SPP vs LPP for 45 ACP

[TomJ]

Almost all of my 45ACP brass uses large pistol primers. I've found some using SPP, and there are enough that I want to use them. Do I need to increase or decrease the amount of powder I use for the brass with SPP?

 

[JCSC]

Yes sir. Drop back 10% and work back up with any component change. Probably not necessary, but a good practice none the less.

 

[Nature Boy]

I run the same load regardless of large or small but I’ll defer to others that may know different

 

[adcoch1]

You will probably have a bit of difference between the two, but I'd bet the spp loads are slower if all else remains the same. Worth a workup to check.

 

[Fine Figure of a Man]

Do I need to increase or decrease the amount of powder I use for the brass with SPP?

I don't.

 

[AJC1]

The spp are a tiny bit slower but unless you crono them you won't know. If your SD is high you won't see it.

 

[dannyd]

I kept the load the same and worked just fine; easier to load with small primers.

 

[gudaki]

Same load for both for me and it works fine.

 

[N555]

If lighting up 5gr of powder it doesn't seem to matter. If lighting up 14gr of ballpowder like enforcer, it might start to matter. I only use LPP for my heavy carbine loads using enforcer.

 

[.45Coltguy]

Haven't seen any difference whatsoever. You're fine.

 

[lordpaxman]

Do I need to increase or decrease the amount of powder I use for the brass with SPP?

I ran a small test with mixed HS large vs small primer .45 using CCI 300 and 500 but keeping the powder the same and there was no difference in the chrono readings. I found a bigger difference when I tried CCI 300 vs WIN LPP, so you may see a difference if you switch brands but in my case it wasn’t a lot.

 

[NC9mm]

Same load, no practical difference.

 

[lightman]

I load them with the same charges and see no noticeable difference. But its always a good practice to start lower and work back up.

 

[kerreckt]

I use the same powder charge regardless of the primer size. Use your own good judgement.

 

[Blue68f100]

There will be around 15-25 fps difference between Small vs Large, with the LP being higher. If at max reduce and work back up. If at BE target level, just load and go.

 

[CQB45ACP]

Interesting question/discussion and would make a great poll.

Reminds me of a thread a couple weeks ago about changing brands of primers and whether you work back up. In that one there were two primary schools of thought 1) yes, always 2) no, never.

The correct answer for both is of course, no.

 

[mdi]

After reading a lot of threads about small vs large primed 45 ACP on every reloading forum I visited, A lot of complaints, a lot of speculation. I did my own test;100 each, same load, same gun. Not enough difference to make a difference. JCSC is correct. "Reloading 101" any time there is a component change, do another load work up. https://duckduckgo.com/?q=Small+primed+vs+large+primed+45+ACP&t=chromentp&atb=v314-1&ia=web

 

[243winxb]

Large primers more velocity. https://www.starlinebrass.com/articles/small-pistol-primers-vs-large-pistol-primers/

Not all primer are created equal, so, only your chronograph would know?

 

[TomJ]

Thanks for the responses. I'll start a little lower just to be on the safe side.