doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Another J. Manton Hammer Gun Question

A low end gun such as yours, and the way it was made, would be a pretty decent new gun today if buying new. You'll make lots of shooting memories with it. Every time you take it out, just imagine it's past owners carrying it afield.

Great news John and appreciate the additional images, which I took the liberty of harvesting. On further review the barrels are Plain or Common Twist which would be in keeping with Kirk's estimated DOM



True Stub Twist barrels were uncommon after the 1880s

John Henry Walsh (Editor of �The Field�), The Modern Sportsman's Gun and Rifle: Including Game and Wildfowl Guns, Sporting and Match Rifles, and Revolvers, 1882
http://books.google.com/books?id=OLwUAAAAYAAJ
At present the selection is from three kinds, viz., first, Damascus; second, laminated steel; and third, plain steel.
The chief difficulty in the present day is to obtain iron of sufficiently good quality to mix with the steel, whether for Damascus or laminated barrels. Formerly horseshoe stub nails were alone thought good enough; but of late years these have fallen off in quality, and are also insufficient for the supply of the increased demand for shot guns since the passing of the present game law.

How in the world could 100 year old "time bomb" Twist barrels survive 1200 BAR Proof?!?

12g 76 mm = 3� LEAD �High performance/Superior Proof�
Service 1050 BAR = 15,229 psi
Maximum statistical individual pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi

Drew,

Doesn't this fall in line with the current testing? With the approx 20,000psi required for deformation, and the 49,000-54,000psi required for catasthophic failure?

Regards
Ken

Just being a smart-azz Bro. Ken

Double Gun Journal Vol. 10, Issue 4, Winter, 1999, �Finding Out For Myself� Part II and Vol. 16, Issue 2, Summer 2005, Part IX, Sherman Bell's destructive testing of Parker GH Dam3 and VH Vulcan Steel. Both guns were subjected to sequentially higher pressure loads at about 2,000 pounds/square inch (psi) increments. The GH testing started at 11,900 psi and one chamber ruptured at 29,620 psi. The VH started with a Proof Load of 18,560 psi. Both chambers bulged at 29,620 psi and ruptured at 31,620 psi.

Looking at the clearer photos of the Proof marks I can tell you that the proof code TC either side of the crossed sceptre marks show that it was re-proofed in 1992. Lagopus.....

Ken & Lagopus,
OK, now you guys are confusing me a little. I'm really a neophyte when comes to older guns. Exactly what are you guys trying to say (dumb it down a little for some of us slower kids in the class )?
Once again, thanx for all ya'lls ("all ya'll" is plural for ya'll) help and interest.
John W.

John: the gun is fine.
Shoot (no steel) & enjoy!

It has been suggested to use a lower pressure so as to keep the gun tight. Said the barrels could take it but eventually the barrel/breach face would begin to loosen up under pressures. I'm going to try and keep pressures around 6000 psi (I'm old and my shoulders aren't what the use to be so the lighter loads work for me).
John W

Short version John

1. Prior to 1924, the Belgian and British Service (using) maximum load for 12g 2 1/2� and 2 5/8� shells was 1 1/4 oz. / 3 1/4 Dram Eq. (1220 fps). The pressure of that load would have been about 8500 psi with BULK smokeless powder; with DENSE smokeless 9,500 - 10,500 psi.
2. With adequate wall thickness (and we also know your gun passed Superior Proof) there is no rationale for advocating "low pressure" loads
3. Desiring lower RECOIL is reasonable with 120 year old wood and lock up. And lower shot weight and lower fps = lower recoil and usually also = lower pressure.

Pick any 1 oz. at 1200 fps load and stop worrying Winchester Xtra-Lite Target 1 oz. is 1,180 fps at 8,760 psi

I use 12g B&P Competition One 7/8 oz. at 1160 fps (5800 psi) because of my hopeless flinch and they are delightful. The 1 oz. is 6530 psi.

What Drew Said;
You can look at any reliable loading manual & find loads with 1oz of shot @ 1200 fps using fast powders giving 10K+ pressures.
You can also find some 1�oz loads at 1300 fps with pressures under 9K.
In this case if you think the 9k load is going to be easier on you or the gun you got a lot to learn.
So many seem to think that MAX PSI is the answer to everything, IT AIN'T.