THREE QUESTIONS (but…they are related)
FIRST – The used Beretta 303 I won in a very casual sporting clays league has a 30-inch barrel and states it is for “2 3/4 inch shells.” I have successfully fired about five cases of 2 3/4″ factory target ammunition through it. A friend borrowed it and promptly shot three boxes of 3 inch magnum waterfowl loads through it without a problem. I know its inadvisable, but, how did this happen?
SECOND – When I tried to shoot 3″ magnum waterfowl loads through the same gun, the connecting rod (“rat-tail”) broke on after about a box of shells. Would you speculate that this most likely caused by shooting the large ammunition?
THIRD – I recall from reading on your website that 390’s had a connecting rod problem at one time. I also seem to recall an after-market or custom connecting rod that was supposedly a better solution than the OEM connecting rod (maybe a better alloy or metal makeup?). Can you refer me to the vendor of this product if you have heard of it.
Hooo boy! You are treading where angels fear to go. I DEFINITELY do not recommend shooting 3″ factory magnum steel in 2-3/4″ chambered guns. This is a BAD IDEA. It reminds me of the joke about the guy who jumps off the top of a building. On the way down as he passes each floor, people can hear him say, “So far, so good.”
Factory 3″ magnums are designed to run at maximum safe pressures. These are by no stretch of the imagination “low pressure” loads. They are right up against the limit to start with.
As to shooting 3″ in 2-3/4″ chambers, there was a recent article in “Double Gun Journal” covering just that. Well it was actually more about 2-3/4″ shells in 2-1/2″chambers, but it did cover 3″ shells too. The author concluded that this practice (long shell/ short chamber) caused a rise in pressures, though it was less of a rise than anticipated.
So, if you are starting out with a max pressure shell and now use it in a way that causes a pressure rise (long shell/short chamber) it stands to reason that you are running excessive pressure.
Now add to that the fact that you may be running steel when you say “waterfowl” loads. Steel does not compress. Period. So, when the steel load gets jammed up in a too short chamber’s forcing cone, pressures- that are too high to begin with- can really skyrocket.
SO DON’T DO IT! Just because you have gotten away with it for a while, doesn’t mean that the next shot will be safe. If you want good 2-3/4″ performance with non-toxic shells, spend the money and get some 2-3/4″ Federal Tungsten Polymer loads or the Kent equivalent. Or Bismuth. They work great and will run at proper pressures in your 2-3/4″ gun.
As to breaking your con rod, it stands to reason. Excessive pressure equals excessive bolt speed equals something’s got to give.
So, if you insist on shooting 3″ magnums in a 2-3/4″ gun, I guess I can’t stop you. But I sure wouldn’t want to share the blind with that hand grenade you’re holding. I don’t recommend what you are doing. The Beretta is an incredibly strong gun, but you are strictly in a “So far, so good” situation. Shotgun Report has a lot of readers, but not enough so that we can afford to lose any of them. I don’t know if you’ve ever seen a gun blow, but I have. What you are doing is not only dangerous to yourself, but it endangers anyone near you. That hand grenade analogy was not chosen casually.
Please, use the proper length shell in your 303. If you insist on saving a few dollars with steel and want to equal the performance of a good lead load, you’ll have to use the new 3-1/2″ shells and that means a new gun. The new Beretta A400 looks like a 3-1/2″ winner here. Of course, you can buy a lot of Tungsten Matrix shells for the $900 the Xtrema will cost.
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)