At what point does work-shortened brass begin to impact crimps?

[C. Latch]

For the last several months as I've gotten back into reloading I have shot my .45 Colt as much as I could, and have noticed that my brass (mostly starline, but some Winchester that I use for my plinking loads) is slowly getting shorter. What started out at 1.279 or so is now down as short as 1.2685 or so. In other words, I've lost 0.01" off my brass.

At what point is this shorter (and, it would seem, thicker) brass going to begin to crimp less and have an inconsistent grip on my bullets? It seems like the brass involved in a crimp is only around 0.05" anyway and losing even 0.01" could manifest itself in the form of inconsistent velocity due to inconsistent pressure needed to break the bullet free of the crimp, especially with slow-burning powders that require firm crimps for best results.

(I'm mainly using N110 but have also used a bit of lil'gun and would be using H110 if I could get my hands on it).

[Larry Gibson]

The shortening of the case is caused from the FL sizing not sizing back to factory original dimension (diameter, especially at the head and expansion ring). That is good as long as the sized cases chamber freely. With the magnum level loads you're apparently using You might want to trim to a consistent length and then readjust your crimp die for the consistent crimp you want/need.

Larry Gibson

[C. Latch]

You're correct that I am not resizing any more than I have to. I actually think my tight seater sizes the case as much as my sizing die.

I don't have a trimmer and don't really have any more room for equipment (I load on the kitchen table and store everything in a closet that's about to spill through the door; hopefully not while I'm standing there barefooted) and am hoping to maintain some sort of consistency without having to resort to limiting my brass to 1-2 full-power rounds before throwing it in the plinking pile.

I sorted 25 cases just now and had 9 below 1.27, thirteen between 1.27 and 1.275, and three above 1.275. I'm thinking I may just start using 1.27" as a cutoff; everything below that I'll just put in the plinking pile.

[Larry Gibson]

Might look into one of the Lee hand case trimmers. They would easily store with the rest of your stuff.

Larry Gibson

[9.3X62AL]

Not meaning to stir up a hornet's nest here......but my own view is that neck tension has a lot more to do with load consistency than does crimp consistency. I strive to keep my cases subject to roll-crimping as close as possible to equal lengths, then set all loads of a given lot with the same crimp level, and usually a light to moderate roll crimp at that. I would think that attempting to maintain equal case lengths over time without a case trimmer would be an exercise in frustration. A case trimmer came very early in my metallic cartridge reloading regimen, for this reason.

[C. Latch]

Thanks for the response. I realize that I need a case trimmer but don't want another 'hand' tool - I do everything by hand and some of it gets tedious - and I don't have the space for a better trimmer. It hasn't been an issue for rifles yet because I don't load enough to really even dent the piles of once-fired brass I've saved over the last 15 years while I wasn't reloading.

I went ahead and deprimed/partially sized/belled the cases in question, and to my surprise they grew by .0080" or so when sized. In other words, they're all back into the ballpark length they started at. I didn't expect that. I've never spent a lot of time measuring pistol cases before and hadn't thought about a fired case lengthening when resized, though the concept does make sense.

[prs]

Maybe the measurment tool is giving some variation in result. Your seating die should not be contacting the case walls other than an excessive bell, that is as bad as final size die mashing the rounds. I roll crimp only enough to establish firm contact between the case mouth and the crinp groove bottom; retention is provided by the stretch fit of the case over the boolit.

prs

[C. Latch]

I considered that the calipers might be unreliable, or I might be using them inconsistently, but I measured the first 10 or so of the cases I was resizing and every single one grew in length by 0.006 to 0.009 after resizing. You may be right about the seater; it may be rubbing the belled part of the case; it just feels rough (with a very minor bell) and I obviously can't see inside it.

[9.3X62AL]

Case length parameters "assume" a resized and expanded case, prior to flaring/belling. Expansion upon firing and compression upon resizing causes the case's metal to go SOMEPLACE when it is manipulated--under resizing compression, that direction is upward & inward from the shell holder and die walls. Expansion upon firing has the opposite effect. USUALLY.

[C. Latch]

Case length parameters "assume" a resized and expanded case, prior to flaring/belling. Expansion upon firing and compression upon resizing causes the case's metal to go SOMEPLACE when it is manipulated--under resizing compression, that direction is upward & inward from the shell holder and die walls. Expansion upon firing has the opposite effect. USUALLY.

I would have never dreamed that a .45 Colt case would vary in length by ~0.0080 between a fired and resized case.

[rockshooter]

something I noticed a long while back with .45 LC is that the extractor groove gets smaller with time and won't easily enter some shell holders. For crimping I use the Lee collet crimper die- I haven't trimmed pistol brass in many years.
Loren

[9.3X62AL]

I would have never dreamed that a .45 Colt case would vary in length by ~0.0080 between a fired and resized case.

That is a lot of variance, but if it is consistent from case to case.......then it is "normal" in the context of the tooling being used. I concentrate my attention on the lengths of sized & expanded brass, and haven't often noted what the differences are between as-fired lengths and sized/expanded lengths. When the sized/expanded lengths exceed safe maximums--or variance from case to case gets excessive on calibers that use a roll-crimp--the trimmer gets a work-out. Neck-and-shoulder cases are FAR MORE LIKELY to require over-length attention in my experience than are straight-wall case designs.

Sometimes our tooling causes us headaches with excessive working of brass. My 45 Colt work bore this out over time. My first sizing die in this caliber--an RCBS tungsten-carbide die--GROSSLY reduced case diameters of my 45 Colt brass, to .469". "Spec" calls for .480" max. Even using 1873-level loads in a now-departed Uberti Cattleman revolver, full-length sizing produced a "Coke-bottle" effect in processed brass--overworked while sizing, expanded out with the 2nd die's spud, and completed cartridges that fit rather loosely in the chambers--and after 5-7 loadings longitudinal cracks in case sidewalls appeared. Not good.

I tried partial-full length sizing, only running the die down far enough to work the case mouth that supported the boolit. This worked all right in the Uberti with milder loads of the 1873 strength. Once I started loading for the Ruger Bisley Blackhawk and stepping on the gas to 1200 FPS with 250 grain bullets/boolits, partial sizing no longer worked. The higher pressures did too good a job of expanding the case sidewalls out to match the cylinder charge holes, and after 2 or 3 such loads the cartridges got balky about fully chambering--and a few wouldn't fit at all. Cuss words.

The final fix was to obtain a sizing die that did sufficient but not excessive case wall sizing--small enough to chamber, but not sloppy and not to an extent that would set up the longitudinal cracks encountered previously. That die is an RCBS steel die of current production, old-school case-lube-needed sizing just like back in The Old Days. Finished diameter is .477" with R-P and W-W brass--case life is no longer an issue--and all of the loads fit in my chambers. Nirvana achieved.

[dtknowles]

I started seating and roll crimping as two separate steps as others here have recommended but when I roll crimp I back out the seating stem and run the die in more that what is needed for the crimp and crimp by feel. I can feel when the case mouth rolls and stop at that point. I seem to get a more uniform crimp that is not as sensitive to case length differences as long as the differences are small.

Tim

[C. Latch]

Nirvana achieved.

I'm going to have to re-read that when it's not so late. My current setup (Lee tungsten-carbide) only sizes the front ~60% of the case, leaving the rear with some of the coke-bottle effect you mention. It hasn't been an issue yet - I honestly haven't bothered to measure a case to see just how bad it really is. So far this brass has survived several pretty warm loadings through a ruger bisley (300 at 1100-1200ish) and still chambers easily. I also have a redding sizing die but have never used it.

[C. Latch]

I started seating and roll crimping as two separate steps as others here have recommended but when I roll crimp I back out the seating stem and run the die in more that what is needed for the crimp and crimp by feel. I can feel when the case mouth rolls and stop at that point. I seem to get a more uniform crimp that is not as sensitive to case length differences as long as the differences are small.

Tim

I hadn't considered that; I've been lucky with my crimping; I set the die up when I first bought it and the same crimp has worked well for everything from mild loads to the hottest thing I have shot; no movement under recoil that I can tell. Honestly, I haven't had any noticeable problems with inconsistent crimps yet; I'm mainly worried about just being aware of when to expect the problems to start showing up.

[leftiye]

45 Colt chambers are abominably oversized. I have opened up (with a taper) my sizing die in an effort to lessen wear and tear from sizing. Consistency is more important than actual length. I really doubt that cases will continue to shorten, but if they do it could be years before it matters, though you may have to back a tenth or two on the powder LOL. Check that brass is uniform in length. As has been said, adjust your seating and/or crimping die to work with the brass.

[dtknowles]

I hadn't considered that; I've been lucky with my crimping; I set the die up when I first bought it and the same crimp has worked well for everything from mild loads to the hottest thing I have shot; no movement under recoil that I can tell. Honestly, I haven't had any noticeable problems with inconsistent crimps yet; I'm mainly worried about just being aware of when to expect the problems to start showing up.

I started doing my crimps that way when I had rounds that would not chamber in my Dan Wesson .357. The chambers must be tight as the slightest (I mean imperceptible) bulge and the rounds would not go all the way into the chamber. My bullets were sized to .357 inches so were the throats and grooves.

Tim

[Old Caster]

Lee will sell you a die that is .002 oversize for a reasonable price. Anything over that and it is expensive.

[bobthenailer]

I allways size my rifle brass & pistol brass first then check length and trim to min trim length if there too long, every time for rifle and every 2 or 4 reloadings for pistol depending what pressures im loading too with pistol