I built a pump action AR pistol that had a buffer tube. Now, it is a bolt action with a notch in a cut down buffer tube just like a regular bolt action rifle. I would like to be able to just 'close ' the bolt carrier without putting it in the notch. There would be no forward pressure on the bolt carrier. I see no reason that the bolt would rotate and fly back. It didn't move with just the buffer spring tension. There is no gas block or tube.

Seriously, I've no idea what you're on about.

inb4 "idk how to post pics," take them with a phone, host them on imgur, get the direct link, click the picture icon when making a post/comment, drop the link there, viola.

Sorry to hear that. I cut off the buffer tube about 1.5 inches behind the treads. Ergo, an open hole. Prevents the bolt carrier from coming all the way out as in normal operation. No buffer spring obviously. Next I push the bolt carrier all the way into the rotated locked position, just like normal operation. Again. there is no buffer spring. There is nothing behind the bolt carrier. Then I load a round by pulling the bolt carrier straight back, then pushing it forward into a locked position and pull the trigger. Only thing behind the bolt carrier is a sort of handle I fabricated. What would you expect to happen? Sorry can't make it any clearer than that. Imagine taking a hacksaw to a buffer tube and pushing the bolt carrier forward. Anyway, I tried it, in my sandbox test fixture,  with a 300BLK light round of TB and it just shot normally. Pulled the bolt back and loaded another round. Same thing. What I expected. This is not your normal operation. One has to think out of the box.

So you covered the gas port? Did you turn the gas block upside down?

"There is no gas block or tube." from my post above. There is an upper and a lower. The upper has a muzzle break, a barrel with no port, a barrel nut, a receiver, a charge bar, a bolt carrier, a buffer nut, a piece of buffer about 2" long and a part attached to the bolt carrier to move the bolt carrier back and forward. Nothing else.

Well it sounds completely stupid to me but as long as you like it. So is there a question in your post or is it just a tale of your adventure?

With no gas to the BCG the bolt will not rotate and unlock during firing. However having no spring keeping tension on the BCG any shaking or tilting the rifle may cause it to travel rearward and unlock. Based off what you described you shouldn't have an issue  using it in a straight pull configuration.

Please post pics if you can.

Over time I would be concerned about the bolt lugs sheering and launching the bolt into your face??
The AR system relies on the bolt lugs, and the buffer/spring pressure to moderate the rearward thrust.

My $00.00002

That's the hard way. Get in imgur, get BB code, paste in post.

I want to see pics of this. Out of curiosity if nothing else.

Cool story.

1) ...Why?

2) Please post pictures

With no gas there is no rearward thrust.

No, The bolt lugs take 100% of the rearward chamber pressure or 50% of the total chamber pressure..  Somewhere between 25K-30K PSI.  The gas impingement system bleeds off a small percentage of the pressure to upset or un-lock the bolt, allowing the chamber pressure to push the BCG rearward.

5.56×45mm NATO
Rifling twist178 mm or 229 mm (1 in 7 in)
Primer typeSmall rifle
Maximum pressure (EPVAT)430.00 MPa (62,366 psi)    <<<<<<<<<<<<<<<<<<<<<<<
Maximum pressure (SCATP 5.56)380.00 MPa (55,114 psi)  <<<<<<<<<<<<<<<<<<<<<<<

Here is a gif of the AR/M4 action, watch the little white arrows as the gas enters the carrier behind the bolt. As the carrier moves rearward, it drives the bolt key(watch it turn) that intern turns the bolt, thus allowing the chamber pressure to push the bolt.

https://g.redditmedia.com/f0VudUP8yNCtND_u4QiNCZACSzxnOhxSxc5CEg6-FCw.gif?fit=crop&crop=faces%2Centropy&arh=2&w=960&fm=mp4&mp4-fragmented=false&s=3fb04680101277674d8c293ba6a67fa1

Doesn't matter, with the bolt locked the pressure is not going to effect it as the expanded case in the chamber is holding a significant amount of the pressure away from the bolt face to begin with. In normal operation the pressure on both sides of the bolt should be roughly equal before unlocking the bolt. The expanding gas also pushes the bolt slightly forward to help unlock it before the cam pin (not the "bolt key") rotates the bolt and the carrier pulls it back with it's rearward momentum. A piston upper is much rougher on a bolt because there is no forward movement of the bolt prior to rotation so the lugs are simply ground against extension as the cam pin rotates the bolt. At least with this bolt gun design the pressure is gone before the bolt is unlocked and rotated.

Here you go.

https://www.tactical-life.com/firearms/handguns/first-look-remington-model-700cp-pistol/

that's a remington 700 action without a buttstock. it really doesn't have any bearing on the current discussion

yes, please post photographs

i'd like to see how the bolt is moved from the rear unlocked position to the forward locked position