case length question

ok...dumb moment. I just ran like 50 PPU cases through my Deluxe Trim...I had it on the opposite side of the trimming spec. So I brought them all from roughly 4.496-4.503 down to under 4.490 and under using the new limit. The cutter chamfers for you, so I just deburred them.


So...now it works haha. I must have been looking at my dial weird the first time because you turn it clockwise to cut more off. I must have seen it from the other direction at first.

So onto the next question...Last year my Federals grouped at .71" more than enough for my hunting loads. That was just trimming like this then setting bullet ogive .03" off lands for my foulers and .10 off the lands for my test loads (I forget the reasoning why). I followed the OCW method.

You mention this precision mic gauge for datum to shoulder length. Once I fire brass in my chamber, isn't it technically going to conform to my chamber? I.E. my last batch of federals (now twice fired) were perfect regarding length. The base of course was widened but length was OK
 
mendozer
Checked out your trimmer on line , nice unit. Glad you figured out how it trims. As far as seating different settings on the ogive measurement, my be best to seat them all to the length that gives you tightest group an keep to there. Then see how far off your cold bore shots are off. Are you starting off with a clean DRY barrel..?
As for the precision mic. I start out using it to get my proper case headspace. My fired cases get shorter & wider. I'll give you an example what happens. My headspace measured with the mic. measures minus 0.0015 Fired case measures minus - 0.003 So I set up my F/L sizer to size back down to -0.0015. I only shoot benchrest with this rifle. The mic. checked the case from the base to the datum line on the slanted part of the case ( between the shoulder & the base of the neck ) the datum is in the middle or that area. Once I get that set an size all my cases, I trim . when you know the distance from the base of the case to the rifling, you can set the bullet to just touch the rifling , jump or jam your bullets. Checking the ogive setting with the mic. My rifle likes a .006 jam & also a .009 jump with a Sierra 168 gr. HPBT bullet. Can do the same with a comparator & caliper. The mic makes it easier for me.
 
For a hunting rifle, I would not recommend seating bullets into the lands. Too much manufacturing tolerance in hunting bullets.
 
CW, last time I chose one seating depth and varied charges. I got my best group, then I was going to take that and then vary charges slightly and possibly seating depths. However, since that batch, I've done archery for deer and those were my deer loads so I haven't done that yet.

Every time I hit the range, my barrel is clean. I'm a stickler for that. Interesting tool this precision mic. I might look into that to see if I'm not satisfied with my groupings.

Dufus, I personally don't feel comfortable seating into lands based on: it's a cheap hunting rifle not a pricey benchrest, I don't know enough about reloading and all the factors of seating depth, and I didn't feel like it was warranted. I wanted to limit the variables when I figure out my deer load and my elk load. After that I can play around with it. I want to have a standard recipe for banging out good loads this way
 
mendozer
When working up a round for accuracy , only change one thing at a time. Start with the charge, with the best group charge. Then with that charge , try different seating depths. For hunting I wouldn't size less the .002 case headspace. You can test a sized case in your rifles chamber , when you feel slight resistance at the lower end of your bolt close, that's about zero headspace, lower your sizing die very little will give you more space. Keep that rifle clean . Hope I helped. Chris
 
I settled on my COAL from base to ogive at 3.625" I was getting land markings (barely) at 3.700. I usually go .1 off lands. But my Federal Fusions measured 3.620 and they were fine. So I just bumped it up to 3.625"

I'll start with that. It was kind of hard to see the land markings eventually.
 
Comparator is the better way to measure. Going with the C.O.A.L. ( base to tip ) I think min. 2.940 - 3.340 max. What bullet are you using for your elk hunt.? Also what is the twist in your barrel.?
 
It's a Nosler Accubond 180. Came back from the range today. 54.2 got about 1/2" spread, 54.7 got three touching holes, 55.2 unknown because I made two mistakes so the group spread. They didn't have a shooting rest so I had to free hand it. My next round is gonna be 54.7, 55.0, 55.3 at a range that I know has a Lead Sled then I'll use that load.
 
54.7 looks good. I would think from 54.6 to 55.0 is where that one hole 3 shot group will be. There are no sand bags at the range. I shoot off a bi - pod with a rear bag ( bunny ear ) My range day is today, not happening today. Hurricane coming , wind now is to strong. Last year I had that dream group, my friend was spotting for me, conditions were perfect. First hole dead center 200 yards next two , same hole, I mean one hole. Saved the target. Was afraid to shoot the forth & fifth to screw it up. My range day is 30 rounds , five shot groups at 6 targets. Takes about two hours with 3 cease fires. Quick clear at the range, good clean when I get home. Good luck with your testing. Chris
 
I also went ahead and just ordered a rifle rest for myself. I'm sure I'll make use of it.

FWIW I was waiting about a minute or two in between shots. If I could hold my hand on the barrel for a minute then it was cool enough to shoot IMO
 
mendozer
McMaster- Carr temp strips on your barrel takes the guess work out of , how hot my barrel is. I have a temperature strip on my barrel when it reaches 113 , I let it cool down. It's a label 1/2" x 1 1/2" I put it on the barrel just after the chamber, works great. They go for $ 10. 00 plus shipping for 10 . Check them out.
 
I have stuff like that for brewing, except a lower range. Too bad they only come in 10 packs. You have any extra? :)
 
I put one on my cz452 & Rem.700 the rest I gave to the guy's I shoot with, that was last year. Sorry. My son in law brews beer, I'm hooked on IPA's Did you pull the trigger on a tumbler. I never had cases so clean, using the wet tumbler with SS Pins.
 
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I use ultrasonic with simple green 10:1 solution. It same with my lock n load kit. My cases are super clean but they don't have the brand new shine like I would with a tumbler but I don't mind. I can still look for signs of failure
 
mendozer
With brass , all that matters is there clean. Your dies will be trouble free, also accurate reloads, less carbon buildup inside the case.
 
Yes I experimented that too with 9mm Luger and 9mm Federal Rimmed.
I only reload handgun ammo.
I discussed that at Cast Boolits and soemone told me the rule is: Rifle cases STRETCH, handgun cases tend to SHRINK.

I experimented case shrinking for my 9mm Luger reloads and was worried about it. After several reloads (5+ times) cases shrank a bit. For Handgun cases you don't even Need a case trimmer unless you cut down your 357 mag/38 spl brass in order to create the 9mm Federal Rimmed ammo for your Revolver. I usually load my cases 15+ times and never had to throw away one yet.

Other Thing is the calipers are not really precise. You have to take an average. That at least is my experience.
 
Stretching depends on pressure building high enough to stick the brass to the chamber before the head backs up against the breech face. If stuck, you get a stretch. If not, you don't. The tapered handgun cases tend to expand fatter and get shorter and resizing doesn't flow the brass back 100%. I once tracked a bulk lot of 45 Auto through about 50 reloads at very light target load levels (3.8 grains of Bullseye and either 185 or 200 grain cast bullets, depending whether it was for 50 feet or 25 yards or if it was for 50 yards). They shortened an average of half a thousandth per reload, and the cases (less than half) still left and not split at the end of the test were 0.025" shorter than new.

Some high pressure revolver loads will stretch. I've had .357 cases that didn't seem either to grow or to shorten. The main reason for a pistol brass trimmer is to make all the cases more uniform than they came from the factory for the purpose of applying a very uniform roll crimp to revolver rounds.

Bottleneck rifle cases can be funny. The growth occurs when the stretched area keeps its length as the shoulder is pushed back during resizing. The extra brass from the shoulder then flows into the neck. However, again with moderate target loads rather than maximum pressure loads, I've had 308 cases were, within one lot with the same load history, I'd randomly get anywhere from zero growth to 0.010" growth, with 0.050" being average. I can't explain the variation easily.


Mendozer,

If you are using a digital caliper, when you have the comparator attached to the jaws, close them and press the zero button. After that your readings should be within 0.0100" of actual. The small remaining error is due to the small radius on the inside of the comparator hole. Generally they read too short anywhere from about 0.003"-0.010". If you need an exact measure, you have to zero with a headspace GO gauge in the comparator, and then look at the cases as being that size ±whatever the caliper then reads.
 
I use a dial one so I had to do math.

Also, FWIW my reloaded rounds seems to chamber with more resistance than factory. I made them the same exact case length too. Maybe it's all in my head because I'm nervous about it blowing up in my face lol
 
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