10 Gauge Bore Dimensions?

Roundsworth · 08-28-2010, 12:12 AM

According to the 'book', my 10 gauge lifter's barrels are the original length, 32". I do not have the proper instruments to measure bores, but I did manage the following:

1) Chambers= .855" ("For the 10A or modern shells")

2) Chokes:
R= .792"
L= .796"

3) Muzzle thickness:
R= .063"
L= .065"

There is barely a 'step down' to the bore from the chamber, which to me is ideal for a thin brass case, not a thick paper shell. The modern 10 bore is about .775", isn't it? Does anyone have any idea what my bore diameter is, or was originally? There is some roughness near the chambers, but the remainder of the bores look pretty good for 131 years! I cannot say yay or nay about any honing in the near or distant past. Cheers!

Milton Starr · 08-28-2010, 12:48 AM

browning and my h&r 10 ga have a bore diameter of .777"
the remington sp1- has a bore of .775

Roundsworth · 08-28-2010, 08:25 AM

Oops! I kinda thought my .755" didn't look right! I will change that. Thanks, Milton. I suppose that bores could have been different from gun to gun back in 1879.

Bill Murphy · 08-28-2010, 09:21 AM

Many Parker bores in that time period were plus or minus .800. Nominal ten gauge bores came in the mid 1890s.

Austin W Hogan · 08-28-2010, 09:32 AM

Many 10 bore lifter guns have bores .800 - .810 or larger; most bore gauges are for 12 and smaller, and the few bore measurements I have are with inside calipers. They may nominally be 13/16 - .812. An early ten with no choke can be mistaken for an 8 if the chamber is not measured.
The original brass shell chamber was 2 5/8; 2 7/8 is needed to fit the same load in a paper case. Winchester and UMC supplied cases or loads longer than this in case lots, and some guns may have longer chambers; but they were never intended for SuperX .

Best, Austin

Bill Murphy · 08-28-2010, 06:09 PM

A thick barrelled early Parker ten gauge would only have to be bored out .035 or less to be measured as a nominal eight gauge. That is only .017 on a side. My little six frame ten could easily be made into an eight gauge, but it is much rarer as a six frame fluid steel ten gauge.