.357 mag tumbling through the air ??


December 3, 2008, 11:43 AM
I just made my first reloads in .357 magnum. Took them out back to see how they grouped. Shot only one group of 6...TERRIBLE!!! At 10-15 yards had about and 8-10 inch group about 8 inches low on the target. I shot them from a Ruger Vaquero with a 4-5/8" barrel that groups well w/ factory ammo. At closer inspection all but one bullet imprinted sideways on the target. What the the heck did i do wrong? the recipe for the cartridge was:

* A mix of brass. lubed, Sized, tumbled, trimmed, and de-burred
* Bulk lead round nose 125 gr in .357
* 7.9 grains of Unique
* CCI 500 small pistol primers
* I decided not to crimp these.
* Overall length was 1.590"

If you enjoyed reading about ".357 mag tumbling through the air ??" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
December 3, 2008, 11:57 AM
My guess is the bullet is either undersize or you're pushing them too fast, and they're stripping the rifling. Try backing off with the powder charge and see if that helps. You should also measure the diameter of the bullets and see what size they actually are. I size mine at .358" for both .38's and .357 Magnum.

Hope this helps.


December 3, 2008, 01:01 PM

7.2 grains is going to give you over 1,000 - 1,100 FPS.
If they are commercial soft-swaged bullets, they might be too soft to handle that kind of speed without stripping the rifling. A 125 grain .357" bullet doesn't have a lot of bearing surface in contact with the rifling!

Check for severe barrel leading right in front of the forcing cone and get back too us.

In the meantime, try loading them with about 4.5 - 5.0 grains of Unique, crimped at least some, and see how that does.


December 3, 2008, 03:17 PM
what does stripping the rifling mean? sounds like i'm wrecking my barrel? It'll probably be a few days till i get a chance to really look that gun over good. What am i looking for as far as "severe barrel leading" ? This is my first reload with lead, and i've only done a couple hundered rifle rounds in copper before this, sorry, just not real experienced.


December 3, 2008, 03:23 PM
It just means the rifling can't "get a grip" on the soft bullet and it slides straight forward a ways before it can get up to rotational speed. That leaves bullet lead stuck/soldered between the lands & grooves of the barrel.

So, it "stripped the rifling engraving" off the soft bullet instead of starting to spin the instant it hit the rifling.

The only harm done is a leaded barrel which you can clean, and tumbling bullets that don't shoot straight.


December 3, 2008, 04:12 PM
Sorry for the confusion. RC's explanation is a good one. Those of us who have been reloading for awhile sometimes throw out terms, not realizing that we might be talking to someone who is just starting out.

If you push a soft bullet too fast, it doesn't have the structural strength to maintain a grip on the rifling in the barrel, and will push straight through. There's no harm to the barrel, as rc noted.

You'll do better with 158 grain bullets in the .357 Magnum when just starting out. There are tons of loading data for that weight and the bullet is more forgiving than one with very little bearing surface, which is the amount of surface actually in contact with the barrel.

Hope this helps.


December 3, 2008, 08:20 PM
it sure does help, thanks for the info. So those bullets i used in the .357mag load earlier, they probably won't be real good in a 38 special because of the diameter? I originally bought those bullets for my 9mm pistol and it sounds like they should be good for that as long as i keep them under 1000 fps?

December 3, 2008, 08:40 PM
I kind of thought they may have been 9mm bullets from what you described. You don't see too many 125 grain ROUND NOSE .38 bullets. Most in that weight are Round Nose Flat Point or Semi Wadcutter in shape, and will usually be .358" in diameter, though I do see them occasionally at .357" diameter.

They will shoot fine in the 9x19 (9mm Luger). You can probably load them to a little over 1,000 fps, but not much, since most data holds them right around that velocity. There are some loads that push them over 1,100 fps, though.

Hope this helps.


December 3, 2008, 09:43 PM
You might also try changing your target to see if the bullets are really tumbling and not just tearing the paper. Shoot into a piece of cardboard or staple your target to a cardboard backer to support it. You may have innacuracy problems and not tumbling.

Can you shoot one of these bullets into a line of milk jugs full of water and retrieve it to look at the rifling marks?

December 3, 2008, 09:51 PM
I originally bought those bullets for my 9mm pistol and it sounds like they should be good for that as long as i keep them under 1000 fps?

I think this is where your problem lies. You are using 9mm bullets that are probably sized to .355 - .356, definitely undersized for 357 magnum/.38 special.

Use only bullets for 357mag/.38 spl, which have been sized to a minimum .357 inch, preferably .358 inch.

December 4, 2008, 07:32 AM
yeah, i originally bought them about 6 months ago for 9mm rounds. Thats what had me confused i think... The box said "09mm .357". When i got home my reloading manual said to use .356 diameter for 9mm so (not knowing with lead bullets you actually need that extra bullet width) it seemed like those bullets would be better suited for my 38 or 357mag. I'll just be using those for a 9mm plinking round now. Thanks! Also, the target i was shooting at was cardboard. I also took the cylinder out lastnight to look down the barrel and it was pretty damn dirty in there, a little more so at the thoat as mentioned.

December 4, 2008, 10:11 AM
Yep, you can't use the 9mm rounds in a .357. Get some jacketed, flat point wadcutters for the .357 and load those using your recipe. I use the same load out of a 6" Colt Peacekeeper and get excellent accuracy and performance. If you are going to be using soft lead wadcutters, you should think about getting some Bullseye powder and loading light. Keep the FPS down to 900 or less.

Ben Shepherd
December 4, 2008, 10:42 AM
Yes sir. Those are too small. They just slid down the barrel without spinning. When they exited the muzzle, the heavy end tried to get around to the front.

December 4, 2008, 10:57 AM
125 .356 bullets will work in a .357 had BIL give me a bunch of speer swaged 9mm bullets 125 gr .356 dia I loaded them over 3 gr of 231 they were fairly accurate.
the 7.9 unique is the problem your probably near 1200fps with a soft lead bullets this is going to lead very fast and cause your problem.
if you back off to 5gr maybe 6 at the top it should work much better.
BTW I'd imagine you'll need to clean the lead out before anything's gonna work.

If you enjoyed reading about ".357 mag tumbling through the air ??" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!