Is .355 interchangeable between 9mm and .380?
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Jim Watson
Member
The default is .355" jacketed, .356" cast for both 9mm P and .380.
Jim Watson
Member
I have loaded 115 gr .380, there is data, but my usual .380 bullet is 100 gr.
I am at present loading 124 gr 9mm P for one gun, but most get 147s.
I am at present loading 124 gr 9mm P for one gun, but most get 147s.
kmw1954
Member
The 380 Auto and the 9mm Luger are relative as are the 38Spl and the 357Mag. Both use the same diameter bullet but one has a longer length. Also with the 380/9mm one uses a tapered case and one uses a straight walled case. Normally the 380/9mm is defined as .355/.356" dia., while the 38Spl/357Mag is defined as .357/.358" dia..
I load 380 Auto pretty much will all 100gr plated bullets and just recently started with some cast lead bullets that range from a 95gr RN and a 95gr FP to what is now my favorite a 102gr RN that actually weighs closer to 104gr because of the alloy I am using. I also have some 105gr SWC that are actually designed to be used in the 38Spl but I read of many people that are loading this bullet for the 380. So far I haven't tried it.
At this time all my 9mm loads are .356" plated 115gr/124gr bullets.
I load 380 Auto pretty much will all 100gr plated bullets and just recently started with some cast lead bullets that range from a 95gr RN and a 95gr FP to what is now my favorite a 102gr RN that actually weighs closer to 104gr because of the alloy I am using. I also have some 105gr SWC that are actually designed to be used in the 38Spl but I read of many people that are loading this bullet for the 380. So far I haven't tried it.
At this time all my 9mm loads are .356" plated 115gr/124gr bullets.
mrawesome22-250
Member
380Auto a.k.a 9mm Kurz a.k.a 9mm Browning Short a.k.a. 9x17mm.
Yes it is 9mm.
Edit: Kurz is German for short.
Yes it is 9mm.
Edit: Kurz is German for short.
Swampman
Old Fart
I'm not entirely comfortable with that comparison. The .380 and 9mm Luger share the same bullet diameter, but that's pretty much it.
The .357 Mag is just a lengthened, strengthened .38 Special and there's no safety issues involved with shooting .38's in a .357.
The same isn't true of .380 fired in a 9mm.
I know you didn't say anything about shooting .380 in 9mm, I just worry that someone might misconstrue "relative" to .38/.357 and make a poor assumption.
kmw1954
Member
Then maybe you should have quoted the full statement. "Both use the same diameter bullet but one has a longer length. Also with the 380/9mm one uses a tapered case and one uses a straight walled case..." You seemed to leave that part out!
748
member
I use .355 and .356 for both.
rskent
Member
You’re not gonna be able to reload that case.
fxvr5
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Traditionally the 380 Auto has used a 0.356" bullet and the 9mm a 0.355" bullet.
Technically, as per SAAMI specs, the bullet for 380 Auto is 0.3565" and the 9mm bullet is 0.3555" bullet.
In practice, they can use either.
https://saami.org/wp-content/upload...FP-and-R-Approved-2015-12-14-Posting-Copy.pdf
Technically, as per SAAMI specs, the bullet for 380 Auto is 0.3565" and the 9mm bullet is 0.3555" bullet.
In practice, they can use either.
https://saami.org/wp-content/upload...FP-and-R-Approved-2015-12-14-Posting-Copy.pdf
WestKentucky
Member
Normal weight bullets for .380 go really fast when loaded in a 9mm. It’s the same concept that Supervel used years ago, and it still works.
Yep. I load 95gr FMJs for my 9mm carbine. Velocity approaches 1500fps!
NATO Reloading
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.356 is a standard caliber for 9MM. Very standard. Almost every bullet weight has option for that size, 115, 125, 147, etc I only buy .356 for it if its in stock. You can also shoot a 380 in a 9MM, one time, it wont cycle it. I have done it many times. I am still alive. Its like a total powder puff load, you hardly recoil at all, feels like a 22LR
Swampman
Old Fart
Wow.
Do you shoot .308 Winchester in your 30-06 too?
Shooting .380 in a 9MM the round will likely be held to the rear by the extractor and fire, but since the case is smaller in diameter it will leak gas and be dirty. Unsafe? I don't recommend it, but dangerous? Not really.Only question is why. In a fix maybe? We see 9MM cases that have been fired in .40 pistols, and .40 that have been fired in .45 pistols at the range sometimes. They are easy to recognize because the forward half of the case is blown way out. It happens. That doesn't mean we should do it on purpose.
But in general we should fire the correct ammo in the correct gun.
But in general we should fire the correct ammo in the correct gun.
Hondo 60
Member
.355 is correct for jacketed bullets.
.356 is correct for lead.
The lower weights are OK for both 9mm & 380
Personally I wouldn't go higher than 124/125 in a 380.
You might start running into OAL issues (if can even find data going as high as 124).
.356 is correct for lead.
The lower weights are OK for both 9mm & 380
Personally I wouldn't go higher than 124/125 in a 380.
You might start running into OAL issues (if can even find data going as high as 124).
iShoot17
Member
I am in agreement with @Swampman on this one, but believe it was simply an inappropriate comparison (full quote or not). Other than the fact that both shoot the same caliber bullets, there is nothing else similar. Making a comparison and saying they are relative is silly, based on one factor of many. Such comparisons would be like saying a 308 Win and .30-378 Weatherby are relative, as are the 38SPL and 357 Mag, because each uses the same caliber bullet, there are just a “few” differences in the cases.
To the OP - yes, a .355 bullets can be safely loaded in 9mm and 380, as mentioned by so many experienced loaders above!
The are both "9mm"
That darn metric system
Another simple question becomes a convoluted debate.
kmw1954
Member
How about this then. Lee makes a mold that is 358-105 SWC. That bullet is meant to be loaded into a 38 cal cartridge yet it has for many years been successfully loaded in both the 380acp and the 9mm.
Ignore the fact that I distinguished a significant difference between the 380 and 9mm, relative in no way distinguishes them as being one and the same.
I can go to Hodgdon, Western or Alliant and find many loads for both the 380 and 9mm that load the same bullet or same powder charge in both calibers. They are also relative even though they are not the same. So if you all want to argue semantics then feel free to do so.
Ignore the fact that I distinguished a significant difference between the 380 and 9mm, relative in no way distinguishes them as being one and the same.
I can go to Hodgdon, Western or Alliant and find many loads for both the 380 and 9mm that load the same bullet or same powder charge in both calibers. They are also relative even though they are not the same. So if you all want to argue semantics then feel free to do so.
Maximum Headspace
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I doubt anyone that can actually read can mistake a reload for a store bought bullet. The 9mm wouldn't fit the .380 mag and vise versa.
Maximum Headspace
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I'm am loading and have shot 9Mm bullets ( currently 90 gr HP Sig great round) the bullets seats great @ .980 and I use 90 gr HP data.
Shoots fine works great No .380 ammo to be found from here to the Midwest.
When its all said and done do what you think is ok for you. I personally think most people on here way over think this. I have been in Aviation for 30 years so I get limits measurements and conversions its all pretty simple.
If its not for you its not for you move along dont load it but don't tell someone else what they should do.
Shoots fine works great No .380 ammo to be found from here to the Midwest.
When its all said and done do what you think is ok for you. I personally think most people on here way over think this. I have been in Aviation for 30 years so I get limits measurements and conversions its all pretty simple.
If its not for you its not for you move along dont load it but don't tell someone else what they should do.
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