Model 700 rear receiver ring height change compared to 722?

[Rem725]

Somewhere I recall seeing that at some time Model 700 changed the height of the rear receiver ring. This would require different bases than what worked on the 721 and 722 rifles. I just can not remember where.



The story that reminded me is I just got a 1970ish 700 308 rifle. I have many 2 piece bases for 722. But I bought a new one piece rail Weaver type for 700 SA. With only the front screws in place and tightened, there is a .010" gap between the base and the rear receiver ring. The rail is not warped
Setting that new base on a 722 257 exhibits the same gap at the rear.

I have never had a 700 rifle before. Many many 721, 722, 725 only.

Am I remembering correctly? Anybody have info on this?

[Rem725]

I will answer my own question. I obtained a much newer 700 SA. That Weaver one piece rib fits and does not have the gap at the rear ring.

I was right in my recall of seeing somewhere that the rear receiver rings of Model 700 rifles did change. The newer 700 has a taller rear receiver ring. Meaning the metal bridge over the bolt opening is thicker at least .010 by my feeler gage.

Choose your scope bases accordingly

I wish I could remember where I saw this long ago.

[600RemGuy]

Height changed for the '74 model year. Previous year's 700s and the 720 series share the same receiver dimensions.

[Rem725]

Yes I just found the info in the Lacy book page 36-37.
1974 and newer 700s, the rear receiver ring is .100 lower than the front ring.
Pre 1974 (including 721, 722, 725) the rear receiver ring is .117 lower than the front ring. I knew I had seen it somewhere.

Now how do we identify bases for the older guns?