Why a 21 (& 28 gun) salute?

I was reading a report on the Queen Mum’s funeral procession: the procession, which started at 11.30 a.m. (1030 GMT) on Friday, was punctuated each minute by a salvo from a 28-gun royal salute.

I’m not sure where the 21 gun salute came from, and I’m certainly unclear on the 28 gun salute each minute. Any answers out there?

I wondered myself. It says here that some sort of numerology is at play. It implies that multiples of 7 are favored. But it also says odd numbers are preferred as a result of some naval superstition about even numbers being unlucky (which must be a pain, given how many even numbers there are).

And then, I found even more useless things I don’t want to know here and realized that this is one of those subjects in which I can probably remain in ignorant bliss.

Here’s a SD Staff Report on What’s the origin of the 21-gun salute?

Thanks Peepthis, that covers the 21 guns. Still wondering about the 28 per minute thing.

From the official Royal Family website, we get this info on Gun Salutes.

However, it makes no mention of 28-gun salutes. From the articles I’ve been reading, my understanding was that there were 28 41-gun salutes: one for every minute of a nearly half-hour long procession (how long was the procession?). I say this because they’re firing from Green Park (a royal park), which means they ought to be firing at least 41 guns.

The 21-gun salute is the basic salute. When fired from a royal park (as with the funeral procession or the Queen’s birthday), they add 20…making it a 41-gun salute. When fired from the Tower of London, they add even more (another 21, bringing the firepower up to 62 guns).