Crossed Gas Tube Experiment

[msgriff]

Does anyone remember an experiment done a number of years ago, where someone (I believe an FFL07) bolted/clamped two identical AR-15s together, then crossed the gas tubes? The handguards were removed and two custom made gas tubes were used so that rifle "L" would cycle the BCG in rifle "R" when "L" was fired, and vice versa. This was done to see if bore pressure was required to cycle the BCG after the bolt unlocked, similar to a blow-back PCC, or if the gas delivered solely through the gas tube was sufficient.

 

[Ernest 5.56]

If there were excessive pressure in the bore would it not just expand the fired case against the chamber walls and add resistance to the bolt

 

[Trigger Monkey]

Tromix Siamese .223

Tromix Siamese M16: Twin Barrels, Full Auto

Looking for a good time? Tromix Lead Delivery Systems can usually deliver. The company is often experimenting with gun projects that just plain look fun.

www.gunsholstersandgear.com

They also did a Trimese

 

[msgriff]

Tromix Siamese .223

View attachment 8205818

Tromix Siamese M16: Twin Barrels, Full Auto

Looking for a good time? Tromix Lead Delivery Systems can usually deliver. The company is often experimenting with gun projects that just plain look fun.

www.gunsholstersandgear.com

They also did a Trimese
View attachment 8205822

That was it. Thanks!

 

[hlee]

So, the conclusion- as the Siamese m-16 functions(ed)- is that the gas tube imparts sufficient momentum to the system to cycle the weapon in the absence of residual bore pressure.

 

[bfoosh006]

If you are "plotting" something interesting... we want to know. Lol

 

[msgriff]

So, the conclusion- as the Siamese m-16 functions(ed)- is that the gas tube imparts sufficient momentum to the system to cycle the weapon in the absence of residual bore pressure.

It would short stroke until the gas ports were opened up, so residual bore pressure does play a role, but not an insurmountable one for that particular set-up.

ETA: the function aspect turned out to be an obstacle to overcome, the original intent of the build was influenced more by beer.

 

[hlee]

the function aspect turned out to be an obstacle to overcome, the original intent of the build was influenced more by beer.

I’m pretty sure this is a prominent line in the abstract of every patent application ever filed…

 

[SporterII]

Longer tubes farther mask the answer. Tube volume/ dwell, etc.