LRP vs LRPM

[Ruger#3]

Please discuss any experience you have with loading magnum primers into calibers calling standard large primers. Powder charge reduction and laddering you suggest would be appreciated. I load .308 specifically.

 

[Dub]

.308……what an excellent cartridge.

I haven’t tried magnum primers in mine…..yet.

Love me some .308.
Versatile, delivers the smackdown, efficient……and sneakier than it’s taller cousins.

A cartridge with short man’s anger ready to prove he can hang.

LW, sporter weight, tactical, bull barrel , AR-10, M1A, Henry lever, single shot……..excels in all.

 

[Ruger#3]

The question stems from LRP being scarce. You still find magnums here and there. Thinking about the wisdom of getting what I can, while I can and adapting.

 

[rosewood]

I have never loaded a magnum LR primer in my life, even though I do have some now. I always used LR primers in even 300wm and 7mag with no issues (always uses stick powders to). That being said, I have used Magnum primers in 38 special before. The only real difference is the magnums are a bit hotter than standard primers and are intended for ball type powders that are harder to ignite. Magnum primer and Magnum cartridge are 2 different uses of the word. Magnum cartridges don't have to have Magnum primers, only hard to ignite powders and also it is my understanding Magnum primers are good in really cold weather.

I would recommend backing down your charge maybe 1-3 grains and test at the range again. Check for accuracy and velocity and tune it until you get to where you was with standard primers. Word on the street is, you get a slight speed boost when making the swap which implies a pressure boost.

Also, the flame produced by various manufacture primers is said to be different, so the same can apply if changing brands of primers.

Rosewood

 

[fauxferret]

From what was explained to me, a magnum primer doesn't exactly burn hotter. It's supposed to burn longer to allow for reliable ignition in cartridges with a lot of powder or as previously stated for difficult to ignite powders and cold weather. I can confirm this at least with my 375 H&H when I first started to load for it I used regular primers over magnum and of the 10 rounds I loaded only about 6 reliably ignited. I will also note I didn't just sit down and shoot them all. 6 were in a cartridge carrier inside my jacket so I will chalk it up to body heat as keeping them warm. The last 4 were sitting on the shooting bench and it was an unusually cold January in south Georgia. As for substituting it has always been good practice to dial back the charge a few grains and don't start at or near max. I have a friend who shoots a 243AI for varmints and swears by using magnum over regular primers. According to him it gives him more consistent velocity leading to better accuracy. Take that for what it is worth.

 

[Ruger#3]

I have never loaded a magnum LR primer in my life, even though I do have some now. I always used LR primers in even 300wm and 7mag with no issues (always uses stick powders to). That being said, I have used Magnum primers in 38 special before. The only real difference is the magnums are a bit hotter than standard primers and are intended for ball type powders that are harder to ignite. Magnum primer and Magnum cartridge are 2 different uses of the word. Magnum cartridges don't have to have Magnum primers, only hard to ignite powders and also it is my understanding Magnum primers are good in really cold weather.

I would recommend backing down your charge maybe 1-3 grains and test at the range again. Check for accuracy and velocity and tune it until you get to where you was with standard primers. Word on the street is, you get a slight speed boost when making the swap which implies a pressure boost.

Also, the flame produced by various manufacture primers is said to be different, so the same can apply if changing brands of primers.

Rosewood

That’s pretty much what I read on other forums. Having no experience with it thought I’d ask the more experienced folks.

 

[tcward]

I use LRM from time to time in non mag calibers…just back off powder 10% and go from there.

 

[Jester896]

I have used small magnum in pistols when the others were scarce. With the same powder charge in the 9mm the round is 50fps faster. I have talked to folks that only use magnum primers in rifles but they reduce their loads. I use srm in my 6 Dasher and the reason I understand is it gives a more consistent burn According to the gurus. I have seen .2 SD with VV powder in my dasher if that is a testament to anything. They will light ball powders better than standard especially if there is a bunch of powder.

as long as you approach it with the right mindset it may be worth a try for you. There is some pretty good info posted on the cautions.

 

[Ruger#3]

I use LRM from time to time in non mag calibers…just back off powder 10% and go from there.

I appreciate your advice. Other forums mention backing off 1-3 grains, I think your idea creates a good margin then ladder up carefully.

 

[tcward]

I appreciate your advice. Other forums mention backing off 1-3 grains, I think your idea creates a good margin then ladder up carefully.

Exactly. The more pressure a particular round creates leads to even more caution when using different components.

 

[rosewood]

Found some LR locally in Warner Robins, but a ride for you.

Rosewood

 

[menhadenman]

PV has Rem LRP today.

But in my experience you’ll get 50 fps more and maybe lower SD (better powder burn). I shot a lot of LRP in my new 7 RM during covid before getting some magnums.

 

[lampern]

Winchester makes primers that are labeled for standard and magnum loads

 

[Ruger#3]

PV has Rem LRP today.

But in my experience you’ll get 50 fps more and maybe lower SD (better powder burn). I shot a lot of LRP in my new 7 RM during covid before getting some magnums.

I find the magnums around locally now but haven’t seen LRP in my area in a while. Like most, try to but local and avoid hazmat fees.

 

[GregoryB.]

I find the magnums around locally now but haven’t seen LRP in my area in a while. Like most, try to but local and avoid hazmat fees.

I find it cheaper to buy several bricks online and pay the fees as apposed to driving my gas thirsty truck a hour to town in hopes of finding anything large rifle or magnum.

 

[rosewood]

Winchester makes primers that are labeled for standard and magnum loads

That is just large pistol, other sizes are not labeled as such. No idea why.

 

[Jester896]

That is just large pistol, other sizes are not labeled as such. No idea why.

I have rifles that are...Next time I'm in the shop I will snap a pic for you. Can't remember if they are older white packs or the newer blue.

They don't say it on the new packs

 

[rosewood]

I have rifles that are...Next time I'm in the shop I will snap a pic for you. Can't remember if they are older white packs or the newer blue.

They don't say it on the new packs

10-4. When I started buying primers, they were blue box. I have picked up a box of old stock LP and SP in white box, they are nickel instead of brass primers also.

Rosewood

 

[fauxferret]

I have used small magnum in pistols when the others were scarce. With the same powder charge in the 9mm the round is 50fps faster. I have talked to folks that only use magnum primers in rifles but they reduce their loads. I use srm in my 6 Dasher and the reason I understand is it gives a more consistent burn According to the gurus. I have seen .2 SD with VV powder in my dasher if that is a testament to anything. They will light ball powders better than standard especially if there is a bunch of powder.

as long as you approach it with the right mindset it may be worth a try for you. There is some pretty good info posted on the cautions.

VV powders are amazing just wish they weren’t so expensive. I use them exclusively for swc 45acp whisper quiet when you get the can on it and the ES is in the single digits.

 

[Jester896]

yep @rosewood they were white box...last one I have.



I might bet money that the only thing they changed was the packaging.