Tuning Open Top Replicas

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nkbj

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Everybody seems to have a little bit different take on the matters so thought I'd ask.

When you tune your open top replicas do you:

Take away any gap at the front of the arbor?

Keep the bottom of the barrel flush with the frame?

Slant the barrel to bottom frame fit to correct the left or right point of impact?

Shim the wedges or push them deeper?

Adjust the slant of the slot in the arbor?

Reshape the top of the hammer for elevation?

Maybe not bother?
 

JamesT

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I probably wouldnt do any of that. There are a few things you can do however to make the revolver work a little better. As you mentioned you can deepen the rear sight notch in the hammer to lower your point of impact and/or adjust windage. Carefully do this using a small needle file. A little at a time only after obtaining a group on paper of course. The most effective tuning tip for the Colt style revolvers I have found is adjusting the forked spring that works against the bolt and trigger. It is located below the trigger guard. You do not want the retaining screw to be turned all the way in or bottomed out if that makes sense. Only tight enough to place proper tension on the bolt. This makes the action much smoother. At least in my mind. Hope that helps.
 

Larry Akers

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Yes to most of your Items. I shim the front of the arbor so it bottoms out in it's hole when the wedge is driven in leaving a .004" gap between the barrel and cylinder. Carefully file the mating surface where the bottom of the barrel mates with the frame to adjust for windage. Fine tune windage by filing the V in the hammer on one side. Install a taller front sight to bring point of impact to point of aim. Polish the nose of the sear and the full-cock notch in the hammer with a hard arkansas stone ( be VERY careful to not change angles!!). If there are rub marks on the side of the hammer, polish the area of the frame. Leave all screws tight--that's the way they are supposed to be. Trigger spring tension can be adjusted by reducing the width of the trigger spring arm--or make a new spring. I made one from a piece of hacksaw blade when my original spring broke. Polish the sides of the pawl and remove any burrs. Don't touch the nose of the pawl. The idea that an open top is not accurate was started by a Remington salesman.
 
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Long list of possible tuning stuff for my "Match" Colts. Why do you feel the need to tune?...c
 

10XPistol

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I have a Pietta 1851 Navy and it’s bone stock. I wouldnt do anything to it. I have seen others however that had issues.
 

nkbj

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Once bought a Pietta .36 1851 new in the box from a gentleman on the forum. The barrel could not be removed because the wedge had been installed at the factory as a forced fit. The end of the arbor was expanded and distorted. It was a mess. Took a long time and a lot of micrometer, file and brain work to turn it into fine shooting piece.
If you might recall the 1851's that Pietta sold with the battle flag grips, it was that long ago. They've come a long way since then.

Finished some fitting on a Uberti dragoon. Once the wedge is fixed will be trying out these 217 grainers.

🤪
 

Desperate Lee

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There are several articles about tuning the Pietta open tops and the Uberti open tops by Larsen E Pettifogger. Google him and his articles. He is with the SASS #32933L and when i have a problem with my Colt replicas i refer back to his articles that i have downloaded.
DL:dunno:
 

brazosland

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I thought I was going to have to educate myself on open top tuning when I recently bought a fluted Uberti 1860 Army.

Maybe not. Pic below is from its first time shooting out back. Range was 15 yards. I called the low left hit. Load was 35 grains of 3F, lubed felt wad and .454 ball.

The first group was 30 grains and was a bit tighter.

A local gunsmith who pretty much only works on black powder weapons suggested relieving the forcing cone would be a good thing to do. Other than that...I might be done!

B038112D-CED1-486E-8AF2-CDB63ECD2CFD.jpeg
 

rickystl

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Have two 1860 Army's and an 1851 Navy. For most, they shoot very high when new out of the box. There are three primary things I had done to them:
1 A smooth 3-lb. trigger pull.
2 An 11-degree cut on the forcing cone.
3 A taller, 5/16's front sight.

I can't believe how much better they shoot. And doesn't seem to matter who shoots them. They shoot right where you point them.

Rick
 

M. De Land

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My early 60 Pietta is a good shooter but it took quite a bit of work. I turned the lower barrel lug back in my lathe on brass centers at both ends of the barrel, made and fit a new wedge of tool steel , made and fit a new trigger of tool steel and made and fit a new taller front blade of brass to hit point of aim. I still don't really see the need to make the arbor bottom out in the barrel well as the wedge is what limits the forward movement. It is important for the barrel slots on either side of the arbor to be in parallel. Parallel wedge slot fit is far more important to accuracy than is a stop for the arbor front. It doesn't really need to bottom out on anything. One is better off setting the wedge depth with a feeler gauge in the cylinder gap than a stop in the arbor well, in my opinion.
 

denster

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Having the arbor bottom out in it's recess so the gun functions as a solid unit is of first importance. Not a problem with Pietta but always a problem with Uberti. Second is a close barrel cylinder gap about .002 is optimal. As to sighting install a dovetailed front sight that will take care of elevation and windage. Do not alter the barrel lug to adjust windage as that will affect wedge fit.
 

Gun Tramp

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One is better off setting the wedge depth with a feeler gauge in the cylinder gap than a stop in the arbor well, in my opinion.
I still agree. Cut-away illustrations in "A History of the Colt Revolver" are why.
 

M. De Land

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Having the arbor bottom out in it's recess so the gun functions as a solid unit is of first importance. Not a problem with Pietta but always a problem with Uberti. Second is a close barrel cylinder gap about .002 is optimal. As to sighting install a dovetailed front sight that will take care of elevation and windage. Do not alter the barrel lug to adjust windage as that will affect wedge fit.
It's a great theory but I think you will find with some experimentation that a revolver can be just as accurate with out the arbor well stop as with , all else being equal and fit up correctly. The pressure thrust at shooting or loading is forward against the slots and wedge. What is needed in my view here is one pressure stop (slot/wedge interface) not two (slot/wedge interface and arbor end stop) usually being unequally in tension.
I would not set up any of my revolvers with that close of a cylinder gap , not even smokeless. Dan Wesson revolvers are the only ones I have ever encountered where the factory recommends .002 cylinder gap. Usually the manuals recommend .004-.006 for modern revolver tune up and I have found it works equally well in my percussion guns. This is particularly important in open framed guns with no top strap for rigid support, to make the gap level around the clock. Very few revolvers of any kind are perfectly level in this regard and is the main reason .002 is not practical.
 
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TNGhost

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I thought I was going to have to educate myself on open top tuning when I recently bought a fluted Uberti 1860 Army.

Maybe not. Pic below is from its first time shooting out back. Range was 15 yards. I called the low left hit. Load was 35 grains of 3F, lubed felt wad and .454 ball.

The first group was 30 grains and was a bit tighter.

A local gunsmith who pretty much only works on black powder weapons suggested relieving the forcing cone would be a good thing to do. Other than that...I might be done!

View attachment 29694
Fluted?
 

brazosland

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Full flutes. The so-called McCollugh Colt. The very earliest 1860s had full flutes. A large shipment was sent to Texas right before hostilities broke out for use on the frontier and by Rangers and militia. The McCollough brothers were both good friends of Sam Colt.

That pistol hits dead on at 15 yards with a six o’clock hold. You can see the unpainted circle I left in the center of the plate as an aiming point. Only mod I did (besides stripping and refinishing the stocks) was to widen the rear sight notch.

Pleased, I am!
 

denster

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It's a great theory but I think you will find with some experimentation that a revolver can be just as accurate with out the arbor well stop as with , all else being equal and fit up correctly. The pressure thrust at shooting or loading is forward against the slots and wedge. What is needed in my view here is one pressure stop (slot/wedge interface) not two (slot/wedge interface and arbor end stop) usually being unequally in tension.
I would not set up any of my revolvers with that close of a cylinder gap , not even smokeless. Dan Wesson revolvers are the only ones I have ever encountered where the factory recommends .002 cylinder gap. Usually the manuals recommend .004-.006 for modern revolver tune up and I have found it works equally well in my percussion guns. This is particularly important in open framed guns with no top strap for rigid support, to make the gap level around the clock. Very few revolvers of any kind are perfectly level in this regard and is the main reason .002 is not practical.
One it is not theory two these are not modern revolvers. All of my open tops are set between .002 and .003 and they run well with much reduced fouling on the arbor. With all due respect since you haven't tried it you are not really in a position to say it doesn't work. Second having the arbor bottom out in it's recess is important to having the wedge be able to lock the two units together as one. This is how the originals were made and for a reason at the point the barrel lug contacts the frame the arbor bottoms out so you have two points in contact when the wedge is tapped in and everything stays consistent. The idea that the barrel cylinder gap should be set with the wedge is a fallacy.
 
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TNGhost

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Full flutes. The so-called McCollugh Colt. The very earliest 1860s had full flutes. A large shipment was sent to Texas right before hostilities broke out for use on the frontier and by Rangers and militia. The McCollough brothers were both good friends of Sam Colt.

That pistol hits dead on at 15 yards with a six o’clock hold. You can see the unpainted circle I left in the center of the plate as an aiming point. Only mod I did (besides stripping and refinishing the stocks) was to widen the rear sight notch.

Pleased, I am!
Ah yes, looking closer at the photo I can see the flute on the side of the barrel now. Very nice.

Great group. I can see why you would be pleased.
 
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