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6.5 Creedmoor - poor neck tension? Login/Join 
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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.


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Posts: 2721 | Location: Memphis, TN | Registered: August 23, 2010Reply With QuoteReport This Post
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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,


 
Posts: 1696 | Location: North Cackalacky | Registered: September 09, 2007Reply With QuoteReport This Post
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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."
 
Posts: 2721 | Location: Memphis, TN | Registered: August 23, 2010Reply With QuoteReport This Post
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quote:
Originally posted by vulrath:
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.


Did I read correctly that you are using Hornady bushings in a Redding Type S bushing die?
 
Posts: 3175 | Location: Texas | Registered: June 20, 2012Reply With QuoteReport This Post
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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.


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Posts: 2721 | Location: Memphis, TN | Registered: August 23, 2010Reply With QuoteReport This Post
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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."
 
Posts: 2721 | Location: Memphis, TN | Registered: August 23, 2010Reply With QuoteReport This Post
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