Fit issues with recoil plates question

[bayoned]

As a rule, do recoil plates require fitting to receivers?
I've had several carbines that would fit some recoil plates, and not others.
All are are USGI receivers, and the recoil plates are USGI as well. Some forged/machined and ID'd by manufacturer, some cast.

What's with this?

[309Carbine]

The cast ones are not USGI. USGI plates can be adjusted to achieve a desired barrel hang, but usually don’t need it. Like all other genuine USGI parts, they are suppose to be compatible with all USGI receivers. A perfectionist might adjust one (there is a procedure for that) to achieve a better fitment and possibly improve accuracy.

The only time I have had one just not hook up at all was a combination of a Universal stock and USGI plate. It would only assembly with a cast commercial plate.

[6 Ring]

First: Do we understand how they are supposed to fit?
Second: Can we tell which recoil plates are too tight, or too loose, or just right?
Third: Chunk the cast ones for now.
To answer the first question, They are not supposed to fit when you drop in the B/R.
The recoil plate should hold the barrel off the stock nose one half to one inch.
This means when the receiver is set into the recoil plate it will be held tight. A bump of the palm or a bump on the floor will seat the receiver into the recoil plate.
If the B/R flops into the stock and recoil plate, the recoil plate is too loose. You should not be able to move the B/R in the recoil plate.