What Kind Of Choke Is This ?

[TomV]

I found a well used Wingmaster to try some Trap Shooting with.

It has a Remington 30" barrel on it, with this choke.

The choke is only marked with "I.M.".

My question is what brand of choke is this? In case I want to replace it.

Also the gun didn't come with a "choke wrench". I assume the choke needs to be more than "finger tight" ?

Thanks

 

[halfacop]

Are you asking what brand of choke or what IM stands for?

As far as the brand - I am not sure................but...............

Improved Modified


The choke just needs to be snug, Not wrenched tight. A remington tube wrench is all you need or just a straight piece of metal stock thin enough to lay in the grooves. Put some choke tube lube on the threads and screw it in and snug it down.

 

[Pete409]

TomV,

I think that Remington calls their chokes "Rem-Choke" (with the possible exception of their latest offering produced just this year). Numerous companies manufacture and sell "Rem Chokes" which should fit that gun.

According to my measurements, Rem Chokes are for 12 gauge bores of about .726" to .727" in diameter.

As "halfacop" said, the IM stands for Improved Modified which is between the Modified and Full chokes. The IM choke is excellent for trap shooting. You might want to purchase an Improved Cylinder choke for a more open pattern suitable for sporting clays and perhaps even skeet.

By the way, the choke tube doesn't have to be tight, just snug. If you don't have a choke tube wrench, a quarter will usually do the job just fine.

 

[TomV]

Thanks Guys,

That answers my questions. I'm going to try some Trap for the first time. So I will see how the gun & I do before doing anything else.

 

[kirbythegunsmith]

Details

What you happen to have is probably a barrel that came without choke tubes and was subsequently fitted with off-brand tubes, since the Remchoke will not fit most older Remington barrels. Look near the breech end left upper side, and a small stamped "MOD" or "FULL" is probably located there. Factory Remchoke barrels would obviously have no such choke marking there.

What you most likely have is a Tru-choke or Colonial style of tube installed. I never installed such tubes since I saw the types of tooling offered to fit these chokes. Some versions use a brace and bit driver at the end of the reamer. There is a fine way to maintain accurate alignment, wouldn't you think?

The most important thing to do is to check the alignment of the tube, as least as far as point of impact on paper is concerned. Why waste money on shooting or more choke tubes if the hole is misaligned? A new hole can be installed straight, if need be, and a straight choke in a shorter barrel is going to be more satisfactory than a crooked choke hole in a longer barrel.



There you can see that the Remington threads are of a shorter length amount of the tube, and fit more deeply into the hole in the barrel vs. what you pictured. The threads appear to be coarser for the Remington tube, and many novices will claim that the Truchoke etc. is a 44TPI pitch. They are wrong, and must have erroneously measured or been mis-informed. The pitch is a double-lead 22TPI, and consequently coarser pitch than the factory 32TPI, but made to be a shorter height (or depth of cut) in the metal.

See my previous postings to understand more about improper vs. proper choke installation and fitting, and more such info. is at my website page.
Look at the page links for "article selection" to see the latest articles linked together.

 

[Pete409]

Kirby brings up a very good point. If the barrel is stamped with some choke on it (such as Full or Modified) then it obviously was originally a fixed choke barrel and the removable chokes in the gun now are some aftermarket type. They may or may not be Rem Choke chokes.

It might help if you counted the threads in one inch (or 1/2 inch) and let us know what the count is per unit length.

 

[TomV]

The barrel is stamped FULL. The choke fits in the barrel nicely.

I'm guessing from the lots of similar wear on both the gun and the barrel, the pair have seen lots of use.

Maybe I'll look for another barrel ?

 

[Pete409]

TomV,

Then obviously the choke is "aftermarket". Nothing wrong with that in particular if it was done right. It's hard to wear out a shotgun barrel.

 

[kirbythegunsmith]

Details

Did you notice the picture I posted with the Remington tube adjacent to the Tru-choke tube?

Scroll up to see the picture he originally posted of the tube from his barrel, and see that it is a perfect match with the Tru-choke and not the Remington tube.

The ruler shows his tube internal section is less than 1-3/4" and the Remington tube is at 2.030", plus the thread appearance is identical.

I counted roughly 34 thread points in his picture, which is about a 3/4" length, and 17 actual threads @ 3/4" = 22 nominal threads to the inch, which is way off from 32 per inch Remington.

Here is something from a posting by someone putting in chokes, and he states that the Tru-choke variants are 44TPI:

1) I am set up for 12 ga Rem Choke in a few pilot sizes.
I can only modify half of my massive beater shotgun collection.
Many of the barrels are too thin for my 32 threads per inch system.
I need a barrel to be .845" diameter.

2) Winchoke is also 32 TPI and needs .845"

3) The Tru Choke system with 44 TPI needs at least a .825" barrel muzzle.

4) The Tru Choke Thinwall aslo with 44TPI needs at least .805"

Since Brownells also has the choke listings for the tube and installation tooling as ...x 44TPI, I guess that other people not knowing better is just the way it is, but you would think that a big company full of technical experts would be more precise. The tubes from various manufacturers have also been listed the same way (44 TPI).

Do you think it would be amusing for some goof with a lathe trying to make a duplicate tube to fit your choke hole, and making it as an actual 44TPI? I had seen just such an un-bee-leev-able job where the totally unaware and clueless dude was realizing only that the tube didn't want to go in more than a turn before it got impossible to continue.
What did he do then? Try to cut the thread deeper, and when that failed to materially improve the situation, he started running the tube in and out while there was some Clover grinding compound smeared in the hole, and he LAPPED that tube in until it would go all the way inside!!!!!


Just another reason why I never want to be involved with any of those type of tube installations: too many possibilities of screw-ups and no way of proving that a bad one wasn't done at your shop, unless you never do them AT ALL.