Wall thickness relative to frame size

[Bill Graham]

I heard recently that smaller framed guns by default had thinner walls than larger framed, in order to have the proper sized bores and fit to a smaller frame. While discussing whether or not the barrels on a #1 frame hammergun are thick enough with a friend recently, we pondered that and I wondered what the consensus is here, and if there’s any information from Parker about this. Thanks.

[OH Osthaus]

well- at least at the breech - that would make sense

as the size goes up -the frame is wider and the firing pin spacing increases so the barrels at the breech end must be bigger -

a wider set of barrels - with the same bore size - would necessitate more metal at the back end

the question would be- as the barrels are struck and the balance of the gun is adjusted

how much of this rear end affect will translate to thicker walls all the way down the tubes

i would guess - it depends on the gun and may not be a hard and fast rule

[Bill Graham]

Thank you. In this particular case, the motivation for thinking about it is that the barrels in question on this #1 frame are on the thin side: Past the forend at 20 thousandths, and then thickening back up in the 30's towards the muzzles. Don't recall the breach end measurements, but there wasn't anything alarming there.

[Gary Laudermilch]

My P grade 1 frame 12 with twist barrels were measured by Mr. Hosford. He recorded .115 at the end of chambers, .090 in front of the forcing cone, and a min. wall thickness of .031 and .032. He also commented that they were one of the most uniform sets of barrels he ever measured.

[Bill Murphy]

I would check that .020 measurement against other guns known to be original #1 frame barrels.

[B. Dudley]

Barrel length can have an impact on wall thickess too. The longer barrels would be finished down more for the sake of balance.

[Bill Graham]

These are 30”.

[Dean Romig]

Wall thickness relative to frame size is equally dependent on bore size. Further, chamber wall thickness, beginning of forcing cone thickness, and probably the first 12" to 15" or so is also largely a result of both frame size and bore, i.e., gauge.





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[Bill Murphy]

.020 "past the forearm" is definitely a sign that the gun has been fooled with. The scariest gun I have ever examined is the probably unique #1 frame ten gauge DH grade gun. It hasn't blown up yet, but the chamber walls are thin beyond description. It is factory original and is in the order book. It is #71767 as I recall. Look it up.

[Mills]

I bought two 32" 12 gauges on 2 frames this year and both of them have about 22 thousandths several inches back from the muzzle with a long taper up to the low 30's at the end. I was wondering if they bored them out so the gun would not be too heavy?