20 Gauge Spreaders


Hi technoid,

Thanks for your response last week about using polywad spreaders in my 20 gauge 870 Wingmaster. I have used the polywad and it does spread things out…almost too much however, since in my modified choke when patterning there are some big holes at twenty yards…(as an aspiring junior technoid, I have done my share of patterning over the last several weeks!)

I have tried the Ballistic brush wads and they have opened things up too, somewhat less than the polywad spreader, but interestingly, the pattern is wider than high. Another words, the shot string is not circular on the paper. It is at twenty yards or so with a 7/8 ounce load about 20 inches wide but only about 14 inches top to bottom.

I am seriously thinking about just taking it to a gunsmith and open it up permanently. He also does a complete 3 screw in choke job for about $80, and other shooters in the area say he is competent. I am leaning more to just opening up the modified barrel to improved cylinder or skeet. What are the diameters for 20 gauge barrels for improved cylinder and skeet?

Thanks for your responses,
Terry

Dear Terry,

I have gotten half a dozen emails on the Polywad performance. Most readers have had the same results that I experienced – open and uniform patterns. Naturally, if you extend the range too far, the patterns will degrade and become patchy. It doesn’t surprise me that a modified 20 gauge would get patchy at 20 yards with the Polywad. It might be just a little bit too far for it. My .026″ choked 20 gauge FN’s upper barrel was just about perfect at 20 yards with the Polywad. I doubt if your Mod 870 20 gauge had that much choke- more like .015″ to .018″. My guess is that your Mod choke would look about right at 15-17 yards with those Polywad loads. By the time the shot got to 20 yards, the pattern may have gone to pieces. In some barrels, that little disk really spreads them out.

I’ve never tried the Ballistic Brush wads, but I am surprised that they make the pattern wider rather than higher. If that happened in my gun, I would sure start testing it a whole bunch more. While it probably means that you just had a couple of aberrant patterns, if it continues, it means that your 870’s bore and/or choke is seriously out of round. The shell couldn’t be doing by itself as the shell could just as easily be put in the chamber 90 degrees twisted around. It would then toss the patterns higher than wider and you didn’t find that happening.

As to 20 gauge dimensions, the nominal bore size is .615, but it is quite common to have 20s with tighter bores. Overboring is not common in the 20s just yet. Skeet chokes for 20s vary from around .002″ to .007″, with .005″ being quite common. IC for 20s would add a few points, probably maxing out around .008″ or so. There really isn’t any hard and fast rule. Remember, technically (I just love that word!), IC choke is any constriction which will print a 50% pattern in a 30″ circle at 40 yards. The dimensions of the choke that will do that will vary with the individual barrel and the shell selected. Nothing is writ in stone. The choke designation refers to the performance of the choke, not the particular amount of constriction.

Best regards,

Bruce Buck
The Technoid at <www.ShotgunReport.com>
(Often in error, never in doubt.)

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FN Superposed


Dear Technoid,

I know that you’re not too interested in “old guns”, BUT – here goes anyhow. The fact is, I’ve run out of resources and hope that a light will go off when you hear my question (isn’t that why we all seek our gurus?)

For some time now I have been shooting what I assumed was a Browning Superposed – but it seemed a bit unusual, as it has 28″ barrels, but is equipped with a factory recoil pad (Browning Logo) and has a trap buttstock (1 1/2 comb, 1 7/8 heel) and chokes (IM/F), yet a very slim forend.

At last it dawned on me that it was an F.N. gun – I looked at the barrel markings (duh) and it is clearly an F.N. That would explain why the engraving is in the F.N. “A-1” pattern, and the trigger is blued instead of gold. The serial number indicates manufacture in 1975, and it does have the late “diamond post” rib and a mechanical trigger.

Now, the remaining mystery is this: in addition to the standard F.N. markings, all in their expected places and applied with the usual light stamp, there is also a heavily struck “Browning Arms Co., Morgan, Utah” overstamp!

While winding along your path of shotgunning discovery, have you encountered F.N. guns, made to European specifications, imported and sold in the U.S. by Browning?

You know how we shooters can obsess over such trivia, and the gun is a favorite of mine. It just smokes 16 yard trap targets, and after 2,500 rounds (by me – who knows how much the previous owners shot it) is still so tight that I have to grunt to open it.

Bill

Dear Bill,

It isn’t that I’m not interested in old guns. I just don’t know anything about them. However, 1974 is not old. 1874 is old. And- it just so happens that since you have come to the feet of the Guru of Gunning Geegaws and Mahatma of Machinery, I think that I have the answer for you. I happen to own several guns exactly as you describe.

Your gun is indeed an FN (Fabrique National) made in Belgium. It is most probably a B-25 model standard Belgian Browning and looking (except for the engraving) very much like all the other American – market Belgian Brownings you see around. Of course, it might be the B-26 or B-27 model- a less expensive effort that FN made to compete with the Japanese, but I doubt it as those guns look a good bit different and you would have noticed it.

The FN B-25s made for the European market had some different cosmetics than the Browning B-25s made for the US market. The engraving patterns were different. A 10 mm wide rib was available in the FN, not on the US guns. The FN came out early with an anatomical trigger blade. The FNs of your vintage came with the Mark 5 mechanical trigger, the best trigger that Browning ever made. It was also rumored that the FNs used hard steel in all their guns, while the Browning B-25s made for the US market used a softer steel in the lower grades. I have heard one gunsmith comment that lengthening the forcing cones on a base grade FN took as much effort and cutting as it did on a Midas US B-25 and that the Grade 1 US barrels cut more easily. I have no idea if this is true or not.

FNs were always brought back to the US on an occasional individual import basis, but when Browning decided to get out of the O/U business in Belgium (and since changed their mind and has gone the custom shop route), they packed up a whole bunch of FNs of all sorts of types and sold what I heard was over 800 of them to Jaqua’s in Findlay, OH. This was back in the early ’80s. Part of the deal though was that the guns first had to be re-roll stamped with the Morgan, Utah designation as the FN no where has on it the word “Browning”. There may also have been other outlets for these FNs beside Jaquas that I don’t know of. I bought some of Jaqua’s FN Super Trap #6s at fire sale prices and have frittered away most of them over the ensuing years. Your configuration of 28″ bbl, thin forend and trap stock surprises me, but they sold all sorts of stuff. Sounds like an ideal pigeon gun.

Krieghoff and Perazzi have their devotees and the inexpensive Japanese Browning is developing a good reputation. But for my money, you own one of the best handling and most durable shotguns ever made.

Best regards,

Bruce Buck
The Technoid at <www.ShotgunReport.com>
(Often in error, never in doubt.)

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Chronographing


Greetings Muezzin:

My spring project is to try and measure the verve and elan with which my special concoctions are exiting the muzzle. Have searched the archives and my own library and haven’t really found a discussion on the subject.

Several pictures I have seen show a chronograph firmly ensconced in a heavy timber fortification. I was thinking more along the lines of a couple of pieces of sheet metal bolted to the bar in front of the sky screens. Sooo, I thought I would come to the well of all wisdom before I start destroying expensive electronics.

Also wondering about distance from the muzzle, calibrating with factory loads etc. What would you think of doing a little dissertation on the ins and outs of your technique for chronographing shotshells, for the benefit of the great unwashed.

Best

Bill

Dear Bill,

You mean you want me to soft soap the great unwashed? To tell the truth, I never really thought much about chrongraphing techniques. I just got a yard stick and measured three feet from the muzzle to the CENTER of my chrongraph’s screens and let ‘er rip five times, ten if I was feeling flush that week.

You can get down range velocity from the tables in Lymans reloading handbook. that’s the easy way. If you simply must, you can also chronograph down range velocities by putting a piece of 3/4″ plywood in front the chronograph with a strategically cut 2″ hole which will permit any pellets which pass through the hole to go directly over the skyscreens. Make sure to always measure with a tape measure from muzzle to the center between the two sky screens. Pacing off or guesstimating really won’t cut it in the world of aspiring Junior Technoids.

When testing for three foot muzzle velocity, I never bothered to tie my chronograph down or protect the front in any way. Muzzle blast never moved it and the LED display never got messed up with burnt powder. I guess that if you wanted to be safe, you could duct tape it to a stand or table and put a piece of clear plexiglass over the LED display on the front.

Calibrating against factory loads has its down side. If you shoot a certain factory load in matches and want your reloads to equal it exactly, then by all means test the factory load and match the reloads to it. On the other hand, never assume that factory loads of a certain dram equivalent will be dead on the nominal velocity. They seldom are. Watch out for consistency with factory shells also. 25 fps variation is not unusual. Some match quality .22 rimfire cartridges are consistent enough to set your chronograph with, but no shotshell is.

I wish that it were more involved so that I could awe the populace with my expertise, but it isn’t and I can’t. Even if it was, I couldn’t. The muezzin just calls ’em in. He doesn’t make the rules.

Best regards,

Bruce Buck
The Technoid at <www.ShotgunReport.com>
(Often in error, never in doubt.)

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