so you mus spawn the bullet a litter front the gun with vec_vor vertex.
so open you gun model in MED look witch vertex are at the front of the gun
example = put this in the action for the gun :
vec_for_vertex(temp,my,xx) xx is the vertex from the gun
temp.x +=5;
ent_create("bullet.mdl",temp,bullet);

and set the FLAG2 tag to the gun and the player

i know that, my bullet is created this way, but it doesn't help.

try this:
right on the first line of wall function:

if(is(you,FLAG2)==1){return;}

by the way your gun, and player, must have set(my,FLAG2); to work

function bullet()
{
.........

while(me)
{
c_move(me,vector(40,0,0),nullvector,USE_BOX|IGNORE_MODELS);
c_scan(me.x,me.pan,vector(360,0,200),SCAN_ENTS|IGNORE_FLAG2|IGNORE_ME);
if (result<5)
{
if(is(you,FLAG2)==1){return;}
ent_remove(me);
}
wait(1);
}
}

and also the player and the gun have Flag2 set, but the engine crashes. Can you correct it if you find mistake in the code pls

You probably have to assure that the 'you' isn't empty.

Other suggestions:
- you could start the scan a few moments later, when the bullet already left the gun.
- Did you try IGNORE_YOU? Although, it has to reset after leaving the gun.
- you could scan from a position ahead the bullet:
vec_for_angle(temp, my.pan);//Get a 'direction' from the angle
//Now, when the position is one quant ahead the bullet, scale the vector/direction to get the position a few quants more ahead, let's say 10:
vec_scale(temp, 10);

I tried all the suggestions:
I made check if(you!=NULL) to do the rest
I made the bullet start the scanning 10 frames after it's created
I put IGNORE_YOU
i made the bullet scan 10 quants ahead it
but maybe I miss something or do something wrong cuz the engine crashes again.
Can you post here the shortest and fastest code for moving entity which destroys itself when hit static entity. Thx

well the crash.. is wird.. give us the acklog, maybe thats better, to check the error.. and where is the actual crash, are sure its from those functions or are others?

Also.after the bullet is created you must put an wait(1); after..

I use this collision code:

function remove_bullets();

function bullet()
{
my.emask|=ENABLE_IMPACT;
my.emask|=ENABLE_ENTITY;
my.emask|=ENABLE_BLOCK;
my.event = remove_bullets;
while(1)
{
c_move(me,vector(40,0,0),nullvector,USE_BOX|IGNORE_MODELS);
wait(1);
}
}

function remove_bullets() // this function runs when the bullet collides with something
{
wait (1); // wait a frame to be sure (don't trigger engine warnings)
ent_remove (my); // and then remove the bullet
}

The collision detection definitely works, but can you just tell me how to make the bullet don't detect the gun and the player models in this case