Can't Hear Childs Blood pressure

I am a pediatric home health nurse. I have an order for weekly blood pressure of a 7 year old. It is very hard to hear the blood pressure and most weeks I do not feel confident with my readings. I don't have an electronic cuff and don't think we are allowed to use them any way. The child is very cooperative so that is not an issue. Does anyone have any suggestions for hearing better? Do pediatric stethoscopes help with blood pressures? I do use the correct size cuff.
Are you using a pediatric sized cuff?

As a former pedi nurse I found a cardiac stethescope very helpful.

Our nurses get the BP on my son every 4 hours and I would say that half of them have a really hard time with it. He is very tiny for 4 with pudgy little arms and weaker than you would expect pulses. I can only get his BP about 80% of the time on the first try. I use either my pediatric stethoscope or the small side of my cardiology one and I generally need a good deal of pressure to get enough contact to hear it. I usually can't hear it at all if he has stiffened up but it sounds like your little guy is pretty relaxed for this. I also have the gauge unattached from the cuff and just laying on the bed.