.45 cases length

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.45 cases length

Post by Paper-Puncher on Mon Feb 20, 2012 6:03 pm

What is the mim. case lenght for .45 ACP..? Ive read several diferent figures ..the lee manual and sierra manual are different..... Ive started to sort case's by lenght .....I seem to have read that .888 is the min. is one place and .893 in another....??? I believe the saami said .888min -898max was the numbers.......so anything under .888 I should throw away .....? is this correct.....

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Re: .45 cases length

Post by dan allen on Mon Feb 20, 2012 8:42 pm

.45 cases shorten with use and vary all over the place. I have never found one over the maximum and seldom near it. If you load to fit your chamber the length of the case means nothing as the bullet controls the head space. Sort if you like but it isn't necessary.

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Re: .45 cases length

Post by Virgil Kane on Mon Feb 20, 2012 9:03 pm

I trimed all of mine to .890. Probably not needed but it made he feel better knowing the crimp was the same on all of my reloads.



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Re: .45 cases length

Post by Paper-Puncher on Mon Feb 20, 2012 9:52 pm

Dan,

Yep , they very ...Ive got 2 boxes sorted now .890-.8915 and .8915-.893........I should be able to start another box of .894-.895......but I got quite a few case's that went as low as .885 never found any over ...

Virgil , I dont think I would have trimmed to .890 ...as the case's shrink as you use them. I understand your thinking on keeping the crimp the same as that why I'm sorting ......most of the guys here dont trim from what I gather but they do seem to sort ...I saterted sorting to keep the big swings in case lenghts from messing with my crimp. anyway if what I read as .888 being the min. length is true anything under .890 I'll load up for IDPA and bowling pin shoots and wont be to cocerned about leaveing it lay for the range to pick up and re-cycle.

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Re: .45 cases length

Post by Virgil Kane on Tue Feb 21, 2012 9:27 am

Cases may shrink but then I'm a firm believer in that the cartridge (.45ACP) should be headspacing on the bullet for best accuracy with the SWC. I have mine headspacing on the front driving band of the SWC's I use. It may also help that when I reamed my chamber I cut it to minimum lenght but I'm sure that others have done the same. Even if the cases shrink I still maintain the same crimp throughout the batch I'm reloading and theoreticly should keep all my shots in the same group. If they go below the minimum lenght then they're still headspacing on the front driving band so nothing is lost. I also never use my Bullseye 45 brass for anything other than loading up with SWC's. I use a different brand of brass (Starline) for everything else related to my 45 shooting and keep these well above the minimum lenght.



Maybe not needed but then Bullseye shooting is as much of a mental game as it is shooting (to me anyway). If I feel that I have the best ammo that I can make then the mental aspect of the match is focused on shooting instead of wondering if the last shot ended up in the 7 ring because of something I missed while reloading. I tried sorting by lenght but it took me as long to do that as it did to just trim all to the same lenght.



YMMV



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Re: .45 cases length

Post by Jerry Keefer on Tue Feb 21, 2012 10:06 am

The reason .45 brass shrinks, is the generous chamber IDs that exist in 1911 barrels. Even many after market "match" barrels have large chamber IDs. When the brass expands from the pressure, the material has to come from, and go somewhere. Thus, the case shrinks in lenght. This can be minimized with chambers under the SAAMI spec.

I cut most chambers at .900, and some less, depending on the shooter's expertise and attention to ammo.

Case length does not show detrimental accuracy effects at shortline, but has a much greater benefit at 50 yards. The late Col. Al Bacon and I once purchased a batch of 460 Rowland Brass, and I machined the cases to various lengths of headspace. Those batches that offered minimum headspace of .003/.005 produced tighter, consistantly round groups from the Ransom Rest.

Early lots of military match hardball had case lengths approaching the high .890s. The military knew way back then that case length/headspace mattered when striving for max accuracy.

When reaming a chamber, it is very hard to control the depth and finish by hand. Standard SAAMI spec off the shelf reamers, leave a lot to be desired and are lacking when bullseye accuracy is the goal. All reamers for target use should have no more than 1-1/2 degree leade, and I personally have found a small amount of freebore to be beneficial.

Custom ground reamers are the better way to go.

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Re: .45 cases length

Post by Paper-Puncher on Tue Feb 21, 2012 9:52 pm

Loading for the chamber all makes sense and thats what my plan is . I will still use any case that is .888 or smaller to load up for IDPA type stuff and if I dont get a chance to pick it up I wont be to concerned ......it'll give me a good reason to go get a few hundred new case's every yr....another reason Ive started to sort is with the new lee factory crimp die I would think the ammo would be maybe a tad more consistent if the lenghts where reasonabley close to each other...and from what Jerry said sounds like the longer cases might be best saved for the long line.......

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Re: .45 cases length

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