Yes, it is. The 600AT was simply sold under the New Haven name instead of the Mossberg brand. It's a Mossberg 500A (12 gauge) intended for targets and hunting (long barrel and great wood). All Mossberg 500 parts fit it.
Yes, the 600 At is the same model as the 500 series, but with a different designation for sale in New haven stores. So yes, all Mossberg 500 after market or OEM parts will fit it.
$175
The value of a Mossberg New Haven bolt-action 12 gauge shotgun actually depends on a couple things. Most important would be the condition of the shotgun.
Mossberg 500Not sure exactly how old, but it's really a Mossberg 500A. I think it's just the store brand from Sears Roebuck. I found one that was up for sale. Here's the info:Mossberg/New Haven 600ATCondition: Never fired. Price: $350.00 The New Haven 600AT series is basically the same as the Mossberg 500 series. New Haven is/was Mossberg's promotional line that was sold by other retailer (Montgomery Wards, Western Auto etc). Most all parts interchange IIRC. Mossberg barrels are rather inexpensive at gunshows and shops as there are so many around. This barrel comes with a factory installed "C-lect" Choke -- the cousin of the poly Chock of the 60's. Beautiful firearm and a fine shooter of the "old" family of firearms made by a Tradename Manufacturer for a company and their private label "New Haven". Kinda like Stevens making guns for SEARS. I think Montgomery Wards went out of business about 10 years ago, so one with New Haven one it you can probably safely assume is at least 10 years old.Please note $120 or so is a more realistic price for a used one. Check on gunbroker or auctionarms
You have Mossberg and then New Haven, depending on condition these are usually valued between $50-150 with the New Havens bringing the top dollar. Again, this based on condition, pits, scratches, and rust on the barrel/chamber will and do lower the value. Stock condition drops as well with any wear too.
Depends on the shape it's in. $75.00-$125.00 would be a good estimate though. This is a Mossberg shotgun made in the 50's most likely.
You will have to contact Mossberg
I have one made by O.F. MOSSBERG & SONS INC. New Haven CONN. U.S.A. NO.83B 410 GA - 3 IN PROOF TESTED
Think you have a New haven 250K. If so, it is the same as the Mossberg 152K, made from 1950-1957.
$300-$450 depending on the condition. Based on a Mossberg 500 and manuf in 1973
I just bought a New Haven 600AB for $150. My understanding is it is identical to the Mossberg 500AB, although it lacks the checkering I see in many pics of the Mossberg. They seem to go for a bit more, up to around $350, and the lowest I've seen was around $130. Try GunBroker.com, and GunsAmerica.com to see what they're going for at auction.