Receiver characteristic question

Hello everyone, I am a new member but have visited this forum frequently for awhile now and I am impressed at the extensive expertise- it makes for interesting reading and research.

My question is what is the purpose of the two small holes (drilled stacked figure 8 style) on the safety side of the forward receiver just behind the chamber. In searching the internet I see the same holes on about every image of No 1 Mk III and 2A1s that come up but I have not found anything that addresses their pupose.

Thanks and I look forward to continued use of the forum.

Gas escape hole in case of a failed cartridge case is my understanding.

As above. Gas escape in case of ruptured cartridge/separated case

Why you don't hear about these holes today is the reason that ammunition has improved to the point that you seldom get a brass failure anymore (reloads excepted). The brass material used in today's cases is more consistent in formulation than previous military brass material and the loading of powder become more consistent. If headspace is really off, you might get a case rupture and material vented through the holes. In the old days, weapon design did not allow for case ruptures and often brass particles and flame blew back into the shooter's face.

Also we confine ammunition procurement to regular makers of the product, whether private or GOCO plants, even in the present war we don't need to rope other people in.

That gas escape hole dates back to the original Lee which was designed in the 1870s:

https://www.milsurps.com/images/impo.../Lees021-1.jpg

At the time, cartridge heads weren't solid, but folded to form the rims. Ruptures were quite common!

all for responding. Interesting and makes sense.

At least you didn't think bubba had been drilling random holes and filled them with weld.

On seeing them that was my first fear- or that it was some form of de-mil process, but after a little work with a pipe cleaner I noticed that the rifles surface finish extended to the inside of the holes. That sparked a move to the computer to look at images and eventually this post when it was apparent the holes are a deliberate design feature.

Like anything else, "brain work before leg work."

As a side note, is there anything significant to the different serial number prefixes? The 2A1 in question has an L prefix, I have also seen AA, E and others.