IMR 4227 not getting complete burn

Looks like you have a Blackhawk. Strong gun. If it were me, I'd up the charge a little. The Hodgdon website says 16.0gr for a 158gr jacketed bullet (Lyman 50th has it at 16.1gr). I haven't shot too much 4227, just 1lb of it. But the kernels disappear with higher charges and higher pressure.

My understanding is that a magnum primer raises the pressure. My personal point of view is that I'd rather raise the pressure with more powder instead.

Up the charge but I have never not gotten leftover kernels in any load with 4227 in 357. They do get under the ejector star in my smiths but as long as they don't get in the action and crunch it should be ok.

Maybe more crimp would help?

One of the reasons I just never warmed up to 4227. The unburned kernals dissipate as you get closer to maximum.
It’s not as popular as it was 30-40yrs ago before. #2400 has been reformulated to clean it up, and everyone knows to not reduce H110/296 more than 3%.

You might try a magnum primer, too.

I had the same results as you. My fix was going back to H110.

Go higher on the charge. Or quicker powder.


Looks like short 4.5 or 5.5 barrel

I always used a Magnum PP when I used 4227 in 357 Magnum loads but have not used it in years. I might start as a friend has offered me 4-5 lbs for free so I might play around with it. Its been many years since I loaded 4227. I just get better results with H110 and 2400.

I have always used magnum primers with 4227. You also need a good crimp and I always load it at least at a mid- range charge level for the bjllet being used

I use 4227 with a magnum primer, a heavy roll crimp, and at or near max on weight. It's a very compressed load.
It's a safe powder, in that I dont think it's possible to cram so much in a 357 case to make it unsafe.
same rule for 44 mag and 30 carbine.

Even at max with good crimp and mag primer it’s leaves kernels in my 44mag carbine.

I recently asked this here, https://thefiringline.com/forums/showthread.php?t=602691 can't say that it applies here, but?

Eject brass with muzzle pointing up.

The only time I use 4227 is in the 308w/cast bullet combo anymore.

In the 357mag 4227 likes hot primers and Heavy loads/bullets/crimps.

Arkansas Paul said:

. . . IMR 4227. . .

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I never could get complete burn in any of the pistol cartridges I tried. It improved with pressure, but never entirely cleared up.

edwardware said:

I never could get complete burn in any of the pistol cartridges I tried. It improved with pressure, but never entirely cleared up.

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I made pretty much the same assessment this year. I love IMR4227 for pistol cartridges in rifles (my primary use is .41 Magnum in my 20" Marlin) but not so much in pistols. I've experimented with both the .45 Colt and .41MAG and IMR4227 in pistols, and while it works, in my opinion it is not the best choice.

WrongHanded said:

My understanding is that a magnum primer raises the pressure. My personal point of view is that I'd rather raise the pressure with more powder instead.

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The use of a magnum primer isn't meant to raise the pressure, it is meant to cause a more complete powder burn. The pressure increase is associated with the increased brisance of the magnum primer.

ArchAngelCD said:

The use of a magnum primer isn't meant to raise the pressure, it is meant to cause a more complete powder burn. The pressure increase is associated with the increased brisance of the magnum primer.

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I know a magnum primer isn't meant to raise the pressure, but it does anyway doesn't it? From the testing I've read, using magnum and standard primers in a side by side comparison, I seem to recall they raised the pressure, but didn't necessarily increase velocities all that much, and in some cases increased the standard deviation of the tested loads. This was of course with powders that do not require a magnum primer.

I'm not saying a magnum primer won't solve the problem (I have no personal experience there). I'm just saying I'd prefer to up that charge within tested data limits, and see if that works.

All interesting stuff. I own quite a bit of 4227 but I haven't yet loaded any into a pistol/straightwall case. I use mine for .300 Blackout and it performs very well. The case capacity seems to be roughly the same in that cartridge and the .357, but the Blackout has a slight bottleneck that is apparently bumping up the pressure just enough that I have never seen the phenomenon being described here.

I did an experiment with primers, IMR4227, and my .41 Marlin... generically speaking, standard, Winchester (either/or,) and Magnum primers made very little difference in fps readings out of the 20" Marlin. I will have to look at my data (which is in NV right now...) to see if it increased SD... I don't remember.

I've also done an informal test with standard vs magnum primers in the 5.56mm and H335 (some load data suggests a magnum primer with this ball powder.) Under a 55grn bullet, the standard primer gave better velocity and lower SD vs the Magnum primer in both my 20" Colt AR and my 16" LRB carbine.

What does all this mean? Nothing. If it's questionable that a magnum or standard primer might be better, go for it... it might work better for you, or it might not.

From a previous post...

I also did the same type work up with IMR4227 in the .41 Magnum... I had some question about using a magnum primer there, it seems the internet consensus is split about 50/50 on it. I found, with a 20grn charge of IMR4227 under a cast 215grn bullet, fired from my 20" Marlin, the CCI standard primers had lower SD than the WLP (standard or magnum, as advertised,) and the Federal magnum primer... all else being equal. I acknowledge that going up or down 1-2grn of powder might change that equation... you never know... which is why I don't typically make blanket standards for reloading.

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