303 uses Beretta Mobil chokes, and 4 notches is IC. Use a quarter or the edge of a hull base to unscrew the choke. Go to the Beretta forum on Shotgunworld.com for good info.
http://www.shotgunworld.com/bbs/viewforum.php?f=57
Mark

 

Thanks for the link. I found this site from online searching, and it seemed to be a good source of info.

I may have hosed myself. The barrel says 3", but I assumed that meant that 2 3/4" and 3" shells may be used in the barrel. Is that correct, or will I have to find a 2 3/4" barrel? The other autoloaders I've had allowed either shell in the same barrel. Something to do with the gas port, or the chamber?

 

they shoot 2 3/4 or 3 inch no problem. All the beretta mobile chokes work. 1 notch full 2 im modified, 3 modified 4 imp cyl, 5 skeet. Best to get choke wrench so you don;t screw up the barrel and notches n the choke tube itself. I would get a 3 notch choke tube and go have fun. You don;t need all those fancy choke tubes form the great manufacturers as the factory ones work pretty good. Some of those guns used an adjustable washer in the stock to change the drop and cast off. Not sure what the early 303 used as the identification is different that the 390/391..motordoc

 

Found out the 303 stock can be adjusted for drop, but not cast. The drop washers come in 60mm through 45mm or so. The one on the shotgun is a 60mm. When I shouldered it, it felt good; there was consistency to my eye to rail/front sight picture. I assume changing the washer to a lower mm drop would affect my POA/POI. I am going to get it cleaned, reassembled, and take it out with a variety of loads to see how it runs.

I appreciate the help. Last time I shot clays was years ago with an old Winchester pump to practice for small game season.

Sorry for the novice question, but what type of loads do people typically use for the different clay shooting disciplines? Friends and I can go to the nearby state ranges and throw clays, and there are some formally built facilities for skeet, sporting clays, and trap.

To respond to the below post, I checked the gas ports, and they've not been drilled out. I found some online port dimensions, and the barrel matches what I found. Seems some will drill them out to apr 5/64, or just one port to a larger size, as a compromise. Perhaps my recoil spring has enough time on it that it'll let the lighter loads cycle.

 

There is not a compensating system to shoot light and heavy loads, on the 303. You may not be able to shoot light 2 3/4" loads through the 3" barrel. Although someone in the past may have reamed out the gas port to shoot light loads, which would make it less able to shoot 3" loads, without beating up the bolt. It's hard to know the history of many old guns. I would try shooting it as is, with the loads you hope to use, and see how it works, first. Then go from there. Mark

 

Beretta has different tubes - make sure you get the Mobile thing cus that's what 303's use

 

two things to do. First replace the hammer spring in the trigger assembly. Second replace the recoil spring in the stock tube. They both get weak and cause malfunctions. You can get the springs from j and p on this site

 

I shot trap with a Beretta 303 field for 3 or 4 years. No problems with 1145 fps shells at all plus shot plenty of 3" hunting loads through it.. Still has all the original springs and tube. I bought a Briley extend full choke which enhanced the pattern.

I found that you had to keep the holes in the barrel going to the piston clean but other than than just clean it like another gun.

You can shoot steel and it will only hold 3 shells total for waterfowl shooting.

 

If you need additional Mobil chokes and wrench-- I have a variety to sell-- welcome to call me. Wally Riebesell. 660-744-4115 cst

 

Also if barrel doesn't work out , I can help-- wally

 

Wally (acss) would know for sure, but I do not think the 302 came with Mobil Chokes. I suspect what you have are aftermarket chokes threaded to the TruChoke pattern. That is not a bad thing. Colonial and TruChoke sell a wide variety of choke tubes for this pattern, and they are inexpensive and well made. If you need Mobile choke pattern chokes, Wally is a great source.
Do not worry about springs. The usual recommendation is every 10,000 rounds and your gun is not close. It probably will work ok with 1 1/8 loads at 1200fps or higher, and may well work with lighter loads. Worry about it later.
There is very little your gun will not work well for with the improved cylinder choke. Good for almost all upland birds, good for sporting clays (particularly until you have more experience) and good for most waterfowl with steel shot. Will work ok for skeet and 16yd trap.
The 303 is a modern classic and is increasing in value every year. You have a great gun.

 

He has a 303, which does use Mobil chokes. You are right that a 302 is before Mobil chokes.

 

Back together and feels smoother. Recoil tube and plunger had some buildup, but no rust/etc visible. Stock cleaned up with a quick waxing. Not sure what is applied to the stock surface, but it's not bare. I was going to tung oil the stock, but I think just a polish and wax would take care of the blemishes and bring out the wood grain. Need a choke tool. Quarter won't budge the one in the barrel, even with a short soak with kroil.

Extended chokes or flush chokes? Seems flush are okay for short ranges, and extended for past 25 yards. At least a novice's opinion based on reading through some forums and chocke manufacturer sites.

Is there a difference in chamber dimension between a 2 3/4 barrel and 3 barrel? Forcing cone closer to the shell in the 2 3/4" barrel? Seems it would keep the pellets contained and undisrupted whereas a longer chamber puts the forcing cone further out, letting the wad and pellets to start moving around before being forced back into the barrel.

Range today with some 7 and 8 shot 2 3/4" shells to see how it runs. Only paid attention to what number shot and shell size, never cared about oz shot, dram, the rest of the info on the box. Dunno if the OEM choke can handle steel shot. I have a couple boxes purchased by accident.

Yea, feels like a solid firearm. Talked the shop down in price a little, so with tax I think I got a good deal. Definitely lighter than a Rem 1100/1187.

 

The 303 Beretta will take a huge amount of shooting before you need to worry about replacing parts. These aren't guns from a different era, they are completely modern and will handle any 2 3/4" or 3" shell you want to use. Getting a choke wrench is no big deal, any decent gun shop will have them along with all the choke tubes you could want. You can also make cast adjustments (move the butt to right or left) with a shim change.

Do yourself a favor and get out and shoot the darn thing before you worry about what might need to be replaced. Also when you do have a choke tube wrench, you will find that the choke will unscrew easier just after you have run a enough shells through the gun to get the barrel hot.

 

Cast cannot be adjusted on a 303, only the drop. Some Trap models didn't even allow that, as they don't have the P shaped shim, only a round washer.

 

I don't think you can adjust drop, either, there is no front shim. the 390-391-400 series have 2 shims, installed by matching numbers for cast & drop.

 

There's a shim near the back of the stock. It must adjust the angle of the stock in relation to the receiver, as there are different height shims.

Took it to an indoor range to test fire. Ran through some 2 3/4" 7.5 shot 3dram. Fed, fired, ejected consistently. Good pattern, POI was level with POA out to 25 yards with an IC choke. I was very pleased with it's pattern and POI. I don't have anything less than 3dram to test. Few parts to clean; solid, all metal construction; chromed bolt and barrel; attractive stocks and details. This thing is a tank. I'm happy with the purchase. Now to round out the chokes and a choke wrench. I think it'll stay with me for a while.