Can I trim 9mm brass to 9x17 for .380?


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jon_in_wv
July 25, 2009, 10:12 PM
I'm planning on ordering a bunch of 9mm brass and I'm wondering if I can trim some of it to make .380 brass for practice with my .380. What issues will arise from trying this? SHould I forget that idea and just order some .380 brass too?

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RDA 226sig
July 25, 2009, 10:17 PM
Buy the 380 brass also.

VegasOPM
July 25, 2009, 10:19 PM
.380 has a slightly smaller base and differently shaped extractor groove. It might be an interesting exercise to cut down 10 or 12 and see if they will function- but I doubt it. First thing I would try is to see if an empty 9mm case will fit the breechface and under the extractor with the slide locked back.

dannyabear
July 25, 2009, 10:47 PM
And if you did, and it worked, you would have the chance of mixing them up being the both would be head stamped 9mm; A 9mm , shortened by 2mm would create a serious over pressure situation should it be loaded to 9mm specs.


Buy some 380 brass, there is a ton of it on gunbroker.

zxcvbob
July 25, 2009, 10:51 PM
I think you can shorten .223 or 5.56 rifle brass to make .380. (there's probably more to it than that) .223 case heads look the same as .380, .30 Carbine case heads look the same as .32 Auto.

jon_in_wv
July 25, 2009, 11:18 PM
Good points all. I guess I'll order the 380 brass. It will save be headaches sorting brass later. I don't know why I didn't think of that?!?!?

rcmodel
July 26, 2009, 12:40 PM
I think you can shorten .223 or 5.56 rifle brass to make .380.Won't work without extensive neck reaming.

The .223 case has way too much case-wall taper that far down.
You couldn't even begin to seat a .355 bullet in a cut-off .223 case.

And case capacity would be greatly reduced by the thicker case head.

BTW:
9mm case head size is .394".
.380 case head size is .374".

They won't fit the gun or the magazine.
Cut-off 9mm cases make 9mm MAK cases.

rc

Ky Larry
July 26, 2009, 12:52 PM
If you're going to buy brass, try to order 2 different brands, if possible. For instance, buy Rem 9mm and Win .380. It will be easier to sort.

Also, IIRC, the 9mm and .380 have different wall thickness. A cutdown 9mm will have thicker case walls and smaller volume that will raise pressure.

rcmodel
July 26, 2009, 01:08 PM
They won't fit in the gun I tell ya!

9mm Luger is .020" bigger around then .380 ACP.
You cannot resize the case head to make the rim .020" smaller!!!

rc

rondog
July 26, 2009, 01:52 PM
Yep, what they said.

You CAN cut down 9x19 Luger to make 9x18 Makarov. The case dimensions are very close, except for length. I just did a bunch last night.

But you CAN'T cut down 9x19 Luger to make .380 ACP, the other dimensions besides the length are much too different.

Watch the Classifieds on this forum and every other gun forum you can, there's always somebody selling .380 cases. Or place a few WTB ads. I personally have bought enough here and there that I have a 2 gallon bucket completely full to the top with .380's. That's a helluva lot of .380 brass, FWIW.

The Bushmaster
July 26, 2009, 02:28 PM
Easy rc. Easy...I don't want have to call an ambulance...:what:

:D

jon_in_wv
July 26, 2009, 03:26 PM
I did hear you could resize 9mm for 9x18 Mak. I was wondering if the same could be done for 380. I already load for 9mm. I wouldn't want to create confusion by mixing them up and having to measure them to figure out which is which. Its likely I might do it when I load up some 9X18 for storage. I would like to load about 2000 rounds of 9X18 that I would store for who knows what. That ammo wouldn't get shot for a long time, if at all, and mixing brass wouldn't be an issue.

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