Looking for an approach to trimming new revolver brass

[kmcdonou]

I know many people do not bother with trimming pistol or revolver brass, but for the latter I would like to do so for my upcoming 45 Colt so that I get a uniform roll crimp. I will be using new Starline brass, like the person from a different forum I am quoting below:

I recently measured 300 new 45 Colt cases from Starline, which is excellent brass. SAAMI brass spec is 1.265" min, 1.275" trim to length, 1.285" max. I found the mean was 1.272", .003" below the trim to length, with a range of +/- .010" around the trim to length, with only 2 brass below the SAAMI min, at 1.261", and 1.263". Arranging the cases by length, the distribution looked very much like a normal curve. I trimmed to .005" below the trim to length at 1.270", but still over the SAAMI min., and tossed the cases below that. After that, no more in-process fiddling with the crimp die. Ahhh, happiness.

I've read that pistol/revolver brass shrinks over time, not grows. If this is true, I don't want to trim too much to start. I have two questions.

1. What is a reasonable variation in brass length that will still allow consistent roll crimps? Just for argument, let's use .005 as a talking point, then...
2. Would it be reasonable in the above example to take any brass over the mean of 1.272 and trim to that length, and then discard or keep in a separate batch, anything below 1.267?

 

[edwardware]

You have a correct approach, but you might be over thinking. Revolver brass does shrink, but it's quite minimal if the chamber isn't oversized.

I'd trim, with whatever tool you have, to SAAMI trim length. If you can catch a few more cases from your batch by taking another 0.010", do that.

Cases under trim length automatically become an experiment in how much difference crimp uniformity make on target.

Alternately, the short brass becomes you Carpenter Bee and Hornet shotshell brass.

 

[kmcdonou]

You have a correct approach, but you might be over thinking. Revolver brass does shrink, but it's quite minimal if the chamber isn't oversized.

I'd trim, with whatever tool you have, to SAAMI trim length. If you can catch a few more cases from your batch by taking another 0.010", do that.

Cases under trim length automatically become an experiment in how much difference crimp uniformity make on target.

Alternately, the short brass becomes you Carpenter Bee and Hornet shotshell brass.

So, if I understand you correctly you would take any brass over the SAAMI trim length of 1.275" and trim to that length. Anything down to the minimum SAAMI trim length of 1.265" you would include too, thereby having a range of brass length within 0.010", or between the SAAMI minimum and suggested trim lengths? And, this variation will allow uniform roll crimps, or at least "good enough" for all but the most compulsive shooters/reloaders?

Yes, as you so astutely noticed, I do tend to overthink things, but to try and balance it I turn to those with more experience for opinions. I do like to reduce hassles in the reloading process, even if it means I take some time initially to trim the brass to a uniform range of length.

 

[Walkalong]

I will be using new Starline brass,

I also trim revolver brass, but you’ll likely find you don’t need to with your new Starline brass.

If it varies .010, then with the crimp set right that is only +/- .005.

Won't hurt a thing to trim it though.

My .45 Colt is all range brass, so I trimmed it.

My .32 Long and .32 Mag is all (was) new Starline, and I only deburred and chamferred it.

 

[edwardware]

So, if I understand you correctly you would take any brass over the SAAMI trim length of 1.275". . .

Yes, but not because there's anything magical about the SAAMI length. I suggest that length in hopes that you'll have few or no cases that don't trim to uniform length.

 

[film495]

if you're going to trim it, getting the varation in length down to .001 is realistic. doesn't take too long to trim and you will really only do it one time per case. I trim some of my pistol brass, also - just to get a nice consistent crimp.

 

[AJC1]

I'm at exactly the same point. I am along for the ride because I have been just crimping by feel so far as adjusting the die still gives inconsistency due to length variations. My brainstorming had me trying to figure out a way to adapt my inch pound torque wrench and using that to get consistency. In lead I think it would work perfectly, not so much in jacketed with cannalures

 

[Charlie98]

Theoretically, you would find your shortest case and trim everything to that measurement.

Personally, .45 Colt is not a benchrest cartridge, I wouldn't waste my time trimming it down to prevent minor variations in crimp application. I have some .45 Colt brass that is pushing 25 years old and I know I've never trimmed any of it... and, no, I don't have problems.

Actually, AJC brings up a good point... most revolver bullets I load for have a cannelure, so rolling into a groove removes many of the problems with minor variations in case length. Most of my semi-auto bullets do not have a cannelure... but I use a taper crimp die on those... again, removing most of the problems with case length variations. I even use a roll crimp on some revolver cartridges, if a heavy roller isn't required.

 

[bigpower491]

I also trim revolver brass, but you’ll likely find you don’t need to with your new Starline brass.

Yes and no on the Starline, at least in some of the lots I've been getting recently.

I personally like cases all the same length, because I always crimp revolver cases, the amount of depends on if it's a magnum or not.
That said, out of lots of 500, I'll take batches of 50 and run em thru the sizing die. Then I'll go back thru and measure every one and find the shortest of the bunch and set it aside. Then run 50 more, do the same thing. I then take the shortest of those cases and set the trimmer to cut to that length. I get a big grin when the shortest one is within .005 of maximum. Especially in the Magnum, Casull cases. I tend to put a very heavy crimp on those, and the extra length I leave let's me trim back as the brass gets worked. I feel I get a few extra firings doing it this way.
I know it's more work than most would do, but I always have ammo I'm confident in it's consistency. Especially with 454 Casull. I learnt the hard way that you need to really give it a good squeeze to get the propellant to work properly(well, 296 anyway)

 

[kmcdonou]

Some of you suggested trimming to the smallest case length. However, as in the example I gave the shortest is below SAAMI minimum trim lengths. You would go below to get uniformity?

 

[gnappi]

I'm surprised to see some trimming revolver brass.

I've only trimmed .44 magnum because hard recoiling revolvers a good crimp keeps the bullets from scooting forward and locking up the cylinder so trimming makes good sense. I never had the problem with .45 Colt... sanely loaded that is. I spend too much time at the bench as it is to trim all of my revolver cases.

 

[jmorris]

The first thing I would do is to take a statistically significant group of the worst variation in brass, a sample of the longest, shortest and a few in between and the same number that happen to have been manufactured perfect and shoot two groups, one with each sample group.

At this point I would hang both groups above my loading bench so it’s easy to take a look at while I am spending the time to trim straight walled pistol brass and know it’s not time wasted or I can just put the concept behind me and carry on, without the extra work.

Worth doing the same thing for mixed brass, weighed brass, etc.

 

[Charlie98]

Some of you suggested trimming to the smallest case length. However, as in the example I gave the shortest is below SAAMI minimum trim lengths. You would go below to get uniformity?

SAMMI is a guideline, not an absolute... if you see what I'm saying. You want uniformity for your crimp, the only way to do it is to trim everything to the shortest case, or discard those cases that are shorter than SAMMI.

I've taken some of my precious .348WCF cases, which SAMMI shows a trim to length of 2.245", and whacked them down to 2.200" as an experiment for a very short barrel leade. The earth did not open up and swallow me... As a matter of good handloading practice, however, I did reduce my powder charge accordingly, and work back up, due to the reduced internal capacity.

 

[eb in oregon]

Some of you suggested trimming to the smallest case length. However, as in the example I gave the shortest is below SAAMI minimum trim lengths. You would go below to get uniformity?

I'll second Charlie98's comments. SAAMI specifications are an industry guideline for manufacture, that doesn't mean you can't shorten them a little under that. It won't hurt a thing. However you have noticed that SAAMI guidelines also doesn't mean brand new brass won't have variations in length. That also means that factory ammunition will have minor variations in case length and the amount of crimp. That too doesn't hurt anything. I've been reloading for about 45 years now and have never trimmed pistol cartridge cases, and some of them (.45 Colt being the oldest) have been reloaded multiple times, and never trimmed. The only time I ever was concerned about the length of pistol brass was when I was using a slight roll crimp for .45acp cartridges. Then instead of trimming it I separated it into lots within .005 in length which gave about the same crimp for those sizes but I had to readjust the crimp die for each size. That process got old after the third coffee can full of loaded rounds so I went to a tapered crimp die as it don't care about length and in my opinion a bit of a difference in the amount of crimp really doesn't mean squat. And I've shot enough pistol rounds of varying caliber and crimp to reach that conclusion. Especially if using lead bullets with a crimping groove.

 

[FROGO207]

I would wait until the brass was in my hands and sort it. I think getting the Lee length cutter and running them all to the minimum trim length using a drill press and the table as a stop would be your fastest option then load them and be happy.

If you want the length shorter remove a bit of the pin. That case has lots of room for smokeless anyway.

 

[bigpower491]

Some of you suggested trimming to the smallest case length. However, as in the example I gave the shortest is below SAAMI minimum trim lengths. You would go below to get uniformity?

I myself would segregate them . All that are under the book minimum I would measure again just to double check that low number. .010 under wouldn't cause me too much concern, new cases under more than that outta the box/bag, I might be firing off and email to the manufacturer.
To the statement that revolver cases shrink on firing....the last run of 45 Colt cases I loaded and fired. Using my method, my TTL came to 1.277. Before sizing I measure 10 of the 50. The numbers were running about 1.266. Dunno if that .011 was from actual fire or from the crimp. 11 thou is about the measurement of 2 human hairs,(probably where the one famous term of measurement comes from, and that even depends on a couple factors), so really not all that much. Could very well be the actual distance the die lowered when the press operator (me, you, whomever) made the 1/4 or so turn to engage the crimping shoulder.
Upon running the cases thru the sizer, they came right back to 1.277, actually a few to .278, so hard to say

I'm surprised to see some trimming revolver brass.

Some of us do.......see jmorris post above. But all of us have our own techniques we use that we feel will make just a little difference in quality of the end product. Something I think would be a real important step, others may feel, meh, not so much

 

[kmcdonou]

Thinking about this issue more and doing more reading, I really don't want to trim cases, particularly if I purchase 1000 Starline at once, which is my plan. I am not worried about the loss of accuracy by not having a uniform crimp on each case, as I question how significant it is. I am not saying it doesn't have an impact, but in my initial cost benefit analysis I don't think it is worth MY time. Maybe if Giraud's trimmer had case holders for handgun rounds I may consider purchasing that unit and doing a one time trim to uniform cases. The process would be quick, and although somewhat expensive, I am not against spending money to save time. The other options for trimming handgun brass don't really impress me for speed and efficiency, especially when faced with 1000 cases.

What I am more concerned about is noticeable under crimping (bullet movement under recoil) or over crimping (case bulging) because of variation in case length. What I am willing to do is sort the brass into ranges of lengths. Then I could set the crimp die to a case in the middle of a range and reload knowing my crimps will be fine. Yes, I will have to adjust my crimp die for different ranges, but I am thinking about getting a 44 mag instead of the 45 colt and Redding sells a micrometer profile crimp die for the 44 mag. I could make quick and accurate adjustments to the die when needed.

What I really would like to know is for those who have had crimping problems do to case length at what amount of variation did the problems occur? If I grouped cases into .005 ranges, and set the crimp die to a case in the middle, which would provide .0025 variations, is that good enough? Could I go more, and group brass into lots that have .010 differences in length, and set the crimp die so the variation is +- 0.005? What is a reasonable variation in case length to avoid any crimping issues?

 

[bigpower491]

I'll use my learning curve with the 454 Casull as the example
I was having a big issue with lower than published velocities, less than acceptable accuracy, and somewhat erratic ignition. I researched and researched every thread on every forum I could find trying to troubleshoot the root cause. Yes I am aware that real world and published velocities canbe and are 2 different things, but a load shooting out of a revolver with the same barrel length as mine it should be close, at least somewhat.
Well, 2-300 fps discrepancy put the red flag up that hey I have to not be doing something right here. Yes, my yrs of loading 44 mag taught me the value of a good crimp, and boy iI sure thought I was giving the Casull enough.
I had always been of the school that said give only as much crimp as necessary, to keep from over working or crushing the brass.
Well, after trying a bunch of different things out, I said screw it, I give the die about 1/2 turn past engagement with the crimping shoulder, took those 6 out back and let em rip. Wellah.....the gun instantly had more ummph, no more unburned powder, and the velocities came up to the neighborhood they were supposed to be in.
An to that, my point on trimming. If I have a bunch of cases that have a wide variance in lengths, the crimp itself will be inconsistent. If one of the longer cases was the one used for adjustment, the shorter cases don't get the same amount of crimp. Other way around, you run the risk of crushing the brass if you have a cartridge that itself requires a heavy crimp like that Casull.
If you have the whole lot of brass sized and trimmed to the same numbers, you never have to worry about inconsistencies caused by simple stuff like a crimp.
I always tell people to do what they think they can handle. You play it the way you want. But it's always a plus when you know the exact number

 

[.38 Special]

The first thing I would do is to take a statistically significant group of the worst variation in brass, a sample of the longest, shortest and a few in between and the same number that happen to have been manufactured perfect and shoot two groups, one with each sample group.

At this point I would hang both groups above my loading bench so it’s easy to take a look at while I am spending the time to trim straight walled pistol brass and know it’s not time wasted or I can just put the concept behind me and carry on, without the extra work.

Worth doing the same thing for mixed brass, weighed brass, etc.

I've actually done sort of that, though not up to any kind of scientific standards. I have records of groups size and velocity, with the .45 Colt in a Ruger Bisley, using trimmed brass. I also have records for the same gun and load in untrimmed brass, albeit all with the same headstamp (Starline). No significant change in velocity, and an improvement in accuracy - but only because I improved my shooting over the years.

For my money, trimming new Starline revolver brass is a waste of time.

 

[.38 Special]

What I am more concerned about is noticeable under crimping (bullet movement under recoil) or over crimping (case bulging) because of variation in case length.

I shoot .500 Magnum, .44 Magnum, .357 Magnum, and max "Ruger-only" .45 Colt. I stopped trimming revolver brass decades ago. I cannot recall the last time one of my bullets jumped the crimp, and in fact no longer believe that crimp is the most important factor in bullet pull. I ensure that the expander ball leaves the case several thousandths smaller than the bullet diameter, and I expect to see a "wasp waist" on the completed cartridge. I strongly suspect that this is far more important to bullet retention and proper powder burn than is the crimp.

 

[kmcdonou]

I'll use my learning curve with the 454 Casull as the example
I was having a big issue with lower than published velocities, less than acceptable accuracy, and somewhat erratic ignition. I researched and researched every thread on every forum I could find trying to troubleshoot the root cause. Yes I am aware that real world and published velocities canbe and are 2 different things, but a load shooting out of a revolver with the same barrel length as mine it should be close, at least somewhat.
Well, 2-300 fps discrepancy put the red flag up that hey I have to not be doing something right here. Yes, my yrs of loading 44 mag taught me the value of a good crimp, and boy iI sure thought I was giving the Casull enough.
I had always been of the school that said give only as much crimp as necessary, to keep from over working or crushing the brass.
Well, after trying a bunch of different things out, I said screw it, I give the die about 1/2 turn past engagement with the crimping shoulder, took those 6 out back and let em rip. Wellah.....the gun instantly had more ummph, no more unburned powder, and the velocities came up to the neighborhood they were supposed to be in.
An to that, my point on trimming. If I have a bunch of cases that have a wide variance in lengths, the crimp itself will be inconsistent. If one of the longer cases was the one used for adjustment, the shorter cases don't get the same amount of crimp. Other way around, you run the risk of crushing the brass if you have a cartridge that itself requires a heavy crimp like that Casull.
If you have the whole lot of brass sized and trimmed to the same numbers, you never have to worry about inconsistencies caused by simple stuff like a crimp.
I always tell people to do what they think they can handle. You play it the way you want. But it's always a plus when you know the exact number

I hear what you are saying. You are reinforcing the opinion that case variation can have an effect on accuracy and pressure. But what if I measure all the cases and group into ranges? If I were going to trim, I would have to measure the cases anyway to identify the shortest case. If instead of trimming, if I group cases into a narrow range and adjust the crimp die to the case in the middle of that range, I can avoid crimp problems and save a lot of time by not trimming. The key is knowing what is a reasonably sized grouping range, where if the die is sized to the a case falling in the middle, the ends would will still get enough crimp? Am I misthinking something?

I shoot .500 Magnum, .44 Magnum, .357 magnum, and max. "Ruger-only" .45 Colt. I stopped trimming revolver brass decades ago. I cannot recall the last time one of my bullets jumped the crimp, and in fact no longer believe that crimp is the most important factor in bullet pull. I ensure that the expander ball leaves the case several thousandths smaller than the bullet diameter, and I expect to see a "wasp waist" on the completed cartridge. I strongly suspect that this is far more important to bullet retention and proper powder burn than is the crimp.

Interestingly you use Starline brass, and the original quote I provided used the same. There was over 0.010 variation in that batch of 300 cases, but I think the company says that will be the case. So, what you are saying is within that amount of variation, you have not had a problem with crimping on the performance of your loaded rounds?

 

[Bartojc]

When I started loading for 45 Colt I had about 80 mixed cases from a box I had bought plus some misc cases. I purchased 250 new Starline.
I sized the Starline, but did not trim. For the mixed cases I trimmed to the ave length of my Starline. I wanted them similar lengths for a better roll crimp like you describe. Revolver pistol that requires a roll crimp is the only pistol brass I trim.

-Jeff

 

[.38 Special]

Interestingly you use Starline brass, and the original quote I provided used the same. There was over 0.010 variation in that batch of 300 cases, but I think the company says that will be the case. So, what you are saying is within that amount of variation, you have not had a problem with crimping on the performance of your loaded rounds?

I use Starline whenever possible, which these days is nearly always. I regard all other revolver brass as second rate. Having said that, I have utterly no idea what the length variation is with their stuff. I stopped caring longer ago than I can recall and have not yet regretted it.

 

[Charlie98]

I use Starline whenever possible, which these days is nearly always. I regard all other revolver brass as second rate.

Everyone's experiences are different... I don't consider Starline first-rate brass, and have had some issues with some of it. Be that as it may, these days it's hard to find 1000 case lots anywhere, and Starline is probably the best place to go if that's your goal.

I wouldn't trim any brass until after I had fired it at least once. Just my method.

Could I go more, and group brass into lots that have .010 differences in length, and set the crimp die so the variation is +- 0.005? What is a reasonable variation in case length to avoid any crimping issues?

I understand your reasoning, but I'm just scratching my head as to why. Do you realize how much work you are making for yourself, for a cartridge that basically doesn't care one way or another?

 

[murf]

I'll use my learning curve with the 454 Casull as the example
I was having a big issue with lower than published velocities, less than acceptable accuracy, and somewhat erratic ignition. I researched and researched every thread on every forum I could find trying to troubleshoot the root cause. Yes I am aware that real world and published velocities canbe and are 2 different things, but a load shooting out of a revolver with the same barrel length as mine it should be close, at least somewhat.
Well, 2-300 fps discrepancy put the red flag up that hey I have to not be doing something right here. Yes, my yrs of loading 44 mag taught me the value of a good crimp, and boy iI sure thought I was giving the Casull enough.
I had always been of the school that said give only as much crimp as necessary, to keep from over working or crushing the brass.
Well, after trying a bunch of different things out, I said screw it, I give the die about 1/2 turn past engagement with the crimping shoulder, took those 6 out back and let em rip. Wellah.....the gun instantly had more ummph, no more unburned powder, and the velocities came up to the neighborhood they were supposed to be in.
An to that, my point on trimming. If I have a bunch of cases that have a wide variance in lengths, the crimp itself will be inconsistent. If one of the longer cases was the one used for adjustment, the shorter cases don't get the same amount of crimp. Other way around, you run the risk of crushing the brass if you have a cartridge that itself requires a heavy crimp like that Casull.
If you have the whole lot of brass sized and trimmed to the same numbers, you never have to worry about inconsistencies caused by simple stuff like a crimp.
I always tell people to do what they think they can handle. You play it the way you want. But it's always a plus when you know the exact number

a minimum of 004" neck tension is also required for the big boomers, imo.

great post,

murf