Why not more DI guns?

[TED]

I actually really like the DI system and appreciate its benefits.

So, why don't we see more guns using it?

In particular I would love to see a DI bullpup.

TED

[georgeib]

My best guess is that the buffer tube/receiver extension part of the system that DI seems to necessitate is not nearly as popular as the DI part of it. There are more compact ways to make the rifle cycle in other words.

[bruin]

Easy - any new DI gun will be immediately compared to the AR, which is proven, likely much cheaper, and enjoys the broadest aftermarket support in gun history.

Plus the popular view is that pistons are more sexy than DI. There isn't any money in a new DI design.

[halmbarte]

DI does eliminate the need for an op rod and moves the gas system back to the BCG. It’s not compatible with corrosive ammo (try to get the gas block and inside of the tube clean) for field use and does require a BCG that can be pressurized, eliminating using a fixed ejector, for example.

DI also wouldn’t work with weapons that need quick barrel changes as you’d have another point for gas to leak out of.

As far as a DI bullpup goes, the Tavor is about halfway there. Gas is ported back 3~4” from the barrel tap to the long stroke piston head. From there back it’s pretty much AK like, with improvements.

H

[amd5007]

Not sure of the history, but Stoner moved away from it. Aside from that I can only think of 2 or 3 other DI gas designs. I think the piston system is a generally more forgiving system and easier to work around. For example, discussion of gas port sizes are almost unheard of in discussions of piston operated systems. In a DI gun, gas port size is vital.

[vicious_cb]

DI does eliminate the need for an op rod and moves the gas system back to the BCG. It’s not compatible with corrosive ammo (try to get the gas block and inside of the tube clean) for field use and does require a BCG that can be pressurized, eliminating using a fixed ejector, for example.

DI also wouldn’t work with weapons that need quick barrel changes as you’d have another point for gas to leak out of.

As far as a DI bullpup goes, the Tavor is about halfway there. Gas is ported back 3~4” from the barrel tap to the long stroke piston head. From there back it’s pretty much AK like, with improvements.

H

DI is absolutely compatible with corrosive ammo. Many of here have shot out 5.45 uppers with corrosive ammo with no cleaning of the gas tube or FSB.

DI quick change barrel uppers exist and work just fine. Look up the Dolos AR-15, there just no need for it.

DI bullpups? Im sure theres a conversion kit out there somewhere but theres not really a growing market for bullpups.

[Aries144]

Why would DI prevent the use of a fixed ejector?

[SteyrAUG]

Not sure of the history, but Stoner moved away from it. Aside from that I can only think of 2 or 3 other DI gas designs. I think the piston system is a generally more forgiving system and easier to work around. For example, discussion of gas port sizes are almost unheard of in discussions of piston operated systems. In a DI gun, gas port size is vital.

Unless it's a US SIG rifle.

[Mr. Goodtimes]

Not sure of the history, but Stoner moved away from it. Aside from that I can only think of 2 or 3 other DI gas designs. I think the piston system is a generally more forgiving system and easier to work around. For example, discussion of gas port sizes are almost unheard of in discussions of piston operated systems. In a DI gun, gas port size is vital.

Gas port size discussions are also virtually unheard of in circles of people who actually just shoot their guns and don’t worry about asinine crap.


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[halmbarte]

Why would DI prevent the use of a fixed ejector?

All the fixed ejector guns I’m familiar with need to have a slot cut into the bolt body and bolt carrier, preventing them from being used as a Stoner type gas cylinder and piston.

Gas port size is critical for pretty much any gas operated gun. I think the reason you hear about it so much with ARs is because of the popularity of home built guns and the possible combinations of barrel length, gas port locations, and gas port sizes.

H