaper and lighter.

Have not seen any more or less accuracy with either system but I agree with your point that pistons are heavier, more expensive and not needed. Like the Blackout and moly coated bullets - After the initial hype dies down the passage of time renders their true worth.

[ahillock]

Have not seen any more or less accuracy with either system but I agree with your point that pistons are heavier, more expensive and not needed. Like the Blackout and moly coated bullets - After the initial hype dies down the passage of time renders their true worth.

Looking at guys in long range shooting competitions, those using an AR use DI from what I have seen. Never seen any run a piston setup.

[85_Ranger4x4]

Piston isn't worth the weight or expense to me. I do like the idea of everything being in line with each other though.

Only piston gun I have fired was dad's M1 Carbine, it was fun but not really comparable to my AR's for use though.

[Mike Wood]

Looking at guys in long range shooting competitions, those using an AR use DI from what I have seen. Never seen any run a piston setup.

You have been looking very far and wide...and you are correct

[Slappy]

Piston if you are going to fire suppressed. They are just easier with a flip of the switch and run cleaner. Other than that DI. BANG BANG!!

[ahillock]

You have been looking very far and wide...and you are correct

I should have left room for the potential that some long range shooters use piston. Just haven't seen it myself. Doesn't mean they aren't out there.

[sneaky one]

I have an Adams Arms piston upper- used to be sold as a Huldra upper through Mills Fleet Farm store. 5.56 It is very accurate, reliable.

Less cleaning is the idea. Not sure if I'll suppress this one. More interest in suppressed hunting tube in Grrr tube.

In fact, I may swap parts out - between the 2 uppers to create my first piston Grrr.,, 16" tubes - both- mid length system. Hmmmm.......