Isreal was given large numbers of surplus American weapons ranging from WWII vintage to M14's and M16's. Israel still maintans a large stockpile of these weapons and many are still in active service with paramilitary security and police forces, not to mention civilians.The IDF has a very large variation of weapons with very little standarziation, until recently anyways... Israeli's seems to be quite fond of the M1 Carbine. They are very popular for use as PDW's by police and civilians. So much so that IMI has made updated the platform and even made micro Galils chambered for 7.62x33 .30 carbine which uses 30 round magazines and is employed by both police and the IDF.
1919A4's in 7.62 Nato are still used by some secondary units. M21's are widely used for the DMR role and standard M14's are still in service. I recently saw two IDF soldiers patroling with
M14's with selectors intact. Older M16 variants like the 653 and Commando are still in service and widely used. Israel seems to really like the 11.5 inch barrel length and issues them widely, sometimes even with scopes, usually the 4x20 Realist carry handle unit. The Galil is still used, but primarily in the SAR form by mechanized and artillery units. The Galatz is also used for the DMR role, but is less common than the M21. The IDF also uses Ruger 10/22's with suppresors and scopes to "intervene" in riots. Special and Elite units are well equipped with new weapons but there is a wide variety of weapons in use by everyone else. Israel is in the process of upgrading and standardizing with the M4 and others, including the Negev. Its doubtful that they will ever adopt the Tavor, at least any time soon. The Tavor will likely be nothing more than a footnote.
The United States does not just give Israel brand new M4's. They pay just like everyone else.
We haven't "given' them weapons since the 70's.