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That was fast! Chaszel may have made a mistake but it got corrected pretty quickly!
That is a good idea re aluminum duct tape! Cheap and easy though you'd have to pull the insert each time to move shims around. Still it is simple and should work and nothing to make. Great idea!
I will be watching with interest!
Longbow
I am also following this thread with interest. Before I had seen the thread I had purchased a 16 gauge double at a local gun show for a similar idea using slugs....but at 50 yards I couldn't keep the slugs on paper. Now I am thinking about inserts but 16 inserts are hard to come up with.
My plan for regulating will be first using the O-rings to center the inserts if using a long barrel.
If using the short coach gun, then I will wrap inserts with whatever tape I have handy to get the inserts centered.
The next step is to use two laser bore sighters to see how close or how far off they are.
I figure the lasers will allow me to play around with the regulation before multiple range trips and burning up a bunch of ammo.
The longer inserts do not have a cutaway for the extractors, the instructions say to index them for point of impact that you prefer, then if you wish cut away or file off enough of the rim to clear the extractor.
I can't see if there is an eccentric to the insert, there may be a mild eccentric to the O-ring channels, if there is it is not much, of course it may not take much.
I can't imagine the inserts themselves having an off centered bore. (on purpose anyway)
I don't see how the point of impact would change much by rotating the inserts unless there was some kind of eccentric.
I will find out once I have the bore sighters.
I was just looking over the Chaszel web site to see what else they have that I might be interested in. They have a lot on their web site, but most all of it is out of stock.
The .45-70 inserts some .410s are about all they have. I think I got pretty lucky with the .45-70s, they still seem to be in stock.
When the rest of my stuff arrives, I will be able to decide how I want to proceed.
The verdict is still out on which shotgun I will use.
In the meantime, I have been thinking about yet another double rifle.
I have an old 16-gauge Damascus hammer gun I bought cheap and some various project barrels I have laying around I should do something with.
More than 15 years ago, one afternoon I was in my range, and a man walked in, walking almost crouched, very old, with horn-rimmed glasses and green lenses. He came in with an old reusable grocery bag. We get closer. He went to the 150 meter sector, and ordered a target to be placed. He took a side-to-side double-barreled shotgun out of his bag. With a small scope between the two barrels. He took a crumpled bag with some bullets, quite large, bare lead boolits. He put one in one of the two cannons and started firing. Most of us hid behind a wall in case it exploded.
Not only did it not explode, but it placed all the shots in a 10 cm circle at 150 meters. It was a 16ga caliber shotgun, and a 44 magnum barrel had been inserted into one of the barrels. He said that he had built it to hunt wild boars.
I never saw him again.
I learned my lesson
:bigsmyl2:
Rotating the inserts do indeed change the point of impact per the laser bore sighters.
I found I can further change the impact point by putting shims under the O-ring at the front of the insert.
Good man!
How much change in POI have you gotten by rotating and shimming? I'm guessing your results are still pretty preliminary so just ballpark is what I am wondering. I will be looking at shotguns when we get to the big city next weekend.
I am leaning towards the Stoeger coach gun because it has 3" chambers and screw in choke tubes, both of which I want for slug shooting if it groups well enough. If not then I will likely order one insert to see how wel it shoots and try that in both barrels. If it looks good and I can get decent combined groups I would order a 2nd insert and follow in your footsteps. If not then I'd accept it as a cape gun with one rifled insert and one smooth barrel.
At worst if it doesn't work out it would still be useful for buckshot, two ball and Tri-Ball loads which is why I want 3" chambers.
Still watching with interest!
Longbow
What I have found with my old Damascus double barrel is it is cross-eyed.
Aiming across my basement the dot on the left is from the right barrel and the left barrel is the dot on the right.
The closest I was able to converge the dots was about 2 and 3/4 inch at 36 feet.
Using shims, I was able to shrink it down it down to one inch.
This is not going to translate very good at 100 yards.
The old Damascus guns have beautiful, graceful lines but are probably not suitable for this application.
The Chinese coach gun is better, I can get the dots to converge at 36 feet by spreading the barrels as much as possible.
It seems the problem with SxS shotguns is the barrels are not parallel, they are closer together at the muzzles than the breech.
This is much more pronounced with the old long barreled guns than the coach gun.
Of course, I have not tried live ammunition yet and the bore sighters leave a bit to be desired.
I think the best bet is the coach gun.
What would be perfect is absolutely parallel barrels, that is that you need to look for or as close as you can get.
To regulate the barrels, you need to shoot it from a standing position. The right barrel will recoil up and to the right, while the left barrel will recoil up and to the left. This will effect where the bullets actually land on the target.
I built a standing rest to regulate my 470 project. It's just 2 2x4s in an L with a 45 degree brace keeping them secure. Now C clamp this to an upright post at the range and put a sand bag on it.
Hold the rifle with your off hand fore arm resting on the sand bag, align the sights, lift up slightly to be on target and touch off.
Shoot both barrels and mark them on the target.
Shim your barrel and reshoot...
Yes, what lar45 said! I used to think that the barrels should be parallel but no! They have to converge some but the convergence is dependent on range, recoil and shooter. That is why double rifles and Paradox guns have to regulated well and apparently normally POI is set for 50 to 100 yards because most of the double rifles are used for dangerous game at moderate to close range. The gun will be regulated with one load for both barrels so that POI is "close" at 50 yards or 100 yards. A change of load may or may not produce reasonable groups.
Petander, who posts here, has a .470 NE he has managed to get good accuracy and close POI to 75 yards using a lightish cast bullet so it shoots factory rounds well but also his cast bullet "plinker" rounds.
H&H claims its Paradox guns will shoot combined groups inside a 5" square at 100 yards.
i'd expect that a lighter recoiling double wouldn't be as sensitive to the shooter as a heavy recoiling .577 NE, .600 NE or .700 NE as they are brutal to shoot and undoubtedly magnify the effect lar45 mentions. A 12 ga. shouldn't be in that class so likely easier to tame. .45-70 at BP levels is even tamer than that. Along with being able to shim the barrels to correct POI some you should be good I'd think. Again, that is a very good idea!
Longbow
Learn something every day.
I guess I won't know until I get to the range.
Perhaps my old shotgun will work anyway.
I don't feel the time was wasted with the shims and bore sighters.
I think a beter way to make the shims is with copper wire it can easily be pounded flat, and the ends tapered in case extra adjustment is needed.
I'd think your shims will have to be held in place pretty firmly because those inserts will likely be moving some due to barrel vibration/harmonics plus the O-rings compressing. Of course shooting is the best way to find out.
No, I agree, you want to find out all you can and you have already found that rotating the inserts does change things and that the O-rings allow shimming and moves POI so time well spent I'd say!
I am getting excited waiting for updates now!
Keep up the good work and reports!
Longbow
The shims were only my way of seeing if I could affect the point of impact and it works but I dislike it.
One thing I dislike about the Chaszel inserts is the rotation to affect the point of impact.
The reason I dislike it is because of the cutouts to allow the removal of the spent cases.
I want the cutouts to be horizontal and not move, that is why I was experimenting with the shims in addition of more adjustability.
My real goal is to make an eccentric bushing that is adjustable from the muzzle with a tool.
This will be accomplished preferably without lathe work.
I want to make something that can be duplicated by someone who does not have access to machine tools.
Im thinking 3 small screws to adjust each barrel then when regulated the can be locktited and cut off and blended to the barrels. 1 will be just above the rib then 2 more at 120* and 240*. Should allow for adjustment and once regulated epoxy could be worked in to make a solid bushing between liner and barrel. If the o ring is far enough back it would act as a seal for the epoxy.
Strips of shims would do the same thing then the epoxy around them to lock everything in place.
More than one way to skin a cat, set screws should work fine.
I am working on a less invasive way to regulate the barrels.
My plan is to make a new extractor to engage the .45-70 brass to make extraction easier than a fingernail or screwdriver.