380 ACP Load Question

[Jeepster48439]

Getting ready to load some 380ACP and realized that the SPP I have are magnum primers (CCI 550). I will be using Bullseye powder and Hornady 95g FMJ.

Does any one have any advice on how to alter the powder charge to compensate for the magSPP?

ETA:
Firearm - Ruger LCP

 

[Jaybird1980]

What no option for using black powder?
Seriously though the magnum primers in a small case could possibly unseat the projectile to early and cause extreme deviation. What loading of bullseye?

Also had to choose bacon of course

 

[Jaybird1980]

I should have asked what kind of pistol also?
Locked breach or blowback?

 

[Jeepster48439]

I should have asked what kind of pistol also?
Locked breach or blowback?

These are being developed to be shot in a Ruger LCP.

 

[Jeepster48439]

What no option for using black powder?
Seriously though the magnum primers in a small case could possibly unseat the projectile to early and cause extreme deviation. What loading of bullseye?

Also had to choose bacon of course

Alliant says 2.6gr of Bullseye. These will be more of a plinking ammo. Was thinking of working up to a load that will cycle the action properly and consistently and stopping.

What's a poll without a bacon option?

 

[Jaybird1980]

Alliant says 2.6gr of Bullseye. These will be more of a plinking ammo. Was thinking of working up to a load that will cycle the action properly and consistently and stopping.

2.6 is a good starting point, load up a handful and shoot them. Make sure they have consistent ejection distance if you don't have access to a chrony. Magnum primers can be harder to seat, some people complain about getting light strikes and say the primers are harder, but I think sometimes they are not seated fully. My biggest worry would be the magnum primer unseating the bullet before powder burn.

 

[Jaybird1980]

Hopefully someone will have actual experience with this, I haven't had actual experience using MSPP for 380

 

[russc2542]

No personal experience but comes up several times a week in a credible FB reloading group I'm in and chrony data given there shows more variation between manufacturers of the same class of primes than consistently between std/magnum primers or pistol/rifle primers (running SRP in SPP applications... reverse is not safe due to cup thickness and probability of blowing it out). the consensus there is work up a load from the bottom of the range.

 

[AmmoManAaron]

What no option for using black powder?
Seriously though the magnum primers in a small case could possibly unseat the projectile to early and cause extreme deviation. What loading of bullseye?

Also had to choose bacon of course

Been there and done that years ago - I had precisely that problem. I was using 700-X and not Bullseye, but I would expect the result to be exactly the same. I'm generally all for reasonable and thought-out experimentation, but in this case I would recommend just getting the correct primers. With the component situation being what it is, your best bet may be trying to find someone who will trade 1:1.

 

[Leadeye]

I've used taper crimp dies to get a more firm grip on bullets. The 9mm would be as close to .380 as I have been though.

 

[NKBJ]

There is so much difference from one make of primers to the next, so much overlap from what is called standard versus what is called magnum.
Just try what you have on hand, work up the load from bottom up, make it work or do something else. But don't ever forget you're dealing with a small case, an inherently weak firearm and that primers' appearance is no reliable indicator of actual overloads. Once the loads are increased in power to the point that they function the action, there you are.

I always used Lyman #358345 semiwadcutter and it was accurate and didn't fail to feed.