Kasteel

Also, when you say all the rounds function fine, I'm assuming you include manual extraction of an unfired round?

Overthinking? Really? Please explain. "2. All the cases were sized to minimum with the die making hard contact with the shell holder and the press set to cam over or maximum shoulder bump." Maximum? Minimum? Ok. SAAMI max/min? For which chamber? What, exactly, is the measurement to which you refer? "3. After these case were fired in my AR rifles a Hornady cartridge case headspace gauge was used to measure "fired" case length. These lengths were compared to unfired military 5.56 Lake City cases and commercial .223 cases." And these measurements were . . . . ? This would be fantastic info. "4. After experimenting with resized lengths I decided to use the Redding competition shell holder .004 taller than a standard shell holder. The resized cases are .001 to .002 longer than the average new case length when resized and function 100% in all my AR15 rifles. This means I have .004 to .005 head clearance in all the chambers and there is no stretching and thinning in the web area of the case." And average case length was?? Chamber measurements?? You are in danger of actually contributing some very useful information. Please hold forth sir. Seriously, you've got some good stuff there. And, as to the original question: how much shoulder bump is too much? Anything? Anyone?

Yes. Now we're getting some big brains (i.e. bigger than mine) in on this act. I'll get to answering some questions to the best of my limited ability on my days off starting tomorrow evening. For now, I'm just loving the BE forums. For now Kamikaze: as far as the issue goes, I'm really being a bit OCD in the view of lots of reasonable folks. The rounds that measure greater than 1.457" will function just fine under most circumstances. As long as you don't need to manually extract an unfired round from a cold chamber, you might never even know there was an issue. The one "practical" issue I've run across is firing ammo that is 1.458+" (probably 1.46+") in a 14.5" DD mid-length barrel. In this rifle, the bolt failed (on occasion) to travel sufficiently far to the rear to pick up another round, resulting in a failure to feed. The added "oomph" necessary for the BCG to extract the insufficiently shoulder-bumped cartridge might account for this. Might. I have, to my dismay, proven that I am an idiot. Or a Murphy magnet. More to follow.

Yeah. Well, a case gauge can present problems of its own: http://www.brianenos.com/forums/index.php?showtopic=179160&hl= I can see a place for the use of both tools in conjunction--in this situation, to determine whether a shoulder has been bumped back too far.

By the way, if possible, I'd love to know the actual base to shoulder measurement in the case you checked

I'm soooo glad I'm not the only one who experiences weirdness. I'll look forward to your update--and thanks for you input!!

After some experimenting, I'm finding that rounds with the shoulder bumped back to 1.457" are good to go: they extract manually without undue resistance. I experienced more resistance the less I bumped the shoulder back. Rounds at 1.458"-1.459" stuck a bit, but would generally extract without need to "mortar" the gun. Starting at about 1.460" resistance was bad, and required mortaring and a solid thump to extract the round. So, for me, 1.457" is max. My question: does anyone know where the minimum is, beyond which unreliable ignition a possiblity? Are there any other issues that may occur with too much shoulder bump?

I loaded 25.0 grains of TAC under 75 gr. BTHP bulk bullets from Wideners, which I heard were of Prvi Partizan manufacture. I got 2707 fps (measured over an Ohler chronograph) out of an 18" barrel. Accuracy was just under 1" at 100 yards from a Black Hole Weaponry barrel. 24.3 grains of TAC under a 77 gr. SMK gave me .75" groups out of my 16" LaRue. Average velocity was 2541. Standard deviation was 18 fps. Used Lake City primed cases from a contractor pull down. That load is .5 grains under the max Ramshot listed on their site for 5.56 NATO loads.

Some measurements for reference: Some of my own 55 gr. FMJ reloads using a couple of my guns to check for smooth chambering and extraction: 1.450"-1.457" The variance is probably due to adjusting die to get a length that worked. Wolf 55 gr. Steel Case 1.453"-1.454" (measured five rounds) Remington 55 gr. FMJ 1.458"-1.4585" (measured five rounds) Remington 45 gr. JHP 1.4565"-1.458" (measured five rounds)

Right. I am looking for commonly used factory dimension.

I've had excellent luck with Ramshot TAC: almost always within 0.1 grain per throw in my 5.56 and .223 loads in a Super 1050. It's very tough to find as well, but TAC should perform well almost anywhere you'd use Varget. I contacted the company about temperature sensitivity, and was informed that although TAC was one of the best in the ball powder world, it wouldn't be as temperature insensitive as a superior extruded powder, like Varget. Also, if you pause in the loading process for any length of time, I'd re-throw the first charge after resuming. That first charge will be as much as a full grain heavier once the powder in the hopper has had long enough to settle!

I think that method would also yield a bit better accuracy, all things being equal, but haven't done or seen any testing on it.

As I understand it, your method is the preferred method to use when you are attempting to minimize work-hardening and wear and tear (by over working) brass you will shoot primarily in one rifle. Sound method. I'm aiming more to ensure reliable function in a variety of rifles.

In cruising around the Internet, my likely candidates for min/max cartridge measurement for headspace: One guy sized brass for his Wylde chamber at 1.420" The smallest chamber headspace measurement I found, for the Wylde chamber: 1.4316 (base to shoulder). The largest base to shoulder measurement was for the Clymer NATO chamber at 1.4380". Several posts suggesting that minimum .223 cartridge headspace dimension is 1.4596" and max is 1.4666-.0070" As mentioned above, my no-exception-smooth-functioning cases measured 1.440" and my measurement of the Federal factory ammo was 1.457".

So, I recently took delivery of a Hornady Lock-N-Load Headspace Guage set to help me out with measuring the headspace of my 5.56 and .223 reloads more precisely. My goal: take once-fired cases from an unknown group of rifles (say military or civilian ranges) and process the cases such that they will safely and reliably chamber, fire, function and extract (manually when necessary) from any appropriately chambered firearm (usually AR-type), always assuming the firearm is within spec. I spent a couple of days looking at various dimensional drawings of .223 and 5.56 chambers and cartridges to get familiar with specs. I also spent some time getting used to the Hornady gauge measuring once-fired cases, resized cases that that tended to stick in some chambers due to (apparently) incorrectly adjusted dies, and resized cases that ran through chambers well. I also took measurements of some factory ammo (Federal 69gr. BTHP Match .223) for comparison. Here are some of my measurements: Cases from the "problem" group that will chamber and fire, but will stick pretty badly upon attempts to manually extract a round from the chamber: 1.460" Cases that chamber and extract from multiple guns smoothly: 1.440" Federal factory ammo: 1.457" My question: exactly what is the accepted headspace standard for ammunition that has sufficient headspace as to ensure easy chambering and manual extraction of an unfired round when necessary, but not so much so as to prevent the firing pin from getting a solid hit on the primer? In other words what is the max/min cartridge case dimension that I should be looking to measure?

Die is back from the machinist. Turning it down .005" appears to have done the trick. Cost me $20. When I took the die in and explained that I was having to give the die a full half turn to get the result I wanted, the gunsmith looked at the die, noted that it was 16 threads per inch and figured he needed to remove a minimum of about .00312". I gave it a try before leaving for my shift, and the results were good with the die lightly touching the shellplate. I'll update when I can do a better examination.

Also, I mentioned to a very knowledgeable friend of mine that I'd removed the firing pin from my BCG to do an actual chamber check on my rounds. Apparently I got lucky. If you try this, your bolt cam pin may get out of battery and lock up your gun very, very badly. If you want to use your gun to check rounds, better file down a firing pin instead of taking it out!!

The instructions for the 650 appear to differ slightly from the instructions for the 1050 Super. Perhaps cam over is not an issue with the 650 as it is with the 1050 Super. Not sure what 1050 instructions say but my XL650 and the Dillon die instructions both say "Re adjust the die as nedded to achive proper headspace". It's pretty clear the back off 1/2 turn is just a starting point. I do feel that it's odd to adjust it to cam-over, but that's what's needed. Dillon instructed me to do it when I called them during set up of my press. As to your gauges, that doesn't seem right that they indicate good ammo when it's not. Prior to adjusting to cam-over my Dillon gauge was giving me a no-go reading. I'd call JP and see what they say.

An update per request: I went out and fired 30 rounds sized without cam-over and 30 with cam-over. The rounds using cam over functioned flawlessly in four different guns: one Wylde chamber(LaRue Stealth) one with 5.56 NATO chamber (Daniel Defense) one very old Colt with the triangle style hand guards, and one frankengun of dubious lineage. The problematic rounds sized without cam-over fired and ejected just fine with two exceptions: The Daniel Defense gun experienced one failure to chamber a round after firing. This gun has a 14.5" barrel with a mid length gas system, and my best guess is that the extra force required to extract the case from the gun caused the BCG not to travel sufficiently far back so as to strip a round from the magazine. These insufficiently re-sized rounds tended to stick in the chambers of the LaRue and Daniel Defense guns when I attempted to manually extract a chambered round. Even these problem rounds, however, extracted manually from the two older guns. The only other malfunction was a failure to fire in the Frankengun. Observation of the extracted round revealed a very light primer strike that I attribute to the "customized" trigger group of that gun.

Caspian Guy: The Dillon tech said using a a fine grit wet/dry sand paper and moving the die in a figure "8" pattern would be a way to go (if you don't hit carbide!) if you didn't have access to a lathe or a machinist. I dropped my die off at my friendly neighborhood gunsmith this morning. As to the "to cam or not to cam" contraversy: the solution to my problem is specific to my set up. If you are using RCBS dies in a Dillon machine, or using Dillon dies in a Lee or Hornady press, the solution may or may not work for you. Ditto a Dillon machine other than the Super 1050. I will say this: applying a solution developed for a Dillon Super 1050 using carbide .223 dies to any other combination of machine and die is no more or less likely to yield the desired results than using load data some shooter gave you that he developed for HIS gun using a given bullet, primer, case and powder combination. Depending on your level of knowledge/expertise (or ignorance/ineptitude) you may succeed or have a very bad day.

Just got off the phone with Dillon. The tech was familiar with the issue under discussion in this thread. He said that adjusting the die past light contact with the shellplate to achieve proper sizing WILL LEAD TO PREMATURE WEAR AND BREAKAGE of the machine, I.e., the Dillon 1050 Super. The tech advised having the die machined down about .005" to solve the problem. Now, I've used the cam over method to reload 2,500 rounds, and the ammo gauges, chambers and functions great, and my machine is fine so far, but a trip to my machinist buddy is on the schedule.

A quote from another post: .223 Am I sizing enough? "If you are loading on a Dillon, you do not want the die touching the shellplate. Did that the first time I loaded .223 on my 550 and set the shoulder back too far. The AR extractor will NOT hold the round against the bolt face to fire. You must use a guage. Pulling 300 rounds and trashing the cases taught me that lesson." Is this comment specific to the 550? This comment seems to imply that setting the sizing die too deeply could bump back the shoulder so far that the cartridge will fit so far into the chamber that the firing pin won't get a solid hit on the primer. Anyone know anything about this???

I spent some time comparing factory ammo and reloads in the JP Gauge last night. Factory ammo sat at least flush with the bottom step of the gauge--maybe just a hair below, such that when examining the cartridge in the gauge you can see a bit of beveled red from the gauge all around the circumference of the case rim--including the portion of the rim abutting the bottom step of the gauge. The time and care needed to perceive the distinction, at least for me, makes it worth it to just chamber a few random cases in a gun with a Wylde chamber during the reloading process to ensure that my tolerances are good. In short, I have come to the same conclusion as stated by one of the contributors above: chamber checkers/gauges are a hit or miss proposition. The timed saved isn't worth the risk of cranking out a pile of out-of-spec ammo. I'll definitely being investing in one of the Hornady gauges though! Thanks for turning me into that tool. Looks like it'll be good for finding the proper seating depth for precision ammo to set the ogive of the bullet the optimum distance from the lands. Useful gadget.

So, what happens if you bump the shoulder back too far? How can you tell? A "doughnut" effect around the shoulder? Any pics of such mishaps?

As to the pictures: look more at the forward edge of the case head in the gauge than the rear. Looking at the rear of the case head looks like the case is slightly below flush. The view of the front of the case head is more representative. The light is a bit harsh on my table.