Choke Variances...

[Joseph Sheerin]

So, I picked up a choke mearuring tool.....

Checking several of my guns, noticed the following.

1926 Parker Trojan, IM/F.
1927 Ithaca NID marked M/F is exact to the gauge as M/F.
1947 Model 12 marked F is exact to the gauge.
1926 AH Fox 16ga , per the gauge, it's IM/XF
1940 LC Smith 16ga IM/XF.
1947 Lefever Nitro marked F/F is F/F.

So, were chokes a bit tighter than todays in the 20's for Fox and Parker?
Or, is the R barrel of the Trojan likely F originally, then someone had it changed to IM? That doesn't make much sense, if you were opening it, why not go to M or IC?

Also, I have some removeable choke tubes from newer guns, that the gauge is way off on per how the chokes are marked.... Original Browing Invectors are true to gauge, but the Invector Plus, the F, shows as M, and the M, the gauge completely slides through it.

I read a review on this gauge where one guy swore it was off, because he had guns that he thought were full or Mod, that showed as Cyl, but the gauge is dead on for my Ithaca, and Winchester vintage guns..... It was all I could do to reply back to the guy that his guns were maybe not what he thought they were.... :D

Mostly curious about the Parker, as I thought all Trojans were F/F or M/F, but my right barrel is definitely IM on this gauge.

[John Davis]

According to the "Flying Ducks" catalog, circa 1913, chokes on a 12 gauge Trojan with 28 in. barrels were mod and full. 30 in. barrels were full and full. 16 and 20 gauge were both mod and full.

[James L. Martin]

What kind of tool did you get? If it's one that only goes into the end of the barrel it can and often is way off.You need a dial type that goes a foot or more into the barrel so you can measure the bore relative to the choke.

[Joseph Sheerin]

What kind of tool did you get? If it's one that only goes into the end of the barrel it can and often is way off.You need a dial type that goes a foot or more into the barrel so you can measure the bore relative to the choke.

Just one of those simple tools, like galazan sells....

[Joseph Sheerin]

My gun is a 1926 gun, with 30" barrels

[Joe Dreisch]

If you are using a plug in gauge similar to the Galazan model you are not getting a true reading of what the points of constriction are relative to the actual bore diameter of the barrel. Those types of gauges are machined and marked relative to the supposed nominal bore diameter such as 12 ga. = .729. My Galazan gauge measures .690 for the full choke ring. Subtracting the constriction from the (supposed) bore would then yield .039 or full. Many early guns were bored different from nominal so what you see from a plug in gauge can be very misleading. You need a bore micrometer similar to a Skeets Bore Gauge to determine actual bore diameter then points of constriction and do the subtraction correctly.
The Invector Plus Browning guns are back bored so the chokes are relevant to their actual bore diameter which make them seem open using a plug in gauge. Hope this helps, Joe.

[Pete Lester]

The only way to measure choke performance (the only thing that matters) is to pattern the gun by shooting into a 30" circle at 40 yards and determining the % of pellets in the load inside that circle. Every other measure merely tells you the constriction, some tools do it roughly and others do it precisely in thousands of inches. I have mentioned before I have a Remington 1900 KE with .014 and .024 constriction and it shoots 72% and 86% or full and super full yet the measurements suggest IC and Mod. I have a barrel on a Lefever 10ga with .018 constriction and shoots 85%. With .018 in 10ga I expected a light modified possibly IC, not super full. Conversely I have a 20ga Trojan with .005 in one barrel, I expected IC, it shot 33%. The other barrel has .012 and it shot 56% which is what I expected.

[Garry L Gordon]

Remember that there is a significant difference between shells made at the time the gun was made and our current offerings, even RST shells. I have found a drop in choke gauge to be *almost* useless. As already posted, constriction is a strong clue, but the pattern board is best indicator. I have found that I can “change” the pattern by a choke designation by changing loads (even without spreader inserts). Always best to pattern the gun with the shells you plan to shoot.

[Dean Romig]

And when these chokes were originally cut, plastic shot cups and shot collars had not yet been invented and some resulting shot deformation was not uncommon. This often resulted in a slightly more open pattern than we might see today using the same load and shot size but with the advantage of cushioned plastic shot cups which protect he shot from a similar deformation... often resulting in tighter, more uniform patterns.





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[Brian Dudley]

If you are just using a drop in gauge, then you do not know what the chokes are. Period.

Those are only accurate if the bore measurement is nominal for the given gauge (ie: .729” for 12g).

[scott kittredge]

the Gauge will get you in the ball park as to what it MIGHT be choked , but you have to put it on paper, that's the only way !
Scott

[George Davis]

Extremely interesting read about Canada and what happens with screw in chokes.

https://myemail.constantcontact.com/For-Immediate-Release---Trudeau-and-Blair-BAN-12-Gauge-and-10-Gauge-SHOTGUNS-.html?soid=1124731702303&aid=qVZNyF4JSg4&fbclid=IwAR1VZ4dn7jyZ5ZbRWVPWmAq2Mv55gsqUxW-WWCVFv5CpXIJHPBAqPrmkry0

[Brian Dudley]

the Gauge will get you in the ball park as to what it MIGHT be choked , but you have to put it on paper, that's the only way !
Scott

Not in the case of earlier guns.
I have had IM and Full choked guns measure as IC or Cyl with drop in gauges. If they are over bored enough. That is pretty out of the ballpark.

[John Allen]

I agree with what everyone has said about drop in gauges.They can be very misleading.The older guns had to have more choke to compensate for the less advanced ammo.Now with harder shot and shot cups much less choke is needed.I have a 16ga.VHE choked cylinder and mod from the factory.The cylinder barrel is true cylinder with zero constriction.It throws a perfect modified pattern at 30 yards and the mod barrel patterns full.You always need to put them on the pattern board to really see what you have.

[Joe Graziano]

Let’s face it, very few guys have bore gauges to measure choke relative to the bore diameter. At best, we had a little drop in gauge to give us a rough idea. If the choke gauge stop at F, odds are it’s going to shoot pretty darn tight patterns. If it drops in to C, it’s gonna shoot a more open patter. Something in between will give something in between. A pattern board helps a lot. Best things is to go shoot clays with it.

[scott kittredge]

Not in the case of earlier guns.
I have had IM and Full choked guns measure as IC or Cyl with drop in gauges. If they are over bored enough. That is pretty out of the ballpark.

We all know or should by now that earlier guns are over bored ( I just take that for granted) that's the ball park part of it. I shoot A LOT of test patterns . I found that for the most part these guns shoot tighter that what the chokes say they should. I have shot 1 oz loads of old Remington 4's from the late 40's to early 50's with out the plastic wads and got 83 % patterns out of my .035 (full) choked 12 ga.. parker would not worry about constriction, they would shoot until they got what pattern they were looking for I would think ??
scott

[Pete Lester]

Let’s face it, very few guys have bore gauges to measure choke relative to the bore diameter.

......and very few guys take the time to pattern their guns. Here is an idea, maybe some of the vintage gun shoots could set up a bench and a target frame at 40 yardsf rom it and sell the pattern sheets at the registration desk.

[Daryl Corona]

Joe from Mo; Don't drive yourself crazy worrying about chokes.

Pete and Scott do it the right way and are diligent pattern testers and their success in the field and on the clays course show it. I pattern every gun I own as soon as I get it and am more concerned with the point of impact (POI). It does'nt matter what choke you have if it's not going where you want it to.

My advice falls in line with Joe G. Shoot all those guns with whatever load is comfortable for you and shoot lots and lots of clays. A comfortable load allows you to shoot more, period.

Remember- Chokes are measured in inches; Misses are measured in feet.
Keep shooting until you are not chipping targets on a regular basis and are getting nice even breaks. Then you will know that target is in the center of your pattern no matter what choke constriction you have. You will be surprised at how well you can shoot a tightly choked gun.

[Harry Collins]

A man could remain happy if he never does the following: pattern his shotgun, checks his cholesterol, or has an AIDS test.

[Joseph Sheerin]

Love all the comments, learned a few things new to me. So thanks for all the input.

I shot 4 rds of trap with the Trojan yesterday, using herters low recoil 1060 fps target loads. I am not the best trap shooter in the world, but it's managing to bust 20+ birds per round, which is about par for me. I am getting better at shooting this gun, and can't wait to have some pheasant or ducks in front of it. Still not shooting it as well as my Citori's, but it's getting better. Seems like it hits just a tad lower than my Citoris.... But that's just the way it feels. They used to have a patterning board at that gun club, but they no longer do... I'll have to go out to the other gun club to pattern it, and that's a bit longer drive for me.

I just find it interesting that my Ithaca made guns are exact to the gauge, and some of my other guns are not. Never realized that the choke was relative to the bore, I just thought a full choke was a specific diameter..... The right barrel is definitely a bit more open, so I assume it's M, and the other F. Unless someone actually did take a F/F gun and make it IM/F. Either way, it's fun to shoot, and it should do nicely on pheasants.