new useing chokes

[SAIGAFISH]

i bought a remington 870 express magnum from the gun show
its in great shape and i traded in some stuff ,brand new scope
military 1911 holster and i also gave him 100.$ i thought it was a good deal
but i had it out on grouse hunt todayand one shot was close to
a daugfur and the patern was pretty tight at about 30 yards.
the guy at the show said it was a modified choke so what
chokes are for what.

[zippy13]

There isn't a hard rule about what choke is for what target. There's a variable involved: range. You'll hear full choke for trap and open choke for skeet, that's because skeet targets are shot at a much closer range than trap targets. As a rule of thumb you use a tighter, or more constrictive, choke the farther you are going to be from your target.

A second factor is also at play: the tenacity of your target. At the same range you'd use a more constrictive choke on turkeys than you would for dove. You'd also use larger pellets on turkeys.

Choke selection is a matter of selecting a starting constriction for the target you are going after and then adding constriction as the range to target increases. Many folks provide charts with their suggestions of choke and ammo selection for various targets and ranges. Here's an extract from a typical chart:

Doves & Pigeons.
Use # 6, 7 1/2, 8 & 9 Lead Shot.
For normal ranges, use # 7 1/2 or 8 shot for light shooting.
For longer ranges, use heavier loads of larger shot.
Modified Choke is the most effective.

Ducks & Geese.

Use # T, BBB, BB, 1, 2, 3, 4 & 6 Steel Shot.

For ducks at normal ranges # 2 and 4 shot are the most popular.

BBB shot is the most effective for geese.

Improved Cylinder Choke, for small ducks up to 45 yds.

Modified Choke, for medium and large ducks.

Full Choke, for geese and large ducks beyond 45 yds.

Fox.

Use # BB & 2 Lead Shot.

Full Choke is the most effective.

Grouse & Partridge.

Use # 5, 6, 71/2 & 8 Lead Shot.

On smaller grouse or partridge, use the smaller shot.

Use larger size shot for heavier ounce loads and larger birds.

Improved Cylinder Choke or Modified Choke, for brush.

Full Choke, for open ranges.

Pheasants.

Use # 4, 5 & 6 Lead Shot.

Use # 4 Lead Shot, for field shooting where long shots are typical.

Use # 5 Lead Shot, for over dogs shooting.

Use # 6 Lead Shot for average hunting conditions.

Improved Cylinder Choke, for close cover.

Modified or Full Choke for long field shots.

Quail.

Use # 71/2, 8 & 9 Lead Shot.

For early season shooting on small quail, use # 9 Lead Shot.

Larger Quail and longer shots, use # 71/2 or 8 Lead Shot.

Improved Cylinder Choke or Modified Choke are the most effective.

Rabbits.

Use # 4, 5 & 6 Lead Shot.
Improved Cylinder Choke or Modified Choke, for brush.

Full Choke, for long, open shots.

Squirrels.

Use # 4, 5, 6 & 71/2 Lead Shot.

Modified Choke is most effective and least destructive.

Turkey.

Use # 2, 4, 5 & 6 Lead Shot.

The longer the range, use heavier ounce and larger shot size loads.

Full Choke - Super Full Choke are the most effective.

Woodcock.

Use # 71/2, 8 & 9 Lead Shot.

Use Improved Cylinder Choke in heavy brushy areas.

Use Modified Choke in more open woods cover.

[ebutler462]

Remember the old brass garden hose nozzles? Screw it tight and the water has a pencil thin stream. Unscrew it a bit and the water spreads out.

Chokes handle shot the same way. A full choke gives you a pencil thin pattern. Modified gives you a wider pattern. Improved cylinder gives you a mist, similar to opening up the garden hose nozzle.

[churchill]

sorry to hijack this thread but could someone tell me.....

i have a modified browning barrel for my 303 with fixed choke..
my question is....i measured the inside dia with digital calipers and it measures 20mm...what size choke would that be....
in english size please if possible.
atb.

if not then in american then i can cross referance it on my chart..

[zippy13]

Churchill,
The one measurement isn't sufficient. Not all 12-ga guns have the same bore diameter. For an accurate reading you need to have the diameter of the bore and the choke. The difference is the constriction and will tell you what choke you have.

FYI: Your 20-mm measurement = 0.787-inch which is out of range for a 12-ga!!!
A 12-ga bore is in the neighborhood of .729 -.731-inch or about 18.5-mm.

Here are quasi-standard choke constrictions, in inches, for a 12-gauge:
(I've interpolated approximate metric choke sizes)
.000-in (18.5mm) Cylinder
.005-in (18.4mm) Skeet
.010-in (18.3mm) Improved Cylinder
.020-in (18.1mm) Modified
.030-in (17.9mm) Improved Modified
.040-in (17.6mm) Full choke

[hogdogs]

Zippy, I think he measured the "muzzle" diameter and used the term, "bore" a bit different then us yanks.

church, If you measured at the muzzle, you are referring to the choked end and folks should be able to work with that.
Brent

[Runngun]

All I can say is I use I/C almost exclusively now, occasionally modified, for sporting clays. Today's modern ammo patterns much better than the old fiber wad, no shot cup stuff of years gone by. I do tend to favor modified for open country quail and chukar hunting here in the west, but for hand thrown clays or the sporting clays course, I/C is all I've really needed. I LOVE straight cylinder for skeet in a 12 ga. If you shoot trap, modified will get you back to the 22 or 23 yard line before needing more choke (I have shot some 27 yard trap with the mod. tube in place, and it will break the targets good if you are a fast shooter). All this is just my opinion, but it has worked very well for me, ymmv.

[churchill]

hogdogs........

yes mate....i put the calipers in the muzzle end and it reads 20mm exact..
i have just been to my friends house and used his choke gauge measuring bung and it reads bore on his gauge..

the biggest reading his gauge will read..
any ideas..?
is the term bore used when talking about muzzle size or choke...

or is it another crazy english thing..

cheers all..
oh...it is a 12 gauge..

[hogdogs]

Bore is the barrel before the choke. Choke means the "bore" diameter has been restricted to smaller than bore diameter...

Your caliper is only accurate if it has thin width tips. If you are using the wide (1/4 inch or so) section, it will read smaller as the edges are contacting leaving a gap in the center of the blades. If it is truly exactly 20mm than it would fall into the "x-tra" or "turkey" full choke.
Brent

[zippy13]

Brent,
I think we can all agree that the nominal 12-ga bore is 0.729" with some makers pushing it to 0.731 without calling it an overbore. If you use a conversion table like mine, churchill's measurement of 20mm = 0.7874". That equates to an expansion of .058", for a standard 12-ga, making churchill's gun a blunderbuss. I suspect an inaccurate measurement. Typically if you use "chunky" calipers to measure IDs, they will measure small, not large.

I don't think there is any confusion over where to measure the choke and the bore. The problem is with the accuracy of churchill's calipers.
(Do they have Chinese made Harbor Freight calipers in the UK? )

Churchill,
Since the accuracy of your calipers is in question, try a low-tech solution: roll a strip of paper in the muzzle (the constricted portion of the choke) and accurately mark where the paper overlaps. Lay the paper flat and measure to the mark (the circumference of the muzzle), and then divide by 3.14159 to get the diameter. Compare the diameter to a choke chart. A full choke (based on a standard bore) is in the neighborhood of .690" or 17.5mm.

If you are going to be doing this frequently, then perhaps you need a simple tapered direct-treading choke gauge.

[churchill]

did i mention the barrel is a browning and was a 28"....but cut down to 24"...

ive been given this english chart to compare..
.000" -.001" true cylinder
.002" - .006" improved cylinder or skeet
.007" -.013" 1/4
.014" -.023" 1/2
.024" -.031" 3/4
.032" -.040" full
.040"+ extra full
and got this reply..

the only thing i can think of if you have removed the barrel section upon a back bored barrel, to work out true choke size of said barrel, you take the cylinder size down inside the barrel, then measure the choke size, (at the end of the barrel), the amount of constriction is therefore your choke size, if you can get that measurement (difference between the 2 sizes) for us we can tell you what choke you have. some brownings have back boring in the barrel which is wider than normal 12g to help with the recoil, i have an sneaky feeling you have chopped into this making it into more of a 10b size .... anyone else have the same opinion ?

[churchill]

the gun in question is the second one down...

[zippy13]

Originally Posted by churchill

.... anyone else have the same opinion ?

If your 20mm measurement is accurate, that's a very plausible explanation. So, it seems you have an overbored barrel with a cylinder, or no constriction, choke. If you want something else, then your options are jugging the choke (more overboring several cm back from the the muzzle) or having screw-ins installed. Both methods are contingent on the remaining tube wall thickness.

[hogdogs]

OOOPPPSSS My mistake!
zippy, I was thinking the other direction Sorry to mislead!
Brent

[zippy13]

Brent,
This episode with churchill's overbored barrel shows us how important it is to have bore and muzzle dimensions when evaluating chokes. I assumed churchill's measurement was off and you assumed a super full choke -- we were both wrong. I've been wrong before.
I'm guessing churchill's cut-down and overbored 303 might be a killer on the skeet field.
Cherrs,
Pete

[SAIGAFISH]

this measurement lesson would be better suited for the smithy.
and is there a way ie some markings on the choke its self
obviosly you dont measure bore in the chamber or where the
choke is

[zippy13]

SAIGAFISH,
Sorry about the detour to the land of the overbored.
Back to your question… Yes, chokes are typically marked.
An 870 like yours, would have two possibilities: If it's a fixed choke gun, then there should be a marking of the left side of the barrel just forward of the receiver. Some manufacturers use codes like a series of stars (**, ***) or quarter fractions (2/4, 3/4) to indicate the choke. Remington uses plain English, my fixed choke trap barrel is clearly marked FULL. If you've got screw-in chokes, then the individual choke tubes are marked. With my Rem Chokes (flush), they are marked in English: but, you have to remove them to read the labels. Other chokes are marked in various ways: I have Briley custom chokes that have just the bore and constriction dimensions etched on them. (It's assumed if you have custom chokes you don't need to be told that a .065" constriction is Tight Skeet.) Some flush chokes have a series of small notches on the face (not to be confused with the larger removing tool indents. The number of notches, like the series of stars on the barrel, corresponds to the constriction. This facilitates ID without removing the choke. With extended screw-ins it's much easier. They can be color coded or have the label exposed. Actually, with a little experience, choke tubes aren't that hard to tell apart. My big bore Remington trap chokes are in something like: full, extra full and super full. If you put them next to each other, even my old eyes can tell the difference by looking at the wall thickness.

[SAIGAFISH]

thank you very much for the info zippy and everyone else
thank you to.so i need to get a choke tool.

[SeekHer]

These might help:

EFFECTIVE PATTERN DIMENSIONS (Expressed in Inches of Diameter)
YARDAGE……10…..20……25……30…..40
Spreader…….23…….27…….44…….51…….66
Cylinder……...20…….32…….38…….44…….57
Imp Cyl……….15…….26…….32…….38…….51
Modified………12…….20…….26…….32…….46
Full…………….. 09…….16…….21…….26…….40

Taken from NRA American Hunter Oct. 2006 Issue page 92

A CHOKES EFFECTIVE RANGE (Expressed in yards)

…………………….…IDEAL……....EFFECTIVE
CHOKE………....RANGE…........RANGE

Cylinder……….....15-22.........10-27
Skeet 1………….…20-27.........15-32
Imp Cylinder…...25-32.........20-37
Skeet 2…………...30-37.........25-42
Modified…………..35-42.........30-47
Imp Modified.....40-47.........35-52
Full…………..………45-52.........40-57
Extra Full………...50-57.........45–62

Choke.....
% in 76cm/30" circle
at 37M/40 yds
Cylinder.....40
Skeet........45
Skeet 1.....(46.5) Approximately
Skeet 2.....(48.5) Ditto
Imp Cyl......50
Light Mod...55
Modified.....60
Imp Mod.....65
Light Full....68
Full...........70
Extra Full….75
Super Full...80

Bore.………....Bore
Size..………..Diameter
.........(inches)……(mm)
04.............1.052……….26.721
08.............0.835……….21.209
10.............0.775……….19.685
12.............0.729……….18.517
16.............0.663……….16.840
20.............0.615……….15.621
28.............0.550……….13.970
67.............0.411………. 10.439
68.............0.409………. 10.389
24.............0.579……….14.707
32.............0.526……….13.360
36.............0.506……….12.852

Constriction.....Constriction.....British.............US..............Pattern at
(mm)…...........(inches)….....Designation…..Designation…..36 metres %
0….......................0…...............Cylinder…..............Cyl…..............40
0.25….................0.01…................¼…...............Imp Cyl…............50
0.5…...................0.02…................½…..............Modified…............60
0.75….................0.03…................¾…..............Imp Mod…............65
1….....................0.04…...............Full….................Full…...............70

[churchill]

the barrel thats been in question is actually a spare one i recieved when buying my 303...
the barrel on the gun is a normal 28" multi choke but he gave me a spare..
its 24" the cut down one.
and thinking about it, he was a skeet man..
i thought maybe i could use it for very close rabbit and fox as i do a lot of ferret and terrier flushing where most of my ranges are no further than 15 yards..
it feels great on the gun,very fast to handle being so short.

can anyone recommend a good size shot for this combination...i was thinking 3#s for fox within 15yards..

cheers all for your time and contribution to this thread.
atvb.

[HiBC]

My bird gun is an O/u Berretta with choke tubes.I cannot just buy a new barrel from Brownell's if something goes wrong.

Long experience with close fits and fine threads suggests you truly do not want a little piece of sand to enter into screwing the choke tubes in.

I suggest you be very kind to your choke tube threads.

Clean them meticulously before assembly,male and female.Lube them with a little choke tube lube.I keep mine safe in a small,rigid Otter Box.

My bird hunting is upland,and I refrain from trying to get lucky on long shots.The "Golden BB" can also be a gut BB.

A skeet 2 choke is between. IC and Mod and would be what I would very often have in an upland shotgun

The wisdom of Grandpa on chokes lingers on,but Grandpa's paper shotshell with no shot cup or buffer are long goneWith today's shotshells,we can use a more open choke at the same ranges,and still put the same number of pellets in the bird.

[SAIGAFISH]

so i figured out why wy pattern was so tight becouse
the choke that was in the gun was a full choke,when i
bought the 870 the guy at the show said it was a modified
choke.im sure glad i did,nt shoot any buckshot thought it
when i took it out the other day.so i went and bought
an improved clylinder and a modified that should cover all
my needs

[hogdogs]

You would not have been at automatic risk of firing 00 through the full choke. Steel shot and some non-lead shot may do damage no matter what size shot you use...
Brent

[SAIGAFISH]

that choke said lead or steal. so i could shoot buckshot though
full choke

[hogdogs]

Your patterns may suffer as the deformation on each 00 pellet is more pronounced so more flyers but your safe to do so. Also if you have not already figured this out... with an open action, you need to poke a finger in the tube every so often to insure it ain't coming loose. The danger is a loose tube. it can have the inner edge rolled into the path of the next round with damaged threads in barrel being the least of your concerns...
Brent