PDA

View Full Version : Thoughts on chokes....


Dave McC
March 29, 2002, 06:04 AM
Someone managed to reach me through E mail on this, and on the premise that if one asks, maybe 100 need to know, here's something on chokes, choke tubes, and the arcane and mysterious world of pellet performance.

Maybe you've stood and waited on a clays course while someone switched tubes for a shot that is maybe 4 yards further/closer than the last one, which they smoked.

Or maybe you've toyed with the idea of spending your hardearned money sending your trap gun to Stan Baker for a rebore, choke work and a shiny new forcing cone.

Well, here's some info that might surprise you.

Briley makes choke tubes in 10 contrictions, and sells lots of complete sets. Now, given the fact that straight Cylinder is a fine choke out to 20 yards, and maybe 25 with a top quality load, and Extra Full can hit things hard at 50 yards, that means the 25-30 yards in between has 8 different chokes possible from this maker. Sounds like overkill, huh? Maybe....

Here's some of that arcane stuff.

Firs,remember that the marking on the choke are merely educated guesses by the maker.

Patterns neither open nor close in a linear manner. Sometimes a change of a few thousandths makes an enormous difference in how the pellets pattern. Pre plastic wads, few true cylinder chokes were around, since the loads of those days tended towards raggedness without a few Points Of Constriction. Newer loads do not, and a true Cylinder choke is a marvelous tool at closer ranges and with good loads.

So, for the obsessed and those wanting to wring the last bit of performance out of their equipment, patterning with those 10 choke tubes and the loads of choice means getting the exact spread and density wanted at a given range. For an dedicated turkey hunter or a quail wizard, this is the same, tho they're looking for performance under criteria that vary.

Same applies to an AA27AA trapshooter, tuning his pattern to give the best spread while maintaining good density way out there.

But this doesn't mean we all have to have the mortgage money tied up in chokes. Figure out the mission, test choke/load combos and go with the best. And remember the load has as much to do with the pattern as the choke.

Brister reported in his magnum opus that changing the load can alter the pellets in the pattern up to 40%. Just switching pellets from cheap soft shot of dubious roundness to hard trap grade shot of better quality will do close to that. Dropping the velocity a hair might also. Fast, soft shot deform under the pressures and accelerational forces of being fired more than hard shot launched as a more sedate pace.

And, my slipshod and rough testing shows that elongating the forcing cone gives about the same effect as tightening the choke almost one increment, like IC to Mod. This is with coarse shot,I've not tested fine shot enough to substantiate similar results.

So, how many chokes should the all around shotgunner have? As many as needed. And that is probably around 3, IF they're the right constriction for the job.

And the job is roughly to produce a pattern at a given range that is as large as possible while maintaining sufficent density to put 3-5 pellets of sufficient energy and size into the vitals of a bird, or 3 pellets into a clay.

And, while the ballisticians preach about 30 inch circles, most folks are doing OK with 26"-28" of spread. Past that, the edge does get ragged.

Barring slugs and steel, a shotgunner that shoots lots of clays and upland stuff should have an open choke, something around Modified, and something tight for starters. Call it around 5, 15 and 25 POC with leeway on all. And again, your needs may vary. A woodcock double choked zero and 5 POC is more useful than the common IC/Mod combo. OTOH, a prairie pheasant chaser who goes after cranes each year might do best with Improved Mod and Full.

And for those with just one choke, all in all I'd pick a light Modified, opening and tightening the pattern as needed with load selection.This would work for 16 yard trap and much bird hunting, tho like all other compromises, not as ideal as a dedicated choke.

HTH, and sing out if there's questions...

K80Geoff
March 29, 2002, 09:11 AM
Cylinder , Lt Modified and Full.

0,.15 and .30.

Will probably handle any situation.

I find 90% of the shots I encounter on sporting clays courses can be handled with Lt Mod or .15 chokes. Long shots need full choke and anything under 20 yds gets cylinder.

That said I have a full series of Briley chokes for both my Remingtons and K80:D

Sometimes I change chokes just to annoy other shooters who complain about my choke collection.

I have noticed that the three chokes I mentioned were the ones I used most often over the years. So owning the entire range or chokes was really just a way of finding out what I really needed.:p

Dave R
March 29, 2002, 07:05 PM
Excellent info, as usual, Dave.

The only thing I can add is to reinforce that the most important thing is to pattern your load with different chokes/distances and see which works best for you.

For example, my ol' Mossy 835 shoots 00 buck tighter at 25 yards with a modified choke, than it does with a full choke. I would not have guessed that if I hadn't tried it.

I suppose that has to do with pellet deformation. Regardless, I now know how it shoots either way.

Nevada Fitch
March 29, 2002, 08:43 PM
I am not talking about taking first place in a sporting clays match here, but under hunting conditions, after many years of hunting I tend to think that modified or full choke makes a pretty good all around gun if the person firing it can shoot.

In my younger years when I was a teenager I quail hunted a lot and my Grandfather always swore by improved cylinder so that is what I used and I really thought it was the best for quail, but I am not so sure anymore, same for phesant.

I also remember a question brought up at a hunter education course I took many years ago. I was probably 28 or 30 at the time, regarding what was the best choke for quail and our instructor insisted that full choke was the best. I was flabergasted. This was the most stupid thing I had ever heard of at the time. I am 45years old now and I am not so sure it was that stupid after all. Now My favorite gun for most any kind of upland game hunting is my Winchester mod. 23 side by side bored modified and full, and I shoot it better than anything I have ever used. I have patterned it some and It does shoot a beautiful pattern with 7 1/2's with both barrels. And I have seen others that had pumps and autos with full chokes all of their lives and were very deadly on just about anything.

At any rate what I took for the gospel in my youth ain't nessarily the whole story.

Dave McC
March 30, 2002, 06:38 AM
Thanks for the responses, guys. A coupla things....

Geoff, I'd wager that your approach can bring in the best results. Again, it takes testing to make sure one is getting the optimum pattern at a given distance. You did that, Huzzah!

Dave R,your 00 results are not unusual. Many shotguns pattern big buck better through a choke more open than Full. Modified seems to be the pivot point, so to speak. Many shotguns pattern beautifully with a Modified choke and 00. My "Deer" 870 does better with Winchester generic 00 with the IC tube, but the Estate works best with Modified in this example.In the last, the difference ins't great.

Fitch, like many of my generation, the epitome of bird guns was a long bbled pump or auto "choked down like a rifle". I was probably 30 before I tried a choke less than Modified. I liked it immediately.

Now, I tend to use better shells, more open chokes, and my bird/shell ratio is much better.

I think the key is finding out what works for you under certain conditions.

BTW, 23s are oneheckuva bird gun.

PJR
March 30, 2002, 09:07 AM
When shooters used fiber wads and soft as butter lead in the old days, tightly choked guns made some sense. Today with improvements across the board in shotshells, more open chokes will get the job done whether at targets or game.

I get somewhat frustrated when I hear a veteran trapshooter advise a newby to use full chokes at 16 yards. It's way too tight and ensures more misses. Most 16 yard targets are hit at 30 to 35 yards and Modified is more than enough.

My preferences are .005, .015 and .025 which translates to skeet, lite mod and improved mod. I agree with Geoff about the suitability of .015 constriction for sporting clays. Its also the left barrel in my game gun and hasn't let me down when called upon.

K80Geoff
March 30, 2002, 01:49 PM
Dave...I am not sure how scientific I have been in choosing chokes. I just looked into the choke box and picked out the dirtiest chokes. Obviously they were the ones I used consistently.

By far the Lt Mod .15 is the choke I use most. Cylinder gets the call for close in targets and bunnies (clay variety). Full choke for those long crossers.

I plan to start shooting Sportng heavily this summer and will only be carying the three chokes in my bag.

The technoid recommends much the same setup .00, .15 and .30 constrictions. He has written copious volumes on the subject.

If I were to set up a SXS for bird hunting I would probably go with .15 and .25. And develop different shells for different situations. But as you know I am not an experienced bird hunter so take my advice for what it is worth.

A shooting buddy who does hunt uses an old LC with Imp Mod and full chokes for everything! Makes use of special spreader loads for some types of birds.

Dave McC
March 30, 2002, 02:25 PM
Paul, there's a good reason for a tyro at trap to use Full choke, or tighter. He/she will miss some birds, but learn to hold tighter. I ran my first 25 less than 6 months after starting trap, IIRC, I doubt I could do that as fast if I had started with less constriction.

However, a complete rookie to shotguns should use a more open choke and .015" sounds good. Rookies need victories. I was no rookie.

Geoff, sounds like you went with what works, always a good approach.

Except for turkeys, I see little need for more than .030" consttiction. With the TB at .038" I'm way overchoked. That's one reason I use 8 1/2 shot in my trap loads, to open the pattern a trifle w/o costly smithing.

labgrade
April 1, 2002, 03:21 AM
And no matter all the good advise above - your shotgun will shoot your load best with what choke patterns it best.

I guess if everyone was shooting #7-1/2 AAs, some correlation could be shown, but with the various promo-loads + being used, you have to pattern. Soone as you change the load, all bets are off.

The only way to be sure it to actually shoot it & see.

DML
April 4, 2002, 04:25 AM
Dave McC and a few others got it right. More often then not the performance of a particular choke depends more on the shot size then the actual restriction. There was an article in the GUN DIGEST a number of years ago where the author got eveything from skeet to full choke patterns from a Remington 3200 O/U by just changing shot size. I seem to remember that the barrels were bored skeet and IC. I'll have to see if I can find that issue and read it again.

Dave McC
April 4, 2002, 05:53 AM
Good point,Labgrade. It boils down to what works, and oft an ammo change works better than swapping chokes.

A little known fact. The folks who really know this stuff tell me that oft a shotgun that patterns well with 7 1/2s will not do nearly as well with 8s, same make and model.Or vice versa.

Dennis,thanks. Since you're a smith, would you care to comment on the effect the forcing cone has on spread and pattern? I think Frankenstein got much better patterns w/ turkey loads post cone work, but I didn't grind out enough patterns first to quantify it.

labgrade
April 4, 2002, 10:56 AM
Not only shot size, DML, et al, but too the hardness of the shot & type of wad/shot cup as well.

I'd bet one could get a decent "choke spread" just by tinkering with these & all without changing the choke at all.

DML
April 9, 2002, 03:19 AM
Dave McC:

I am far from an expert on this, but from what I have seen, lengthening the forcing cone does 2 things. It reduces felt recoil, but not everyone seems to notice. Small folks like me notice it more then big dudes. It's hard to quantify, but it is there.

The 2nd effect just makes common sense. When the shot charge leaves the shell it will expand to fit the chamber in front of the forcing cone. When it runs into a steep forcing cone it has to be jarred and a certain percentage of the shot has to be deformed. It seems to me that a long tapered cone would smooth the transition from the chamber to the bore and maybe the shot will stay round. It seems to me that round shot will fly truer then flat shot.

There must be something to this if Remington and a couple of other companies have been making berrels with longer forcing cones since Vang Comp made the process part of their barrels with very good results.

It would be nice if someone did some scientific testing to see what really happens, but it would be very expensive and probably not worth the effort.

labgrade is correct. Changing anything in the shells will have an effect on the patterns. Unfortunately, the only way to tell what that effect will be is to test the shells yourself and different guns may respond differently.

Dave McC
April 9, 2002, 05:03 AM
Thanks, DML. Brister mentions Stan Baker altering forcing cones in Shotgunning,which was copyrighted in 76. So does Nash Buckingham, who did most of his experiments before WWII. Supposedly, Uncle Dan Lefevre went with long cones in Nash's Heavy Fox 3" mags.

I can't feel a difference in recoil. Others seem to. 00 patterns improved when I had my HD 870 done, and so did my Deer 870.

I'm glad that the big companies are taking note. The short cone has been obsolete since cardboard wads were replaced with plastic...