Feb 1 (Reuters) - A GameStop-inspired frenzy of retail investment in silver has left physical dealers from the U.S. to Singapore scrambling for bars and coins, but the rush to buy was much more muted in the leading Asian consumers of physical bullion, China and India. Silver prices extended a blistering rally on Monday as small investors answered calls on social media last week to buy the metal to push up prices. “There are massive shortages. We’ll be completely out of stock if it carries on like this; the first time since our company opened in Singapore 7 years ago,” said David Mitchell, managing director at Indigo Precious Metals. Many customers even sold gold to buy silver, said Gregor Gregersen, founder of Silver Bullion Pte Ltd, another dealer in Singapore. “There’s a definite shortage of popular silver coins developing (especially North American coins),” he said. “However, we’re still able to source 1,000 oz good delivery bars at nearly the same premiums for now.” U.S. bullion broker Apmex warned of delays in processing silver transactions because of surging volumes. Other U.S. dealers, including JM Bullion and SD Bullion, warned customers of shipping delays of 5 to 10 days. Chinese investors too piled into the futures market and mining company stocks, but dealers said the rush was yet to actually translate into physical constraints. “In the short term, stocks may run out since it takes a long time for sea shipping, but overall supply is ample,” said Peter Fung, head of dealing at Hong Kong-based Wing Fung Precious Metals. Around 1 billion ounces of silver are produced and consumed each year, and supply has been in surplus for most of the last decade, consultants Metals Focus said. The other major physical buyer in Asia, India, seemed to have bucked the trend even more strongly. “In contrast to what’s happening in other parts of the world, silver is seen as more of a consumption, rather than investment, commodity in India,” the bullion division head of a Mumbai-based silver importing bank said. India and China typically account for a quarter to a third of global demand for retail silver investment products such as bars and coins, according to Metals Focus data. (Reporting by Arpan Varghese; Additional reporting by Asha Sistla and Bharath Govind Gautam in Bengaluru; Editing by Peter Hobson and Jan Harvey)