I purchased a set of lee dies, collett neck sizing and dead length seater. Upon sizing some of the cases I noticed I could seat flat base bullets about half way into the neck on some of the cases. I had checked and dble checked the die to make sure it was adjusted correctly. 2full turns after touching the shell holder, using a lee hand press. I was concerned about inconsistent and insufficient neck tension, so I ordered an undersized mandrel from lee (they are cheap). It was .001 under the standard. Wow what a difference, I seated some bullets and I could feel the tension difference, it was very noticeable. I then pulled some bullets using a kinetic puller, 3 very firm whacks later the bullet released. With the standard size mandrel a light, single whack was all it took. I'm putting this out there in case anyone else has similar concerns and is considering the undersized mandrel. My guess is the undersized has too much tension, however I will load em up and test against the standard mandrel to be sure.
Lee collett die information -fyi
- Thread starter 1stmar
- Start date
Did you neck-turn your cases (for constant case wall thickness) and maybe have case walls that are now well under standard thickness? Three whacks doesn't sound like excess bullet pull.
Measure the case neck ID after sizing with both mandrels. The case neck ID should be 0.001-0.002" under bullet diameter. Measure the case neck ID and bullet OD after pulling a bullet to determine if you might actually have excess neck sizing.
Measure the case neck ID after sizing with both mandrels. The case neck ID should be 0.001-0.002" under bullet diameter. Measure the case neck ID and bullet OD after pulling a bullet to determine if you might actually have excess neck sizing.
I learned recently (been reloading since April), that I shot my best groups back when I was using the Lee Collet die.. AND.. although it's not recommended for target shooting out of a bolt gun, putting a light crimp on my loaded rounds. That was my method early on it load development. Unfortunately, you can't get by with neck sizing alone (hard chambering and extraction). I switched over to a Forster Shoulder Bump Neck Bushing die used in conjunction with a Wilson Case Gauge. A couple of rounds of reloading later (approx. 200 rounds), neck tension variation was clearly evident in the pressure required for seating. Booh.
I've since then (with very positive results), removed the neck bushing and decapping assembly from the Forster, essentially making it a pseudo shoulder / body die, and am back to neck sizing with the Lee Collet. I reduced my mandrel size by almost 0.002", to get back to what I felt was equivalent to the original setup I used with the crimp die.
Long story short, I'm back to my original accuracy load from May, and putting 10 rounds on a quarter at 200 yards.
I've since then (with very positive results), removed the neck bushing and decapping assembly from the Forster, essentially making it a pseudo shoulder / body die, and am back to neck sizing with the Lee Collet. I reduced my mandrel size by almost 0.002", to get back to what I felt was equivalent to the original setup I used with the crimp die.
Long story short, I'm back to my original accuracy load from May, and putting 10 rounds on a quarter at 200 yards.
I had lee send me a mandrel that was .001 and another .002 under standard, they were cheap and I wasnt sure how much of a difference .001 would make. Neck tension, like so many other reloading subjects, has a lot of differing opinions. I'm not saying the standard or undersized mandrels are either good or bad, just putting this out there for reference so others have a data point. I looked and didnt find any references so I thought I would start something. Proof will be in the testing, I will compare the results to see what works and what doesn't. I like the Lee collett die, especially since no lube is required, just looking for equal performance I get from my rcbs fl sizing die with pout the mess of lubing.
That is the adjustment of the die but the second variable is how much force you put on the press handle. If you don't apply sufficient force, the neck will not be properly sized.
I use Lee collet dies on about every rifle caliber I load for. When I first receive the collet die I disassemble, clean and polish the mating surfaces then lube them. This greatly reduces friction, eliminates any galling, and improves the operation of the die. The die internals can come pretty ugly from the factory. Especially the cuts in the collet portion.
The only time I have found my set up didn't adequately size the case necks with the standard mandral is when they have been full sized numerous times and have work hardened. The brass is more elastic when it gets harder and springs back more. The solution for this is to anneal the case neck.
I use the Redding body dies to bump the shoulder back when necessary.
I understand this hasn't been your experience.
Last edited:
Smokey Joe
New member
Lee Collet Dies...
1stmar--I too like the Lee Collet Neck-sizing Die. Like Jepp 2, I find that keeping the collet lubed is important. Haven't gone to the step of polishing the collet myself.
Discovered that some brands of bullet, though nominally the same caliber, are a smidge smaller in diameter than other brands. So when I changed from .308 Sierra Gamekings to Nosler Accubonds, for example, the Accubonds wouldn't stay in necks that had held the SGK's just fine.
Solved this by chucking the collet into a drill press, and emery-paper-ing it down a thousandth or so. With that modification, the NAB's stay in the necks just fine.
1stmar--I too like the Lee Collet Neck-sizing Die. Like Jepp 2, I find that keeping the collet lubed is important. Haven't gone to the step of polishing the collet myself.
Discovered that some brands of bullet, though nominally the same caliber, are a smidge smaller in diameter than other brands. So when I changed from .308 Sierra Gamekings to Nosler Accubonds, for example, the Accubonds wouldn't stay in necks that had held the SGK's just fine.
Solved this by chucking the collet into a drill press, and emery-paper-ing it down a thousandth or so. With that modification, the NAB's stay in the necks just fine.
jepp2, I recognize those two pics of me polishing my Lee 260 die parts.
But instead of being in photo bucket xx220/ClarkM, they are in photobucket ab170/jeep2.
That's ok.
I have seen my pics used on ebay and in sticky FAQs.
Here is a pic a friend, Roger, emailed to me of his MAS-36 paint job.
I put it in MY Photo bucket and I am posting it on the internet
Ben Franklin never patented anything. He just wanted to share. And he was a prolific genius.
But instead of being in photo bucket xx220/ClarkM, they are in photobucket ab170/jeep2.
That's ok.
I have seen my pics used on ebay and in sticky FAQs.
Here is a pic a friend, Roger, emailed to me of his MAS-36 paint job.
I put it in MY Photo bucket and I am posting it on the internet
Ben Franklin never patented anything. He just wanted to share. And he was a prolific genius.
Last edited: