Author Topic: Case length question  (Read 384 times)

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Offline farmerboyMT

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Case length question
« on: December 27, 2003, 03:29:42 PM »
I just got a RCBS reloading kit and am really enjoying it I have one question however.  Can there be too short of a case length?  I'm reloading .223 Rem with 50gr TNT HPs in Federal Cases with 20grs of IMR 4198, per the recomendations of the Speer book.  The brass came from factory loads that I saved shot out of the rifle for which I am reloading.  I found the maximum case length is 1.760.  I've noticed most of the brass is between 1.738 and 1.746 after sizing.  I've loaded a few rounds but have yet to shoot them.  I've been keeping the OAL at about 2.223 since that seems to be the lenght my rifle cambers them the best.  While I'm at it does anybody have any good .223 loads?  And I was given some SB dies with the kit.  Will this present a problem with a bolt action rifle.
Any info would be great.
Thanks
Bryan Danley

Offline Thomas Krupinski

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Case length question
« Reply #1 on: December 27, 2003, 03:47:06 PM »
I trim mine to 1.750 before sizing for use in both Contenders and an AR rifle.  Don't think you will have any problems with the short ones you mention.  

Although the small base sizing die should not be necessary for your bolt gun, I don't believe it will cause any problems other than shortening case life a little.

The powder I am using is Accurate Arms 2200 Data powder for both commerical and military cases.  It is a eastern bloc surplus military powder and performs pretty well in the .223 with 22.5 grain charge under 55 grain bullets.  That is a little less than maximum and works well for me, especially during hot weather.  Although I don't think it's available any longer, a little slower powder AA2230C is currently available but I haven't loaded any of that in the .223 as I still have a adequate stock of the 2200 designated for the .223.

The bullets I have been using are the Winchester 55 grains from Midway, both the flat base soft points and the boat tail full metal jackets.  Primers are Winchester small rifle primers.

Offline Donna

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Case length question
« Reply #2 on: December 27, 2003, 04:40:12 PM »
Hello Thomas, :D

To answer your question, Yes you can trim too much off. The convention is to trim about 0.010 back from max length but in reality even if you trimmed back to 1.730 you should still have plenty of case neck left. My roommate trims hers to 1.740, of course after sizing. She uses the VihtaVuori’s N135 for 69-grain bullets, for a velocity of 3600+ fps, but now she uses the N140 or N540 for my 90-grain bullets that I make for her, for a velocity of 2700 fps. But she is shooting a single shot, bolt action, AR-15 that she built herself with a 26-inch Krieger barrel. Below is a pic of her firearm, oh ya I forgot to mention her’s is chambered for the AI (Ackley Improved). If you want the best in accuracy get a set of Redding dies and Sinclair International’s “Primer Pocket Uniformer”. The RCBS’s one is not made to the same tolerances and quality.



Quite something isn’t it?!

Hope this helps.
Donna :wink:
"Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath: For the wrath of man worketh not the righteousness of God. James 1:19-20

Offline JBMauser

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short necks
« Reply #3 on: December 28, 2003, 05:06:14 AM »
farmerboyMT, As I understand it,  short necks have no effect except as they relate to neck tension and resistance.  The guideline is that the neck length should be at least the Cal.  If you could measure the necks pressure to hold back the bullet until release pressure was reached, you could trim away until you made a change to that factor.  I will note that the release pressure is not much as a primer alone with no powder will expell a bullet.  Some large bore straight walled BP shooters use the rifling to offer the bullet resistance and they have no neck tension.  They could trim their brass back to just hold the bullet edge to center it somewhat.  If your short brass holds you bullet as concentric as a full length you should have no problem.  JB