The BHO is a useless PITA since the bolt will go forward once you take the mag out. Also AKs don't have bolt releases like ARs so you are going to have to crank it back anyways.
I'd have to disagree with you on that. It lets you know when you're empty so that you can start reloading rather than being under the delusion that you still have at least one rd left, aiming and then trying to fire.
If you're interested in an experiment to see if your conclusion has any merit try this :
Pull out your shot timer or if you don't have one beg, borrow or steal a shot timer from somewhere or download a shot timer app onto your phone.
Have a shooting buddy load up a regular AK Mag (without a BHO) where the number of rds put into the mag is unknown to you and then have him load up one rd into another mag for the purpose of forcing a reload.
Have him load the mag into the rifle and chamber a rd and put the safety on so that you won't be able to tell by the approximate weight of the mag how many rds are in there. Then when you're ready have your buddy say 'Go!!' and start the shot timer, you then take the safety off and fire the unknown number of rds into a target at 25 to 50 yards while getting good hits (they need to be A zone hits for it to be a clean run). When the mag runs dry do a reload and fire one more accurate rd at the same target stopping the clock.
The extra mag can be any place, back left jeans pocket, mag pouch, table or truck bed. Doesn't matter just so long as they're both in the same place. The range is also close to take accuracy out of the equation a little, but the A zone accuracy requirement is put in to keep the shooter from just zipping through the rds without hitting anything to just get to the reload and get a good time.
Then do the same thing with the BHO mag using the same number of rds that you used in the regular AK mag and one rd for the reload mag.
Would be nice if the 2nd mag was a Croat or Yugoslav BHO mag as well, but it doesn't really matter since you won't be pulling the 2nd mag on the timer.
You can also try doing it a second, third or fourth time switching out the mags and having the Yugoslav/Croat mags go first and perhaps having a different number of rds.
Which time do you think is faster?
For me it's always been the BHO mag simply because it let me know when the mag was empty rather than having me go through the unneeded process of aiming the rifle and squeezing the trigger when I didn't even have a rd in there.
AK's aren't exactly dainty, gotta reload with vigor. Using the Russian method of butting the catch and empty mag with the front new mag to be reloaded and letting the bolt slam forward or hitting the catch with your thumb and rocking the mag forward slightly and pulling it out and letting the bolt slam forward, putting the mag in your dump pouch, grabbing a fresh mag, inserting it and then cycling the bolt doesn't cost you any time at all and requires no additional effort just so long as you're reloading the AK with a moderate amount of force.
Try it out on a timer. You'll see what I mean. Everything changes with a timer. Some shooters may dislike the bolt slamming forward when the BHO mag is yanked out. Q : Are these huge gains in time? A : No, they aren't. Admittedly they're measured in seconds and points of seconds.
However it does alert you that your rifle is empty and regular AK mags don't do that and in some cases those extra seconds and fractions of seconds could matter.
Why the Russians didn't include that feature on the AK when they did with the SKS is beyond me.
At any rate we had a fun time trying both the Croat and Yugoslav BHO mags out yet again and trying our hand at twin and quad loading a semi shotgun (Stoeger M3K) at the range on the clock. Something that neither my friend or I are much good at compared to some competition shooters, but we're improving and a day at the range trying this stuff out beats a day at work any day.