Lesson learned...slug your barrels

[jamesp81]

Decided to re-slug my 1911. I'd done this years ago and was sure it was a .451" barrel. Apparently I remembered wrong, because I slugged it out to .452" just now. No wonder I was getting bad leading with .452 boolits...they're too small.

Good thing to do before spending $150 on a custom mold from Accurate. I'll have to order a mold at .453 or .454 for this pistol...haven't decided yet, but it'll be one of the two. I am concerned about getting .453 or .454 boolits to chamber...my crimp will be swaging down the front part of the boolit somewhat I am certain to get the cartridge to chamber. Am I right in saying that as long as the base remains .453 / .454, I should be ok?

If I can't get them to chamber, I'll have to get the barrel reamed.

[gnostic]

My Lee 200gr SW drops bullets at .454 with 1-40 alloy. I wish I'd purchased a 6 cavity rather than the 2..

[runfiverun]

the 6 might not have dropped them at that diameter.

before I bought a new mold I would do some more measuring.
a fired case would be a good place to start.
then working through each die and figuring a solution from there to get to the end result you desire.

fixing the mold you have now is like a 45 minute thing.
ruining those efforts is forever frustrating.

[Whitespider]

Whenever I don't see a forth decimal place in the measurement, the first thing that enters my mind is a question...
What are you using to measure the slug??
And is that measuring tool you're using the same one you used "years ago" when you slugged the barrel??

You really need the measurement to be precise in ten-thousandths of an inch.
When I slugged my 1911 barrel I got three different measurements across the 6 grooves, .4504, .4505, and .4506. With the alloy I'm using my boolits come out of my .452 lube-size die at .4517. So, my boolits are just a touch more than .001 over groove diameter. If I wasn't using a precise measuring tool (i.e., a micrometer capable of measuring ten-thousandths) I wouldn't know that. If I was using my dial caliper, and depending on how I manipulated it, I could easily get a .451 measurement for all four of those values, leading me to believe my barrel and boolits are the same size. Or, I may see it as .450 for groove diameter and .452 for sized boolit, leading me to believe my boolits are .002 over groove. When, in fact, neither is true.

If you don't have the precise information it's only as good as guesswork. Are your .452 boolits actually .4520 and is your .452 barrel actually .4520?? Unless you know for sure you may be chasing your tail. For example, it may be the base of your boolit is being sized down during boolit seating... or maybe your alloy is too hard for the .45 ACP low pressures.

Just sayin'.
*

[rondog]

Are your .452 boolits actually .4520 and is your .452 barrel actually .4520??

Um......

Sorry, couldn't resist!

[DougGuy]

Yep, dimensions are looking like caliper readings, possibly too hard an alloy, likely more than one thing contributing to the problem. You are welcome to send the barrel and a few boolits or dummies for another opinion/evaluation.

[gwpercle]

My Lee 200gr SW drops bullets at .454 with 1-40 alloy. I wish I'd purchased a 6 cavity rather than the 2..

I have noticed that 2 cavity moulds will sometimes cast boolits a little larger than the same design in a 6 cavity mould. Don't know why ....but it does show up. Whenever some one asks about the size of an as cast boolit I always specify the number of cavities the mould has....sometimes there are differences . Chances are if you bought the 6 cavity it wouldn't be the exact size ....
Gary

[Char-Gar]

Well, you measured wrong one time, but which time was it? As other said, what did you measure with?

At any rate, shoving a .452 cast bullet down a .452 45 ACP barrel is not likely the cause of your leading issue.

[popper]

Slugging won't tell you if it will feed, fit the throat or shoot good. Slug the bore to 4 decimals then add the recommended 1-2 thou. for fit? Silly. Just pound a boolit in far enough to find general groove size, order one larger and size to fit what shoots good. Go a step farther and do a pound cast & select or design one to really work. Revolvers are a different story.