Because the "true" history of the trigger is unknown it is time to get it fixed. The 721 rifles I have been around are good shooters. In times past somebody may have tried to adjust the trigger and made it unsafe. Nobody knows, your friend should take this oppertunity to make it safe. The price is right.
Print out the following information for him.
http://www.remington.com/safety/safety_center/safety_modification_program/models_721_&_722.aspSafety Modification Program
Remington Model 721 & 722
If you own a Remington Model 721 or 722 rifle:
All Remington Model 721 and 722 rifles were manufactured with a bolt-lock mechanism. These models were discontinued in 1961. If you participate in the Safety Modification Program, your firearm will be cleaned and inspected for proper functioning, by a qualified gunsmith. Once the condition of your firearm has been assessed, you will be notified of one of the following:
Your rifles trigger assembly is otherwise in good operating condition and the gunsmith will proceed to physically remove the bolt-lock feature so that your rifle can be loaded and unloaded while the safety remains in the S or On Safe position; or
Your rifles trigger assembly is found to be in an unsatisfactory or potentially unsafe operating condition because of any number of factors, including wear, alteration or maintenance. The entire trigger assembly will be replaced with a new factory trigger assembly, which does not incorporate a bolt-lock mechanism.
In either case, the total cost to you is $20, shipping and handling. You will also receive a safety redemption certificate to complete and submit in order to receive a free blaze orange hat (one hat per certificate).
How to participate in the Safety Modification Program
Complete the General Repair Form and
Send or deliver your firearm and the completed repair form to either:
a) A Remington Authorized Repair Center; or
b) Ship your firearm to the Remington factory at:
Remington Arms Company, Inc.
Ilion Firearms Plant
Attention: BL Safety Program
14 Hoefler Avenue
Ilion, NY 13357
Remington will bill or arrange for payment once your firearm is received and evaluated.
CAUTION: It is your responsibility to comply with all laws and regulations