Is A Primer's "Sensitivity" A Real Concern?

Yes, Federal pistol primers are "more sensitive". Those of us with custom guns and light hammer falls consider it a feature rather than a bug. Some of my guns simply don't go off unless they are using Federals.

Does that make them more likely to detonate during loading? I honestly don't know. Any brand will cause troubles when mishandled. I have loaded hundreds of thousands of rounds with Federal pistol primers on several different Dillon presses and have never had a problem.

Federal primers are softer, but from a shooting perspective it shouldn't matter unless you have changed your spring weights from stock.

As far a detonating during the reloading process, I've yet to see it after using about 10k of them. The only primers that have ever detonated on me are Remington 5 1/2. Out of 20k, I had 3 go off while priming cases. All of them were 9mm cases without the crimp removed.

It’s a real concern if you have a lightly sprung revolver in that you need the more sensitive Federal primers to retain 100% ignition, where others go “click” vs “bang”.

Have loaded many thousands of them, using lots of methods of seating including a number of Dillon progressives 650’s being some of them.

If you want to avoid setting off a primer, don’t force them quickly. Before the Internet, I heard of people setting primers off seating them. Had already mangled them many ways, sideways into pocket, etc and even crushed a few in a bench vise and they didn’t go off.

Dismissed it as something you hear at a gun shop after that. Until the Internet provided me with enough evidence to know goofy things happen. Even seen more than one powder measure blown up. So don’t put things past people as far as what can be done. The right guy can mess up an anvil with a rubber mallet.

After 30 years of loading I was finally in the presence of one such primer detonation while loading though. A friend had called me up because he was having an issue with one of his presses and couldn’t get it running correctly. So, I go over there and start working on the problem press and he moves on down the bench and starts trying to load on another press. I hear the sounds of frustration coming from him and sounds I do not associate with reloading (unless your using a lee hammer style loader) and a few minutes later “pow” he lit off a primer.

It was at that point I realized why I have never lit one off while others have had it happen more than once. If I am frustrated, I stop and walk away. The “oh yeah, I’ll fix you! (With force), mentality might work for breaking a horse it’s not ideal around compounds that ignite with impact.

If things don’t fit, I don’t force them. People that light off primers, do so because of their technique. If it wasn’t something they did we would all be blowing up primers. Once you understand it’s your fault and nothing else’s, you can adjust you, so it doesn’t happen…

Speaking here about LPP. Federals have the softest cups. Makes them easy to press in but I watch out for compressing the primer. Because they're soft they can also show over-pressure early (where a Win wouldn't show yet. CCI has the reverse issue). They also have a little less energy than the others. Winchester being the hottest, I have to bump up the charge slightly (0.1gr) when using Federal vs Win for my bullseye gun to cycle reliably.

Never had one blow up. I did have one get caught somehow in the press when setting up the 750 and when it indexed the primer cup was slowly ripped apart with no kaboom. I noticed a smear of bright yellow primer paste/powder and traced it to the mangled primer. They should require a sharp impact to ignite, regardless of make.

And yes not needing Federal specifically, but one of my semi auto pistols is not reliable on ignition with CCI. Federal and Winchester never had light strikes.

As others have already said Federal primers are noticably softer than most others. My S&W 610, when I was shooting it in USPSA competition was tuned to reduce double action trigger weight and only reliable with Federal primers. I loaded tens of thousands of Federal primers, large and small on my Dillon XL650 without issue, no better or worse than most any other primer.

I have crunched some number of primers that got misaligned in progressives, but have only popped two.
I think they got in a position where they were sheared rather than mashed, which set them off against the edge of the primer pocket. Separation between the priming station and primer tube was enough to prevent gang fire. I don't know what is happening in those cases that set off the whole stack.

Several truths apply here...

• Idiots abound in every walk of life
• Four words you will never hear an idiot say: "I made a mistake"
• When an idiot makes a mistake, it's always blamed on the equipment
• The Internet is the new refuge of the liar, deceiver and idiot. Truth is no longer the dominant force in our culture.

Conclusions....
1. When you consider how many BILLIONS of Federal primers have been loaded in the last 30 years, versus the number of "danger reports" on the web, you simply have to write these off to improper handling. Especially when the report starts with... "A buddy of mine...."

2. Just because a REPORTED error happened in your area of interest, doesn't make it any less likely to be FAKE NEWS. The US Congress is not the only venue for false reporting and tall tales.

3. I load Federal primers almost exclusively on a Dillon 650 into "mixed brass". The number must be up around 20,000 by now. Yes, I have screwed up. I have mashed and mangled several dozen Federal primers in the press, and I have dropped another dozen onto a concrete floor. I have installed Federal primers sideways into the primer pocket and mashed them into oblivion. I have NEVER experienced a primer mis-detonation in my entire loading career, which started in the late 1970's. And this includes during insertion AND live primer extraction.


My wife and I go out to dinner once a month at high-end restaurants. We read the internet reviews. There is always one bad review blaming "burned french fries" on the chef. We just have one question (while we roll on the floor laughing): Who goes to a $40+ a plate restaurant and orders french fries ??

IMHO, the OP's entire premise seems to be based on vague and undocumented reports of these same "burned french fries".

All the best.

This has been a problem with the Dillon 650 since it was introduced. I was at a local gun store back in the late 70's where the store had one detonate and had the primer tube stuck in the ceiling. This was long before the we had the www to search. So Dillon has know about the issue for a very long time. I'm guessing a law suite(s) finally forced them to stop making the 650, the reason for the newer model. In any case an experienced user knows not to force anything on a AP, nothing good happens when doing so.

Lee had a note on there manuals not to use Federal primers. But the reason was that Federal did not provide any primers for them to test. Federals have been know to have more sensitive primers. Winchester 10 yrs or so decided to make their primers more sensitive , removing the Nickle plating on the primers caps. The result was users started blowing primers. I still have some of the old Ni ones. They hold up like CCI. The newer ones show pressure signs earlier in the form of piercing. Alot of users switched to different brands after this.

Blue68f100 said:

Lee had a note on there manuals not to use Federal primers. But the reason was that Federal did not provide any primers for them to test.

Click to expand...

I was under the impression that Lee never did any testing....only copied recipe's from other sources. In today's lawsuit happy world, I highly doubt Federal would make primers that were unsafe.

.38 Special said:

Yes, Federal pistol primers are "more sensitive". Those of us with custom guns and light hammer falls consider it a feature rather than a bug. Some of my guns simply don't go off unless they are using Federals.

Click to expand...

Yup! I have a few revolvers that I only use Federal SPP with. Snubbed hammers and DAO actions with light springs and slick actions. Quick pointing and all kinds of fun. It's not a big deal and I *could* put stronger springs back in those guns but, why would I if the only inconvenience is using Federals? Be careful and don't get in a rush and you'll be fine. Life's just too short to be in a hurry.

The 650 rotary primer feed was supposed to be safer than bar.
From Internet reports, it seems not. They have replaced it with the bar feed 750.

I have know of one first hand account of a primer explosion on a Dillon and it was a Squared Deal B. Never had and issue with my XL650 and I am 40K plus through the machine. Keep it clean and don't force something that does feel right.

rfwobbly said:

Several truths apply here...

• Idiots abound in every walk of life
• Four words you will never hear an idiot say: "I made a mistake"
• When an idiot makes a mistake, it's always blamed on the equipment
• The Internet is the new refuge of the liar, deceiver and idiot. Truth is no longer the dominant force in our culture.

Conclusions....
1. When you consider how many BILLIONS of Federal primers have been loaded in the last 30 years, versus the number of "danger reports" on the web, you simply have to write these off to improper handling. Especially when the report starts with... "A buddy of mine...."

2. Just because a REPORTED error happened in your area of interest, doesn't make it any less likely to be FAKE NEWS. The US Congress is not the only venue for false reporting and tall tales.

3. I load Federal primers almost exclusively on a Dillon 650 into "mixed brass". The number must be up around 20,000 by now. Yes, I have screwed up. I have mashed and mangled several dozen Federal primers in the press, and I have dropped another dozen onto a concrete floor. I have installed Federal primers sideways into the primer pocket and mashed them into oblivion. I have NEVER experienced a primer mis-detonation in my entire loading career, which started in the late 1970's. And this includes during insertion AND live primer extraction.


My wife and I go out to dinner once a month at high-end restaurants. We read the internet reviews. There is always one bad review blaming "burned french fries" on the chef. We just have one question (while we roll on the floor laughing): Who goes to a $40+ a plate restaurant and orders french fries ??

IMHO, the OP's entire premise seems to be based on vague and undocumented reports of these same "burned french fries".

All the best.

Click to expand...

I guess that is one way to put it!

Now how about the Lee Factory Crimp die???

I have installed Federal primers sideways into the primer pocket and mashed them into oblivion

Click to expand...

That makes me feel better, I thought I might the only one that tried installing them sideways. (which does not work well)
Once you start them crooked in a Lee hand prime the only way to get the case out is to continue to mash them in.
Had this happen a couple times and I mashed them quite firmly but slowly. No bangs yet.
Surprising how much you can mangle one and not have it go off.

I’ve worn out two Lee presses, a P1000 and Loadmaster.
I’ve loaded 2+ million rounds in the process.

The vast majority with Federal primers.
Thoughts:
1. YES! Federal primers ARE more sensitive than others. My comp revolvers are tuned to use them.

2. Yes! I’ve popped Federal primers TWICE! First time, almost full tray. Primer was cocked and I applied too much pressure. Operator error. It was after midnight. Made a mess and a sliver of plastic cut my finger. Box of miscellaneous items behind primer tray was shredded. Mostly just a mess. New primer tray full of primers, new, clean underwear, and 5min with shop vac and I was back in business.
Second time only a dozen primers. Not much of a mess.

3. Lee knows about sensitive primer issue. Warning is CYA. BUT, they also make and sell a blast shield....

Just know what you’re dealing with and proceed carefully.

There is some information about primer sensitivity at the end of this article:
https://www.shootingtimes.com/editorial/spring-rates-and-trigger-pull-weights/383919

This is a timely thread. I recently had a primer go off while seating it. Yes, it was on a 650. I move a lot slower than advertised just because I like to be able to feel things while operating. If something doesn't want to go, I don't make it. Even so, I also get primers sideways, upside down, mashed, and until this experience, hadn't had one go off. I've used CCI, Remington, and Federal. In this instance, it was a CCI small rifle primer.

That pop! sure got my attention!

I have reloaded thousands of Federal primers on my Redding T7 and Dillon 550. No explosions. No drama. And I would snatch a few thousand now if I could find the darn things. To me they are no different than any other primer.

For information purposes I have found if one can go from large primers to small, you don’t need the most sensitive primers. Revolvers that would only run with Federal LPP will run with other brands if I switch to using SPP.

As for blowing up stacks of primers separating them as much as possible would help but doesn’t ensure against one setting off another. No machine has them as close to one another as they are packaged, except the APS strips for RCBS equipment.

Would have liked to have seen a video of this one, I came across years ago. I thought I had already seen it all…

I have been reloading since the early 70's on a SS press. I routinely fill a gallon jug with used primers every year. I usually buy them by the case. In all that time, loading all brands of primers while mangling a fair number every year. So far I have not set one off. Probably cursed myself now LOL. I wonder if I could sell the loaded ammo with sideways inserted ones to those guys that shoot their guns sideways.

Take the "It doesn't happen to me because I know better" with a grain of salt. I've loaded 10-15k rounds per year for the last 10 years and I'm 3 primers away from saying the same thing myself. It can happen to anyone, but it doesn't happen often.