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357 magnum primers

2035 Views 41 Replies 15 Participants Last post by  drone
Will small rifle primers fit in the pocket of 357 brass?
I have many small rifle primers but small pistol primers aren't very easy to come by.
I'll be using the rounds in a mod 92 lookalike soit's not for pistol use.
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Yes, I've used small rifle primers in 357 handgun loads with no ill effects.

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RJ
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Checked Midway USA yesterday, they had small pistol primers in stock
The gunshow today was awash with primers at $130/M but nobody was buying that I saw.
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drone lives in England which means getting them via International shipment will be a problem. He's good to go with the small rifle primers he has, as RJ said.
The only qualifier I would add depends on the powder he wishes to use. He only says he has 'small rifle' primers, no mention of standard or magnum. With slow powders, like H110, Win. 296, magnum primer might perform better.
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An additional thought; Since he is asking about using them in a Win. 92 clone, rifle primers (standard or magnum) may be better suited anyway, should have no 'light strike' issues in that rifle platform, that might happen in a (some) revolver when using a thicker cup primer, just a thought.
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I use them most of the time. I鈥檝e never had a problem setting off any powder. I use a lot of WW296 and H110 (same) and they go bang every time in my revolvers. Load up a few and try them. I know a lot of guys use just small rifle.
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I have substituted small rifle primers in 357 mag. when things got tight. Just be sure to reduce the charge and work up.
Small rifle primers are standard for 357 Max., that's why I tried them for the 357 mag., that and the fact I was out of SP.
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The only issue in 357 Mag is likely to be in a gun that has had the mainspring lightened to lighten the trigger. Magnum small rifle primers (SRP) often have brass cups about 0.025" vs. 0.020" for standard SRPs, so they will be harder to set off in the event of marginal firing pin strike energy.
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The only issue in 357 Mag is likely to be in a gun that has had the mainspring lightened to lighten the trigger. Magnum small rifle primers (SRP) often have brass cups about 0.025" vs. 0.020" for standard SRPs, so they will be harder to set off in the event of marginal firing pin strike energy.
See #6 above.
I noticed it. I am making a general statement for others reading the thread that may try to substitute primers in other guns. Though, now that you bring it up, strictly speaking, I haven't seen anything to say the gun does or doesn't have a factory-original spring set in good condition. So the precaution might conceivably apply there, too.
Though, now that you bring it up, strictly speaking, I haven't seen anything to say the gun does or doesn't have a factory-original spring set in good condition. So the precaution might conceivably apply there, too.
You are correct, as so often happens, posted questions look for simple answers, where the 'rest of the story' can lead to totally different, or at the least qualified answers. I call it 'the dental approach', it's like pulling teeth.
Many thanks for your interest and responses.
Basically the rifle is a rossi r92 which is stock in the spring department, powder will vary between titegroup, universal and H2400, but not at the same time. Primers are S&B standard small rifle.
Reason I asked was I once saw, can't remember where, that there was a difference in depth specification on some primers but I also cannot remember if it was small pistol and small rifle or on the large ones, my bad.
Rifle is due in a few weeks once my licence is varied by the police.
My only worry is that I will get to prefer the gun to my 94 win in 30/30 as the action is a lot smoother. Probably why John Wayne used the 92 :oops:.
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Many thanks for your interest and responses.
Basically the rifle is a rossi r92 which is stock in the spring department, powder will vary between titegroup, universal and H2400, but not at the same time. Primers are S&B standard small rifle.
Reason I asked was I once saw, can't remember where, that there was a difference in depth specification on some primers but I also cannot remember if it was small pistol and small rifle or on the large ones, my bad.
Rifle is due in a few weeks once my licence is varied by the police.
My only worry is that I will get to prefer the gun to my 94 win in 30/30 as the action is a lot smoother. Probably why John Wayne used the 92 :oops:.
The only depth difference is between large rifle and large pistol. Large rifle is higher鈥.often referred to as 鈥渂eing proud鈥.
The only depth difference is between large rifle and large pistol. Large rifle is higher鈥.often referred to as 鈥渂eing proud鈥.
Yes on the large size, and the small size, rifle vs. pistol, are the same depth (height). Sierra has a pretty good reference on the subject here, referencing SAAMI specs.: Primer Substitutions - Sierra Bullets

P.S. You will note that, contrary to most advise shared in this post, Sierra advises against any such substitutions. In todays 'legal world', I would expect nothing else from a manufacturer in writing.

BTW: The last sentence in the Sierra link must be a typo (as typed, it doesn't work!): "It is possible to substitute LRP for Small Pistol Magnum Primers in certain situations if the certified loading data supports it."
I think they meant SRP, not LRP. Assuming I'm correct, this does somewhat support the substitution being discussed here.
DRONE, if memory serves, the originators of the .357 Magnum round used small rifle primers almost exclusively through the round's development. I believe this was because the had to resort to using rifle powders intended for small-case rounds, to obtain desired velocities. The rifle primers not only assured more thorough ignition, but its thicker cup also added an extra safety margin against piercing from high pressures (so high, that they exceed current modern limits).
I, too, use small rifle primers EXCLUSIVELY in my "heavy" .38 Super reloads, and will use them when making hunting/defense-level loads for my .357 Magnum revolvers. Because the propellants I use in both calibers are easily ignited by small pistol primers, the use of small rifle primers is strictly a concession to safety on my part.

As has already been recommended (probably), If you are not starting with a minimum load, go back to minimum and work up in 0.1-0.2 gr. increments, so that if the hotter primer is jacking up pressures, you'll see it coming before it does any real damage. THIS is where a chronograph comes in VERY handy, to detect disproportionate velocity increases, or velocity
"plateauing", which are both excellent indicators that reducing the charge is desirable.
MY experience with "reading primers" to determine if excessive pressures are reached is that this is more difficult to devine from SRPs than SPPs due to the former's thicker cup. When the SPP on a reload is more flattened/cratered/ punctured than on a factory load, it is likely that you are at or above SAAMI MAX pressure with that load. If a SP primer with a thicker cup is substituted, the deformation will be lessened, despite the high pressure. This makes it difficult to decide what's happening, pressure-wise.
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Probably why John Wayne used the 92
No, that's what the 'prop. man' handed him!o_O:rolleyes:;)
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I have a chrono, a magnetospeed that is a PITA to use on my lever gun due to the magazine interfering.
I've been looking at it with a view to making a cantilever to hang the thing off but however I look at it it's still a dog's dinner of a lash up.
However, many thanks for reminding me as I'd forgotten all about it when I got my new red dot. I had to give it a try.
The pic here shows the chrono fitted to the barrel and I can actually see the sight AND target, I'll try it out on Saturday.
I just hope the muzzle blast doesn't affect the equipment, but I simply can't get the band in between the mag and the barrel on the muzzle side of the gun. Building Window Grey Door Electric blue
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I just hope the muzzle blast doesn't affect the equipment
Maybe not in the sense you mean, but it does. There is a consumable patch on the magneto, which gets eroded by muzzle blast/powder over time.

Cheers
As others have said yeah they work. Not so with large pistol and large rifle. Keep those separate.
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