Doco Overboard
Ultimate Member
Yes and no to a certain extent. A3 barrels are not milled different for the rear sight collar they are turned to a slightly diameter where the rear sight collar is located. They are close but can be determined by eye with careful observation.
The milling for the front sight base is the same between an A3 barrel and a rebuild 03 barrel. It's like 3/32 off the top of my head.
What this comes down to is that an A3 front site band and a 03 band are interchangeable with the same internal diameter.
The difference is the length of the spline or key used to support the band internally between the two drawing numbers.
The 03 has a longer key than the A3 so when you interchange the two an A3 key is to short to fill the space left at the end of the band at either end and the 03 key needs to be shortened when used with an A3 barrel.
In short they will swap.
Criterion replacement and 03 rebuild barrels like the one pictured above have identical milling under the band.
The only difference is the diameter of the barrel profile towards the breech....and the length of the key used to support the band(s)
SA, RIA and AVIS barrels have a simple slot milled into the barrel at the muzzle with out the additional fly cuts that stride the key way.
The breech of both barrels look like this and are the same. If you ever look through a 03 barrel that is two or six groove it has had a A3 barrel fitted to it made by either Remington or High Standard (SC) CBI barrels are 4 groove with a A3 front site milling to aid modern production.
If you need a 03orA3 barrel they are the ones to get for shooting if you can find one somewhere at this time.
