doublegunshop.com - home Forums Thread Like Summary - Spanish gun proof?

I was looking at a few Spanish 20 gauges. I don’t know anything about Spanish guns, so I figured I would ask. The flats were marked for 20/70 chambers and 900 KGS. Is this proof level safe to use with modern American 2 3/4” loads?

Spanish guns proofed under CIP rules are also suitable for US ammunition with the caveat (in my opinion) that very heavy loads should be avoided in the lighter weight game guns. This isn't because of chamber pressure but rather recoil that can damage stocks, especially side lock guns with a lot of wood removed from the head of the stock to inlet the locks.

My wife and I have 5 Spanish guns: 28 GA BLNE, 2 20 GA SLE's, 16 GA BLE, and 12 GA SLE.

Our maximum loads are based primarily on the recoil that we are willing to stand, rather than the maximum load the gun might be able to stand. Our target and small bird loads are:

28 GA - 3/4 ounce at 1200 fps
20 GA - 7/8 ounce at 1200/1210 fps
16 GA - 1 ounce at 1165 fps
12 GA - 1 ounce at 1180 or if shooting 50 rounds or less in a round of clays 1 1/8 ounce at 1145

For those times that "more" is needed when shooting early season pheasants in SD or sharptails in MT:

20 GA - 1 ounce at 1220 fps
12 GA - 1 1/8 ounce at 1200 fps
12 GA - 1 1/16 ounce at 1325 fps (Bismuth "just in case" a friend and I hunt a Waterfowl Production Area in MT - we haven't yet, the box is still full)

If I can't break a clay or kill a bird with one of these loads I can't do it with a load that might break the gun or my shoulder - my 74 year old shoulder is more delicate.

Several years ago I read a thread on Shotgun World about a cracked AyA No 2 SLE stock - the original poster had been warned that the 1 1/2 ounce at 1440 fps was too heavy for an AyA No 2 but he ignored the good advice he received. The recoil of that heavy, fast load is 54.5 foot pounds - the heaviest load I listed above is 26 foot pounds - the load that cracked the stock had slightly over twice the recoil of the heaviest load we will shoot. Keep your loads reasonable and a Spanish gun in good condition will be fine with SAAMI loads.

Thanks Ted. I read but rarely feel a desire to post :-)

Best right back to you.

What Ted said Kyrie.

Would a 1970s Spanish double, of decent make, come with a hang tag and recommended loads?
What load would have been recommended for a 850 or 900 KGS 20g? 24 gm?
12g? 32 gm?
Thanks.

Found a Sarasqueta hang tag, with reference to the Proof Certificate but no load recommendation



Ted: bet those gunshop fellas got turned around a time or 10 in the Boundary Waters without a map

Some of us need ‘em, some guys didn’t. I had a chart last time I was there, and a handheld GPS. But, the guide on the last church retreat I took there as a kid, perhaps 45 years ago, didn’t. Canoeing around for a week, he knew where he was. He had canoed all over the world. He guided at Y camp Menogyn for thirty summers.
He had a wood framed, canvas covered canoe that was an antique, then. Wonder what happened to him?

Anyway, back to proof. A while back, I noticed that pre 1923 French single proof at 65mm is the exact same pressure level as the 1000 Spanish proof applied to my 3” chamber Uggy, 14,233. I haven’t concerned myself with what I feed the Uggy, and would feed it steel or some other nontoxic if the powers that be told me to. Maybe not the 1500 FPS stuff they sell, but, it is a rainy day gun, bought without a lot of concern for how it holds up. It’ll last as long as me.
Same with the Frenchy. I have been feeding it 2 1/2” ammunition, don’t have a ton of it left, but, I’d sneak a 2+3/4” AA light target load in, here or there without too much concern. Same deal, rainy day gun (I have wealth in rainy day guns).
Photos of barrel markings and non glamour shots of two users.






Best,
Ted

______________________________________________
Put a sock in it, ed. Took me a minute to find my pictures.

When the Aspen Outfitting Company were still selling their Ugartechea shotguns, Jon Hollinger had produced a small brochure for their light game guns which instructed such procedures as assembly, loading, operation, maintenance, choice of ammunition, use of steel shot, etc. I believe at the time, they were offering a lifetime warranty on their AOC/SG Ugartechea light game shotguns.

For the choice of ammunition he had specified as follows:

12 GA. Guns – 7/8 oz. to 1 1/8 oz. of # 6, 7 1/2, 8 or 9 shot. No more than 3 drams equivalent of powder.

16 GA. Guns – 7/8 oz. to 1 oz. of # 6, 7 1/2, 8 or 9 shot. No more than 2 3/4 dram equivalent of powder.

20 GA. Guns – 3/4 oz. to 7/8 oz. of #6, 7 1/2, 8 or 9 shot. No more than 2 1/2 dram equivalent of powder.

28 GA. Guns – 1/2 oz. to 3/4 oz. of # 6, 7 1/2, 8 or 9 shot. No more than 2 dram equivalent of powder.

_________
TC

Thank you Tim.
Those guns were likely proved to the post-1970 Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives standards
12g 50mm, 65mm, and 70mm “Standard Proof” lead or steel (limited to no larger than 3.25 mm and max. fps 1,300).
Numbers are transducer BAR converted to PSI.
Maximum Average (SERVICE) Pressure 740 BAR = 10,733 psi;
Maximum Statistical Individual Pressure 850 BAR = 12,328 psi
Mean PROOF Pressure 960 BAR = 13,924 psi

Both 65 and 70 mm 16g standard is SERVICE 780 BAR or 11,313 psi;
MSIP 900 BAR or 13,053 psi;
PROOF 1020 BAR or 14,794 psi.

Both 65 and 70 mm 20g standard is SERVICE 830 BAR or 12,038 psi;
MSIP 950 BAR or 13,779 psi;
PROOF 1080 BAR or 15,664 psi.

850 kg/cm2 proof was commonly used for entry level Basque 12/70 guns of the 50's through the early 70's. Better grades carried 900 or 1000 kg/cm2 proof with some 12/70 pigeon guns 1200 kg/cm2.
Kg/cm2 as determined by lead crushers is a different measure of pressure than BAR as determined by modern piezo transducers.
BAR was used only after the CIP standards were adopted about 1970

70 mm = 2 3/4"

850 kg/cm2 proof = 12,090 psi for a service pressure of 566.6 kg/cm2 or 8060 psi BUT as measured by lead crushers, so by modern piezo transducers the pressure would be + 10 - 14% or about 9000 psi
900 kg/cm2 proof = 12,801 for a 600 kg/cm2 = 8534 psi service pressure + 10 – 14% or about 9500 psi
1000 kg/cm2 proof = 14,223 psi for a service load of 9,473 psi + 10 – 14% or about 10,500 psi
1100 kg/cm2 proof = 15,645 psi for a service load of 10,430 psi + 10 - 14% or about 11,500 psi
1200 kg/cm2 proof = 17,068 psi for a service load of 800 kg/cm2 = 11,380 + 10 – 14% or about 12,500 psi