Can anybody provide proof of a successful reenactment of Oswald's feat?

[John Iacoletti]

Ask for evidence, be given evidence, suggest evidence is fake.  The old CTer impossible standard of proof.  Oswald's own wife confirms that he practiced with his rifle.

Did Marina ever see him practice?  If not, then it is no "confirmation".

  You don't like that fact so it must be false.

Something isn't a "fact" just because you want to believe it.

  Just dismiss it and move on.  The WC concluded that Oswald had practiced with his rifle including dry practice as described by Marina to improve his proficiency with the rifle.

Marina didn't describe him "dry practicing".  She heard a noise that may or may not have been him working a rifle bolt.  That's all.

[Jerry Freeman]

  The WC concluded that Oswald had practiced with his rifle

They had to...they had already concluded that he was the lone assassin 

  Confirmation from his own wife who spent more time with Oswald than any other person is compelling.

In this country a wife cannot be compelled to testify against her spouse.
 Marina's civil rights were violated. Someday you may even be compelled to agree.

[Bill Chapman]

Oswald was probably working the bolt.

[Richard Smith]

They had to...they had already concluded that he was the lone assassin  In this country a wife cannot be compelled to testify against her spouse.
 Marina's civil rights were violated. Someday you may even be compelled to agree.

Good grief.  Marina's civil rights were violated when she voluntarily cooperated with the WC?  You are going round and round in circles.  At first you appeared to dispute that Oswald had practiced with his rifle.  Then when confronted with evidence from his own wife that he had practiced with his rifle, you cast doubt on her testimony and falsely suggested that the WC didn't believe it.  Now you are arguing that the WC had to believe it because they concluded that Oswald was the assassin (likely based on the overwhelming evidence of such) and that Marina was compelled to testify (a falsehood).  And this wasn't even a trial so it's unclear that any "privilege" would apply.   You have invoked multiple falsehoods and inconsistent narratives.  Typical CTer nonsense.

[Jack Nessan]

No they didn't and no it's not.

The Marin Corp thinks it is practicing.

[Jack Nessan]

     MARINA said she had never seen OSWALD practice with his rifle or any other firearm and he had never told her that he was going to practice.(Warren Commission Hearings, vol.22, p.763 [Commission Exhibit 1401])
     She cannot recall that he [Oswald] ever practised firing the rifle either in New Orleans or in Dallas. She does not think he did practice in New Orleans because as a rule he stayed home when he was not working. When he did go out, she did not see him take the rifle.  [Commission Exhibit 1403]
     The reporting agent interviewed Marina Oswald as to whether she knew of any place or of a rifle range where her husband could do some practicing with a rifle, and whether she ever saw her husband taking the rifle out of the house. She said that she never saw Lee going out or coming in to the house with a rifle and that he never mentioned to her doing any practice with a rifle. (Warren Commission Hearings, vol.23, p.393 [Commission Exhibit 1785]
     Marina Oswald was asked if she ever saw her husband doing any dry practice with the rifle either in their apartments or any place else, and she replied in the negative.  [Commission Exhibit 1789]

     Marina changed her tune when she testified...MARINA advised that OSWALD had told her after the WALKER incident that he had practiced with his rifle in a field near Dallas. She said further that in the beginning of January, 1963, at the Neely Street address, he on one occasion was cleaning his rifle and he said he had been practicing that day. She said [that] on an evening in March, 1963, … OSWALD left the house at about 6:00PM. OSWALD had his rifle wrapped up in a raincoat … When OSWALD returned about 9:00PM, he told her he had practiced with the rifle. She said [that] on an evening in March, 1963, … OSWALD left the house at about 6:00PM. OSWALD had his rifle wrapped up in a raincoat … When OSWALD returned about 9:00PM, he told her he had practiced with the rifle. Warren Commission Hearings, vol.22, p.197 [Commission Exhibit 1156] 
     Unfortunately, the rifle which Marina Oswald had apparently watched her husband clean early in January 1963 did not [reportedly] come into his possession until more than two months later, toward the end of March (Warren Report, p.119)
    The Warren Commission was aware that many of Marina Oswald’s statements were contradictory and unreliable, and that she was under pressure to tell the authorities what they wanted to hear. According to an internal Warren Commission document, which became public 15 years after it was written, “Marina Oswald has repeatedly lied to the [Secret] Service, the FBI, and this Commission on matters which are of vital concern to the people of this country and the world” (HSCA Report, appendix vol.11, p.126).

Interesting, 2 paragraphs of her not being aware of him practicing with the rifle and one paragraph of the unbelievability of her statements. If you can't believe a word she states and that is true, why are you quoting the summations of Marina's interviews about him practicing? She only states she is not aware or she did not go with him while he practiced. She is not saying he did not practice. The WC explained his training which included dry firing his rifle and Nichol explained how the marks on CE 543 were the result of multiple operations of firing the rifle. Dry firing the rifle is practicing. LHO stated he practiced by shooting leaves in the park.

 The forensic analysis presented to Rankin by Hoover discusses the mark on the side of the shells as a "chambering mark." JosiahThompson notes the chambering mark is on every shell he saw that had been fired in the Carcano had the chambering mark including C141 the unfired cartridge found by Capt Fritz.

[Jack Nessan]

It wouldn't... as the firing pin merely strikes air in a centerfired rifle [or pistol]
 If dryfiring is a form of active practice...why has the military then spent millions for range ammunition?

It is a little more complicated than that. There is a such a thing as snap caps. That is what LHO was doing when he used the CE 543 as a shell so that the firing pin would not break. A carcano firing pin is prone to breaking because it has a tapered shoulder that that strikes the bolt face if it is over extended during dryfiring.

The marksmen chosen to fire the Carcano for the WC chose not to practice dry firing the rifle for fear of breaking the Carcano's firing pin.

CE 543 shows the marks on the shell casing that it was used as a snap cap by LHO. That was the observation of Dr Chapman when he examined the shells and noticed the dished in primer. To recock the carcano to dry fire with it, the only movement that is needed is to raise then lower the bolt. That motion recocks the firing pin. Unless Marina stood there and watched LHO work the bolt she would not have known he was practicing trigger control.

[Jack Nessan]

Begging the question.  Even if CE 543 showed signs of dryfiring, that doesn't mean that it had anything to do with Oswald.

In any case, Marina didn't see or hear anything that would indicate that Oswald ever "practiced" by pulling the trigger on this or any other rifle.

Marina explained she had no knowledge of firearms. She would not have known what he was doing. Look at how many people just on this site have no understanding of the act of dryfiring or what is its purpose. You do not need to live fire to practice shooting.