Efficiency mod?

[hill160881]

So i was tinkering around with putting an oring somewhere on the powertube to reduce bolt wear and maybe seal up a bit better when the bolt is forward. I did this by clamping the brass piece in a drill and held a fine tooth reciprocating saw blade to it as it turned.

Normally i get around 1600 to 1700 rounds on a 88 ci 4500psi fill. After installing the moded brass power tube thingy i got 1500 on a 3500 psi fill with the same tank? It also had a big difference in sound. A side by side comparison left no doubt that it was quieter. I only need to do a chrono test to confirm my results.

Any thoughts? Has this been tried before? Could the rate of fire affect the efficiency, meaning will shooting in full auto at 20+ bps cause it to get better efficiency.?

[BigEvil]

Nice.

[hill160881]

This is after 5000 rounds. Notice how flat the o-ring is. I think a urethane o-ring would hold up better though.

[Smoothice]

Interesting. Very interesting. Thats pretty cool.

[Sniper Steve]

I am impressed, I want to try this myself.

[M98Punk]

How many balls have you put through this?!?!?

This sounds like a worthy mod to do with my micropistol..... ya know after I finally get the spring feed fixed :-P

[Old School 626]

Thinking about this section of the marker and how things work I think you'd be better off sealing the valve to the body where there less a probability of tolerance issues.

What you are doing is sealing off any wasted gas escaping back down the sides of the power tube. You could do the same thing with an over sized OD on the bumper such that the bumper seals against the side of the body. It'd likely be marginally less efficient if you believe that volume reduces efficiency but probably more reliable in the long run.

Good on ya for trying something new!

[RogueFactor]

Any thoughts? Has this been tried before?

It has, but not publicized. This was something I tinkered with back around late ~2006. I did it on both a L10 and L7 tip, here is a pic:

[Spider-TW]

Thinking about this section of the marker and how things work I think you'd be better off sealing the valve to the body where there less a probability of tolerance issues.

What you are doing is sealing off any wasted gas escaping back down the sides of the power tube. You could do the same thing with an over sized OD on the bumper such that the bumper seals against the side of the body. It'd likely be marginally less efficient if you believe that volume reduces efficiency but probably more reliable in the long run.

Good on ya for trying something new!

You would still loose the air through the sear slot.

Bolt leaks are indeed annoying.

[hill160881]

Thanks everyone and good ideas. I will try a chrono test this next weekend.

I warn anyone trying this mod to GO SLOW or go to far.

[Spider-TW]

It has, but not publicized. This was something I tinkered with back around late ~2006. I did it on both a L10 and L7 tip, here is a pic:

Any opinion?

[hill160881]

It has, but not publicized. This was something I tinkered with back around late ~2006. I did it on both a L10 and L7 tip,

I totally guessed on the location of the oring. Did you get any test data?

This valve can be viewed ripping with this mod at 25 bps. Its the valve in the minigun mag.

[RogueFactor]

I totally guessed on the location of the oring. Did you get any test data?

I did, which is why the idea was shelved. The benefits were negligible. It did however lead me in new directions with my testing and prototyping, which was really the benefit of it all.

Any opinion?

Its an interesting modification for the tinkering type, but by itself it was not something I found worth pursuing.

[hill160881]

So could the sustained high rate of fire be what is giving me better efficiency?

And what about putting the oring inside the bolt like a sail oring? Then it would maintain contact with the power tube the entire time.

[pinkanese]

Did you ever try putting a seal at the front of the breech or perhaps adding a ring to the bolt? Seems like doing this mod and sealing the front end of the bolt could have a larger impact.