This type of problem only comes in older version of SAP(till SAP4.6) not in current one.
Basic steps to update J_1IRGSUM table:
1)Go to Table J_1IRGSUM ,enter your material xxxx and execute it. This table will give you the details of Cumulative receipts and Cumulative issue for the material against the excise group.
2)Again go to table J_1IPART1 and enter you material xxxx for which you want to make update.Here you will find the details of material ,material document ,excise group with goods movement type(receipt(R) and issue(I)).
3)Compare the goods receipt and goods issue for material xxxx from both the table(J_1IRGSUM & J_1IPART1).
If there is any mismatch for the data(receipt and issue) then you need to update it to SAP.This is a common issue for older version of SAP(till SAP 4.6)with J_1IRGSUM table.
The steps you need to follow is that first you need to take approval from Business to make the changes in J_1IRGSUM table.
After taking the approval from business you need to raise SAP OSS message for the same and open the connection for the respective system(Production system).
The OSS connection will be open for a limited time period. Once the connection will be open ,you need to give the basic data like material ,Excise group, register name(RG23A) ,cumulative receipts and cumulative issue to SAP.
SAP need the login credential(User name and password) to make the changes in the system. Once the SAP will get it they will update the register (RG23A)
for the material xxxx.
You can see the updated material quantities in J_1IRGSUM table and now you can able to post the RG23A part1 register with J1I5.
Regards,
Shashi