doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Choke opening process?

I think I need to open up the chokes on the R13 Darne I have worked on. After putting the stock back on I was able to shoot it more extensively this week. I have used both RST best loads and WR gameshot that pattern tight, (the barrels are well regulated and the stock fits me well). The shot was #7 and #7.5
After removing the pits from the bore, both barrels showed an increase in diameter from .669 to .674 thus increasing the overly thight chokes that I started with. Now, RB is choked .030 and LB is.037. It seems that this is outrageously tight for a 16 ga.
I will have to do more patterning as well to better define the chokes on the board and not base my desision on the choke measurements.
What I would like to use the gun for is upland hunting, pheasants and grouse.
First question, is it reasonable to have more open chokes, somewhere in the IC/M range?
Second question, I would love to do it myself. I would use a Brownell's choke adjustable reamer with access from the breech, going slowly and checking patterns on the patterning board. The reamer should have a bore guide and a chamber guide. Any problems with that?

No, do it.

Well yes, Sliver, there are several problems with that. Where to start? First off the reamer. I don't imagine you intend to get a set of reamers made up to your exact requirements so that leaves an adjustable one. A lot of 'em are pure crap. Lets suppose you get a good one, you then have to make up a shaft with appropriate size guides to hold said reamer securely. I know that you had to straighten the barrels of your gun but are they perfectly straight? Just sliding your reamer and shaft down the bore can leave scars that you will then have to polish out. Ask me how I know. Do you have access to a lathe? I'm not saying you won't be able to do it. I am saying that this job can turn into a disaster real quick. When you add up the cost of tooling required, stuff you may never use again, and compare that to the cost of sending the barrels to Mike Orlen there's no contest. He has the gear and experience. Opening chokes is a very simple process for someone with a long bed lathe and the knowhow but even with the knowhow but without the lathe can be something you'll wish you'd never gotten into.
npm

Just opened the choke tubes on a set of Kolar tubes, The Brownells reamers did a very good job on the Stainless chokes so I am sure they will cut Darne tubes. Go slow , I used lard oil for my cutting oil. My industrial former life indicated it(lard oil)provided the best finish.
bill

I have done it many times using adjustable reamers and tools to hold them that I made myself. I am not a machinist, just a lifelong tinkerer with a good set of brains. If you will really only do this one set, having a reasonably priced 'smith like our good friend Mike Orlen do it is economically sound. However, Mikey just told a friend of mine that stock bending was the only thing he wanted to do, now. If that's not correct, I hope Mike will 'splain what I heard.

I would be interested in reading more about the correct method and tools to properly open chokes. I'll never do it myself, but would like to learn more about the methodology.

The above comments about a lathe are interesting, but I don't understand the purpose, nor can I easily visualize. Any photo's?

Also, how does an adjustable reamer function?

Are chokes reamed from the muzzle, or from the chamber to provide more support?

How does the operator know he is not altering the point of impact? Or does he?

Any explanation will be appreciated...

Nials,

The piloted reamer system Silvers mentioned works very well. If you had trouble with it, you tried to take too big a cut. I take out about .002 every cut. I think that is 2 flats on the adjustment.


Silvers,

The piloted reamer from Brownells is easy to use and there is no doubt that you can do it, If I can do it, it's not hard. It does not have a chamber guide. The pilots on mine are brass rings that come in different sizes to match your bore, You can make them out of brass bushings if you like, and guide the reamer from 2 points. It is cheaper to have it done for one gun. I've probably opened up 8 or 10 guns with mine. I just lube mine with oil, It ain't rocket science.

Call me if you have questions, Dick

"It ain't rocket science." I have done several from the muzzle, no guides, nothing fancy, just a adjustable reamer. The best advice is take very light cuts, pattern between every cut. I have actually fixed a gun that had bad POI by ever so lightly 'leaning' on the reamer. Some people are just afraid of their shadow, if you have average or better mechanical ability you can do this.

Friends,

Thank you for your encouragement. You don't know how much it matters to me. However, I am trying to be reserved in my optimism because I know I don't know.
Every new step I go through is a new territory that I have to explore cautiously. If I make it alright, there is great reward to be cherished. Sending it out would be the easiest thing to do and most cost efficient. But I would be missing the excitement of the discovery. I obviously am an adrenaline junkie.
Nial brings an important point. My barrels were bent up and I straighten them to the best I could. I know they are not perfectly straight, just by looking at the light reflection. Here is the problem. One wants to ream the chokes from the chamber with a guided reamer so that the chokes do not come out of alignment. If the barrels are not perfectly straight, the reamer may be misguided and the choke cut out of POI.
I might do better with a nonguided wooden dowel and emery cloth to allow a selfcentering tool to do the job?
The other option is to go very slowly and pattern after each cut to catch on an early changed POI which I am going to anyway.
The third option is to use a concentric guide close to the muzzle and see if the shaft would need an eccentric guide at the chamber, assuming that the last third of the barrel preserved its straight path.
Maybe I am complicating things too much. After all it's a shotgun, not a rifle.
Again, thank you for your support.

Sliver, I went the wooden dowel/emery cloth way with my sons 16 bore Simson.
It worked out quite well. Took my time and used a wet t-shirt to wrap the muzzle
to avoid excessive heat while polishing away. Patterns great. JMTC.

JC

I pondered opening my own chokes many years ago. Finally bought Ralph Walkers book "Shotgun Gunsmithing" and read it carefully. I followed his directions to a T.

I always pattern a shotgun to see POA before even starting. After a couple dozen barrels, never had a POI change. A friend and I changed the POI on a 410 by carefully putting more pressure on the choke, in the opposite direction it was shooting. Took a few tries to get it right, cause you cannot put metal back.

Lenard

Bill, I sent you a pm, but got to thinking you might not receive it. So here goes. What are you using for a holding device if that stainless choke was a choke tube? Am I correct in assuming you are not using carbide blades on the reamer. I would like to open some choke tubes, but haven't figured out the fixture.

Lenard

One thing of great importance in using an "Unguided" adjustable reamer from the muzzle is whether or not the original choke is a conical parallel or taper choke.
"NOBODY" can guarantee to maintain alingment with an unguided reamer in a taper choke. If you have the parallel section & take the light cuts you should it will tend to "Follow the Hole". Try it on a taper choke & you best for sure know how to use it to correct POI. Take this for what it's worth from a 35yr machinist.

JayCee,

I feel more comfortable with the wooden dowel and the emery cloth as I have already the experience of the barrel polishing. And it is so much cheaper...

Lenard,

I did a search on Amazon.com for the R. Walkers book, but did not come up. Is it an older edition? Could you mention about the method used in this book?
Edit: I did find the book:
http://www.amazon.com/Gun-Digest-Book-Sh...2980&sr=8-1

2-piper,

Thank you for your observation about the wandering of an unguided reamer in a conical choke.
The chokes are about 2" long and seem to have a short .25" segment that is parallel, then they open up a bit more towards the muzzle. With the use of a wooden dowel and emery cloth, the cutting area would be penetrating through the choke and should be self centering. As the choke opens up, the muzzle part of the choke becomes more parallel. I don't know if this is a problem or an advantage. Please correct me if I am wrong.

Silvers, it is a gun digest publication. I think Ralph has been dead for some years now. Ralph used an unguided reamer that has been sold by the thousands. There is one key to using these reamers. One is to not take over .002 thousands per pass, that has been said on one of the posts. The next is to mount the barrel verticaly, using lots of oil and not much pressure. Now, I will agree with Miller, if one is heavy handed without patience, then it is not a good method. Or, if the chokes have been manipulated before, like I have read about the Parker reproductions, then on is in real trouble, no matter what the method. Gunsmiths have been using this method for years and I agree that some barrels might have been screwed up by this method, but I have never had a change of impact.

The real reason I started doing it, was that it took any smith I sent it to, way too much time. Besides, I can remove a little metal, pattern and continue the process until I get what I want.

Lenard

I just heard from Mike Orlen and he assured me that my friend had definitely misunderstood what Mike had told him. I have no problem imagining this particular friend misunderstanding things. Mike is no longer doing "general gunsmithing" but is still interested in all sorts of barrel work AND stock bending. This is not even real news. I apologize if I caused any sort of misunderstanding. Mike Orlen continues to be the first person I would recommend for shotgun barrel work, etc.
jl

I had chokes opened by the gunsmith at the local gandermountain. He used a reamer piloted from the muzzle. Cost me $130. I recently had chokes opened by Mike Orlen. It cost me less than $100 including shipping both ways. He pilots from chamber and bore. This is what this guy does, day in and day out. Let me tell you, there is a dramatic difference in quality. In my mind, it is a no brainer. For less than $100 you can ship those barrels from MT to MA and get it done right.

stevehaun, I am not trying to be a wise guy, but what did Mike Orlen do that was far superior to what the Gander Mountain smith did? Just curious.

Lenard

Leonard,
There are a number of good ways to hold a choke tube. A soft collett bored to fit the O.D. of the tube would work. Also, a set of "soft jaws" bored to fit the O.D. would do as well. Boring and singlepoint internal threading a piece of barstock like a barrel prepped for the tube would work well.

Stevehaun,

I completely agree with you. But sending the barrels out I would miss the fun. If I mess them up, I send them out.

Lenard,
That is a very fair question. First, at gandermountain, it took two attempts to open the barrels to the POC that I requested. Second, the milling left several deep gouges in the bore of both of the barrels. I have tried to polish the gouges out with OOOO steel wool but they are too deep. Now I must admit that the POI did not change and the gun patterns well. Mr Orlen's work was very nicely done (milling was perfect with no gouges) and the gun patterns well. So, you could make the argument that both choke jobs were good - at least when it comes to the patterning board.

Sliver,
I understand what you are saying and I have a tendency to approach life in a very similar fashion!

A good adj. reamer will cost around $130. Don't buy the cheap ones- they leave gouges and don't cut worth a damn. A couple of us have opened up 15 to 20 SxSs from the muzzle with no problem . I own an inside dial caliper so we know where we're starting and what's being removed. A friend had a Darne, and it had " jug chokes " in it. Don't know if that's common or not for them. I'll be getting a Remington 1894 Trap gun that has only I/C choke in the right barrel. Gonna jug choke that side and try to bring it back to Mod. choke. Paul

A good adj. reamer will cost around $130. Don't buy the cheap ones- they leave gouges and don't cut worth a damn. A couple of us have opened up 15 to 20 SxSs from the muzzle with no problem . I own an inside dial caliper so we know where we're starting and what's being removed. A friend had a Darne, and it had " jug chokes " in it. Don't know if that's common or not for them. I'll be getting a Remington 1894 Trap gun that has only I/C choke in the right barrel. Gonna jug choke that side and try to bring it back to Mod. choke. Paul

The "right way" is the method the individual operator can perform correctly the first try. The most professional one is, I suppose, a chamber and near muzzle piloted reamer that carries the choke profile out to the muzzle. The other end of the spectrum is a self centering cutter/grinder used very slowly and cautiously with frequent pattern shooting to verify POI vs POA. This method will generally be used to cut a short parallel section between the choke constriction and the muzzle, thus reducing the overall constriction. Both, and all varieties in between, can work if the operator is skillful and careful enough.

A lathe can be used to very finely control depth of cut, speed of cut, concentricity, ridgidity of fixturing, etc. In the hands of a pro, it will dramatically reduce risk of wrong cuts while increasing productivity.

Stevehaun, The reason for the gouges is that when reaming a choke, use only minimal cuts, like .002 at a time. Secondly, the mistake the guy at Gandermountain made, was reversing the reamer. One particular point that Ralph Walker made, was that the reamer must be turning clockwise as it is pulled out. Or, as Ralph says in his literature, it will cause gouges. I know, I did it on one barrel while learning. Because I was taking more out, I worked those gouges out getting to the dimensions I wanted.

I have bought the reamers, several sizes from Brownells, and never had a problem one with them. Take care of them, use lots of oil while cutting and clean them frequently while opening chokes. With care and patience, and a lot of measuring, one can do an admirable job. And for all of us gun nuts who do open chokes, it allows us to cut to get the pattern we want. There can't be enough good said of that practice.

Lenard

I have sucessfully reamed several chokes using the Brownells's adjustable set by basically the method Lenard described. As he said use light cuts only & "never" turn any reamer backwards in a hole, adjustable or otherwise. The set I bought came with instructions writen by Ralph Walker. It is noted though, those directions did not differentiate as to type of choke. So again I "Warn" "IF" you have no paralell section to start with you are purely operating on "Luck" to maintain alignment. I know Lefever, fox & i believe several other US makers used the "Taper" choke systemn. I would strongly recommend against using an un guided reamer to open one of these. When you make that first cut, you have only one point of contact & no way to insure alignment. Once started crooked it will then continue to follow the hole you have started.

Gentlemen,

I have learned a bunch on this thread. I equally appreciate both your words of cautiousness and encouragement.
Tomorrow is the "opening chokes" day. I will post results of the operation.