I asked Tim Sundles (of Buffalo Bore Ammunition) the same question when I purchased my 7600 carbine in .35 Remington.
Here's the Q&A cut and pasted from my email:
Your assumption that item 17A should be safe in the Rem (7600) pump is
correct. That ammo produces only 40,000CUP and is quite safe in the Rem.
7600.
Tim
----- Original Message -----
From: "xxxxxxx xxxx" <xxxxxx@comcast.net>
To: <info@buffalobore.com>
Sent: Wednesday, November 24, 2004 9:09 AM
Subject: QUESTION REGARDING THE "HEAVY .35 REMINGTON"
> My question regarding the "Heavy 35 Rem." ammo (item 17A) pertains to
> the rifles it can be used in safely. I understand that it is only
> recommended for the Marlin lever-action, T/C Contender, & bolt action
> rifles in that caliber. I want to know if it would be OK to shoot in a
> modern (manufactured in 2004) Remington 7600 pump rifle? This rifle is
> chambered in other calibers that are substantially more powerful than
> the .35 Rem., including the .308 Win. & .30-06 Springfield, which leads
> me to believe that your Heavy .35 could be used in this rifle as well.
>
> What's your opinion on this matter?
> Also, what chamber pressure does this round develop (PSI)?
>
> Thanks in advance,