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ChuckyPete 01-15-2021 11:58 AM

1903/1903A3 Barrel Question
After the feedback from my previous post on which barrel to mate to which rifle, I wanted to ask about the difference between the front sight machining on the 1903 and 1903A3 barrels. My understanding has been the 1903 front sight base rides over a stud that is machined from the barrel itself, while the 1903A3 has a central groove machined into it running towards the muzzle along with two cross grooves that the front sight base is attached to. I had purchased that HS 10-44 barrel with the grooves machined into it thinking it was an A3 barrel (and because it was listed for sale as an A3/A4) but based on the previous posts feedback and the measurements of the barrel at the receiver it would seem to be made for a 1903.

Here is a pic of the A3 grooves Iím referring to:

John Beard 01-15-2021 12:19 PM

All M1903 barrels had an integral spline machined in the barrel at the muzzle for the front sight. Almost all M'03-A3 barrels had a groove machined in the barrel as depicted in your picture and a key was inserted in the groove. The height and width of the key were the same as the M1903 barrel spline. So front sight interchangeability was maintained. And incidentally, the groove and key were quicker, easier, and less expensive to machine than the integral spline.

All HS barrels were originally manufactured for the M1903 rifle, not the M'03-A3. So the breech end was machined for the M1903 rear sight fixed base. But HS didn't manufacture or install the rear sight fixed base (or the front sight either, for that matter). So some HS barrels eventually "escaped" with no fitted M1903 rear sight fixed base. And you apparently have one of those.

Happy New Year!


ChuckyPete 01-15-2021 12:37 PM

Thanks as usual John. I had read one of your previous posts on the machining process on the 1903 barrel to make the spline and wondered about that front sight interchangeability with grooves.

Kleanbore 1 01-15-2021 01:14 PM

Were 1917 barrels machined the same way as the this pictured barrel?

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