I would say that the factory basic "Standard" frame sizes by gauge are as follows...

28g: 00
20g: 0
16g: 1
12g: 2 (but then later the 1-1/2 frame became much more common)
10g: 3

Anything beyond this is simply personal preference as to what the individual shooter likes.

A clue to this factory "Standard" would certainly be how they decided to standardize the Trojan grade. Only built in 0 frame 20, 1 frame 16 and 2 frame 12 (with the exception of EXTREME rare occasions).

Now... it is important to say that there is NO mention in any Parker literature about "Frame Sizes" or what the frame sizes are. Only mention of the factory being able to build a gun for proper balance or to any customer specification required.

Thank you, Rich. Is that a Braque d'Auvergne in your avatar photo? I have one also. Great bird dog

Thank you, Brian. This is the information I was looking for.

Richard if your referring to me the dog is Gunner the best GSP to ever point a bird.

Were any 00 frame Twenty's made? I have some 0 frame 16's and they are sweet to shoot but a 28ga frame 20 maybe sublime.

Yes. The third Parker 20 is on a 00 frame, as are a (very) few others of the early ones.

further to the above, the first 20ga. Parker, 4634, is on a 1 frame. The 0 frame had not yet been made, and I don't know what the first 20 on an 0 frame is. I believe 5410 is the 2nd, and 6999 is the third, though in the serialization book, it is listed as a 30" 10gauge.
I believe 10165 is the 4th 20, and that is also on a 00 frame.

I am not sure calling these early, very small framed 20 gauge guns 00 framed guns is correct, in that no 0 frame gun predates them, but the dimensions are within a few thous of what is listed in TPS as 00.

15837 and 15838 are the 5th and 6th 20s, and it is likely that these are on the 0 frame, as the first 16ga lifters were right in this neighborhood.

The enclosed pictures are of the barrel of 6999, which the Research Chairman has confirmed is in the order book as a 20ga.

The firing pin spacing on 10165 is actually a few thousandths narrower than the 00-frame spacing.

No hammerless Parker 20, that we know of, was made on such a small frame size.

This is 10165...

No, I do not have an especially large hand... 10165 is an especially diminutive Parker 20.


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To be contrarian to my learned senior members, I always prefer a 1 1/2 frame for a 12 walking in the field. Now a duckblind or truck bed letting dove come to me...a 3 frame and a short days work...even shorter with the longer 10 ga barrels. I am not aware of the existence of an effective gauge below 12 so I will not sully myself with such discussions :)

I have 13011 a 16ga lifter on the O frame with lightening cuts.