Loading 358-105-SWC in .380 ?

[pt4u2nv]

Need a little help here on a few concerns on this combination. First , has anyone loaded this boolit in the .380 and made it work ? If it is not feasible then I will have to reconsider my endeavor. Second as an overall question , how do you determine when a boolit is seated too deep in a case that it will create a high presure situation ? Where I am at right now with this is I have slugged my barrel at .356", got my boolit sized and lubed at .357" for starters. It has been necessary to seat this boolit at .915" OAL to get it to chamber and cycle manually. All of my manuals list an OAL minimum even with a cast 120 gr RN at .950". My main concern going forward with determining my charge ( probably go with Unique) is that the boolit being seated this short how do I know what pressures I will be creating and is it safe ?

I did a small comparison with a Hornady 90 gr XTP that I have specs on and the 105 gr SWC is taking up approx .112" more case capacity than the XTP. A little paranoid at this point to go any further with the seating depth and subsequent load workup till I get some way to determine if this is acceptable or not.

Thanks in advance for your help.

[beppe]

Hallo !
I reloading a 380 with 90 grs Lead bullets and i charge 3 grs of n320
when I load Boolits from 95 grains fmj, load 4 grains of n320, you must use a chronograph to see the speed of the bullet. berette in my 84, the bullet goes to 1050 fps.is better to use a bullet size 356, in this way the pressures are correct.

[pt4u2nv]

.356 is too small. Bore is .356 I will use chrono once I determine that the oal is not too short for this small case.

[Larry Gibson]

I use the Lee 105 SWC and the 105 RN in my AMT Backup and have used them in a couple other .380s. I size the bullets .356 and they work fine in numerous .380s. Sometimes I think we "overthink" what should be straight forward sizing and reloading of cast bullets, especially in the type of guns the .380 is chambered in. I use a soft NRA 50/50 lube. The oal for the SWC is .952 and it's .965 for the RN. Functioning at those oal's has been 100% in numerous .380 pistols.

I use Bullseye primarily but have used 700 and WST also. I consider Unique and Herco but they are too slow for the shorter barrels for best results. I started at 1.5 gr and worked up until recoil and ejection was about the same as factory loads but still stayed within published data. My Primary load for both is 2.5 gr Bullseye. Velocity is 760 fps for the SWC and 740 fps for the RN out of the 2 3/4" barreled AMT Backup.

I used to carry the AMT as my "backup" when a LEO. I had to "qualify" with it every quarter and these loads never failed me in that or other practice/plinking shooting I've done with them. I even managed to kill a couple snowshoe hares for the pot once with the AMT using the SWC. I've had zero malfunction with either bullets and no leading due to a presumed "undersized" cast bullet.

Larry Gibson

[smithgar3840]

I've used the 105 from lee in 2 different 380's and several 9mm's.I size the 380's .356 and do not size at all for the 9's. I have consolidated powder and used universal in both plus most of my other handguns for midrange loads. It makes a good load in both.

[Muddydogs]

I just started loading the 105 in my Ruger LCP. I have tested 2.5 to 3 grains of Unique with no pressure signs. 2.5 grains didn't cycle reliably but 2.7 to 3 grains cycled just fine. My LCP slugged at .356, I sized the bullets to .357 and .358. The .358 will not chamber in the LCP. I have to seat the 105's so the case mouth is at the top of the crimp groove against the front driving band to get the rounds to chamber. The load is a nice shooter and very accurate.

[pt4u2nv]

Thanks all for the info. Muddydogs, you did not mention your OAL except to reference the relation to the front driving band . What was your OAL ?

My concern is that I have to seat at .915" to get mine to drop the whole way into the barrel doing the "plunk" test and to chamber properly. I see Larry is at .952" which is much better and I would feel comfortable at but .915"..............:shock:

The gun I am using is a S & W Bodyguard and evidently this has a much shorter chamber than the LCP. At least it appears that way to me. At .917/.918" the boolit actually gets marks on the nose from the rifling, hence me going to .915" to get it off the rifling grooves.

I am also getting slight bulging with the boolit seated so deep. Does not affect cycling or fit so I was not too concerned about that issue.

[Muddydogs]

If the round chambers and plunks then you have nothing to worry about with seating depth as long as you work your load up. Start low, maybe 2 grains and work it up. If you don't have enough powder the pistol won't function and you should see pressure signs in the cases before you get to much pressure. OAL in the books is just what the test round was loaded at and is a good starting point but has no real bearing when loading a bullet thats not listed. Most of the OAL for the 380 are for round nose which will be way shorter then the SWC.

I would have to measure my OAL which I never did, I plunk tested a round until it chambered which as I described the bullet is seated so that the case mouth just touches the front driving band. I then loaded 6 test rounds starting at 2.5 grains of Unique, 2.7 grains and then 3 grains. I picked a load of 2.8 grains knowing that my powder measure throws +- .2 grains and 2.5 grains didn't always function right.

Some of my cases have the hour glass bulge also due to the bullet seating depth but a little spent gun powder and the sizer die will make it all right again.

[backroad]

I had exactly the same problem with that bullet in colt mustang.Just to long and i size to 357 so it was bulging case switched to ranch dog 100g rnfp and problem solved.I am not sure if that mold is still available or not but it is a sweet little bullet.

[Mohavedog]

You are very smart to be cautious of loa when using loading data from a different boolit than the one you are using. What you need to do is know the lgth of the boolit in the data then subtract the lgth of the boolit that is out of the case when loaded to the recommended loa. This will give you the amount of the boolit that is inside the case. Then do the same with the boolit you are going to use. If the amount of boolit inside the case is the same or nearly so you can use the data in the book. But the advice is still to start low and work up. If your loa puts your boolit farther into the case than the book example then you should start even lower than the book says. A few thou less powder capacity will make a very big diff in pressure in a small case like the .380.