The ATF in its infinite wisdom has decreed that a military rifle loses all collector interest once modified from its original form. Apparently the ATF cannot imagine collectors interested in sporters. Anyone know if this ruling is infinite with regards to date? Seems to me that a military rifle that was modified over 50 years ago should logically be considered C&R qualified since it has existed in its current form for the required 50 years. But of course logic has nothing to do with the ATF. Anyone know if the ATF has ruled on this question? Thanks.

While I know of no ruling, an awful lot of 50 year old sporting rifles (M70s, 721s, 722s, M61s, M63s etc) as well as sporterized 03s (that exact DOM data is available for) have been bought and sold by C&R holders.
Never heard of any arrests and the C&R rules have been so liberalized (no record inspection, no turn in records when you give up license) that risk is almost zero.
If a customer went to Griffin and Howe in the 1930s with a nickle steel 03 action they had bought from DCM that had never been on any rifle, and G&H built it into a sporter, how does one determine "original configuration" ?
What about the G.I. who brought back a brand new Mauser action he liberated from the Mauser factory ?
Many guns are "C&R" that are far less than 50 years old, all you have to do is apply for an exemption.

For example:

"Section IV — National Firearms Act Weapons Classified as Curios or Relics Under 18 U.S.C. Chapter 44
Auto Ordnance Corporation, Model 1928 Thompson sub-machineguns, all calibers (including .45 and .22), manufactured in the 1970s and 1980s in West Hurley, New York"

Any modified military rifle, even with just a shortened stock, is no longer C&R eligible. I have a letter from ATF somewhere on it. I was also asking about replacement stocks on commercial sporters and even they aren't C&R unless the stock is a period replacement. No plastic stocks for sure.

Nope that's not 100% correct.

See: http://www.atf.gov/publication...os-relics/index.html

and download the 6MB "book" plus all updates. You will be amazed.

In the body of the ATF explanation note the criteria:

"To be recognized as C&R items, 478.11 specifies that firearms must fall within one of the following categories:

Firearms which were manufactured at least 50 years prior to the current date, but not including replicas of such firearms;

Firearms which are certified by the curator of a municipal, State, or Federal museum which exhibits firearms to be curios or relics of museum interest;
and

Any other firearms which derive a substantial part of their monetary value from the fact that they are novel, rare, bizarre, or because of their association with some historical figure, period, or event."

Note ONE of three NOT all three.

Since Federal law bases the identification of a "firearm" on the action markings, not the stock, scope, sights, recoil pad etc., your 1944 M-1 that has a replaced replica stock made in 2008 is still a C&R rifle.

C&R (collectable) firearms are the entire firearm (not the frame only).

The ATF Technologys Branch made a ruling sometime back on the question of altering a C&R firearm and wether it removes it from C&R Status.
The ruling still leaves a lot open for intrepretation as to the degree one can change the gun from it's original manufactured form and still remain a C&R.
But there is some room to do so.

From the BATF Website re: C&R,,FAQ

Q: What modifications can be made on C&R firearms without changing their C&R classification?

The definition for curio or relic (“C & R”) firearms found in 27 CFR § 478.11 does not specifically state that a firearm must be in its original condition to be classified as a C&R firearm. However, ATF Ruling 85-10, which discusses the importation of military C&R firearms, notes that they must be in original configuration and adds that a receiver is not a C&R item. Combining this ruling and the definition of C&R firearms, the Firearms Technology Branch (FTB) has concluded that a firearm must be in its original condition to be considered a C&R weapon.

It is also the opinion of FTB, however, that a minor change such as the addition of scope mounts, non-original sights, or sling swivels would not remove a firearm from its original condition. Moreover, we have determined that replacing particular firearms parts with new parts that are made to the original design would also be acceptable-for example, replacing a cracked M1 Grand stock with a new wooden stock of the same design, but replacing the original firearm stock with a plastic stock would change its classification as a C&R item.