Auto 5 barrel compatibility question

[SigfanUSAF]

I have a 1953 vintage Belgiun made 12ga standard weight Auto 5, originally with a 30" 2 3/4" full choke barrel. I replaced the barrel with an 18.5" 3" barrel of similar vintage.

The problem I'm having is the left hand shell stop won't deactivate when the barrel is "all the way home", thus not releasing the shell and binding the action.

Does anyone know of a fix, or of any compatibility issue between the 2 3/4" and 3" barrels?

From what I can see, the channel on the left side of the 3" barrel extension is too long to activate the stop. Is the 2 3/4" one of a different design?

Thanks for any help!


ETA: Would anyone with a Belgiun Auto-5 12ga 3" and a set of calipers measure the distance from the front of the receiver to the front of the ejection port for me?

 

[Superposed]

A 3-inch Browning A5 barrel will definitely NOT fit a 2 3/4-inch A5 whether it is a standard model or a Light-12.

 

[SigfanUSAF]

Why?

 

[Jeff Mull]

Sig fan.

The difference between the guns is not just the depth of the cylinder. They are different in many dimensions mechanically. There is no way you can get a 3" chamber Auto-5 barrel to work on a 2 3/4" Auto-5 receiver.

If you dont believe me look at the distance between the barrel ring and the barrel extension.....they are 2" off. In addition the extractor claws are different.

By the way, your definition of similar vintage must be different than mine. The 3" gun was not in production when your gun was made. The very first Mag was not even made until 5 years after your gun was built.

Jeff

 

[Two Cold Soakers]

Jeff is correct. I have been all through this years ago. Your best bet is to locate a 2-3/4" Japanese bbl and hack it off.

A costly endeavor, but much less sacreligious than cutting Belgian steel, which will spread sorrow across the universe and make mermaids and unicorns cry.

 

[SigfanUSAF]

Jeff, what do you mean two inch difference? The only thing not functionally working is the shell stop. Everything else lines up and functions properly, extraction, ejection, and firing.

As I sold the 2 3/4" barrel years ago, I have nothing to compare it to.

My definition of similar vintage would be within a few years either way, 5 years would fall into my "similar".

 

[rcmodel]

All I can tell you for sure is it won't work, and you can't make it work.

You need to sell or trade the 3" barrel and get a 2 3/4" barrel.

http://www.barrelexchange.com/

http://www.corsonsbarrels.com/

rcmodel

 

[Jeff Mull]

Maybe this picture will help explain my comment.

The top barrel is a 1958 Light Twelve, 2 3/4" chamber, 28" long

The bottom barrel is a 1958 Magnum, 3" chamber, 32" long

Same year, zactly.



The 2" difference in the position of the barrel ring is just the start of the fun.

 

[loosecannon]

When you do find the correct barrel and cut it off, you may still have problems. Over the years I experimented with three different auto-5's which functioned perfectly until the short barrel was installed, and then the jamming started.

Why? Cutting the barrel reduced its weight, which affected the recoil mechanism My tubes were 18". Today I would have cut them at 22"

Also, the pressure curve changes with the shorter barrel, and some say this can mess things up.

I fixed the problem by setting the friction rings to light load setting, using magnum loads, and heavily oiling the tube. Recoil was bone jarring and teeth shattering.

I feel that others may have had better luck with this modification.

 

[SigfanUSAF]

Okay, my barrrel is definately the lower style in the pic.

Perhaps I'm wrong about my receiver?
the serial is 3914xx.

I made a .150" shim to set the barrel back a little in the receiver (it's a RamLine forend) and function is now 100%, achieving full lock up with the bolt to the extension, and feeding properly with 2 3/4" shells.

Any thoughts? I looked up the serial on the 'net, perhaps that was wrong? Though according to Sweeneys "Gunsmithing Shotguns" book, the 3" guns have 5 friction rings, while the 2 3/4" has 2 with a band around the bonze ring, as mine does.

I'll try to post some pics this weekend. Thanks for the help!

 

[brasskeeper]

Have you fired the gun?

 

[SigfanUSAF]

Not yet, I can't make it to the range until we get some gas in my area. Every station in at least a 15 muile radius is out

 

[Jeff Mull]

Sweeney may not be wrong but he sure is not complete. There were 3 different spring and friction ring sets used on the Mag over the years. One version even had 2 recoil springs coiled together.

Is the ramline forend made for a 2 3/4" gun or a 3"? I'm guessing it is a 3" or you could not even get the mag cap on it. And what about the magazine tube? what length is it for...all these things matter.

Even if you can get the gun to feed 2 3/4" shells you still have all the mechancal issues that have to do with the length of stroke needed to move the mechanism far enough to handle a 3" shell, and then there is the ejection port which is too short to eject 3" shells.

Quit while you are ahead, give up on the whole Frankengun thing and get the right barrel for this old classic.

(pardon my prejudice for originality)

Jeff

 

[SigfanUSAF]

The RamLine forend comes ready to fit the 3" and with a 2" spacer for the 2 3/4" guns.

I'm not concerned with feeding 3 inchers, 2 3/4" is fine by me. I would love to have a correct barrel for this, but this was the only one in my budget I found after a 6 month search.

 

[Jeff Mull]

12 ga A-5 barrels are not expensive.

And buying the wrong one is more expensive than buying the right one.

Jeff

 

[SigfanUSAF]

I paid $72 for the one I have, where are they not expensive?

 

[brasskeeper]

Well I hope this works and your able to put you shotgun back in service. I encourage you to find a original barrel when you budget permits.

 

[Jeff Mull]

$150 for an A5 barrel is not expensive.

$72 is cheap if you get it to work, and expensive if you cut it up and end up throwing it away.

How much did you get for the original barrel when you parted out that otherwise decent Auto-5? I hope you got a lot for the barrel as breaking up a classic gun should not be done without good reason.

Though I am an idealist about these things enough money might be a good reason for me too, but as my grandmother once told me "the only difference between a whore and a cheap whore is the price".

Jeff

;^)

 

[SigfanUSAF]

Regardless of what I got for the parts, I only originally parted it out because the guy I bought it from drilled and tapped the receiver for a Weaver Quikpoint scope.

I sold the original stock set and barrel and actually intended on parting it the rest of the way out.....'till I fiound this barrel on GB.

 

[SigfanUSAF]

Here's what I've got. The barrel isn't shown in it's entirety, it's 18.5". You can see in the 3rd pic the .150" shim I made, and in the 4th pic the 3" markings. The last pic shows the horrid modification this guy did to the receiver (he said his dad did it years ago).

 

[Jeff Mull]

Considering what your doing to it now the tapped holes in the receiver are not so bad....The metal cut out on the front of the ejection port is particularly wretched.

You might want to stick a couple of bolts in those holes like the ones in Frankensteins neck.

But to each his own, so I'll sign out before I feel compelled to fling any more criticism...but with one last comment.

Classic guns (even the ones with a few warts) should be preserved rather than hacked up and converted into mall ninja POS's.

 

[SigfanUSAF]

Jeff,
If you felt that strongly about it you should have bought it when I had it for sale in it's entirety here and on AR15.com for $250.

Or you could have bought it when I had it without the barrel and stocks for $125.

Thanks for the less than encouraging comments on what I've done here.

 

[Jack2427]

I have a 1956 A5 that I cut to 18.5"(it was a beater to start with), put a tritium from sight and a synthetic stock and forearm, added a sling swivel mag cap, and was in business. The only problem was mousing the friction rings a little, and then settled on standard 2.75" buck. 00, 0, 4 and 1 work flawlessly. Anything lighter gets iffy, but who would want lighter? Great trunk gun and with the mag cut off can be carried chamber empty so a shell of choice can be dropped in, or just racked to bring the round out of the mag. Of course loading is a snap when you are empty, drop one in push the button, then decide if you need to shoot RFN, or have time to reload mag.