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| Caught in a loop |
Okay, so I sat down to do some loading for my 6.5 Creed monster (ARC Nucleus) last night and got super confused and frustrated. I'm not new to reloading, just to reloading for precision. Equipment - Lee Challenger press - Redding FL Type S bushing die - Hornady LNL 0.290" steel bushing - L.E. Wilson chamber type seating die - 1 ton Dayton Electric arbor press - Imperial sizing wax - Hornady One Shot spray lube Components - once-fired Starline brass - Federal LR magnum primers - IMR 4155 (test run of 41.7-42.2 grains\) - Berger 6.5mm 140gr target hybrids (PN 26714) Objective: 1000 yards, fed from a AI style magazine (I currently have PMAGs, but that could change). I might compete with this rifle eventually; right now I'm not a good enough driver. Now, what I'm finding is that I can push the bullet with my finger tips after seating, and more importantly it seems that the action of stripping a round off the magazine and pushing it into the chamber is enough to drop the COAL by as much as 0.040". That's a huge amount; unacceptable, really. I clean using dilute Hornady One Shot solution in an ultrasonic cleaner. Only thing I did differently this time compared to my 308Win loads was skipping my usual second dip in the US before I started loading. Is it possible the leftover lubricant is contributing significantly to my piss poor neck tension? Should I decap and wash everything again? I also found that my neck tension on a loaded dummy round was almost 0.001" oversized, as measured by my Brown & Sharpe micrometer (based on what I saw I'd put it at 0.2906-0.2907"), even with the expander ball removed (which helped dramatically, actually). I'd expect some springback because that's how metal works, but would going down a bushing size help? I even went so far as to take a random bullet and check it with the mic (it was a little over at almost 0.265"). Is there something I'm missing? This is nothing like what I saw with the cases as-new. Edit: left out a 0. "In order to understand recursion, you must first learn the principle of recursion." | ||
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Member |
For what it is worth. For Starline 6.5 Creed Brass, I measure 0.2956 OD (fired) and 0.265 ID (fired) in my Tikka. So 0.0153 wall thickness. This is measured with a Mitutoyo digital pin micrometer. With my target of 0.003 tension with allowance 0.002 of "spring back" I use a 0.290 bushing as my Lapua and Hornady bullets are 0.2642 and 0.2643 diameter. Therefore, (bullet diameter + 2 times case wall thickness)-.003 (tension) -.002 (spring back). The spring back can vary with brass hardness. I think this is where the process of annealing can reduce neck tension variables. My Forster neck and full length sizing dies put too much tension on the Starline brass so I have to use the bump sizer. Edited to add Starline brass issue in Forster dies. Lapua are fine.This message has been edited. Last edited by: huskerlrrp, | |||
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| Caught in a loop |
So a quick update: I dropped a few unprimed cases back into the ultrasonic cleaner after resizing again. Rinsed and dried, then set up a dummy round. Neck tension was perfect. I have been able to get to something approaching a reasonable facsimile of proper neck tension on most rounds by sizing again, then cleaning with a nylon bore brush and mop with a little bit of rubbing alcohol on it. I completely forgot to consider annealing as a variable. Half of my brass was annealed before its first firing on a friend's Bench Source annealer, the rest I just used as-is. I've been trying to mark all of the brass that's not seating properly. Since I'm using an arbor press it's pretty dang easy to tell when it's got proper tension. I also have 0.288 and 0.289 bushings on order, set to arrive tomorrow. I'll experiment with bringing the neck a little smaller but my math looks a lot like yours - the 0.290" bushing SHOULD have been correct. "In order to understand recursion, you must first learn the principle of recursion." | |||
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| Member |
Did I read correctly that you are using Hornady bushings in a Redding Type S bushing die? | |||
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| Caught in a loop |
Yeah. I was working with what I can get that was in stock when I ordered it. I was told they're compatible across brands, but I'm not sold on that any more. at the very least I'm starting to question the numbers on the Hornady bushings. Should I junk it in favor of a Redding bushing? Are they THAT much better? The percentage of "dud" seats has gone down dramatically since I started cleaning. Removing the expander ball also helped significantly. "In order to understand recursion, you must first learn the principle of recursion." | |||
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| Caught in a loop |
Update: I dropped down a bushing size and my tension issues seem to have gone away, at least in the few dummy rounds I threw together last night. Not exactly sure why some rounds are doing this while others aren't, though. Perhaps some kind of lot to lot inconsistency issue? "In order to understand recursion, you must first learn the principle of recursion." | |||
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| Member |
After thinking about measuring the OD and then the ID between two different tools, I went ahead and purchased a ball end micrometer with 0.0001" graduations. Upon remeasuring my brass I found the following neck thickness (done in three places around the circumference). Lapua 6.5 Creedmoor Small Primer: New (5 sample): .0137" SD .0002 1x fired (10 sample): 0.0137" SD .0003 Starline 6.5 Creedmoor Small Primer: 1x fired (5 sample): .0137" SD .0003 Hornady 6.5 Creedmoor Large Primer: 2x fired (5 sample): .0136" SD .0003 Between the three brands they were all pretty consistent for neck thickness. The 308 Winchester rounds I measured were not the case. I found .002" of a inch difference between Lapua and Winchester for example. | |||
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| Edge seeking Sharp blade! |
I suggest a Lee Collet die. | |||
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| Caught in a loop |
I need to get a ball mic. Alas, it will need to wait. Still have other reloading priorities. I'm open to ideas, but I'm not ditching the full length sizer. Dropping one bushing size seems to have worked. Perhaps dropping another could help drop my group size even further. Another thing to test head to head later on once I finally get my load dialed in all the way. "In order to understand recursion, you must first learn the principle of recursion." | |||
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| Edge seeking Sharp blade! |
I've never used a bushing die, but I'm aware of their dependency on uniform neck thickness, which means neck turning or lots of measuring and measuring equipment. Sizing on the outside of the neck just has more variables than sizing on the inside. I've never needed more accuracy than I've gotten with a Lee Collet die. I mainly started using them because they are easy on brass and that case lubing step is eliminated. The accuracy made me a believer. I'll surmise that anybody chasing accuracy has had it go to crap at some point due to neck tension problems, either from cases that needed annealing, or sizing problems. Your problems now are just going to make you a better reloader. edit: reading the OP more carefully, the S bushing die appears to function like a conventional FL die, but with bushings to minimize neck sizing before the sizing button passes through. Having sized brass without the expander in place in conventional FL dies, they definitely go way beyond the resizing needed to cover all situations, at the expense of overworking the brass and assuredly brass life. Sounds like the system you are using will work good once you figure out which bushing to use, and your bushing choice isn't as critical as a normal bushing outside only sizer. | |||
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| Caught in a loop |
Experience IS the best teacher. "In order to understand recursion, you must first learn the principle of recursion." | |||
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| Member |
I too have Lee Collet Dies, how are you using yours? I bump the bottom and than turn the case a bit and bump it again before withdrawal. | |||
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| Edge seeking Sharp blade! |
First thing I do is deburr the collet where it contacts the neck, using a narrow strip of wet or dry. Lightly polish mandrel. Clean die and collet, and grease angled portion at top of collet. Clean neck area with a bronze bore brush and steel wool outside of neck and neck rim. Size, turn slightly and resize. A good exercise to learn the amount of pressure required when using a collet die, is to try to size a case allowing a slip fit to a bullet. You learn how little press pressure it requires to do at least some sizing. | |||
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| Member |
I will have to look at deburring mine in the next couple of days, Thanks. | |||
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| Caught in a loop |
So a quick post from the dead on this. I finally got to play on the reloading bench yesterday, and I dropped the bushing down a size because I wasn't happy with how much of the neck I was having to size just so the top of the neck had the proper tension (I should be sizing about 0.33-0.5% of the neck, and I was probably sizing 0.66%). I haven't gotten to shoot yet to test my theory, but I think this will really shrink my groups. That said, I was ringing steel consistently at 450 yards 2 weekends ago, so I'm not unhappy with the results I got from the first drop in size, just not happy enough. "In order to understand recursion, you must first learn the principle of recursion." | |||
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