If it is a 1943, then the Springfield would be a WWII rifle. The H&R's were made post-WWII. Quality should be the same (I know that there are people who will say one or the other is better), and all parts should be interchangeable, regardless of manufacturer, in fact many WWII M1 Garands nowdays will have Winchester and Springfield (the only two WWII manufacturers of M1 Garands) as well as post WWII parts of many different revision levels.
Of course, when the Korean War broke out, contracts were let to H&R, and International Harvester to supplement the Springfield Armory production of M1 Garands (Winchester was no longer in the picture except for some parts and barrels). The parts from all of these manufacturers will interchange. All of the M1 Garands from the original manufacturers (Springfield Armory Gov't, Winchester, H&R, and International Harvester) were made in .30-06. Springfield did some work on converting some M1 Garands to 7.62 x 51mm, and they were issued to the US Navy, though most of those were reconverted to .30-06 when the US Navy received M-14's.
You would be able to purchase a Springfield M1 Garand from the CMP for about $550.00, if you don't have to have it, TODAY.
Do not confuse the Government Springfield Armory of Revolutionary War through early Viet Nam fame, with the Commercial Company called Springfield Armory that exists today in Geneseo, IL. The Commercial Company purchased the name after the Government Springfield Armory was shut down (it was shut down by MacNamara in about 1968), the name was purchased in the late 1970's, and has changed ownership at least one time when it was in Texas, before moving to Geneseo, IL.
Springfield Armory Commercial built some M1 Garands in .30-06, 7.62 x 51mm, and some in .308 (it is marked on the barrels). The receivers of these are Investment Castings not Forgings as used in the USGI M1 Garands. The Springfield Armory Commercial parts do not always work well, and their early M1 Garands used USGI parts, but those are getting harder to find and the prices are getting too high for Springfield Armory Commercial to install them in their products.
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