Are Pressure Measurements Useful?

[Austin W Hogan]

The original Parker 1 and 2 frame designs preceeded chamber pressure measurements by forty or more years. King's addition of the zero frame size came less than 10 years later.A matrix accompanies this, showing the shot column length of load weight against nominal bore diameter. The 1890 Winchester and other catalogs show that the 20 ga was introduced at 1/2 and 5/8 ounce, the 28 at 5/8, the 16 at 7/8 ounce. The pre 1900 ten gauge load was 1 1/4 ounces.
Examining this matrix indicates that, in the days before pressure measurements, King and others simply used a criteria that a shot column less than .8 bore diameter was compatable with a frame width comparable to bore diameter, plus a minimum chamber wall thickness.
The traditional loads are entered in red. Note the adaptability of the zero frame to loads of 1/2 to 7/8 ounce through the 28 to 16 gauge range. The loads that exceed .8 are shown in blue; perhaps this accounts for the preponderance of 1 frame 16 ga guns in later production as well as the long barrelled 1 and 1 1/2 frame twenty ga guns. The 1 1/4 ounce 12 is in blue; has anyone found a 1 1/4 ounce hang tag on a 1 frame 12? We know that there is a one frame ten gauge gun; Bogardus and others preffered a 1 ounce ten gauge load for upland hunting in the 1880's, note the orange entry of .6 for a one ounce ten ga load.
This could make a very interesting and useful story - we need some hang tag and frame size observations to support this.
The matrix exceedes postable txt dimensions. I will scan a copy a post it as a jpeg
Best, Austin

[Austin W Hogan]

The best guidance to show respect for the age of most Parkers might be to limit the length of the shot column to 3/4 of the bore diameter. Twenty eight ga and 410 bore guns might be an exception, and need some further research.
Excuse my excel; it refuses to show 7/8 as anything other than July 8. It not very faithful in printing rows and columns if the grid is removed.

Best, Austin

[Bruce Day]

[QUOTE=Austin W Hogan;24199]..... a shot column less than .8 bore diameter was compatable with a frame width comparable to bore diameter, plus a minimum chamber wall thickness.....
/QUOTE]


Austin, nothing said about powder charge at all? Surely that makes a difference and I'm sure King considered that in some manner. Parker designed gun barrels for smokeless powder in what, 1890?, and it was no longer true that a person could just stuff the hull with as much powder as it could take. Bulk smokeless took up less volume than black;ergo, the concept of dram equivalents.

Second, the charts demonstrate that 20ga shells take 3/4 or 7/8 and 12ga will take anything 1 1/8 and lower, but 16ga take 7/8 and are marginal with 1 oz. Looking at Parker ga/shot load table ( Small Bore Shot Gun brochure) Parker shows the 7/8 load for 16's and states 1 oz is not made and not recommended. At some later point, 16ga 1 oz loads began to be made and used in Parkers, but I don't know when, late 20's?? We think about 40% of 16's are 0 frame, 60% 1 frame. Most of the early 16's seem to be 0 frame. So was there a transition to 1oz 16ga loads and when?

Perhaps those charts mean that 16ga 1oz 3d loads are not made but 16ga 1oz 2 3/4d ( DuPont bulk smokeless) are. But even that would be incompatible per King's table.

[Hammer Fan]

Very interesting information. One question I have, is there any consideration as to shot size? Wouldn't 1 1/8 oz of 4's be "longer" than 1 1/8 oz. of 8's? I always understood loads of the same weight, would generate similar pressures regardless of shot size, everything else being equal. Hmmm, maybe this would make for a very good series of articles.