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Old August 19, 2014, 03:42 PM   #1
caocao
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Questions on a Browning A5

In about 1960 my grandfather gave me his 16 gauge Browning FN Belgium Auto 5. It is Serial Number 90646. Solid rib, Factory fancy walnut stock
It has the pre-1930-style front-to-back sliding safety mechanism through the front of the trigger guard. But according to one reply on “A couple Browning A-5 problems” thread, the SN range for 16ga A5's made in 1930 is from 82751 to 90500, which would put the gun I have in 1931, I guess.
When I tried a year or two ago to use the Browning Web site to date the manufacture of this gun I had a bit of a problem because the Browning Web site seemed to show some different number/dating rules for 16 gauge Automatic 5’s from the other gauges.
Best I could figure it I thought it was a 1931 manufacture based on that chart so that seems consistent with the other post. My grandfather never mentioned what year he actually bought it, but he and my dad both confirmed (and the gun shows it) that Grandpa custom ordered it from the Browning Company with a fancy-grade Walnut stock.
Anyway I joined in the family pheasant hunts every fall through the 1960s and maybe into the early 1970’s shooting with this gun. Seems like our family was a 16 gauge family, because my dad also used a 16 gauge, a Winchester Model 12. His Model 12 (which I have) is serial 628799. It is prominently marked both 2¾ FULL on the barrel and 2¾ on the bottom of the receiver underneath the serial number.
My dad and I both used the same 16 gauge ammunition on those hunts. I would have sworn it was 2-3/4 inch ammunition we used. The Browning performed just perfectly for me all those years. I do not remember a single jam or failure to eject or any malfunction in all the years I was hunting. Seems like all the years I was shooting it, either it MUST have been chambered for 2-3/4 inch, or I must remember wrong and we used 2-1/2 inch ammunition? It was 40 years ago I was shooting it, so my memory sure ain’t perfect.
The Browning’s barrel is not marked as for 2-3/4 inch ammunition. The receiver ejection port looks perfectly smoothly machined, no rough edges or other evidence of the injection port having been enlarged aftermarket for 2-3/4 inch shells, and THE MAXIMUM LENGTH OF THE EJECTION PORT IN THE RECEIVER IS EXACTLY 2-9/16 INCHES. Neither my dad nor my grandfather ever said anything about it having to be converted from 2-9/16 chambering (or 2-1/2) to handle 2-3/4 inch ammunition.
But could I have been shooting 2-3/4 inch ammunition cleanly through it all those years while it is chambered for 2-9/16?
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Old August 19, 2014, 04:17 PM   #2
James K
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I don't think there were 2 3/4" 16 gauge shells before WWII, but am not sure. The best (or maybe the only) way to know for sure is to measure the chamber or do a chamber cast. The chamber must be cut to allow the shell to fully open before the forcing cone, so figure that into the measurement.

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Old August 19, 2014, 06:33 PM   #3
caocao
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Thanks

I figure a trip to a qualified professional gunsmith is definitely required to get the chamber accurately measured. I'm wondering if the chamber might have been lengthened to handle 2-3/4 inch ammunition but the gun worked fine with just that change, even without the ejection port expanded or the other changes ... to the bolt etc.
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Old August 19, 2014, 07:01 PM   #4
Jim Watson
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Look at the Belgian proof marks. If you do not see kind of an elongated omega around "16-70" indicating a 2.75" chamber, the default is a 65mm = 2 9/16" chamber. Probably the case for a pre WWII gun.

Ream the chamber without enlarging the ejection port?
Sure, like the lawyer dramas on TV, it is (distantly) POSSIBLE, but is it likely?

The complete conversion used to be a fairly standard job, but I cannot now find it at Briley or Simmons, or even Browning. I bet somebody still remembers how to do it.

Or you can pay a little more for 2.5" shells and move along.
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Old August 19, 2014, 07:44 PM   #5
caocao
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Thanks James!

Bingo!

Careful inspection with a magnifying glass revealed an elongated omega on its side with 16-65 inside the omega, on the left side of the barrel next to where it goes into the receiver. The forearm wood almost covers it up, but with a magnifying glass I could see it and read it clearly.

So the barrel was definitely made and proofed at 65 mm -- 2-9/16 "

Thanks to your help, I'm confident we know that for sure.

To be discovered (by me taking the gun to a professional gunsmith for a chamber measurement) is whether the chamber was ever enlarged to 2-3/4 "

I'm guessing the answer to that will be no.

As for the question whether it functioned perfectly with 2-3/4 " loads for years even though it was chambered only for the 2-9/16 " ...
OR
Whether I was really firing just 2-1/2 " rounds with it all those years 40-50 years ago and my memory has been wrong in thinking I was firing 2-3/4 " rounds.

The smart bet on that, I think, would be that my memory is/was wrong!
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Old August 19, 2014, 09:51 PM   #6
Jim Watson
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Odds are you were shooting it with 2 3/4" shells and never knew it.
Brownings are strong and you would have to shoot it a lot to beat it up.

I would not do it as a routine thing, now that 2.5" shells are available again for the old guns.
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Old August 20, 2014, 01:48 AM   #7
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You most likely have a 2-9/16" chamber. 2-3/4" 16 ga was an American improvement and was not around before 1940. If it has been modified, it is fairly obvious, if you know what to look for. It is not too difficult to do the conversion, I have done several of these. The chamber has to be reamed to accept 2-3/4" shells, the forcing cone lengthened, the ejector has to be changed to the sliding type (like the 20 ga 3" magnums), the port has to be enlarged to 2-3/4", and the forend has to be modified to let the barrel sit 3/16" farther forward. All in all, about 4 hours worth of work. I used to have a really pretty 1927 A5 in 16 ga (sliding safety, solid rib, like yours) that I converted and hunted with, I later sold to my brother.
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Old August 20, 2014, 10:10 AM   #8
caocao
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Thanks, All!

I sure found the right Web Site here to connect me with folks who can help!
Now, exploring the subject of 2-1/2 " rounds versus 2-3/4 " ...

1) Back in the 1960's and early 1970's, was the 2-3/4 " load already the 16 gauge rounds that most large and small ammo sellers in the US carried, or was the 2-1/2 " load the most common load? If you just asked for a box of 16 gauge shells, field loads with number 5 shot, do you think most ammo sellers would have automatically handed you the 2-3/4 " ? Or would they have most likely ASKED YOU whether you wanted 2-1/2 " or 2-3/4" ? Or do you think the most commonly used size in those years have been the 2-1/2 " so that's what they would have just handed you?

2) Accepting that firing some 2-3/4 " field loads through a Browning A5 that had only a 2-9/16 " chamber would not have damaged the barrel, the receiver, the bolt, or the extractor, it still seems strange to me that the rounds would cleanly fire and cleanly eject, with no jamming, without the other modifications you describe in the conversion.
The chamber size and the pressures created by a chamber too short for firing the round seem obviously critical concerns. But if the 2-3/4 " rounds feed and eject perfectly, what are the critical reasons for doing any more than just reaming out the chamber to the correct length for the longer rounds? Why bother with all the rest of that conversion stuff if the chamber is the right length and the 2-3/4 " rounds feed and eject perfectly?
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Old August 20, 2014, 12:28 PM   #9
James K
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In a shotgun, the front of the shell "unfolds" into the chamber behind the forcing cone. If the shell is too long (2 3/4" in a 2 1/2 chamber for example), the front of the shell will open into the forcing cone after the shell is fired. That will raise pressures a bit, but since shotgun pressures are fairly low, and steel barrels, even those made in the 1920's, are plenty strong, the "problem" is almost never noticed. Now whether the longer shell will seat depends on the design of the chamber and the forcing cone. Usually, a shell 1/4' or less too long will seat, though sometimes with difficulty. A more common problem in an autoloader or a pump with a shell that is too long will arise with the carrier, which might or might not handle shells of varying length.

As to ejection ports, I don't have any measurements at hand but usually they are made longer than absolutely necessary to handle any variation in the ejection cycle. So it would not surprise me if a 2 1/2 or 2 9/16 gun would eject 2 3/4 shells.

Jim
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Old August 20, 2014, 01:34 PM   #10
Jim Watson
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I hesitate to contribute to the delinquency of a gunowner, but there was a guy who did a study reported in the Double Gun Journal several years ago.
He concluded that shooting a 2.75" shell in a 65mm chamber might increase the chamber pressure by 10% or even 15%. Or it might not.
This might lead you to think that a load 10% below the maximum pressure might be ok even though the shell was longer than the chamber. But I'm not saying so.
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Old August 20, 2014, 08:14 PM   #11
James K
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I have seen several reports and those figures pretty much agree with what I have seen. But a 10% or even 15% pressure increase won't be a problem with any reasonably modern gun (old time twist barrel guns are another story, but I strongly recommend against shooting those anyway). The shape of the chamber and forcing cone has a lot to do with it. That is in a double barrel or a single shot gun. With pumps or autoloaders, other factors like the carrier and ejection port come into play.

Jim
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Old August 21, 2014, 05:17 PM   #12
caocao
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Thanks, Jim and James

Appreciate your input very much.

The way it seems most likely now is that back in the late 1950's and 60's and maybe as late as 1972, when I was shooting the Browning on pheasants every year for a dozen years or so (but seldom hunting more than one or two weekends a year with that gun, firing not even a whole box of 25 shells per year), I was in fact firing 2-3/4 " shells successfully, just fine.

I got away with it, no problem, and maybe I still could get away with it, and be tolerably safe too, by staying away from "16 gauge 2-3/4 inch magnum" loads, or steel shot loads, or slugs.

BUT
I think I'll just keep it as is, original chambering and all, for the nostalgia as a keepsake, a collector gun. Maybe someday sell it. But not fire it any more. Thanks for all the great, knowledgeable answers!
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Old August 21, 2014, 11:52 PM   #13
Jim Watson
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Why put it out to pasture?
If you don't want to insult it with 2.75" shells any more, there are several brands of 2.5" that it was made for.
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