1977 Pattern/Trial Great Britain 10 Pence

7Jaguars

Just got this which NGC called an “error”. I doubt that as the planchet it was struck on was very large but not quite crown sized. NGC did not weigh it. One picture group is with a normal 1977 10 Pence:

ELuis

I have seen that, but on a earlier year and on the proper 10 Pence coin size:

7Jaguars

I am thinking about cracking it out and weighing it and also getting a metal content on it.
Luis, that flans is dreadful on yours with all due respect & looks like post minting damage also.

ELuis

@7Jaguars said:
Luis, that flans is dreadful on yours with all due respect & looks like post minting damage also.

It is not my coin, I just have that image saved from many of my searches on the net and noticed that it was similar to your coin, that is why i posted.

Sapyx

It's not a "pattern" - 1977 was in the middle of the period where this coin design was used, so there's nothing new here that needs testing or demonstrating. It's would also be odd for a "pattern" to clearly be on a "wrong planchet".

What I'm pretty sure we have here is a "die trial" - before the presses start up to make a batch of coins (perhaps after down-time for maintenance, or after repairs from some incident) , a low-pressure test might be run to make sure everything lines up and works properly. Being low pressure, they'd need a piece of soft metal handy to test it with, rather than a regular coin blank.

I think a composition test would be warranted, as I'm pretty sure if the die trial theory is correct, then this should be made of lead or a soft lead alloy.

It was 1977, and the Mint was probably making all kinds of trinkets for the Silver Jubilee, so probably had bits of lead lying around for testing with.

If it comes back as cupronickel, then what we've got here is a "wrong planchet", but where they've clearly put the 10p dies in place for the press intended to make 25p Jubilee crowns.

7Jaguars

I used a euphemism and do not disagree with your assessment. I do not believe the coin has the size or weight of a crown planchet however.