If the LOC IV was built with the nosecone option, not the center-break option, then the volume to pressurize is more than doubled. And the mass of just the nosecone is less than the constructed payload section, so there’s less momentum to pull the chute from the compartment. Plus the compartment is just much longer, leaving more room for things to get hung up. That’s why the LOC IV and similar rockets like the G-Force are better if built center-break style. But with an inherited rocket, you get what you get.
You probably do need more powder, to give the nosecone more momentum to yank the chute out. You can just pull the red cap out of the charge well and dump the supplemental powder in on top of what’s there, then push the cap back in. If the powder takes up too much room to get the cap back in, stuff a bit of dog barf in on top to keep the powder packed, then seal it up with masking tape. Or if you need a really big charge that’s bigger than the charge well, you can wrap masking tape around the end of the charge well to build up a cup, pour the powder in the cup/well, then pinch it closed, and seal the whole thing up with tape. However you choose to do it, try to make sure the powder is compressed or packed a little bit, not loose with a lot of space.
A couple other things to check or try — review your recovery loading technique like
@Antares JS mentioned to be sure nothing is getting hung up and everything is set to be pulled out in the proper order. You don’t need a very long leader from the nosecone to the chute bundle, maybe 3 or 4 feet. The only thing sitting on top of the chute bundle should be that leader, and the rest of the shock cord needs to be loaded into the tube first, with the chute bundle on top of it. The nose cone pops and pulls the leader, leader pulls the chute bundle out, chute pulls the rest of the shock cord out. Last in, first out, nothing out of order.
You could add some weight to the nosecone to help it pull the laundry out, but if you add very much, you might have trouble using an F67 due to weight.
You might be able to add a chute shelf to keep the recovery gear forward and shorten the distance it needs to travel to get out of the tube. This wouldn’t make the volume any smaller, so you might still need more BP, but it would help to prevent the chute from hanging up inside. There are probably lots of ways to do it. One way would be if you were given the bulk plate for the unbuilt payload section, you could drill some holes in that to make a baffle, add the eyebolt for the recovery system anchor, and glue it into the tube at some point forward of the existing forward centering ring. You’d have to look inside the tube at where the coupler is to see how much room is available and be sure to leave enough room in the chute bay for everything to fit with the nosecone installed.
Good luck!