Boolits too big?

I need some advice from this community. I have a Uberti 45 Colt six gun that I plan to load and shoot a cast Lee 452-255-RF boolit. I’ve cast, powder coated and sized these boolits to .452/.453 dia. This is a mic’d diameter, the boolits are slightly out of round hence the .001 dimensional variance. I check the cylinder bore mouth with my calipers and they measure .453/.454 dia.. That said, when I drop a sized .452 dia boolit, the boolit sticks in the cylinder cartridge bore mouth and will not pass through without being forced. In machinist terms, the boolit is an interference fit in the cylinder mouth. I believe I have a difference of about .001 between cylinder mouth diameter and boolit diameter. I don’t think this is an issue and may even be desirable, but I’d like your opinions/experience with this before I pull the trigger on these loads.

Should my cast boolit freely pass through the cylinder mouths?

This is a fun gun to shoot. I plan to load/shoot this 255 grain cast RF boolit with a load velocity of around 750-800 fps, will try a few loads over Red Dot, 700X, and Unique as I have all powders on hand and available load data as well.

Thanks all.

JJ

Someone else will come along with more detailed advice soon but I will give you my version. The bullet should be easily pushed through the cylinder. It should not drop straight through. So slight resistance is good.

Size those casts @ .4525" and see if they are snug in the cylinders...all of them. Not 'drop through' but an easy push in without any effort fit.

Well, as I said in the OP my boolits measure .452/.453 depending on where you take a measurement on the circumference. I checked a handful of boolits, they all measured the same, very consistent. Sized with a Lee push through sizing die. I suspect that the resistance seems worse in the cylinder mouths because of the drag of the powder coat. I have not yet tried to force a boolit completely through the cylinder mouth to see how much pressure that would take. But again, as measured with my micrometer and calipers, there's about .001 interference. I don't trust my calipers accuracy as much as my micrometer, but I'm not using cheap tools either way (used to work as a machinist many years ago).

Wait...I'm confused...did you size before or after PC'ing the casts...or before and after?

Have you tried loading a "dummy"cartridge with these boolits?If you can chamber a loaded cartridge in the cylinder the boolits will size themselves when shot.Suggest you check a few to be sure they'll chamber all the why in each hole before loading a bunch.

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Originally Posted by jeff100

Well, as I said in the OP my boolits measure .452/.453 depending on where you take a measurement on the circumference. I checked a handful of boolits, they all measured the same, very consistent. Sized with a Lee push through sizing die. I suspect that the resistance seems worse in the cylinder mouths because of the drag of the powder coat. I have not yet tried to force a boolit completely through the cylinder mouth to see how much pressure that would take. But again, as measured with my micrometer and calipers, there's about .001 interference. I don't trust my calipers accuracy as much as my micrometer, but I'm not using cheap tools either way (used to work as a machinist many years ago).

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Just load some and shoot'em, with the fit that good they should shoot good and not lead
the cylinder or bore, if they do not lead then there good to go.

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Originally Posted by OS OK

Wait...I'm confused...did you size before or after PC'ing the casts...or before and after?

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I sized AFTER powder coating.

JJ

I do have a question. You are using "cylinder mouths" is this the opening the boolit is feeding into or are you talking about the cylinder throats where the boolit exits the cylinder? Proper boolit/cylinder fit is when you can push a boolit through the cylinder throat with a bit of resistance. It is also helpful to know the groove diameter of your barrel to make sure there is no problem with cylinder throat/bore relationship.

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Originally Posted by Bzcraig

I do have a question. You are using "cylinder mouths" is this the opening the boolit is feeding into or are you talking about the cylinder throats where the boolit exits the cylinder? ...

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Cylinder mouth e.g. the exit end of the cylinder bores. I did load one dummy round and checked the fit in all six bores, no problems there so at this point I will load up my cartridges and shoot these boolits. Thanks everyone for your time and feedback, much appreciated.

JJ

just shoot them.

Accuracy will probably improve IF they are symmetrical. I had that problem with a 357 I was chasing a leading problem with.

I do not see how they are elliptical after sizing. That don't sound right at all. I would hastily abandon said calipers in favor of a Mitutoyo digimatic 0"-1" mic that reads in .0001" which can be had on fleabay for around $40 used in good condition. And if you REALLY want to turn a Chevy into a Cadillac, buy one of those weighted stands that hold the mic so you have both hands free.. Under $20 usually for the cheaper ones.

Uberti has a modern bore diameter, .451" on most that I have checked, and you do want the boolit to be a light drag fit in the cylinder throats. It really doesn't hurt anything if they are a little harder to push through, but keep in mind that the boolit will exit the front of the cylinder at throat diameter, regardless of what it is sized to before firing and sizing larger surprisingly makes some guns shoot quite well, but for most of them doesn't do much but raise pressures a little bit, a little more if the boolit is hard cast and even a little more if it is significantly larger than the throat.

Forget the calipers. Get a soft lead sinker large enough to cast in your mold. Cast a pure lead boolit, shove it though a cylinder throat, and measure that. Re-melt and do this six times, you know the throat measurement of each chamber. You have a mike, give yourself something to measue. Then get back to us.

In your case with PCed bullets there should be no problems, the coating will deter leading. As far as "light push through", "drop through", "snug push through" these are not measurements and can mean different things to different people. Measuring a small ID with calipers isn't accurate just because of the tool's design; jaws will have a flat surface, not knife edged, and give erroneous measurements of a circular ID/surface. I use pin gauges to determine cylinder diameters and sometimes slug the cylinder, just like a barrel, to find throat diameter. If a lead bullet is smaller than the cylinder throats, gas cutting/leading will occur because gasses are not "sealed" at the throats. If the bullets are larger than the throats, they will be swaged/sized down to throat diameter as the bullet passes through, and sometimes lead will "spray" on cylinder face, frame and forcing cone.

So, having said all that, I'd recommend sizing the bullets, plain or PCed, to the same size, measured, as the cylinder throats...

Good advice given . . . .

Chuck the calipers and slug your cylinder throats - then use a micrometer to measure - and do all six. That will tall you the true size.

I'm a little confused when I read your posts but it's probably me! LOL I have a Uberti 45 Colt Cattleman - 7 1/2". I have a variety of molds. Now I don't PC - I just tumble lube in alox/pastewax - I know PC is a bit different.

First, the cylinder chambers in mine are on the generous side. I have several .452 molds as well as several Lyman/Ideal 454-190 - the traditional RNFP. I can cast and end up with a .454 boolit and they load in my chambers just fine. I have not measured my throats nor the bore as I haven't really had to. Some of my molds as well as some commercially cast I have purchased fall at .452. Certainly no issue in sliding them in the chambers. The odd thing is that it doesn't seem to make much difference with my Uberti if the boolits are .452 or .454 - they all shoot well. Perhaps it is just my Uberti or I am lucky? I usually just load them as they drop from my various molds - but if I end up with a few plump ones, I run them through my Lee .452 push through sizer.

If you are sizing them - they should be "round"? And, if I'm reading right, you are sizing them after PC ing so they should again be "round". Load up some dummy rounds and slide them in the cylinder - if they fit, then there shouldn't be an issue - shoot 'em and see how they shoot.

A Ruger SA seems to have issues with cylinder throats that are under size - usually due to the way they ream them, reaming wear, etc. and sizes can vary from chamber to chamber - DougGuy gets them straightened out in good order from everything I've read. I have a New Vaquero in 357 that has that issue and I really need to have him fix it.

I can't speak for Ubertis - I have the 45 Colt and I have a Uberti 357 Mag Bisley - 4 1/2". That revolver is also a great shooter and seems to have generous chambers and the throats seem to be very uniform - it shoots well so I have never slugged the throats nor the bore - if it ain't broke, don't fix it. Others with Ubertis? Their experiences may be different than mine.

Load up some dummy rounds and try them - then they fit O.K., load up some real ones and try them and see how they shoot. I she always found the 45 Colt to be one of the easiest and most forgiving cartridges to load - at least for my pistol - and my Uberti Cattleman to be very accurate whether the boolit is .452, .453 or .454. YMMV

Good luck and let us know how it works out! You'll enjoy it I'm sure! And just as a side not - I use the Lyman Cast Bullet Handbook for loads and have had very good luck with Unique, Red Dot and Green Dot.