25 replies to this topic

[PK.]

If you have several spare parts barrels (take off’s should be considered 2ed echelon) with witness marks and a receiver (or section of one) handy, screw the spares into the receiver and see if the marks on the barrels go to the same point on the receiver (regardless of the place on the receiver). If they do, it would indicate that the barrel threads are, indeed, timed. It wouldn’t make sense to time them though as the mil prints for the receiver do not indicate thread timing for that part.

The sample (number of parts) should be as substantial as possible and the makers of the barrels recorded.

I have wanted to do this for a long time but haven’t figure a way to get a large quantity of parts barrels here at the same time.

[PK.]

Phil,

Some interesting and quite plausible theories.

Others more adept at research than I have failed to discover manufacturing records sufficient to clarify this question, I don’t know why I maintain hope that I would be able to find such, but I fear the question will haunt me still.

The bottom line is proper headspace- wherever the witness mark falls. If you machine to line up the marks you will likely have to re-chamber.

[PK.]

Phil- yer killing me with laughter!

[ws556]

I was just wondering is you can put new semi-barrel on a full-auto?

[Arthur Fliegenheimer]

The question is why would you want to?

[PK.]

While the semi barrels will go into the receiver fine, the contour is heavier and requires a bit of fitting to the gripmount (depending on which style is used) and horizontal foregrips are contoured for the different barrels (semi/FA)