Thank you so much for the kind words. It is very much appreciated. I really like this forum because I'm learning a lot off you guys. I mostly have always stopped at 1966, so I've been reading all your guys posts on the newer rifles and learning a lot of new material.
When I first started to research Marine 03's, it was common held belief that AHA was a Marine inspector stamp. I have no idea where that thought originated from, but there was never any evidence I found of that marking being Marine. So that is probably where that gentleman makes the comment of it being an Embassy marking. But that I know is not correct. The true meaning of the AHA is probably to one of the countless Ordnance rebuild facilities or inspectors that have been lost to time. Everytime I dig in the archives I find new locations I have never heard of and I have no real doubt it belongs to one of those locations. But the AHA has never shown any real connection to the Marines.
The blocks on this rifle are a later style than the standard O & E Unertl 03 Blocks and more the kind I see in say the 60's and up. They would mount an Unertl scope just fine, but they are not the correct style for an authentic Unertl Sniper build. The front block also looks more forward on the barrel than they normally do. They are usually placed at 7.2'' spacing for the click adjustment increments at known ranges, of the scopes of the day. This one sort of looks like the front block is more forward than that and the spacing might be over 7.2''. But it might be the pic, or it's possible since the handguard has been sanded way more than they normally are, it makes it appear that way.
The High standard barrels are usually known as really good barrels, and I've always heard they are really accurate. So as long as the fitment of that stock is good, I bet that rifle can really shoot.
Also I should add, the 1.40 range is known by many collectors as a good NM range. But the polishing on that bolt does not look SA from the limited pic. The bolt looks like it was polished on a commercial buffing wheel and some areas look deformed because of it. Also the rails of the receiver do not look NM polished. Of course a HS barrel is not original to a NM, but I just thought I would mention it because some might see the polished bolt and instantly think it might be an original NM. If it ever was, it's been thru a full rebuild and erased the traits.
At one time a polished bolt was considered legit on an Unertl Sniper rifle. I'm sort of glad I was able to sway collectors away from that, because that is absolutely false. So I sort of think maybe someone was trying to make a Unertl clone of this rifle. Or maybe someone found a 03 with blocks on it and then decided to polished the bolt to make it look more like the accepted view of an Unertl sniper back then. Anything is possible.
I'm sure it probably crossed your mind wondering if it might be a legit Marine sniper but I'm sorry to say this one was built in the commercial market and does not show any traits of being a Marine rifle.
As long as that spacing isn't jacked up too much on those blocks, it would be a good candidate for the vintage sniper matches. Just make sure it's not a converted drill rifle. Look at the area around the mag cuttoff switch and look for areas that were welded.
I hope this helps some and if you have any questions just ask.