Case Trim Question

plh

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Apr 16, 2010
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I'm starting on the 3rd round of reloading a case of Hornady Match brass with FL resizing and would rather shoot than do all the trimming/chamfering/deburring falderal. The case mouths look great and are only .001-.003 longer than my established trim length of 2.010 after the 3rd trip through the FL die. How much accuracy gets left on the table if they are not all the exact same length? My Giraud isn't here and I'm getting lazy.
Merry Christmas!
 

BuzzBoss915

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Re: Case Trim Question

Length of neck not a factor. UNTIL it starts crushing in chamber if excessive length. Otherwise, (as far as I'm concerned) slight difference in neck length does not affect accuracy. BB
 

plh

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Re: Case Trim Question

Thanks for confirming what I suspected. I guess the brass is getting a little stiff as the first 2 resizings produced cases exceeding the 2.015 recommended limit.
 

gadbmw

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Re: Case Trim Question

Pete
I think its the Sierra book that has 2 trim lengths a max length and a trim to length. Kinda gives you a range for your brass to work in.
 

Leaddog

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Re: Case Trim Question

Different case lengths equal different pressures, release times and diminished accuracy. Unless you are shooting in the 2's and 3's, or shooting extreme long range, a couple of thousandths won't make a difference. Just stay in spec.
 

plh

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Re: Case Trim Question

Most shooting is limited to 200 yds tho some of these rounds will be seeing 6-800 yards. Would you expect .002-3 length differences to have noticeable effects at these distances?
 

BuzzBoss915

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Re: Case Trim Question

I certainly would NOT. I'm not sure exactly what leaddog is saying, but if he means that having necks a few thousands different results in different pressures, I cannot agree? I have no way of actually measuring pressure, but I doubt it. I think Oehler makes a Model 43 Ballistic Lab? but as most of your cases will have some differences in volume, that in itself would indicate that pressures will be approximately the same, not identical. Therefore, since your cases all have fractionally different volume, loading with equal weight of powder will result in slightly different pressures, not withstanding the necks varying by a few thousanths in length. But, since you are seating to the same depth, I don't get what he is driving at? BB