.45 small pistol primer vs large primers

[viper12161]

Hey guys,

Is there a performance difference between reloading .45's with the small pistol primers vs large pistol? I bought some brass in bulk and have a ton of small primer brass. I have just been tossing it aside for now, but I was talking with a buddy at the range about it and he said to just grab some SP primers and load them up. Has anyone seen any differences between the two?

Thanks!

[sghart3578]

I am not a competition shooter by any means but I shoot a lot of 45 ACP and I see no difference.

I have shot identical loads over the chronograph with SPP vs LPP and the velocities were the same.

I wouldn't worry.

[Chainsaw.]

Steve test it fairly well here. Fairly conclusive IMHO.

https://youtu.be/DouAFTGmoAA

[viper12161]

Awesome, great to know! Thanks!

[Unclenick]

It's an interesting experiment. I posted in comments under the video asking for the SD's that went with the velocities to see if something about ignition consistency can be gleaned from them. I also commented in response to another commentor, for reasons explained there, that these results can depend on the primer make, how well the primers are seated, and, obviously, on what powder you are using. If you use a fast target powder that lights quickly, like Clays or N310, I would expect less apparent difference.

I avoid the small primer pocket cases just so I don't have to flip anything around in my loading gear. I also mostly just shoot brass I bought as new bulk originally, which saves me some bother.

[rodfac]

No difference over my chronograph nor on the target out to 50 yds. Rod

[briandg]

I can see no reason for a problem. A .357 lights efficiently with a small primer. Charges for .45 are similar in weight, iirc. The high volume case of larger bore high capacity rounds really need a slightly larger starter charge, I suspect.


Bottom line is that ammo makers spent years, testing literally hundreds of thousands of rounds before releasing the change. There doesn't seem to be any cost benefit to the change, is there? If the ammo makers aren't saving money, why would they go to the trouble of changing such an important thing?



If there isn't a cost incentive, there is another reason to completely overturn the status quo. The only reason to do this, unless they are literally saving hundreds of thousands of dollars, is that they find that it works better.

That's it, simply put. I can't see that it is cheaper to make them. Retooling cost a fortune. Occams razor stipulates that the only other reason can be is that they work better, even if the improvement isn't even visible to casual observers.

[mikld]

A very common question... https://search.yahoo.com/yhs/search;...%3D%3D&iscqry=

[Rifletom]

No meaningful difference. Like poster #2 said, over the screens and at the target, can't tell any difference. Load and shoot away. FWIW, I use Clays or Unique with CCI/SPP and LPP.

[Bayou]

Same my way - I can discern no difference between the two....

Bayou

[briandg]

Where exactly do these come from, anyway? Any specific makers?

[Chainsaw.]

I use 45 as trading stock for other brass, I always go through and remove any messed up cases to be a good trader, in my cullings I have found blazer brass to be the more common to come with SPP.

[briandg]

It's certainly not an issue of economics. I do wonder why. One of the possibilities that have come to mind is that the cartridge capacity is small enough that it just doesn't need a large primer. The only reason that it was designed with a lArge primer is that the big case head of other rounds were, and no change was necessary.
It is probable that the enormous improvements in priming compounds and design have made large primers for that cartridge literally obsolete.

[snuffy]

^^^^^^^^^^^^^^^^^
And they produce higher pressure right in the front of the primer pocket. This was causing the primers to back out of the pockets. The flash holes had to be enlarged as well.

As for economics, if they only had to stock small primers, they could save money on storage. Also converting from small to large primer feeders on the loaders in an ammo factory is even harder than it is for us on our machines.

This Steve guy sure was all shook up about unburned powder. It simply is of no legitimate concern. Unless and until it causes problems with chambering. But it would have to be really excessive to do that.

I remember H-2400 powder causing problems when excessive amounts of unburned flakes preventing .357 revolvers from closing the cylinder completely. Usually happened with starting loads, or not enough roll crimp.

It looked like he was shooting off-hand while testing those rounds. His accuracy results are therefore of little use. As well as his velocity results.* I would never give out how big off-hand groups are for accuracy reasons because I just can't shoot good groups while standing. Neither can anybody else!

* How you hold any gun relates to your recorded velocity. If his grip was tight and EXACTLY the same each time, then okay. But he would have added a bit of velocity across the board if he would have sat down and shot off a rest.

[Don Fischer]

Just a guess but I'd bet there's a reason some primer's are designated rifle and other 's pistol!

[briandg]

I don't know if the ransom rest is still used, but one way or another, the serious testing labs will go to any length to insure consistency from shot to shot, year after year, even, to eliminate every possible bit of inconsistency, just as snuffy said. There is a practice at some labs of using bolt receivers with changeable barrels that are bolted rock solid on tables. Pressure testing mostly, because I suppose that it would be really time consuming to burn through cases of ammo testing accuracy or other problems, like velocity spread.

Testing by hand should never be taken very seriously but it has its place as casual information gathering and sharing.

Twenty some years ago there was a guy who did "professional testing". This guy got a "super durable" scope. To test it, we screwed it to a board and threw it down a hill a dozen times. Then, he set it on the ground and drove over the objective bell with a minivan. Several other things.

he didn't test until after he tried to destroy it. He was pleased that accuracy and performance were adequate.

This isn't science, and science is what makes this information useable.

[Unclenick]

Yes. Rifles generally shoot at higher pressures than handguns do, so the rifle primer cups are generally thicker. The firing pins for higher pressure guns are generally are assumed to have higher striking energy than, say, a target pistol firing pin, and the extra energy strikes through the thicker brass cup better. That said, a board member claimed to have got from CCI that their standard small rifle primers and their small pistol magnum primers for higher pressure handgun cartridges had the same priming mix and cups, and that they were interchangeable. I have not confirmed this, but you are welcome to ask them.

The comparison to a magnum primer means the rifle primers will make a larger volume of gas, though they sometimes do it more slowly. In some testing this reduces pressure and velocity and in some it increases both. I recommend working the load back up from about 5% reduction when you change primers. When you have adjusted the powder charge to produce the same average velocity as the original primer produced, see if the velocity SD for at least ten rounds (20 is better) over the chronograph has increased or decreased as compared to the original load. SD is a very telling number in that if, for a given velocity, it gets better, your ignition is more consistent. If it gets worse, ignition is less consistent. In a handgun you don't usually mind that velocity varies a bit from the standpoint of what the bullet does at impact or how well it shoots from a machine rest. What is a practical concern is that wider SD's mean the total lock plus barrel time is varying, often more than is proportional to the velocity variation. Ignition delays, in addition to barrel time increase, that are on the order of the lock time of the weapon can occur if ignition is erratic. That's enough time for small disturbances in your hold to make a difference to group size and shot placement on the target.

[briandg]

A rifle in many cases will have a bolt or pin much heavier than the equivalent sticker or hammer, springs seem to be heavier, in general, and if tested, in general, it would probably be found that rifle actions will hit the primers with far more energy. I still don't believe that higher pressures or pin impact can ordinarily cause a failure of a primer cup. There is always a primer dent, an imprint of the bolt face, and a solid grip by the primer wall to the brass, right? That primer is literally supported everywhere. It would take a very thin metal to fail. The things are made to be far stronger than they need to be to survive handling.

One of the things that I have read is that some priming compounds generate only flame. Others are designed with flammable particles that throw sparks far forward of the flame to aid in quicker full charge ignition.

Don't ask me if it's true, a manufacturer provider the information along with photographs to demonstrate, but I have no evidence.

[XDmShooter]

I went to the range yesterday to test this. I made 10 rounds each of small and large primed 45 ACP. I used 5.8 grains of Win231 powder, with 200 grain powder coated lead bullets. I made the first 10 rounds with the small primers, and then all I changed was the primer feed tray and ramp. Then I made the 10 rounds of large primed rounds. I was using a Lee turret press, with the Autodisk powder measure system. I did not remove the powder measure system when changing the primer feeds.

I fired them over the chronic, and the small primed rounds averaged 810 FPS, with a deviation of 25.32 FPS. The large primed rounds averaged 924 FPS with a deviation of 16.23 FPS.

That is a difference of %14. Such a large difference that I will adjust my recipe if I use large primers.

My conclusion is that there IS a difference in performance with the different primers.

[std7mag]

So we manufacture new casings. There are 380auto, 9mm Luger, 40 S&W, 10mm, and lastly 45ACP.
The 45 is the only one to use large primers (that i'm awsre of).
You already have the tooling set up to do small primers, why another set of tooling, and the labor tome it takes to change it over?
Not to mention the larger bulk buying of the small primers, storage area, etc...

[Slamfire]

I shoot Bullseye Pistol and the real experts tell me that there is no difference in velocity or accuracy going from large to small, or small to large.

However, most everyone has heard of progressive presses blowing up when small primer brass is loaded when the progressive press is set up with large pistol primers. One shooter, he saw some pictures of a Dillion 1050 that disassembled, and he told me that he could not believe the damage that occurred. It must have been spectacular.

This is another situation where industry off sets their costs on society. The reloading industry is making higher profits using cheaper primers but selling us the loaded ammunition for the same amount, and we, we have costly accidents when small primer brass gets mixed in with large primer brass.

[Stats Shooter]

So we manufacture new casings. There are 380auto, 9mm Luger, 40 S&W, 10mm, and lastly 45ACP.

The 10 mm uses LP primers boss... Often the LP magnum primers due to the pressure of the cartridge.