What standard of accuracy for rifled chokes?

[Naphtali]

I searched current threads but didn't find my question discussed.

I am having shotgun barrels altered to accept removable choke inserts. There are many manufacturers of rifled inserts. Since I can have Stan Baker alter my barrels for any maker's inserts,

1. What kind of accuracy should I expect to 100 yards from these rifled chokes using factory ammunition.

2. Among the many rifled choke inserts, which are the most accurate? Whose rifling is deepest?

3. If ammunition type is important, please identify ammunition that allows a rifled choke to be accurate. If you could briefly explain why this is so, that would be helpful.

4. I have 12-, 16-, and 20-gauge shotguns that I want altered. Considering only accuracy, is there a significant difference among the three bore sizes when using factory ammunition with rifled chokes?

5. If I want to try making my own "slug" ammunition reloads, what factors in bullet/projectile selection are important? I wonder about how the rate of twist such a short rifled tube works [together] with a bullet's shape?

[savageT]

Naphtali,
Some excellent questions ............
I personnally believe that rifled chokes are a poor substitute for a full-length rifled barrel.  I believe you will find accuracy with a smooth bore-IC choke bbl. to be as good as one with a rifled choke. Why go to the expense of altering a barrel for screw-in chokes unless you want them for other types of hunting as in duck, geese, turkey, or field use?  There are rather inexpensive new barrels made with rifling for slug use (Remington, Mossberg, Hastings).  Let's think this over from a different perspective.  What did Mr. Baker say to you about your plan?

Jim

[Naphtali]

Stan will do what I request. His expertise is regulating barrels for shot, and in doing what he contracts superbly.

The situation is that I have shotguns with additional barrels. The cost to create additional barrels is prohibitive. The cost to adapt an existing barrel is acceptable.

I accept that rifled choke inserts are not as accurate as full-length tubes. Unfortunately, this cannot be achieved. I rule out buying a shotgun specifically for shooting slugs.

So we revert to what results should I reasonably expect from rifled choke inserts. I suspect some unrepentant experimenter has tested myriad options to identify the information. All we need to do is get him released.

[BH]

Naphtali,

I will attempt to give you some general input here but as you’ll see it’s not, for the most part, going to directly answer your questions.  My experience with rifled choke tubes is limited mainly because the few my friends and I have tried to make shoot well have been big disappointments. After spending more on ammo experimenting than it would have cost me to buy a fully rifled barrel I gave up on the tubes.

With sabot slugs in a rifled choke, accuracy will not be much better than an open choke smooth bore shooting Foster slugs and sometimes much worse.  I’ve seen several combinations of rifled tubes and sabots where the bullets were tumbling and it was hard to even get them on the paper at 25 yards.  Inspection of the sabot sleeves indicated that the rifling never fully grabbed the sabot (sleeves were tore up with no clear rifling marks).

It is nearly impossible to answer which inserts and ammo are better other than saying that I think the longer the tube you can get (within reason) the better.  There are so many variables involved (sabot design, bullet weight, bullet shape, tube twist rate, velocity, the gun itself, etc.) in addition to the fact that even shotguns and tubes of the same make seldom perform exactly the same with the same ammo.

Considering only accuracy, I don’t believe there is a “significant” difference among bore sizes when using factory ammunition with the same barrel type and slugs (although I’ve never shot slugs through the 16).   I do believe the 20 has a very slight edge over the 12 although not enough to make it a real determining factor.

As for making your own slug ammo there are a number of Foster type slugs/molds and recipes that work well but I’m assuming your talking sabots here.  I’ve tried for many years to load sabots that performed as well as factory loads (including making my own bullet molds) and have yet to achieve equal performance to the factory offerings.  The only one I found that came close was called “Collet Cup” Sabot (I used to get them through Ballistic Products) but the cost was so high that I just started using factory ammo again which gave me a little better accuracy.

Possibly someone here has found a rifled tube/ammo combination that shows marked improvement over a smooth bore and will give you some better direction but don’t be disappointed if the same setup doesn’t perform as well for you.   Unfortunately the tolerances involved with shotguns and their ammo are considerably looser than than those of rifles and predicting there performance is problematic at best.  Personally, I would either go with an open choke tube and the foster type slugs or byte the bullet and go with a fully rifled barrel and sabots.



Good Luck,
Bob.