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Discussion Starter #1
I recently loaded some BTB 0.432 290 LFNGC for a 444 using Marshall's tried and true load of 57 gr H335, WLRP and Remington brass with a COL of 2.54". The load is compressed and I am having trouble getting a consistent COL, it appears that the case tension is not sufficient to hold the bullet in place. I am seeing variances as much as 0.015". The dies are RCBS and I am expanding just enough to get the gas check started. Crimping is with the Lee Factory Crimp Die.  Any ideas?
 

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I'm wondering if perhaps instead of the issue being with the case neck tension, if it could be inconsistentcy of how the bullet aligns with the seating punch in your loading dies?  Are you using an unmodified RCBS nose punch?  

Try using your calipers on a few loads prior to crimping with the Lee Factory Crimp Die, and see if there is any variation before crimping.  

I'll bet that a switch to a generic type pure flat bullet seating punch would cure the problem.

Let us know what you find!

God Bless,

Marshall
 

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Marshall & Roger,
I have the exact same problem with the 330 gr bullet with 56.0 gr of H-335 or 50.0 gr H-322.  Near as I can tell, the back pressure of the compressed powder simply exceeds the bullets ability to hold its place in the case.  At first I was having to keep reseating the bullet until the loa was right.  That meant measuring the loa every time the cartridge came out of the seating die, before going into the factory crimp die.  

Part of the problem is that I seat the bullet shorter than Marshall calls for in his Part III 444 Marlin article.  I seat to (330gr LFNDCGC in .432) the cartridge to 2.570 which give me about 1/16" engagement to the lands.  I notice Roger is going even shorter with loa.  I imagine that seating the bullet with a light crimp might hold the bullet still till it it put through the factory crimp die.  

My cure for the problem has taken 2 directions.  First is that before seating the bullet, I tap the case (with the powder charge in it) lightly on the table about 30 times.  That settles the powder some and makes for less compression.  The other thing I did was drop down 2 grains in both the H-335 and H-322 loads.  It cost me a grand total of 70 fps and is noticeably easier on the shoulder (porting timing).  There was a nice drop in pressure too. I have ultimately settled on 48.0 gr of H-322 (Marshall suggested I try this powder) for 2010 fps out of my Outfitter.

I use Redding dies with a flat seating stem, Rem brass, WW primers.    

Marshall, maybe you have a shortcut that will make all this easier without having to change or drop powder charges.

God bless...............  Bill M
 

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To Bill and everyone,

How does the diameter of your expander compare to the bullet diameter?  If it's not a good 0.005" less than the bullet diameter, I'd consider trimming it down or replacing it with the Lyman "M" equivalent.  With compressed loads I'd want all the neck tension I could get.

Even if you just barely bell the case mouth, the rest of the neck could be large enough that it's not getting a good grip on the bullet.

Just a thought...
 

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Thanks for the comments Mike.  I just ran downstairs and measured the expander on my Redding die.  It measured a very round .428 .  I don't really know if this is enough.  I do know it gives a pretty good buldge in the case where the bullet is seated.  

God bless................  Bill M
 

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Discussion Starter #6
I measured the expander on my RCBS dies and it is 0.427" and I can also see the case bulge after expanding. Is the expander too large? I am using an unmodified nose punch, what is the procedure for the modification?

I used the same remedy as Bill M in reseating the bullet several times and measuring each cartridge to get the correct OAL. Anything over 2.50" will not consistiently feed through my 94 Timber Carbine. Thanks
 

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Mike and all;

As a matter of course, with a new set of dies to be used with cast bullets, I take the expander out to the work shop for a bit of customizing. I chuck it into the drill and as it spins I hold progressively finer grits of emory cloth to it until I polish it out with crocus cloth.
I also drill out the seating stem to rest on the driving band of SWC, rather then the nose of the bullet.
These little tricks have worked for me and made life a bit simpler.
Jim
 

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Roger,

Sounds like your expander is plenty small at .427". You'll want to watch running an expander that is too small. With the straightwall cases, they tend to start bulging out one side as you are actually using the bullet to expand the case when seating.

Ball powders are much more difficult to compress as they are already in a dense state from the get go. I would back off the charge a bit like Bill recommends. Too much compression with ball powder can also lead to poor or erratic ignition with the powder almost becoming a solid mass under heavy compression.

Notice that Bill illustrated he only lost about 70 FPS with a 2 grain drop in powder. That should tell you something about the burning efficiency under heavy compression.

FWIW,

Ray

(Edited by Contender at 10<!--emo&:0--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'><!--endemo-->4 am on Dec. 18, 2001)
 

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Doesn't sound like the expander is the problem.  .427"-.428" should be just about perfect with .432" bullets.  You must be compressing the powder quite a bit.  I don't have much experience in this area so can't offer anything else than to suggest backing off the powder charge a bit.

I the opposite approach to Jim on the seating punch.  Instead of drilling out the middle, I grind off the outer lip so it's completely flat.  Sounds like either will work, at least with SWC's.  For the LFN/WFN, I would think that a completely flat seating stem would be the better way to go - just personal opinion.
 

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Roger N

Another approach you might take, and I know we will hear some arguement about it, is to seat the bullet just a few thousandths short of where you want to be the final overall length.  Then adjust the final length by using a roll crimp and crimp until the bullet is squeezed back to the correct overall length.

The only thing you need to be really sure of is that before starting the crimp the mouth of the case is somewhere over the crimp groove.  This may work with a Lee factory crimp die if the bullet will stay within .005 or so of the final length, but will probably not work well.  A roll crimp die is probably best.

This operation serves two functions, setting overall length quite precisely, and assuring that the crimp is really tight and actually bearing on the bullet providing resistance to initial movement.

This is admittedly one of those things which "works for me", that's all I can say to qualify it.  What got me started doing it this way was the latter, assuring a crimp bearing tightly on the bullet and holding it back against the initial primer pressure pulse.  The primer can not only push the bullet through a loose crimp, but, in some circumstances actually push the bullet well down the barrel causing other potential problems.
 
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