sizing cylinder throats

[castmiester]

Don't know where I should have posted this but, I figured this is a good a place if any.

Thoughts on the best or correct way of slugging or measuring all cylinder throats. I found this thread post here through google, and wish I had had better results searching here but I rarely do. So I think this guy has some good advice but maybe you all could chime in, thanks.

https://castboolits.gunloads.com/showthread.php?421446-44-mag-bore-diameter&p=5146641&viewfull=1#post5146641

[gc45]

For many years I have used fishing egg sinkers pushed thru each cylinder hole with accurate results. Pin gauges are also helpful in finding differences one hole to the next.

[littlejack]

You can slug each chamber (revolver) and measure the results. In a perfect world, they would all measure the same. But, that's probably not going to be your results. So, if all you want is to not have trouble chambering all the rounds, just size the boolits to a friction fit to the smallest throat dimension. If you want it done correctly and professionally, get hold of DougGuy here on the forum, and let him know what you have. Many of the members here (myself included) have had him hone their cylinder throats. He does great work at an affordable price, and fast turn around. If you decide to just size the boolits to
the tightest throat, only expect mediocre accuracy with the revolver.

[rkrcpa]

Pin gauges are the best, easiest way to get good information.

[mehavey]

Although... a "custom" pin gauge (called a properly-sized bullet)
should suffice to judge whether it can be pushed through the
cylinders-in-question with just a modicum of "feel."

Post-Scriptum:
https://www.brownells.com/tools-cleaning/bore-barrel-tools/reamers-cutters/revolver-cylinder-throating-reamers/

[HamGunner]

When in doubt, ream it out. Your group sizes will decrease. The tendency to lead the bore will decrease as well, if one or more throats were small and causing the bullet to be sized down before entering the forcing cone.

Cylinders are reamed out usually with gang reamers, so you have different reamers for the different cylinder holes. If one of the reamers gets dull, they sharpen it a bit and so between wear and sharpening, they eventually get smaller, but not necessarily the same degree for each reamer. Thus we end up with multiple size cylinder throats from the factory.

I have used 4 D rentals for throat reamers and done it myself. Nothing to it.

https://4drentals.com/products/reamer-rentals/cylinder-throater/

[Dusty Bannister]

So, if all you want is to not have trouble chambering all the rounds, just size the boolits to a friction fit to the smallest throat dimension.
If you decide to just size the boolits to the tightest throat, only expect mediocre accuracy with the revolver.


A little clarification may be in order. It is not a drastic problem to use a bullet that is larger than the cylinder throat, the throat will reduce the bullet diameter to match the throat when fired. If you size the bullet to lightly pass through the smallest cylinder throat, it will be loose in all the other throats and lead will be gas cut from the sides of the bullet as it passes through the cylinder throat, and transitions into the forcing cone and inaccuracy and leading will occur.

[reddog81]

I would say best and correct way to measure the throats are pin gauges. If the throats are consistent and you can push sizes bullets through with a bit for pressure you will probably be fine and don’t really need specific measurements.

[castmiester]

Ok so my casts vary.. Someone mentioned elsewhere in another one of my threads about grip on the mold handles, and believe that's why the sizes are vary.... .358 to .361. Couple of days ago I laid sized bullets in the mold after taking it apart to inspect and clean it. The mold wouldn't close all the way and had a considerable gap. I was also told about over sized bullets .001 to .002. I just ran a sized .360 bullet that a friend honed my Lee sizer to .359 with, and it would not pass through with a light push, yep spring back. I asked for .359 and probably is but have spring back, forgot about the extra thou, shoulda asked for .360. Concerned about even with Cowboy dies with an oversized bullet would bulge the case and not chamber.

Calipers measured .361 on the throats, which trying to pass through a .360 bullet shows that calipers don't measure correctly. A .357 jacketed bullet falls through all buy one, that very light pressure is needed. A sized cowboy case is .373 OD and a seated bullet is .375. Typical .002 neck tension. Chambers freely. Does the Expander work in conjunction with the FL CB die ?

The cowboy dies....how far can a bullet be over sized before the sizer die doesn't under size the case and cause a bulged case that won't chamber ?

[littlejack]

So if a person sizes the boolits to fit the largest chamber, said person will have difficulty chambering the rounds in the smaller throats, if said person is using boolits with the first driving band larger than the smaller
throats.

[castmiester]

So if a person sizes the boolits to fit the largest chamber, said person will have difficulty chambering the rounds in the smaller throats, if said person is using boolits with the first driving band larger than the smaller
throats.

Then that said person will have pressure spikes in the tighter chambers, l believe.

[bcraig]

You can size the cylinder throats to the size of bullets that you want to shoot after slugging the barrel.

What you really need to check for is the the throat where the Barrel is screwed into the frame.
On most Revolvers and especially the Ruger single action pistol's there is a constriction where the barrel is screwed onto the frame.
That play's havoc with accuracy as the constricted area will size down the bullet then you have a bullet that is undersized for the bore of the barrel.

A good way to get rid of the constriction or tight spot in that area without removing the barrel is to fire lap the barrel.

You can read up on firelapping a barrel on the web,Basically Taking a lead bullet and rolling the bullet on a hard flat piece of metal or glass and inbedding the bullet with lapping compound then loading the round with a tiny amount of a fast burning powder so that it just barely exits the barrel until the constriction is gone ,once it is gone your accuracy will be better as the bullet is not being constricted anymore.
Start with a load that will not exit the barrel and then drive the bullet out of the barrel then use a tad more powder until the bullet just barely exits the barrel.
Check after each shot to keep from firing a second bullet in a obstructed barrel.

As far as the cylinder throats Veral Smith recomended to use a piece of cold rolled steel with a small slit cut into the center end of the cold rolled steel then place a piece of fine emery paper into the slit and wrap the emery paper around the cold rolled steel until a it is a snug fit in a throat then with the cylinder locked in a vice to prevent movement use a drill with the piece of cold rolled steel chucked in it place it in the cylinder and going slowly from the end of the cylinder(the end where you load the rounds in)push it in until you reach the cylinder throat that you want the Bullet of the diameter that you want to shoot. and start drilling ,making sure that the end of the cold rolled steel with the emery paper is centered and not cutting at an angle.
For example to determine if you can with just a little pressure push the lead bullet that you are wanting to shoot through a particular cylinder throat then dont ream that particular cylinder throat.
Do Ream the cylinder throats that the Bullet will not push through until they will.

Then proceded with the firelapping of the barrel.
After the firelapping of the barrel make sure to clean the Lapping compound from the cylinder and the barrel.
Once finished you will have a gun that the cylinder throats are uniform and matches the bullets
that you are wanting to shoot and the barrel throat matches the Bullet and the bullet matches the barrel bore .

[stubshaft]

^^^^^^^^^^
What he said!

I have seen a good number of pistols with constricted barrels. Slugging a bore with one just gives you the diameter of the constricted portion and not the actual barrel diameter.

[Dusty Bannister]

So if a person sizes the boolits to fit the largest chamber, said person will have difficulty chambering the rounds in the smaller throats, if said person is using boolits with the first driving band larger than the smaller
throats.

Please keep in mind that the chamber of the revolver is where the loaded cartridge lays in the cylinder. Then there is a transition taper to the smaller cylinder throat. It is entirely reasonable to use the largest bullet diameter that will easily chamber and be removed without a sticking bullet.

The point of bullet fit is in the throat regardless of the chamber size. Undersized bullets will likely lead the bore if the groove diameter of the barrel exceeds the diameter of the throat.

[DougGuy]

As far as the cylinder throats Veral Smith recomended to use a piece of cold rolled steel with a small slit cut into the center end of the cold rolled steel then place a piece of fine emery paper into the slit and wrap the emery paper around the cold rolled steel

DO NOT do this. This is the FASTEST way I know to ruin cylinder throats. I don't give a dang WHAT Veral says it it a NEANDERTHAL way of enlarging throats. There is NO WAY of achieving concentricity as you work, there is no pilot or guide to ensure the tool is parallel with the chamber, you have nothing accurate to go on, and your results MAY shoot a good group if you are lucky.


I have used 4 D rentals for throat reamers and done it myself. Nothing to it.

Nothing to it haha. What are you going to do when half the throats ream successfully, and the throats on the other side of the same cyilnder bog the reamer down until it is SQUAWKING when turned and you think you are going to break the shank off the reamer. Anyone who has reamed enough Ruger cylinders will undoubtedly have ran into this issue and know exactly what I am talking about.

Ruger cylinders are notorious for uneven heat treating of the billet steel rods from the steel mill, temper varies WIDELY from cylinder to cylinder and even from one side to the other side of the same cylinder.

In this scenario, the harder temper throats will finish considerably smaller in diameter than the throats on the softer side of the cylinder. The reamer itself is HSS and WILL CRUSH when forced through the harder throats and cut a smaller hole.

For THIS REASON I got away from reaming cylinders and adopted the Sunnen hone exclusively for ALL cylinder throat resizing. Not only is the finish superbly done, the stepless adjustment afforded by the hone allows for honing all the throats to consistency regardless of the temper of the metal or any changes in temper from throat to throat, allowing the user to achieve a consistent light drag fit on the pin gage, something that CANNOT be done with a reamer alone due to the variations in temper of the metal itself.

[mehavey]

The REST of the story. . .https://castboolits.gunloads.com/showthread.php?366409-I-Have-QUIT-Reaming-Cylinder-Throats!-Exclusively-Sunnen-Hone-Now&p=4440004&viewfull=1#post4440004

( ... tho' I admit, I am a reamer Philistine by historical default )

[Loudenboomer]

My 2 cents would be to borrow or rent some pin gages. Throats are probably small and multi sized. Doug corrected a 44Spl. Black Hawk and a 480 SBH for me. Happy customer.

All that's left is load development and practice. Rince and repeat. Rince and repeat :)
Merry Christmas

[castmiester]

Merry CHRISTmas.. to all you casters.... I hope and Pray you receive Him in your heart today.

Just now I measured my sized bullet from a few years ago. they measure .359. Yes I see spring back, just like after casting.

They don't fall through the throats, nor easily pushed through. But I would like to use them to see what the throats are. It wouldn't take much to get them through to see what they actually are. Once I do that Doug, I'd be interested in sending you the cylinder to hone. It's off my Taurus 66 .357 mag.

I just ran .359 casts through the throats. All but two, were pushed through were pushed a little hard, no hammer. The rest easily through, with a very little persuasion. They measured .359. Again the .357 jacketed fell through but the casts varied going through. I'm thinking 5 out the 7 throats are ..359, the other 2 are .360-.361ish, I guess.

[littlejack]

You can measure the diameter of the pushed through boolits to see how much they were sized down. You can get an approximate throat size.

[castmiester]

You can measure the diameter of the pushed through boolits to see how much they were sized down. You can get an approximate throat size.

Sorry should have posted before. All but two are .358, the other two are .359

I appreciate all the responses, especially Dougs. So I get the variable cylinder throats, and one other poster that mentioned before and in this thread about the Barrel/forcing cone needs attention. If I slugged from the muzzle and stopped at the throat, and drove the slug back through the muzzle. My question is drive to see if I have an issue at the barrel/frame it may show up slugging or it may not ?

[Bass Ackward]

Well, …. if you can’t win fair in life, CHEAT. Use the sizer that came with the gun.

Slug the bore and use that. It’s not flawless, but it will tell you if you have a problem(s). If want to shoot a lot, then you can use that same slug after your throats and bore wash up. If your using light / short for caliber bullets as defined by how far out any misalignment is, then you will have force executed on a side of the slug that will lead heavier at that point because of friction. This will tell you if you need a heavier slug (more time) (or sometimes a harder bullet) for the clocking to occur. It also keeps your throats from wearing oblong over time. If do you this every so many rounds, you’ll know the round count before you have to clean THAT gun. I always keep the initial slugs for judging wear.

[castmiester]

Well, …. if you can’t win fair in life, CHEAT. Use the sizer that came with the gun.

Slug the bore and use that. It’s not flawless, but it will tell you if you have a problem(s). If want to shoot a lot, then you can use that same slug after your throats and bore wash up. If your using light / short for caliber bullets as defined by how far out any misalignment is, then you will have force executed on a side of the slug that will lead heavier at that point because of friction. This will tell you if you need a heavier slug (more time) (or sometimes a harder bullet) for the clocking to occur. It also keeps your throats from wearing oblong over time. If do you this every so many rounds, you’ll know the round count before you have to clean THAT gun. I always keep the initial slugs for judging wear.

By eye I can't see any abnormal leading before. I'm loading 158 SWC and used them to measure the throats. Even with 9 BHN shooting ?


Never realized that much went into accurate shooting with pistols or even rifles too. I managed to narrow down my deer rifle accurizing and loading better.

[murf205]

castmeister, if you want to, you can go to Meyer Gage Co and buy individual pin gages for about $4 apiece. Then you can know where you stand with regards to cylinders and know whether or not to ream. I bought my 35 cal gages starting at .355 and went up to .360 in .001 increments. Make sure you clean the throats and LIGHTLY oil them. Meyers website is getting revamped right now but their phone calls are answered by very helpful people. There is no need for a boolit caster to buy the entire set, thank goodness. I bought pins for 44 cal as well as 45. The "Z" guages are accurate to .0001" which is plenty for a wheel gun. The pins are also a great way to verify your micrometer setting.

[castmiester]

castmeister, if you want to, you can go to Meyer Gage Co and buy individual pin gages for about $4 apiece. Then you can know where you stand with regards to cylinders and know whether or not to ream. I bought my 35 cal gages starting at .355 and went up to .360 in .001 increments. Make sure you clean the throats and LIGHTLY oil them. Meyers website is getting revamped right now but their phone calls are answered by very helpful people. There is no need for a boolit caster to buy the entire set, thank goodness. I bought pins for 44 cal as well as 45. The "Z" guages are accurate to .0001" which is plenty for a wheel gun. The pins are also a great way to verify your micrometer setting.

Ya that's what prevented me form buying them.... a whole set, ugh ! Thanks... I figured I could get individuals.

[castmiester]

On most Revolvers and especially the Ruger single action pistol's there is a constriction where the barrel is screwed onto the frame.
That play's havoc with accuracy as the constricted area will size down the bullet then you have a bullet that is undersized for the bore of the barrel.

I keep reading this from time to time.

I used to be a plumber, and understand pipe threads, the male threads are tapered and the fittings are not, maybe I'm on the wrong track here but how can a threaded barrel have a restriction in the threaded frame? They're straight threads. The pitch and diameter are the same, or are they ? I never hear about slugging a rifle barrel having this restriction.

[Three44s]

The threads are cut in separate operations and with the intent of the barrel ending up tight. The incidence of barrel constriction is very common.

But it is also not exclusively there as it can also be where a dovetail is cut for some reason like for a sight.

I do not have the correct attachment for my Sunnen Hone but being loosely familiar with them I can tell you that from many reports from members about Dougguys work and my basic knowledge about the hone he uses, I would send my cylinder to him for a job without hesitation.

In fact I likely will send him a cylinder to hone in the future, my main hold up is I need to get a dimension from my bore size on one revolver of mine that shows a couple of oversized throats. I would like to get a final bore dimension and get my throats sized accordingly.

Three44s

[castmiester]

The threads are cut in separate operations and with the intent of the barrel ending up tight. The incidence of barrel constriction is very common.

But it is also not exclusively there as it can also be where a dovetail is cut for some reason like for a sight.

I do not have the correct attachment for my Sunnen Hone but being loosely familiar with them I can tell you that from many reports from members about Dougguys work and my basic knowledge about the hone he uses, I would send my cylinder to him for a job without hesitation.

In fact I likely will send him a cylinder to hone in the future, my main hold up is I need to get a dimension from my bore size on one revolver of mine that shows a couple of oversized throats. I would like to get a final bore dimension and get my throats sized accordingly.

Three44s

Could you explain in threads are cut in separate operations?

[Tatume]

Listen to DougGuy, then send your cylinder to him. He will do a super job on the throats. Each one he has done for me has improved accuracy as a result.

[castmiester]

Listen to DougGuy, then send your cylinder to him. He will do a super job on the throats. Each one he has done for me has improved accuracy as a result.

Will do

[JonB_in_Glencoe]

Ok so my casts vary.. Someone mentioned elsewhere in another one of my threads about grip on the mold handles, and believe that's why the sizes are vary.... .358 to .361. Couple of days ago I laid sized bullets in the mold after taking it apart to inspect and clean it. The mold wouldn't close all the way and had a considerable gap. I was also told about over sized bullets .001 to .002. I just ran a sized .360 bullet that a friend honed my Lee sizer to .359 with, and it would not pass through with a light push, yep spring back. I asked for .359 and probably is but have spring back, forgot about the extra thou, shoulda asked for .360. Concerned about even with Cowboy dies with an oversized bullet would bulge the case and not chamber.

Calipers measured .361 on the throats, which trying to pass through a .360 bullet shows that calipers don't measure correctly. A .357 jacketed bullet falls through all buy one, that very light pressure is needed. A sized cowboy case is .373 OD and a seated bullet is .375. Typical .002 neck tension. Chambers freely. Does the Expander work in conjunction with the FL CB die ?

The cowboy dies....how far can a bullet be over sized before the sizer die doesn't under size the case and cause a bulged case that won't chamber ?
Funny no one has mentioned this yet, but unless you have a calibrated thumb, you can't measure lead bullets accurately with a Caliper. You should use a 0-1" Micrometer with a slip clutch.

Also, Calipers are designed to measure flat surfaces, you can't get a reliable measurement of a round hole.

To best measure a cylinder throat, you should push a pure lead slug through it, then measure the slug with a 0-1 Mic. repeat with a new lead slug for each throat in the cylinder. BTW, pure lead doesn't have spring back.

Good Luck.

[JonB_in_Glencoe]

I keep reading this from time to time.

I used to be a plumber, and understand pipe threads, the male threads are tapered and the fittings are not, maybe I'm on the wrong track here but how can a threaded barrel have a restriction in the threaded frame? They're straight threads. The pitch and diameter are the same, or are they ? I never hear about slugging a rifle barrel having this restriction.

I can't explain the "Why", but Thread Choke is a real thing in revolvers and Long Rifles.

Here is a thread that talks about it, and solutions.
https://castboolits.gunloads.com/showthread.php?395260-Anyone-try-to-remove-barrel-choke-in-a-revolver

[JonB_in_Glencoe]

Don't know where I should have posted this but, I figured this is a good a place if any.

Thoughts on the best or correct way of slugging or measuring all cylinder throats. I found this thread post here through google, and wish I had had better results searching here but I rarely do. So I think this guy has some good advice but maybe you all could chime in, thanks.

https://castboolits.gunloads.com/showthread.php?421446-44-mag-bore-diameter&p=5146641&viewfull=1#post5146641
Some specific things are best found with this websites "advanced search" but it helps to know some details about the thread you are looking for.

For general topics, I also use Google's website search. To search castboolits, you type your keywords and then "site:castboolits.gunloads.com"

So for this topic I typed in, measuring revolver cylinder throats site:castboolits.gunloads.com
and found pages of threads.
Good Luck.

[castmiester]

Some specific things are best found with this websites "advanced search" but it helps to know some details about the thread you are looking for.

For general topics, I also use Google's website search. To search castboolits, you type your keywords and then "site:castboolits.gunloads.com"

So for this topic I typed in, measuring revolver cylinder throats site:castboolits.gunloads.com
and found pages of threads.
Good Luck.

Hey thanks for the tip ! Appreciate it.

[DougGuy]

For anyone considering buying single pin gages from Meyer, you would want the ZZ minus pins ( -.0002") and be SURE to get them in .0005" increments instead of .001" yeah that adds a few more bucks to your order but .001" increments are too coarse for any serious cylinder measuring.

[bcraig]

DO NOT do this. This is the FASTEST way I know to ruin cylinder throats. I don't give a dang WHAT Veral says it it a NEANDERTHAL way of enlarging throats. There is NO WAY of achieving concentricity as you work, there is no pilot or guide to ensure the tool is parallel with the chamber, you have nothing accurate to go on, and your results MAY shoot a good group if you are lucky.



Nothing to it haha. What are you going to do when half the throats ream successfully, and the throats on the other side of the same cyilnder bog the reamer down until it is SQUAWKING when turned and you think you are going to break the shank off the reamer. Anyone who has reamed enough Ruger cylinders will undoubtedly have ran into this issue and know exactly what I am talking about.

Ruger cylinders are notorious for uneven heat treating of the billet steel rods from the steel mill, temper varies WIDELY from cylinder to cylinder and even from one side to the other side of the same cylinder.

In this scenario, the harder temper throats will finish considerably smaller in diameter than the throats on the softer side of the cylinder. The reamer itself is HSS and WILL CRUSH when forced through the harder throats and cut a smaller hole.

For THIS REASON I got away from reaming cylinders and adopted the Sunnen hone exclusively for ALL cylinder throat resizing. Not only is the finish superbly done, the stepless adjustment afforded by the hone allows for honing all the throats to consistency regardless of the temper of the metal or any changes in temper from throat to throat, allowing the user to achieve a consistent light drag fit on the pin gage, something that CANNOT be done with a reamer alone due to the variations in temper of the metal itself.

I am sure that your way of doing this is a Great way of doing this.
And I am sure that you do great work.

I am also sure that doing it the Way Veral Smith describes has worked for ME on 3 different Rugers.

Just trying to help the OP with his issues as it worked for me.

I only work on MY OWN guns as I enjoy it, BUT would think that Having a PROFESSIONAL such as yourself Do the work ,would be the Best way to get the best results .

[georgerkahn]

I just sent two Ruger cylinders -- the .45 Colt and the .45ACP cylinders from same revolver, to DougGuy and, imho, his work was/is "magical"! The best testimony I might add is ONLY financial constraints for me presently -- land taxes on six parcels, auto insurance premiums, and seasonally added heat/electric use expenses -- with Homeowner's premium due in February -- are keeping me "broke", :) and not yet having posted these to him! BUT, the moment I will (God willing) see the $$$-light at the end of then tunnel -- two Vaquero cylinders will be posted to him.
For "me" I have spent sooooo many dollars on any/every die, press, brass, primer-type -- you may know it as, too, you also may have been there -- to get those fired bullets into smaller groups. Who'd thunk a MAJOR contributor is not necessarily casting, sizing, and loading skill -- but that from which the projectile is being sent?
I can't wait (figuratively) until my :( forthcoming expenses are met and I may send those Vaquero cylinders to him!
geo

[Char-Gar]

Pin gauges are the way to go if you are starting in this. I bought a set of Starrett expandable hole gauges in 1969 and with a good Starett micrometer have been measuring the inside diameter of any hole since that time with these. Take a little time to get the feel for these, but then giver very accurate results.

[castmiester]

considering that a cast .359 fell through 5 out of 7 chambers, and two had to pushed relatively hard, I'd say the thing needs work. Cheap and effective way to check to do business with Doug. It's not a competition pistol, or a hunting pistol. Hunting pistols don't need to be that accurate, nor home defense pistols. I'll never get into competition so saying that, thanks for the help.

[Bass Ackward]

[QUOTE=castmiester;5663375]Even with 9 BHN shooting ?

If the 9 BHN is just lead tin? No. If you PC? No. If you use a base or gun protector? (Sometimes called a GC) No. If it is PB and has antimony in it? Yep.


Ever use sandpaper? The harder you press, the more it cuts. Now, using the same logic, and just picking numbers, what will 15 k psi push out harder on, 9 or say 18? I just rebarreled a 44 spc Blackhawk the grandkids abused and my 357 Freedom to include a new cylinder for just those reasons. Coarse were taking 10s of thousands of rounds. It also occurs if you clean more often.

[castmiester]

[QUOTE=castmiester;5663375]Even with 9 BHN shooting ?

If the 9 BHN is just lead tin? No. If you PC? No. If you use a base or gun protector? (Sometimes called a GC) No. If it is PB and has antimony in it? Yep.


Ever use sandpaper? The harder you press, the more it cuts. Now, using the same logic, and just picking numbers, what will 15 k psi push out harder on, 9 or say 18? I just rebarreled a 44 spc Blackhawk the grandkids abused and my 357 Freedom to include a new cylinder for just those reasons. Coarse were taking 10s of thousands of rounds. It also occurs if you clean more often.

aware it's not just lead, but just curious if it would take alot longer to wear out throats.

[mehavey]

...curious if it would take alot longer to wear out throats.You're not going to wear down throat surfaces using cast lead -- of pretty much any hardness.

[fredj338]

Pin gauges are the way to go if you are starting in this. I bought a set of Starrett expandable hole gauges in 1969 and with a good Starett micrometer have been measuring the inside diameter of any hole since that time with these. Take a little time to get the feel for these, but then giver very accurate results.

^^THIS^^ I bought a set of pin gages, pretty cheap. It lets me quicky measure any ID accurately. IMO, a must for revo cast bullet shooters.

[Three44s]

Could you explain in threads are cut in separate operations?

The two components involved in a thread crush condition are the barrel and the frame. They are machined separately by necessity, likely by different machinists. Assembly is likely performed by a third person.

Three44s

[castmiester]

The two components involved in a thread crush condition are the barrel and the frame. They are machined separately by necessity, likely by different machinists. Assembly is likely performed by a third person.

Three44s

thread crush barrel and frame.. that is a given. Machined separately..... what for ?

[Tatume]

thread crush barrel and frame.. that is a given. Machined separately..... what for ?

I suppose it is possible to machine a frame and barrel from one piece of steel, but it would be cost prohibitive to do so.

[DougGuy]

With a Ruger, they calculate how much "interference" fit they need to torque the barrel so the front sight (which is already installed on the barrel) is rotated up to 12:00 when it reaches the specified torque.

If the gun shoots to the left, they torque the barrel some more so it moves the sight blade to the left, this makes the barrel point more to the right. Here is where it gets thread choked.

You really don't need to worry about thread choke in a .357 because the barrel stub (the threaded portion of the barrel that screws into the frame) is much thicker than a 44 or 45 caliber barrel.

45 Colt barrels are the worst ones for thread choke because the barrel walls at the threaded stub are thinner than any other caliber they produce on a single action frame and torquing the barrel distorts the inner bore easier, creating choke as they tighten.

[castmiester]

With a Ruger, they calculate how much "interference" fit they need to torque the barrel so the front sight (which is already installed on the barrel) is rotated up to 12:00 when it reaches the specified torque.

If the gun shoots to the left, they torque the barrel some more so it moves the sight blade to the left, this makes the barrel point more to the right. Here is where it gets thread choked.

You really don't need to worry about thread choke in a .357 because the barrel stub (the threaded portion of the barrel that screws into the frame) is much thicker than a 44 or 45 caliber barrel.

45 Colt barrels are the worst ones for thread choke because the barrel walls at the threaded stub are thinner than any other caliber they produce on a single action frame and torquing the barrel distorts the inner bore easier, creating choke as they tighten.

Thanks for the clarification Doug ! Guess the frame is harder than the barrel according to your explanation ?