I thought we were there. Snow on the ground was melting and receding, icy stalactites were loosening their grip on the gutters, and the house and driveway were previewing the magnitude of clean up that would keep me busy through spring. Mud season.
Then the snow began to fall, heavily. Stirred by fifty mph wind gusting up the hill, even stout trees bowed. The downside? The forecast is snow on and off all day and into tomorrow. Clean up will be a chore. The upside? The start at spring clean up will be deferred for at least two days.
Conformity’s role in accuracy
If dimensions and weights of cartridge components vary, it will show as pressure and velocity differences from one round to the next. Those velocity differences will result in shifts in point of impact from one round to the next. The more severe the variations, the more severe the inaccuracy.
There are many ways to address this issue, some as simple as exercising care in component selection, uniformity and assembly. What follows had been applied to “The 45 Automatic +P Trail Gun” handloads, but not detailed within the article.
Not too big, not too small, but just right
SAAMI spec bullet diameter for 45 Auto Match is 0.4520″, 0.4530″ for the standard and +P. These dimensions, combined with brass wall thickness equal assembled cartridge maximum diameter, as covered in the follow on section. As every component brings its own dimensional tolerance, control of each is of consequence.
Three examples of 45 Auto bullets measured, at the shank, respectively 0.451″, 0.452″ and 0.453″. My goal was to have them a uniform 0.451″ in diameter.
A couple of ways to get bullets to a specific size. Left, the Lee Classic Bullet Sizing Kit SKU: 90061 Manufacturer part number: 90061 MSRP $25.98 works in any reloading press. In this case, it is the sizing kit I use to turn .0358″ rifle bullets into 0.356″ bullets for use in highly accurate 350 Legend handloads.
The device on the right, sitting in front of a 185 grain, 45 caliber mold, is an RCBS Lube-A-Matic press sizer die. This particular die is marked 0.452″, but they are available in 0.451″and 0.452″ and many other sizes above and below those diameters. The press and die combination size bullets and, where applicable, pack grooves with grease. Why the 0.452″ die to get to 0.451″? Because that is the size bullet that particular die pokes out. Sometimes, it pays to measure and not take markings as gospel.
I had moved my casting gear to where my welding gear is being set up and I could not guess which box had what pieces. Yes, I had marked the boxes. However, less than exciting penmanship and inadequate descriptions “Misc. Stuff”, I was forced to climb up into the shop loft to see what I could find.
There I encountered a backup Lube-A-Matic 2, which had not been used since 2001, and a sizer die packed in a small green box with a 185 grain 45 caliber cast bullet mold. Also found an RCBS Rock Chucker, assorted Lee presses and the balance weights for my telescope that I gave up for lost three years ago. Good deal.
The straight and narrow…
A problem I have encountered with the 45 Auto is a combination of barrels with tight chambers and maximum specification diameter rounds. The first, the result of installing minimum dimension chamber match barrels, the second the result of case mouth flaring and seating hard cast bullets.
A SAAMI 45 Auto Match chamber is 0.4732″ diameter just aft of the case mouth. The standard and +P spec is 0.4744″. When chambers are spotless and cartridge assembly is with care, it is still possible to end up with a cycling slide stopped out of battery and wedged tight. Nobody likes a wedgy. Details? Sure…
Big mouths are always a problem…
The case mouths measured, as pictured left to right, 0.473″, 0.472″, 0.473″. What they have in common is that all, in one of my 1911s, caused a failure to feed and all jammed out of battery.
The solution to the wandering and maximum size dimensions was a Lee factory crimp die that sizes an assembled round to assure clean chambering, while applying a taper crimp to assure proper case mouth headspacing for reliable and consistent ignition. In this case, running assembled ammo through the die set case diameter at the mouth at a uniform 0.471″.
The Lee die, carbide version, is SKU: 90864 Manufacturer part number: 90864 MSRP $28.96. The factory crimp die is also included in Lee’s 4 die 45 Auto carbide set SKU: 90968 Manufacturer part number: 90968 MSRP $78.00. Weren’t Lee dies the last budget source?
Conclusion
A couple of quick steps does not add much effort to the handloading, but they do contribute measurably to reliability and improved performance .
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