2 3/4 or 2 1/2 ??

[Matt Michael]

How do I know if my parker is chambered for 2 1/2 or 2 3/4 ?
I own a old 12 ga hammer. Ive shot some low power 2 3/4 shells thru it and it was fine but i dont want to continue if i should be using the shorter shells.

[John Campbell]

Matt:
The best way is to take the gun to a competent gunsmith and have him measure the chambers for you. Any decent bloke will do it for free. Otherwise, get a Brownell's chamber plug gauge or Galazan leaf gauge (about $30 and good for gunshows etc.)

Finally, if you shoot low pressure/velocity loads with tapered case mouth construction (like Win. AA or Rem STS), you should have no problems in good barrels. You apparently have found this out already. Of course you can certainly use the shorter cartridges.

Best, Kensal

[Dave Noreen]

Chamber depth is considered to be the distance between the breech end of the barrels and the joint between the chamber body itself and the forcing cone, which reduces down to bore diameter. This is loosely based on the length of the "Fired" shell. Today, theoretically when the crimp opens on the shell being fired the end would land at the junction of the chamber and cone. Prior to WW-II many companies had the practice of holding the chamber about 1/8 inch shorter than the shell for which it was intended. Fly in the ointment is nominal measurements often differ from actual ones in both chambers and shells. A very good method I have found of measuring chambers without much outlay of cash, and is quite accurate enough for virtually any situation, is a common 6" flexible machinist's scale which you likely have. Hold the barrels with muzzles toward a light source, not necessarily a concentrated one a window is great, while looking into the breech and the cone will be thrown in a shadow. May have to move the barrels around a little until it is distinct. While still looking into the chamber simply slide the scale in until you observe the end coming flush with the shadow line & mark position of breech end with your thumb. Remove and read the scale. I usually repeat this a few times to insure I am getting a consistent reading, but you will be amazed how accurate this can be done. While I own a Galazan chamber gauge, I use this more often than not. The chamber body itself has a taper of about .005" per inch. Sometimes chambers were cut with slightly worn reamers giving a slight undersize chamber. If the chamber is a bit undersize a gauge made to "industry" standards will not go in to the true depth of the chamber. A.H. Fox Gun Co. shotguns are known for having tight chambers. The machinist’s scale method can be more accurate.

[Matt Michael]

Thanks for the info guys, I have a machinist scale and was also thinking of using calipers. So here is another question, what is the timeline for the different length shells? My gun was made in 1876 if i remember correctly so were the longer shells even being made at that time?

[Fred Preston]

1876? Guns of that time were most likely chambered for brass cases. If so, the chamber stops abruptly (no forcing cone) at about 2&5/8" for tens and twelves and goes to bore diameter. For that the short shell is in order.

[Rich Anderson]

I have solved this dilemma by only using 2 1/2 in shells in everything. I can break any clay target and kill any gamebird with the proper shot size. No worries on chamber length, pressures or excessive wear and tear on a 100+ year old gun.

[Rich Anderson]

I have solved this dilemma by only using 2 1/2 in shells in everything. I can break any clay target and kill any gamebird with the proper shot size. No worries on chamber length, pressures or excessive wear and tear on a 100+ year old gun.

[Dave Suponski]

Rich...After all these years I didn't know you studdered....:)

[Rich Anderson]

It was takeing forever to post the first time so I hit the send button again then what with all my computer genius and savvy I deleted the second post in a vain attempt to cover my technological ineptitude, We know how well that worked out:banghead:

Inept oral communication is but only one of the internal mystries that make up COB:rolleyes: