9mm into 380

rickdavis81 · April 9, 2009, 07:12 PM

Here goes what may be a stupid question but I gotta ask. I have an over abundance of 9mm brass but no 380 brass. And I can't find 380 brass or ammo. Can I turn my 9mm brass into 380 brass? I've looked at the measurements and they are close. I can trim them to 380 length. Thanks.

Sevens · April 9, 2009, 08:40 PM

The length is the first thing you'd have to alter. Then you'd have to alter the size of the rim, as 9mm is larger than .380. Then you'd have to stuff 9mm shells in to your .380 sizing die, and I'm not sure how much effort that would take. (seems to me that you could try this right now, just to see what happens...) If you got the external dimensions within tolerance, you'd now have to figure out if the internal dimensions are within spec, or your load data will be altered due to the space inside.

No matter how you get down to it, there's way too much work involved to make this a good idea, even if it were possible. It's a Rube Goldberg.

Your best bet is to find someone that has used .380 brass and offer to buy, or trade 9mm for it, even if you have to trade more 9 than you get .380 in return.

Shoney · April 9, 2009, 10:14 PM

The short answer is NO!

The 380 is smaller in diameter and has a different size extractor groove. and in addition the web of the 380 is also smaller.

FrankenMauser · April 10, 2009, 02:30 PM

To turn 9x19mm cases into .380 Auto; you must do all of the above, and...

You must ream the inside of the case. Doing so on sized cases will leave the walls too thin. Doing so on unsized cases will leave the walls too thick. Take your pick.

So, the short list looks something like this:
1. Trim to length.
2. Rebate the rim.
3. Thin the rim.
4. Widen extractor groove.
5. Inside-ream.

The_Vigilante · April 10, 2009, 09:05 PM

Have you checked Gunbroker for .380 brass? I have seen it there many times.

RidgwayCO · April 10, 2009, 09:16 PM

Order 500 or 1000 cases from Starline, and you should have them by this time next month. The price is right too.

http://www.starlinebrass.com/index.p...445890823ad338

Starline is good tough brass that I've used a lot.

April 9, 2009, 07:12 PM	#1
rickdavis81 Senior Member Join Date: April 3, 2006 Location: Missouri Posts: 398	9mm into 380 Here goes what may be a stupid question but I gotta ask. I have an over abundance of 9mm brass but no 380 brass. And I can't find 380 brass or ammo. Can I turn my 9mm brass into 380 brass? I've looked at the measurements and they are close. I can trim them to 380 length. Thanks.

April 9, 2009, 08:40 PM	#2
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	The length is the first thing you'd have to alter. Then you'd have to alter the size of the rim, as 9mm is larger than .380. Then you'd have to stuff 9mm shells in to your .380 sizing die, and I'm not sure how much effort that would take. (seems to me that you could try this right now, just to see what happens...) If you got the external dimensions within tolerance, you'd now have to figure out if the internal dimensions are within spec, or your load data will be altered due to the space inside. No matter how you get down to it, there's way too much work involved to make this a good idea, even if it were possible. It's a Rube Goldberg. Your best bet is to find someone that has used .380 brass and offer to buy, or trade 9mm for it, even if you have to trade more 9 than you get .380 in return. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

April 9, 2009, 10:14 PM	#3
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	The short answer is NO! The 380 is smaller in diameter and has a different size extractor groove. and in addition the web of the 380 is also smaller. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

April 10, 2009, 09:05 PM	#5
The_Vigilante Senior Member Join Date: May 17, 2008 Location: Far West Texas Posts: 200	9mm into 380 Have you checked Gunbroker for .380 brass? I have seen it there many times. __________________ The_Vigilante Keeping the streets safe! A man can never own enough guns!

April 10, 2009, 02:30 PM	#4
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	To turn 9x19mm cases into .380 Auto; you must do all of the above, and... You must ream the inside of the case. Doing so on sized cases will leave the walls too thin. Doing so on unsized cases will leave the walls too thick. Take your pick. So, the short list looks something like this: 1. Trim to length. 2. Rebate the rim. 3. Thin the rim. 4. Widen extractor groove. 5. Inside-ream.

April 10, 2009, 09:16 PM	#6
RidgwayCO Senior Member Join Date: March 22, 2008 Location: Western Colorado Posts: 244	Order 500 or 1000 cases from Starline, and you should have them by this time next month. The price is right too. http://www.starlinebrass.com/index.p...445890823ad338 Starline is good tough brass that I've used a lot.