Welcome Hobie,
Your 1916 arrows' outside diameter is 19/64", having a wall thickness of 0.016".
Pipe cutters work well. I use hot-melt glue sold by archery suppliers, that isn't so brittle.
Cut, clean arrows with alcohol (to degrease), dry, screw field point into insert, hold w/pliars, flame the insert to melt the glue around it, insert the insert into the cut/cleaned shaft and twist to bottom it out, squeezing out the glue, as you push the point againt a 2x4. Drop the arrow shaft/point/insert into a plastic bottle of water for about a minute to cool and harden, pull off the excess glue ring with a cloth or old tee shirt. Shoot it.
If you cut your arrows, and cannot reuse your existing glue-in inserts for screw-in points, you'll need PDP Converta Inserts Item # 3480008, but they're backordered.
These inserts for aluminum arrows are sized to fit the arrow size: 1916 and ordered as such.
Then order field points that have an outside diameter equal to or less than the outide diameter of the shaft/insert head. In your case, 19/64" (equal) or smaller (9/32"). Larger diameter field points will work, but they sometimes get hung up on target coverings and are harder to pull out of some targets materials.
Keep in mind, some aluminum insert heads flare out larger than the outside diameter of the shaft, to accept a slightly (next size up) larger OD point. Say a 1916 (19/64") flaring out to a 20-series size (20/64" = 5/16"). So, in this case you could order a 5/16" OD point to fit the flared insert head. To get the higher weighted field points (> 125 grains), usually this is the route to go, as smaller OD points do not come in the higher weights.