There wasn't much difference...in the different sub models of the 525 series ...between the sporting and the field model...although the sporting model typically had an upgraded stock ( grade III/IV ) vs grade II/III on the field models...and the sporting models usually came with 5 chokes...and the field grade guns came with just 3 chokes ( IC, Mod and Full usually) but whoever owned the gun before you - might have just added some extra chokes.
Some of the sporting models had an adjustable comb.../ and in some years, I think the sporting model came with extended chokes...some years it just came with the flush mounted chokes...( but all of the 525's in 12ga and 20ga I think had the Invector Plus chokes...where the 28ga and .410's had the older style Invector chokes...) .....but your choke tubes will be marked. I had a 525 - when they were first introduced ( I think it was 1998 - but my memory is terrible - it was the sporting model )...I know it came with 5 chokes but I don't remember if they were extended or not..but they might have been the Midas grade extended. One of my buddies shoots a 525 sporting that was made in 2009 I think ..and it came with Diana grade extended chokes...
but my point is, there were subtle changes in the 525 model...as it evolved.
The 525 series was new in around 1998 ....and they stopped production on it sometime early in 2012 I think....( it was replaced by the 625 series, now the 725 series) .....the 525's predecessors were the 325 and then the 425...
As far as steel vs lead chokes....just don't shoot Steel shot in any choke tighter than a Modified ...your chokes tubes ( on the Modified one ) probably says Mod-Lead...and Full-Steel.../ meaning its a modified choke when you shoot Lead shot and its a Full Choke when you shoot steel - because Steel does not compress in the choke the way lead does.
You can go to the Browning website ....look up the serial number on the gun and find the date of mfg - if that matters to you. You can still download a manual for the gun as well....although any Citori O/U manual ...is virtually the same ( and they don't tell you much).
Last edited by BigJimP; April 29, 2013 at 12:49 PM.