barrels throats and slugs!

[guncheese]

brought home a new gal yesterday
http://goo.gl/6X87q4
and yes the gun has frost on it, as it was fresh off the fedex truck and its cold as witches brass monkey up here


so after leading the heck out of it in 32 rounds
i slugged everything
here is the map of the results forgive my hen scribbles
http://goo.gl/HUUfF7




what should a fellow who shoots .452" soft lead do?
i powder coat most things
but the lead shavings from yesterday were 45/45/10 lubed


i dont see a whole bunch wrong with the numbers
and by what i have read its way better than what most see


happy new year!!!

[guncheese]

i shoot the same load i use in my 1911 and it stays bright and shiny but then again it is Kart barrel.....
i just wasnt expecting it to be that bad
i had just picked the thing up and ran to the range
then right away when i got home i looked at the leading, then cleaned her up and slugged everything and those numbers look good to me as well
the bore does look like it needs a bit of a polish
and there is that couple tenths of constriction at the threads
i could fire lap the thing
but i could make up a lead lap and have at it

for Monday ill shoot only fairly hard bullets that are powdercoated
and see what the what is

[DougGuy]

Your throats are perfectly sized for 0.452" bullets

Sorry Tatume, I have to disagree with this statement. OP your throats are too small for .452" boolits as you have already documented your throats being less than .452" in diameter. Very common with Rugers to show throats exactly as yours. The throats need reaming to at the very least, the diameter of a .452" boolit, and I take them to .4525" with a reamer and hone them to finish about .4527" which is 5 to 7 ten thousandths over the diameter of a .452" boolit. This is about perfect if you want to shoot .452."

If you can't push a .452" into the throats from the front, they are definitely too tight. You can load a .452" and seated deep enough most will chamber, but firing through tight throats sizes the boolit down to the throat diameter, doesn't take a rocket scientist to tell that a .452" won't go through a hole smaller and still be .452" on the other end. This also can cause pressures to rise dramatically, and the harder cast your alloy is, the more pressure rise you will get.

Some of the leading may come from the area of the barrel that is threaded into the frame. With a clean bore, remove the cylinder and put a piece of white paper at the firing pin and shine a bright light on it. This will illuminate the bore, and if you can see a very slight, hazy distortion in the bore where the barrel and frame meet, this is an indication of a thread choke. You can very tightly patch a cleaning jag into the barrel, and push it through, if it gets stiff to push or stops altogether at the same spot, that is the constriction that you are feeling.

If it isn't too bad, you can firelap this out, but get the cylinder throats reamed before firelapping, so you won't downsize the lapping boolits before they even get to the choke in the barrel. If it's pretty severe, it may need to go back to Ruger, IF they will address it, because that 416 series stainless the barrel is made of, is TOUGH material, and you could easily have to lap enough to damage the remaining good rifling in the barrel, before the choke is lapped out.

I offer as more of a convenience to shooters than anything else, a service of reaming cylinder throats, and in worse case scenarios, Taylor throating barrels in .45 caliber revolvers. You may send a PM to inquire, the work is fast and very affordable, professionally done. I do quite a few Ruger cylinders, yours sounds typical, you can look for much improved groups and a LOT less leading by having the throats addressed properly.

I use soft lubes, Felix when and if I can get it, but usually if you have an alloy that you can scratch with a thumbnail, and soft lube, they work really well with Ruger twist rates of 1:16" and Ruger's rifling. I got really bad leading from shooting hard cast alloy, with hard lubes like what you get when you order commercially cast boolits.

[tazman]

My neighbor's Ruger Blackhawk in 45 Colt also leaded like a beast with any lead boolit and any lube. It didn't matter the brand of lube or hardness of the lead. His cylinder measurements were more consistent than yours and slightly larger but the groove diameter of the barrel was the same.
We ended up powder coating. That stopped the leading and improved his accuracy. Just something you may want to try.

[DougGuy]

This post has been edited to remove replies made to posts that were deleted by the author.

Just about every one here has dealt with Ruger cylinder throats, and it is a widely known fact that they are tight from the factory, and if you shoot a boolit through a tight throat, the boolit becomes swaged to the size of the throat, which any 3rd grader could tell you after doing the math, and this causes a lot more problems which by the way, are fixed in a nice fashion by reaming the throats.

The reamer cuts very precise ROUND holes, which again Ruger is well known and quite documented for having oval, out of round throats. We say here fitment is KING.

In a perfect world, a cast boolit is .001" to .002" over bore diamter, which makes a great seal in the bore when fired. You can prove the fitment of this in the bore by driving a lead ball the same diameter as the bore through the barrel, it goes very easily, as it slides down the bore, you can begin to see light in the corners of the rifling, as the lead minutely changes shape as it travels. Should you try this with a lead ball .001" or .002" larger than the bore, you will find that this ball seals itself in the rifling MUCH better than the same-diameter-as-the-bore ball you tried this experiment with first. It is a natural for good obturation in the bore when the boolit is .001" to .002" larger than groove diameter.

In a perfect world, the boolit you send into the bore would NOT be sized down by any part of the gun, the cylinder throats, OR the threaded area of the barrel, so that it truly remains as-sized and assembled when it is fired. The long and short of a revolver, is that it needs to be dimensionally quite like a funnel. Larger diameters at the back, where the boolit begins it's travel, gradually decreasing as the boolit makes it's way into the barrel, so that it maintains a good seal all the way to the muzzle.

How do you suppose to achieve this, with a cylinder throat that is undersized? Well, hold the phone, the truth is, YOU DON'T! Plain and simple.

Cylinders when they leave my tiny shop are correctly dimensioned, those dimensions are EVEN within .0003" from one throat to another, and they are nice and ROUND. This is a claim the factory cannot begin to make, and there are quite a number of shooters right here on this forum who from their own personal experience with the services I offer, will attest to this being a true statement.

The OP has a classic example of a New Model medium framed Ruger, reaming the throats on these guns fixes one of their well known small problems, recutting the forcing cone to 11° is the bee's knees for shooting cast boolits, and removing one leg of the trigger return spring and letting it hang, the PMTJ or "Poor Man's Trigger Job" is ALL that is necessary to accurize these classic wheelguns to a very acceptable level of performance and shooter satisfaction. Ask ANY of my customers. Better yet, SEND me a cylinder and see what you think of it when it comes back!


A good combination of alloy and lube will get this gun shooting without risking ruining it by modifying the throats.

guncheese is shooting .45 ACP not .44 magnum or .45 colt where there would be enough pressure to seal a soft enough alloy in the bore after it cleared the cylinder throats and thread choke. THIS is how softer boolits will swage down, then bump back up in the barrel. It takes at the very least a very hot loaded .45 Colt, approaching near max pressure listed in the Ruger Only load data, a .44 magnum will easily swage the boolit back, but a .45 ACP? No way. Even the +P loadings of 23,000psi don't have enough force to obturate the boolit once in the bore after being swaged down.

[bedbugbilly]

I think Doug has stated very well what is going on with the revolver and I have seen a number of Rugers that suffer from the same . . and that greatly benefit from a good ream job. The analogy of the funnel and starting big is a good one.

Ruger makes good handguns - I love mine - but sometimes they need a "tune job" - no different from any other revolver - to get them shooting well. Yes, many are shot as they come out of the box - and often they shoot well - but if you want to get the most out of this SA - you will probably need to tune the throats up.

OP - if you don't want to do that - then play around with your alloy and lube and see what you can come up with and if it you get rid of the leading and see if it shoots well. Nothing ventured, nothing gained. If after experimenting with the various things you still aren't happy, have a good smith ream the throats. What Doug says makes perfect sense.

Good luck and have fun - you have a great looking SA! Enjoy!

[tazman]

I take it some one deleted their posts. The references aren't there for some of the current ones anymore.
For a minute there I thought DougGuy was talking about something I was supposed to have said until I realized posts were missing.

[DougGuy]

Yes it does read rather oddly now doesn't it? Let me see if I can fix that with editing..

guncheese if you see this, I will be glad to assist with getting your cylinder throats correctly dimensioned if you choose to do so.

[guncheese]

wow excitment,intrigue,mystery!!!!
i did take a long hard look at the map i made
and took the plunge and made them 29/64"
i need to make a split stick and polish them up
but its done.......
im sure its going to keep me from creating a lead mine in the bore
i know they are not perfect but a .452" bullet drops thru 3 holes and pops right thru the other 3

i will report the results
if i run out to the range tomorrow ill be running some .452" powder coat swc that are harder than the mush gobs i normally shoot (it will be below 0 and windy.....)

[DougGuy]

Well, if it patterns like a shotgun call Ruger and get a ticket for it, let them make another cylinder for it.

Either a twist drill or a chucking reamer comes in 29/64th and neither one is capable of maintaining concentricity of the existing throat. I shudder to think that someone would take either to a cylinder but I guess Tatume was right! I have seen some ruined cylinder throats, users that bought the right reamer but too cheap to buy the pilots so one guy chunked a .448" pilot (the one the reamer comes with by default, which Ray Charles could drop through the cylinder throat, THAT's how loose it fits!) and proceeded to totally wreck two cylinders. He got off center SO bad 3 or 4 of the throats had an eyebrow of the old throat showing on one side of newly cut throat.

If you have 3 that are large and 3 that are tighter, they will each shoot to their own point of impact and likely can be as much as 4" to 6" difference in just 25yds.

[guncheese]

i made sleeves to keep the reamer centered
im pretty sure they will be fine
i have 19 years of prototype machining experience and since i was forcibly retired i so dearly miss my machines

[MtGun44]

There is no way I would even consider reaming that pistol right away.
The throats are .451+ every where and the groove diameter is
a hair smaller, this is essentially ideal for a .451 or .452 boolit
to work well.

Some folks are like the guy whose only tool is a hammer - after a while
everything starts looking like a nail.

Besides - NEVER, EVER do a permanent modification to a gun until you
have FULLY explored what it will really do with different loads, different
boolit designs, alloys, lubes and sizes. LOTS of guns never read the
rules and shoot very well indeed with dimension that some folks would
say "aren't right". In the end, Mr. Target is the ONLY one that knows
the answers.

Bill

[guncheese]

update!!
today was the 2nd time out with the reamed throats
the first time was a lead free success but it was so cold i wasnt shooting well (-12f) but still did fine for the conditions
today i shot dead soft (or darn near) swc that i cast from almost pure and powder coated them sized to .4523"
all i got in the bore was a bit of powder spooge, the bore was nice and shiney!!
and i was pretty pleased with accuracy
shooting at a pretty good pace i can keep 4 of 6 on a 6" steel at 25 yds (im still trying to figure where to hold this thing so much shiny !! i cant see!)
very happy so far with my work!
so if you have a tight throat ruger send it to DougGuy (i probably should have done that myself but im talented and cheap)