Advice wanted on my .45 colt revolver measurements

[Andy]

I have a large frame vaquero in .45 colt that I haven't loaded for before and just did the chamber/bore slugs, wanted to see if you guys think my plan of action is appropriate given the measurements. It is my first time loading for a revolver other than 100 or so low power plinking rounds for fun.

Cylinder slugs were obtained by pounding pure lead slugs through each cylinder, catching them in cloth and measuring with a micrometer. Each slug was measured at least 3 times in different places, if any measurement disagreed with the others then the slug was measured 6 times to confirm and a range is given for those situations instead of just one number.

Cylinder 1: .4510
Cylinder 2: .4510
Cylinder 3: .4510-.4512
Cylinder 4: .4510-.4511
Cylinder 5: .4510-.4515
Cylinder 6: .4512-.4515

Bore slug was pounded muzzle to breech and caught in cloth, measured 10 times in different locations on the slug, and extremes were triple checked but I still had a range of .4500 to .4510.

As the slug was pounded through the bore it was tight toward the muzzle for the first inch or two, then dropped effortlessly to the breech area and maybe 1-1.5" from the breech it tightened up a very small amount. I'm aware of these guns in this caliber being notorious for having a constriction in this location and don't know if I should regard mine as in need of attention or not. It was a very light feeling constriction.

I am sizing to .452 right now as that's the die I have (and would like to stick with if possible). I figured I would make up some starting "ruger only" loads and see how it shot before debating messing with anything as far as reaming/fire lapping etc.

Am I within specs to have a reasonable chance of success there or should my cylinders get reamed or bore firelapped before doing load development? I own a 320gr Accurate mold I'll be working with for this, gas checked, and would like to work up to mid-high ruger loads eventually.

Thanks,
Andy

[drklynoon]

Andy,
I have a Large model Vaquero that measures close to yours. I size mine to .452 and they are a tight fit in the chambers. I would size a bullet with your .452 sizer and try this. I use trailboss and load it as high as I have room for and have not run into leading problems with a plain base "Keith style" 255gr WDWW. I would suggest trying out what you have and if you have problems revisit. Your bore appears to be about a thousands smaller than throats which should work well for you if your sizer is on the tight side. If your sizer makes a fat .452 you may need to get a .451.

[flyingmonkey35]

I shoot mine at a low power plinking round.

230 grain Lee round nose p/c over 4.7 grains of tight group.

With and with out a poly fill. As filler.

That load is something you can shoot steel at all day long. And make the gong ring.

[w5pv]

I also am close to what Flyingmonkey35 uses but I go 5.5 grains of Titegroup it is my most accurate loading for my gun.I haven't killed anything that has blood but it does fine killing paper.

[flyingmonkey35]

I also am close to what Flyingmonkey35 uses but I go 5.5 grains of Titegroup it is my most accurate loading for my gun.I haven't killed anything that has blood but it does fine killing paper.
I have used between 4.7 to 6.4 grains of Tight group. .

Plinking paper and steel 4.7. If am after a more tighter group (pun intended). I'll go 5.6

If I want a fun round to impress my friends 6.4. Or 35 grains of holy black.

Wow that ones fun.

[str8wal]

Cylinder 1: .4510
Cylinder 2: .4510
Cylinder 3: .4510-.4512
Cylinder 4: .4510-.4511
Cylinder 5: .4510-.4515
Cylinder 6: .4512-.4515

If it were my gun I'd uniform the throats to .452", but that's just me.

[Char-Gar]

Ruger makes those things to shoot jacketed bullets. If I was the owner of you handgun, I would have the cylinder throats reamed to .4525 and be done with it. I will draw some fire for this, but this "constriction" thing is way over blown. After the cylinder ream, just shoot .452 cast bullets and have a great time.

I have loaded many thousand 45 Colt rounds over the past 50 years, and everyone of them has been loaded with either Unique or Bulleye powders. I am certain others will work, but that is what I do.

[DougGuy]

Your measurements are typical, including the inconsistencies. This is VERY common.

Truth be known, it really does not matter at all what you size to and load assembled ammo with, your boolits are going to come out the front of the cylinder, at throat diameter. This is precisely why the throats need to be "dimensionally corrected" so that your boolit is presented to the forcing cone at the diameter you initially intended it to be.

In your case you do need .4525" throats so that your .452" remains a .452" all the way through the cylinder. The throats also need to be even and consistent. I strive to send cylinders out of my shop within .0002" of each other. THIS is the most important part of the whole shebang, you can always size to the throats regardless of what their diameter is, but having them even removes a key variable, and this is one of the known causes of inconsistent pressures. Inconsistent pressures whether it is due to inconsistent powder charges or primers or neck tension or crimp, OR cylinder throats does one thing. It causes the gun to recoil differently from shot to shot and the muzzle will not be at the same position every time when the boolit leaves the barrel. Now you have poor groups. The more variables you can bring in line and make consistent, the smaller the groups will be. This is completely normal with any handgun but the single action revolver even more so.

If you plan to firelap, you will definitely not want to attempt it with tight throats since all that will do is downsize your lapping loads.

In my own loads for .45 Colt and .44 magnum, I weigh each charge. It's not that slow once you get in a groove of doing it on a digital scale and it does improve accuracy.

[DougGuy]

As far as the barrel inconsistencies, you could firelap, and there is a silver lining here, the lapping loads will remove the choke at the threads as you have described it as not being too severe (severely choked = the lead slug stops and you have to beat extremely hard to continue moving it) and once past this initial constriction they lose their effectiveness and since your bore is larger in the middle they will not lap at all, and by the time they get to the muzzle they won't lap it enough to measure and this will leave you with a tapered bore, which for shooting cast boolits is PERFECT!

A dimensional flow chart of a good revolver should read like a funnel. The largest dimensions at the back, getting progressively smaller as the boolit journeys to the end of the barrel. This ensures the boolit will be presented to the forcing cone at throat diameter, sealed in the rifling at the forcing cone, and as it travels the barrel, will be progressively squeezed even farther until it is free of the bore.

The 3 best bang for the buck things you can do to any Ruger single action revolver are 1.) Correct it's cylinder throats and make them EVEN all the way around. 2.) Cut an 11° forcing cone that extends into the bore far enough to top out on each of the lands. 3.) Swap in a Wolff 30oz. trigger return spring. This spring will assist greatly in your being able to hold the sights motionless as the hammer falls.

This is CRITICAL to mastering the single action revolver. If you can hold the sights motionless when the hammer falls, you will shoot good groups. If the front sights moves any at all when dry firing, keep working with it until you can hold it perfectly still.

[Andy]

Thank you for all the thoughtful replies everyone.

DougGuy I appreciate your detailed responses. You said you like to get the cylinders to .0002" of each other, mine are all within .0005" of each other right now, is that .0003" difference pretty meaningful in the accuracy department?

I guess I'm curious where my cylinder throat consistency stands compared to a typical "bad" cylinder, am I closer to a good one or a bad one right now?

Why is it that we want the cylinder throats slightly larger than the bullet? I know this is widely accepted I'm just curious why not have them the same size as the bullet or slightly smaller?

[DougGuy]

Thank you for all the thoughtful replies everyone.

DougGuy I appreciate your detailed responses. You said you like to get the cylinders to .0002" of each other, mine are all within .0005" of each other right now, is that .0003" difference pretty meaningful in the accuracy department?

I guess I'm curious where my cylinder throat consistency stands compared to a typical "bad" cylinder, am I closer to a good one or a bad one right now?

Why is it that we want the cylinder throats slightly larger than the bullet? I know this is widely accepted I'm just curious why not have them the same size as the bullet or slightly smaller?

I have a Mitutoyo mic that reads in .0001" increments, and as light a touch as you or I or the ratchet stop could impart to a soft lead slug, you/we re still using flat anvils to measure a round dead soft slug. I highly suspect that .0003" differences could be picked up by my excellent mic because the anvils WILL make a slight flat spot when they measure, thereby adding error to the actual measurement. I do find however that one can use friction to gauge how close holes are and be fairly accurate with it. A pin gage will not measure a hole that is equal to the gage, so they make them in minus classes so you can get one in the hole. I use Z minus gages and can tell a slight difference in the "feel" of the gage in the throat that will tell me more about how even the throats are than any mic and a soft lead slug can tell. The slug is soft. It is a guessing game from start to finish and it has little consistency from one measurement to the next. Also .0002" is such a SMALL increment when it comes to putting a boolit through a metered opening that it won't make enough difference to record a deviation that you could attribute to a .0002" variation in hole size.

You have a "good" cylinder as far as the original large framed Vaquero cylinders run.

The issue with seating a .452" boolit in a .451" throat is that they don't fit! For best accuracy, the boolit NEEDS to be supported by the throat in front of the case mouth. This ensures the boolit is held concentric to the throat when the round is fired. If it isn't the cartridge can lay in the bottom of the charge hole, which places it on an eccentric with the cylinder throat. This will have a detrimental effect on accuracy becuase it deforms the boolit during the firing sequence. It is very obvious that a load assembled with a .452" boolit that is long enough to seat into the throat, will not seat fully in a .450" or .451" throat because of the interference. At this point many shooters decide to have their cylinder worked over so their ammo WILL seat properly.

There is also the fact that with less resistance in the boolit's path, there is less of a pressure spike upon firing. Secondary sizing occurs when the alloy is soft enough that when a heavy charge of magnum powder is touched off, the boolit will obturate in the cylinder throat and will upon firing exit the cylinder at whatever diameter the throats are. Unless you are shooting BHN24 or harder, or you are shooting standard pressure .45 Colt loads or even 23,000psi tier 2 loads, you can figure on the boolit growing slightly on firing.

In a perfect world what works the best is a cast boolit .001" to .002" larger than groove diameter, and a cylinder throat .0005" to .001" larger than boolit diameter. A revolver with these dimensions will shoot great, and if all else is correct in the load, the lube, the alloy, will not lead the bore. << This is what we ALL want when it comes down to it!

Edit: Also very much worth mentioning, is the fact that according to how much antimony may be in a given alloy, many boolits tend to "grow" .003" to .006" as they "age harden" and so having a throat that is .0005" OVER the intended boolit diameter will allow for as much of this "growing" as the difference between the boolit when it is sized, and the throat size.

I have been there done that with my own .44 SBH, I sized the throats to a .432" boolit I had in house and was using, and 3mos later, they wouldn't seat in the cylinder!

[drklynoon]

Andy,
I reread my post and I do not think I was clear enough. Your cylinder is not perfect but it is as close as I would expect for a factory job. Your cylinder is also .001-.0015 larger than your bore diameter. This is correct and I would not change it. I would check to see if your .452 sizer is actually sizing to .452. You want a snug push through fit on your bullets through your cylinder throat. I really doubt that you would notice a difference between reamed cylinders and your factory cylinder if your bullets are sized correctly. I have one I have to send in because the throats are smaller than the bore and wildly inconsistant, that is when you have to send it in to get fixed. If you want to make it as perfect as possible then send her in and get its forcing cone cut while you are at it but I doubt that it will be necessary to have an accurate fun shooting gun.

[DougGuy]

Your cylinder is also .001-.0015 larger than your bore diameter.

He also mentioned there is a slight thread choke and the measurements on the barrel slug were taken after the slug was driven through the choke so this would in error make the cylinder throats larger than the groove when in fact they are only larger than the choked portion. Ruger .45 barrels have been right on .451" groove diameter for a good long while now.

[drklynoon]

Doug,
If the gun is not fire lapped and the choke persists than the projectile will be sized to the choke point almost immediately entering the barrel. In this case wouldn't a .0015 over the choke be as close as you could get it?

[DougGuy]

Doug,
If the gun is not fire lapped and the choke persists than the projectile will be sized to the choke point almost immediately entering the barrel. In this case wouldn't a .0015 over the choke be as close as you could get it?

Pretty close. Since the OP mentioned fire lapping and seeing how meticulous he is with measuring and documenting, I figured that he might do just that, and .4525" throats would be better afterwards when there is no choke. That said, I would rather work the throats before lapping so that A.) the lapping boolits do LESS work in the throats and more in the choke, and B.) the larger lapping boolit would work better than the smaller one as it would maintain more resistance as the choke grew larger and smoother.

[Andy]

I really appreciate all of the time and thought you guys are putting into the responses here, thank you very much.

I didn't realize that the throat being oversize of the bullet was sometimes a requirement to get the loaded round to fit in the chamber. I have already made some dummy rounds with a COAL of 1.680 (320gr bullet) and they fit fine due to the front portion of the bullet being slightly smaller than the driving bands so I am okay as regards the cartridges physically fitting in the chamber.

So it seems like from what you guys are saying the gun is on the better end of the bell curve as far as the measurements and it is sensible to just try out some loads with this and see if it shoots okay, and if not to then proceed with reaming the chambers and fire lapping.

I should have a chance to load/shoot a batch or two this week or next and will post back here with an update when I do. Thanks again guys.

[Andy]

Loaded up 6 with a starting load of h110 and shot them just to make sure everything looked/felt right/functioned and that went fine. I shot on paper but just at 7 yards offhand so nothing worth noting as far as a group. Cases dropped right out almost as easily as a plinking load and no signs of flattened primers or anything.

Is it important to seat in a crimp groove with these loads? I am just barely in one now but the chamber could take a good bit longer if I crimped on a driving band. 1.66" puts me right in the crimp groove and I'm at 1.68 which is the farthest out I can go and still say I'm using the crimp groove.

Going to load up 25 or more today and shoot them off a bench for groups.