I’m spending more time at the loading bench lately. This morning I discovered I am very low on standard primers and have a good supply of magnum primers – in small and large sizes. I load for a variety of lever rifles – all the M1873/1892 chamberings, all the 1894 chamberings, over half the M1886 chamberings, many of the 1895 chamberings, plus .45-60 and so on. What knowledge, experience, references or advice do you have for substituting magnum primers? I am not using black powder or black powder substitutes. I am using powders such as 5744, 3031, 4895, trail boss, 4227, unique, 231 and many others. I lean toward black powder load equivalents where appropriate (e.g. not the .30/40 in the M1895).
Thanks in advance.
Let me throw this in the mix. When shooting, “old” Winchesters, there is a span both of age/strength of materials and action strength. In those I shoot, I have early M1873’s contrasted with later model M1892’s. I’m thinking the thoughts/advice about one might not be the same as thoughts about the other end of the span.
I had read somewhere that you should load black powder rounds using a magnum primer. Of course, that was years, if not a decade, after I had started loading black powder rounds using regular primers with no adverse effects. Best to leave that alone, and so I have no real need nor use for magnum primers.
TR said
Steve, I have always used mag. primers on all my 1886 and 1876 loads. The guy that got me started loading said it worked better in the big cases, I just did what I was told.
That would make sense, because a small charge of fast burning powder is going to be spread out over the length of the case, not back against the primer…unless you raise the muzzle before each shot. I’ve been loading reduced .30-06 loads using small charges of Unique, so I might start using mag primers myself–I’ve got almost 1000 left over from shooting BP.
By the way, can anyone familiar with the programs that compute pressure & muzzle vel. based on powder & bullet wt. provide me with an estimate of MV produced by 11.5 g. of Unique behind a 100 grain jacketed bullet?
TR said
Steve, I have always used mag. primers on all my 1886 and 1876 loads. The guy that got me started loading said it worked better in the big cases, I just did what I was told. My loads have a little less powder than the loading manual calls for at any given velocity. T/R
TR are you shooting smokeless or black powder? The only gun I shoot with black powder is the 76. I would rather not over pressure my guns especially the 76. I will go back and do some research about using magnum primers.
I reload for all my old winchesters including calibers for the 1873, 1876, 1886, 1892, 1894 and 1895. I use medium speed powder, preferably 5744 for most of them. I always use magnum primers for all the straight-walled cases in my old Winchesters. I chronograph all my loads and find that the magnum primers do not affect the velocity much, but they do improve burn consistency, giving a lower extreme spread in my chronographed loads. If I have to (i.e., ran out of magnum primers, then I’ll use standard primers in my straight-walled cases, but my preference are the magnums, especially for larger capacity cases like the 45-70, 45-60, 45-90, 40-82, 38-72.
The only exception is my 30-30 loads. Because it is a bottleneck cartridge, and pretty much full of IMR 3031, I use standard primers on that cartridge.
Of course, for the 32-20 loads, I use either small rifle or small pistol. It doesn’t seem to make a difference in velocity or accuracy with the medium speed powders I use.
I should mention that I keep my loads to around original velocities and a bit lower peak pressures with medium burn rate smokeless powders. Magnum primers are entirely safe in those conditions and even desirable for more consistent burning. If one is using hotter loads, then All bets are off.
Kev18 said
I wouldnt use magnum. I did in the past when I just started reloading for the 40-82. I was wondering what the sparkles were flying out the barrel. I was blowing the necks off the brass… Thats when I learnt. And my rifle doesn’t have a new barrel on it so I keep low pressure at 1500fps factory spec.
Wow – that .40-82 of yours looks like it is one precise shooting rig. Thanks for sharing your experience. You mention blowing the necks off. I also note that Kirk (above) mentioned using magnum primers but in straight wall cases. Kirk – I would assume that means you don’t use them in .40-82 (or similar case)?
Kev18, If you are having case failures be careful, one small piece of brass left in the bore can bulge the barrel. Do not use balloon head brass, old brass, brass that has been channelured to hold the bullet up, or has internal corrosion from black powder. Some 40-82 brass is reformed by stretching and requires close examination after every use. Check each ejected case before firing the next round. When the rim of the cartridge separates from the case on a 86, fire flies out the top of the breach, safety glasses a must. T/R
November 7, 2015

In my limited experience the best answer is “maybe”. If I observe vertical stringing with standard primers and medium to medium slow powders in medium to large straight wall cases I’ll consider magnum primers or match primers (if I can find them). I’ve gotten better results by simply switching among brands of primers and using Federal Match primers. Some powder/cartridge combos will work better with magnum primers but only careful load development will determine that. Sometimes I just tighten up the roll crimp a tad. Quite honestly I’m not a fan of magnum primers in the lever gun cartridges I load but only because I haven’t found a load that requires them….yet. Will they work as well as standard primers? Probably.
I suspect that you’re a seasoned reloader but I’d be remiss if I didn’t suggest that you reduce the powder charge by a grain or two when stepping up to a magnum primer from a standard. Just in case someone with less reloading savvy is lurking here and doesn’t know any better, of course.
Mike
steve004 said
Wow – that .40-82 of yours looks like it is one precise shooting rig. Thanks for sharing your experience. You mention blowing the necks off. I also note that Kirk (above) mentioned using magnum primers but in straight wall cases. Kirk – I would assume that means you don’t use them in .40-82 (or similar case)?
Are you using vintage brass? Early 1900’s bottle neck brass often cracks at the neck. I have boxes of unfired rounds that are cracked. Depending on where it is cracking you may want to anneal the brass.
steve004 said
Wow – that .40-82 of yours looks like it is one precise shooting rig. Thanks for sharing your experience. You mention blowing the necks off. I also note that Kirk (above) mentioned using magnum primers but in straight wall cases. Kirk – I would assume that means you don’t use them in .40-82 (or similar case)?
I did have a 40-82 for a short period of time and reloaded for it, but cannot recall what sort of primers I used back then. I would certain use mag primers in them if I were reloading now, however. The 40-82 and 38-72 (which I did a lot of reloading for, and experimentation) don’t have much of a bottle neck on them. When I said I wouldn’t use mag primers in bottleneck cartridges, I meant something that really steps down, with shoulders on it like the 30-30 or the 303 British, or most modern cartridges. The bottle neck provides enough of an obstruction that powder burn is much more consistent than in straight-walled cases or near-straight walled cases. Having said that, I have experimented with mag primers in 30-30 but there was no significant improvement in burn consistency/Extreme spread, so I don’t see any point in using mag primers for the 30-30. Other modern cartridges I don’t have much experience with, but I would only want to use prescribed primers in a modern cartridge. It is mainly in cartridges originally designed for BP that I use mag primers with smokeless and that is because there is so much empty space in the case that some smokeless powders experience improved burn consistency with mag primers.
1 Guest(s)
