Chamber pressures for 12 Gauge VH

[gary cutler]

Can anyone tell me what the PSI is for the Winchester AA 2 3/4" low recoil, low noise 7/8 oz. target loads?
Are they safe to use in a 1901 VH Parker No. 2 frame?
Gary

[B. Dudley]

I cannot tell you the pressures of that shell. You may have to contact Winchester o get that information.
But... I can say that with your gun being a VH with fluid steel barrels. Shoot them.

[Bruce Day]

A 1 1/8 oz 3 dre load was an intended load for all Parker 12's as made. A Parker service and proof load pressure table is provided in TPS for those interested. Parker loads for 12 through 28 ga are provided in the Small Bore Shot Gun pamphlet for those interested.

[J.B. Books]

Bruce what is the date of the Parker Service and Proof load table in the TPS? If I recall correctly it lists pressures for both 3" 12ga and 20ga guns/shells which suggests to me it applies to guns made in the mid to late 1920's and forward.

Of course I believe every fluid steel Parker made has and will shoot every factory shell in the correct chamber size without problem. Now whether that is good for 70 to 120 year old guns is another question.

[Bruce Day]

The origination date is unclear. P. 515, TPS. The table is based upon historical data from American manufacturers for gauges 10, 12, 16, 20, 28, 32, and 410. Although the table was published in a 1934 article, I have been unable to identify any differences between turn of the century guns and late 1920's guns that suggest that earlier guns were intended for less pressure. Parker shot guns met SAAMI pressures when SAAMI was established, and the pressures used by Parker and other noted makers became the foundation for SAAMI standards ( Small Arms and Ammunition Manufacturers Institute).

Assuming Mr. Cutler's VH 12 is a standard for the type, his gun was intended for a service load limit of between 9500 and 10,800 psi. Not knowing present condition of the barrels, I make no current recommendations. It would have been targeted with 1 1/8 of No. 7 shot at 3 dre if it is like most other 12ga 2 frame guns.

[J.B. Books]

Originally Posted by Bruce Day

I have been unable to identify any differences between turn of the century guns and late 1920's guns that suggest that earlier guns were intended for less pressure.

I have observed one difference in the earlier guns, thinner wrists. Most likely beefed up to handle greater recoil of heavier loads rather than greater pressure.

[Drew Hause]

Per Tom Armbrust:

3 Dr. Eq. 1 1/8 oz.
Winchester Trap Load
1,202 fps 9,600 psi

AA Xtra-Lite 1 oz WAAL12
1189 fps 8000 psi

AA 'Low noise Low recoil' 15/16 oz
980 fps 6,200 psi

[J.B. Books]

Originally Posted by Bruce Day

Assuming Mr. Cutler's VH 12 is a standard for the type, his gun was intended for a service load limit of between 9500 and 10,800 psi. Not knowing present condition of the barrels, I make no current recommendations.

Bruce according to the Parker Proof Load Table you reference, your numbers come from "Theoretical Service Pressure Pressure Limits...." on the left side. As you can see that would mean 2 3/4" 12ga guns were built to handle 125% greater pressure than 2 5/8" chambered guns. That looks like a little chink in the armor that 2 5/8 chambers were meant for 2 3/4 inch shells to me.

[J.B. Books]

Bruce one of the things I find confusing in the Parker Proof Load Table is the "Definitive Proof Pressure" information. As an example, how the heck do you get 2.5 ounces of shot in a 2 7/8" 10ga much less 260 grains of any kind of powder?

[Bruce Day]

Pete, I don't know, but makers of proof loads do. They make proof load cartridges for shotgun makers and also for industrial guns to blast out slag from furnaces. I assume that wadding is not an issue and there is likely just a thin spacer between the shot and powder. I have seen proof loads but never taken one apart.