doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Merkel chokes

I have a 16 ga SxS with IC and Mod fixed chokes.
Do those chokes have the same amount of constriction as a 16 ga made in countries othet than Germany. Or is the amount of choke restriction standardizes across geographies?

Thanks

Hi, German guns tend to be choked a bit tighter, but that's not cut in stone. The only real way to find out is to get a good bore gauge that you can measure the bore diameter, then what the choke diameter is. For example, if the bore diameter is .729 (12ga) and the diameter at the choke is .709 you have a constriction of .020 which would be Modified. Bore diameter will vary from gun to gun and if a O/U or SxS barrel to barrel. Choke will also vary like the bore diameter. So you really need to measure. I have guns (and choke tubes) that are marked Mod for instance, but really measure out at IC or IM depending. But, then to make sure what choke your throwing, you'll have to pattern the gun, which will take time and even then, the choke may vary from load to load. Just a matter of time and experimenting.

I can suggest a quality gauge, accurate and easy to use, not cheap, but it's a quality product:

http://www.theunloader.com/

Good Luck!

Greg

Many shotgun gunsmiths have special tools to measure bore diameter, and the amount of choke.

If you live near a Cabela's, they also have this tool in the Gun library section of the store.

Most will measure for you at no cost.

It may also be worth your while to pattern each barrel on a large piece of paper.

gold40

About ten years ago I reviewed a Merkel 2116 SxS with 20 and 16 gauge barrels. Both barrels were marked Improved Cylinder and Modified. The 16's bore was .007" overbore (.677 instead of the nominal .670") and the chokes measured .008" and .018" constriction.

That's it for a sample of one.

Bruce

In fact nominal size for a 16 gauge bore is .662" or 16.8mm. At .677 that bore was actually .015" oversize. At one point L C Smith bored their 16's to .650" or .012" under nominal. Later on they changed to the standard .662", with I presume a bit of manufacturing tolerance.

I'm predominately a Fox guy and factory bore for early Foxes were always under .662. They ran more around .658. I've owned several Merkel's over the years including 16 gauge and they ran under .662 also.

Many makers bored their barrels to other than nominal size for the gauge. Some were over while others were under. If you look in the proof house specs though you will see the nominal bore for the 16 is .662". This is based on the volume of a .662" diameter ball of pure lead will weigh 1 ounce or 16 to the pound. Matters not what any individual maker bores their barrels to, this is the nominal gauge size.

German guns, in general, seem more likely to be underbored than overbored, and more likely to be choked tighter than the typical constrictions for the given choke. But the only way to know for sure is to measure with a bore and choke gauge, as indicated above. The "drop-in" type choke gauges only give an accurate reading if the bore in question is standard diameter, or very close to it.

In some cases, the Germans are helpful in telling you how the gun is bored. I had a 20ga Sauer from the 1930's, A&F import, that was significantly overbored. In effect, a 19ga rather than a 20. But that was marked on the barrel flats, so I was not surprised when my bore gauge read close to .630 rather than the 20ga standard .615. And in the case of that gun--and others that are significantly overbored or underbored--the drop in choke gauge will give very misleading readings.

I have 3 Merkel SxS's in 28, 20, and 12 gauge. the bore dimentions are on the bottom of the barrel flats. The bore measurements are very close to standard published dimentions, if not slightly overbored. The chokes on all 3 guns are marked IC/MOD, and all measure .008" and .018". Odd indeed, but the big mystery to me is that all 3 throw beautiful IC/MOD patterns. I had the barrels measured at each purchase and found that the forcing cones in the choke area are somewhere around 6-8 inches long.
I have 2 Browning BSS-sidelocks in 12 & 20 gauge which measure conventionally, go figure.
Karl

df06, FWIIW, choke effect is controlled almost exclusively by constriction. Therefore, you really must be able to measure it reasonably accurately if you want to know what choke a barrel has. "Accurately" means within 0.003". And that basically means a caliper type tool. You must be able to measure bore diameter just before the constriction and the minimum constriction bore. Compare diameter constriction to the standard choke constrictions for a name for the choke.

Patterning. Can't recommend it unless you are really invested in knowing. Even with the very best shells and guns, there is so much variability from pattern to pattern that you must have 10 patterns per load and barrel combination. Further, you must run a statistical analysis on all 10. The first pattern might actually be an average pattern or it might be an outlier - no way to know.

Fortunately, if you are willing to shoot the patterns, digitally photo them, and run them through the Insights program, you can know for sure. It is a lot of work, but it is real.

DDA