Substitute LPMP for LPP

[Doghouse_Riley]

Reloading .45 ACP. Currently using CCI LPP, 200 gr RN and 6.3 gr WSF.

Can I use large pistol magnum primers instead of large pistol primers? Do I need to adjust the charge weight? If so, how much?

[slayer61]

Consider this...

Winchester LPP are used for STD AND Magnum!



You'll be fine. Maybe start out a couple tenths lower & work from there.

[Doghouse_Riley]

Consider this...

Winchester LPP are used for STD AND Magnum!



You'll be fine. Maybe start out a couple tenths lower & work from there.

Thanks. I read similar advise on another forum. But I trust Calgunners more. A little more anyway.

[sbo80]

generally, yes. However it's possible there are (probably minor) differences in performance depending on the powder you use. Using those winchester primers on either std or magnum loads, isn't the same as trying a different primer, with the same loading. Some youtube videos show negligible velocity difference in SPP and SMPP (which implies no real pressure change). But I don't 100% trust that since they don't test all that many different powders or combinations. Most vids I've seen were 9mm. It's probably true for most loads. But I would not be surprised if some of the really slow powders get a bump if you use magnum primers. Or possibly just a larger standard deviation on velocities. I'd be more concerned if it was already a compressed load because a different burn rate seems more likely to affect the peak pressure in that case, but I'm not sure on that. That said, unless you are chasing power factor for competition I doubt it's usually relevant. Personally I would do it, but just do as mentioned and drop it down a tad and work back up, same as if you were trying any other new component/powder/bullet. You'll likely find yourself right back at the same load. But you'll know it's safe.

[pennstater]

OP, I have used mag LPP in .45 acp and .45 Colt, but, only with Unique or Universal. I noticed no difference. These were with mid/upper mid loads.
Everything looked fine regarding different primers. Don't get carried away and you should be fine.

MLC

[Sandspider500]

Some powders reaction to changing the primer is dramatic, I don't know if wsf is one of them.

[smoothy8500]

But I trust Calgunners more. A little more anyway.

Yeah, but which ones? We see a lot of "questionable" responses almost on a daily basis.

[ar15barrels]

Yeah, but which ones? We see a lot of "questionable" responses almost on a daily basis.

The lower the post count and later the join date, the more trustworthy they are...

[Doghouse_Riley]

The consensus I'm getting so far is that I should reduce my charge weight (it's a mid load) but not below the published minimum and don't be surprised if there are some differences in performance from using LPP.

I still have some LPP and maybe some more will turn up before I run out. If not the LPMP would be back up.

[Divernhunter]

I use them all the time and do not lower my load for them. Never had a problem.

[smoothy8500]

Over the years several members have run chrono numbers comparing similar pistol loads and switching standard and mag primer, me included. MOST reports presented chrono differences were way less than 30fps, usually 5 to 15 if memory serves correctly. Some said no real difference. One person linked a post from another forum that said "over 130fps" which is quite dramatic and immediately brings to question that result.

Of course all non scientific stuff here has to be taken with a grain of salt. However, with most midrange pistol loads you can consider dropping a couple tenths to be safe. No real need to work up at lowest starting load again.