Magnum Primers & Fouling

[robertbank]

A friend of mine in Texas has posed a question to me that we thought we could find the answer to amongst members of this forum. Will the use of magum pistol powders in the 9MM case reduce the amount of soot and fouling from lube and powder?

We both size our bullets for the FN Hi-Power to .357 and have very good results both from an accuracy point of view and consistancy (velocity). After his recent shooting session using magnum primers he noticed a distinct difference in cleanliness of his gun.

Take Care

Bob

[Firebird]

It depends, on the primer, the powder and the cartridge.

Remington has said that there is no difference in the amount of primer compound between there small pistol and small pistol magnum primers, the magnum primer just has a heavier/stronger metal cup to handle the higher pressures of magnum pistol cartridges. The 9mm pressure level is at the higher 35-36,000 psi magnum pressure levels; not the lower 38 Special/45 ACP pressure levels of 15-18,000 psi so it does make sense to use a magnum primer from a pressure standpoint.
Other primer manufacturers use more primer compound or a hotter mix of primer compound in their magnum primers. The hotter primers seem to work better with the slower ball powders that can be difficult to ignite like H110/W296, while stick or flake powders like 2400 sometimes actually work better with the standard primers, exhibiting more consistant velocities etc.

It's best to use what the manual says for the load, that way you know the primer is up to containing the pressure levels and matches the powder type. If you want to experiment then follow the safety guidelines for a new load componant and re-work the load from the minimum powder level; don't just switch primers.

[robertbank]

Thanks thats what I was looking for. In my testing I have found little difference in performance between the two types of primers. We aren't using top end loads and are well under maximums using the 9MM case.

Take Care

Bob

[Bass Ackward]

You just can't say for sure. Things change based on flash hole sizes and firing pins strikes along with headspace and yada, yada, yada. Sometimes a longer burning, cool primer can provide better ignition than a short, hot spark from a magnum.

Just prime empty cases with different primers. Chamber each one at a time and hold the gun vertical. Place a penny on top of the barrel. Then pull the trigger. Watch how high the penny goes and you can decide what primer you may want to try from what you were using.

Primers can and will differ from batch to batch within the same brand. Results will be different in different calibers too. I have seen standard primers hotter than magnums. You simply have to try the batches you have on hand to know. You will visually see a difference.

[Oregunner]

I had an interesting result from an experiment I did a few weeks ago regarding magnum vs. standard primers. I was working with a new Contender barrel in .45 Colt. I had loaded six each of 16, 17, 18, 19 & 20 grains of IMR 4227 under a 250 grain Lee SWC, CCI LP primers. I shot a three shot group with each over my little Chrony. 16 grains gave a 2" +/- group @25 yards. 17 grains was smaller & 18 grains was magic! The first group was just over a quarter inch. 19 & 20 grains started to open the groups back up. Then I went back through & did them all a second time with nearly identical results. The 18 grain group was just over .3". However, I had quite a bit of what appeared to be unburned powder laying around from all the loads. In the cases, in the barrel, there was even some in the Chrony!

So I decided to try CCI magnum primers. The average velocity was about the same. There was somewhat less unburned powder. The standard deviation was quite a bit less, but the groups were 2"-3" . I tried several times with the same result.

I have no explanation but that's what happened. I might try some different brand magnum primers at some point but for the moment it's back to standard primers & I don't care if there's some powder laying around, as long as the boolits go in one hole.

[robertbank]

You say you shot the loads over your Chrony. Was there a velocity difference between the use of magnum and regular primers given the same powder charge? I ask this because IF there was a difference this might just be a case where your gun is at it's best at x FPS achieved by Y+1 gr using the regular primers and only Y gr using magnum.

Take Care

Bob

[felix]

Also, keep in mind about primer strike by the hammer. A tougher primer as seen by the hammer (spring) will be less potent, and sometimes by quite a bit. So, the primer "powder" mix might not even play that much in accuracy attainment across brands/lots. In general for certain, you can only compare primers that are on your bench. I buy primers these days mostly based upon on how they fit the cases I have. I like a tighter feel just because it makes me feel mobetta. It seems the quality control within a brand for external quality is tighter than for chemical mix. ... felix

[AZ-Stew]

I have no explanation but that's what happened. I might try some different brand magnum primers at some point but for the moment it's back to standard primers & I don't care if there's some powder laying around, as long as the boolits go in one hole.

Oregunner,

You have achieved True Enlightenment, Grasshopper. :idea:

To many reloaders, Nirvana is clean brass and a shiny bore after a shooting session. To some of the rest of us, it's one-hole groups. Personally, I'd much rather toss some sooty cases into the tumbler and wipe some fouling out of my barrel (I have to clean it anyway) than be able to brag about how "clean" my loads are while spraying shots all over the landscape.

The Elmer Keith classic load of 22 grains of 2400 with his design of SWC bullet, primed with standard pistol primers is consistently accurate in all guns I've used it in, but it ALWAYS leaves bunches of unburnt kernels of powder in the barrel. If they're there after the last shot, they're there after the first shot, meaning that from the second shot to the last, I'm not only pushing the bullet out the barrel, but also a bunch of unburnt powder kernels. This does no damage to the gun and doesn't affect accuracy. I plan to stick with it (with the charge adjusted for today's faster-burning lots of 2400).

My .41 Magnum load of a Keith-style 215gr SWC over 6.7 grains of IMR 7625 (gray can) and a standard primer is also keenly accurate and produces 950 fps. The empties drop out of the open cylinder when the muzzle is raised, but the cases usually come out about 1/3 covered in black soot. I suspect that part of it is powder soot and part is burnt bullet lube (Lyman Alox), but who cares? It's accurate, easy to shoot and very easy on the brass.

"Clean" is nice, but in my opinion, accuracy is far more important and is the first goal of all my handloading.

Regards,

Stew

[BluesBear]

I'm currently in the middle of a primer testing project.
(Currently on hold awaiting a new chrono)
One thing I noticed in my research is the lack of information regarding primers from different manufacturers.
We've all heard the old adage whenever you change ANY component reduce your load and then work back up.

But in reality there are a lot of people who bypass that part. Even the more enlightented reloaders who finally got the memo that seating depth affects the combustion chamber volume and therefore it will alter velocity/pressure.

But there's still many who figure a primer is a primer.

A good example I've been using recently is the load data for the new Trail Boss powder.

The 2006 IMR handbook shows;
125gr Lead Flat Point bullet + 5.3gr Trail Boss

952fps@13,400CUP in a .38 Special case
1035fps@79,900CUP in a .357 Magnum case

It then shows;
158gr Lead Flat Point bullet + 4.2gr Trail Boss

804fps@13,400CUP in a .38 Special case
865fps@17,900CUP in a .357 Magnum case

Now a larger combustion chamber SHOULD create lower velocity and lower pressure.

All things being equal.

However if you go to their website THERE it shows that the .38 Special loads used Winchester Small Pistol primers (WSP) and the .357 loads used Winchester Small Pistol Magnum primers (WSPM)
So in this example a different primer made a noticable difference.
If you used the WSPM primer in the .38 Special case you could have a real problem.



Now this info is based strictly on IMR published information. The printed handbook has typographical errors that incorrectly shows the .38 Special pressures in PSI whereas the website shows it in the correct CUP format. (verified via telephone)

[boogerred]

robert-i regularlly shoot a lyman 358429 over 2400 in my 357 ruger.after several hundred rds i got bit by the clean bug and tried some mag primers.much like orygunner i found mag primers opened up the groups. with std primers i could 3.5" groups at 30 yds often with 3 or 4 touching or nearly so. with mag primers i still got 3.5" groups but with none touchin. the bore and cases are cleaner. the mags also seemed to have a bit more kick and roar and a bit of primer flattening.