Rifle - Mag vs Regular Primers

[Farmland]

I have tons of pistol primers but no rifle primers. Can a large Mag Rifle premier substitute for a large regular rife primer. Of course I would work my load up from the min suggestion.

Rifle - H&R single shot heavy barrel 25-06 Breech Load. 85 Grain Nosler R-19

[Unclenick]

Yes. Just knock your powder charge down 5% and work back up watching for pressure signs. Large pistol primers cannot be substituted for large rifle primers of either type, both because they are too short in the large size, and because their cups are too thin for rifle pressures.

[Farmland]

That is about the same info that I have found. I was able to buy some Federal Mag rifle primers, so I bought 200 hundred just to give them a try.

[Red_Eagle]

I use magnum primers when ever I use ball powder. Adust the load data back 1 grain.

[T. O'Heir]

Yep. Magnum primers burn a bit hotter for a bit longer and are made to light hard to ignite powders and for cold weather shooting.

[DiscoRacing]

i load .270, 7mm, .06, and .308 alll with mags that calls for regs in the book

[Major Dave (retired)]

So, how much difference does it make when you use mag primers?

Specifically:
In the load volumes?
In shot-to-shot velocity?
In overall velocity?
In group sizes?

[Buck88]

but can it be done in reverse? I got a ton of std. LR primers, but can't get my hands on any mag primers. Loading a .300WinMag with IMR4350, would it give me trouble igniting?

[purpledragon]

Usually in a large case like the big magnums you need the extra burn time of the mag primers to light all that slow burning powder.Certainly when its cold weather.

[Major Dave (retired)]

How cold? Like first week of November in Colorado at 9,000 to 12,000 ft elevation - for elk.

[TheNatureBoy]

Buck88, to answer your question, yes "it can be done in reverse". About two weeks ago I loaded some 180 grain Berger VLD pills for my 7mm rem mag sendero. I accidentally used large rifle primers vs magnum primers. Using 62.3 grains of IMR 4350 powder it chronyed at 2865 fps. I emailed Walt Berger and he sent me load data i needed. I'll probably use his recommendations vs what I was trying to work up.

[Unclenick]

It should be noted that benchrest shooters typically try to get the mildest primers they can because, in comparison to the powder charge, those primers make the least contribution to peak chamber pressure. That, in turn, is considered desirable because it means the loader is controlling the pressure more completely with the precision of his powder charge, even if he needs a tad more powder with the lighter primer.

That said, the BR guys all deburr their flashholes so that whatever primer flame they have works more consistently, and they choose charges that fill the case well with powder so there is little or no room for any of it to fall away from the flashhole. If you are using a coarse stick powder, the gun probably won't care what primer you use, as long as you work the load up to a sweet spot. If you are using a spherical propellant in a large case with a standard primer, I can say I got a considerable improvement in consistency from that.

I would not be taking such loads out in sub-zero conditions. Anything below the freezing point of water I generally would avoid with standard primers. They'll work below that temperature, but once both the powder and the primer are being affected by temperature, that can go downhill fast. The exact temperature that occurs at depends on the individual powder and primer. If in doubt, go to the range when the weather is at the temperature in question.

[Buck88]

I'm thinking I'll just bend over and buy some mags from gunbroker... Don't know what the weather will be like in the unit I'm hunting in November, so I'll just suck it up and buy some.

[UniversalFrost]

just backorder some on cabelas.

remember to read the emails they send because they will slip one in requesting you to call (usually around week 6). as of late my orders of primers were only on backorder for a week or two and never got the email asking to call to verify your order status.

and mag primers create a bit more pressure, so start at minimum and work up. as of late i had to substitute large rifle primers instead of mag large rifle since I was out. turned out rather well and was able to increase loads a bit. no noticeable difference in accuracy with the loads in mag or normal primers.

just my 2 cents.