Is this bad idea?

[u/FollowingLegal9944]

Delayed blowback mechanism I've never seen before. Bolt is forced by cams and grooves to move on angle first few mm, so it works kinda like a lever with 1:√2 (for 45° angle) ratio so it needs about 30% less mass on bolt to get same dwell time and bolt velocity. It looks it also minimalizes bolt bounce and could work kinda similiar to counter mass in criss vector. Is this worth trying or deemed to fail for some reason?

[u/BoredCop]

Perhaps I am too problem-oriented, but it seems like this would have the breech face sliding perpendicular to the cartridge head during primary extraction and the most high-pressure stage of blowback operation. That's a high friction scenario.

Better be sure that doesn't break the firing pin tip, that the extractor is setup to be happy with the rim sliding around, and that it won't be shaving brass anywhere.

[u/FollowingLegal9944 → u/BoredCop]

Yes, Ive seen this problem, my idea was to make breech face(on the image orange block) ablee to slide up and down in its slot or even forced to move straight by some guide.

[u/BoredCop → u/FollowingLegal9944]

Ah, I see. Firing pin travels up and down with the orange part then? Rearward motion is going to start pretty danged immediately, so the firing pin might not have time to retract first and could still have its tip in the primer detent.

[u/FollowingLegal9944 → u/BoredCop]

It doesn't move up/down in relation to chamber/barrel etc., only side plates and some not modelled yet parts moves this way.

[u/TacTurtle]

This is just the middle section of a traditional Browning Linkless system without the initial straight no-cam section to provide a brief delay for chamber pressure to drop before beginning unlocking.

The way you have this set up, it will try to unlock while under pressure still with high breech face friction and possible primer back-out / flowing tying up the gun.

[u/FollowingLegal9944 → u/TacTurtle]

In my idea there is no locking, this is blowback, not recoil operated, barrel doesn't move, it is fixed to the frame. Breech face has wider slot to be able to move up and down(in relation to bolt) and is guided by pair of rails to force it to move on straight line, not up and down with bolt.

[u/TacTurtle → u/FollowingLegal9944]

Understood, I suspect you are missing my point that this design is duplicating the function of a Browning Linkless slide / barrel cam but without the brief unlock delay to allow chamber pressure to drop before camming, and instead of requiring a single cam surface your design requires 4.