Bullets Tumbling....What's Up?


November 6, 2008, 07:20 PM
I shot my new S&W 642 for the first time this week. AT 7 yards a number of my handloaded bullets appeared to be tumbling (ugly holes in the target)

I'm loading 158gr RN Lead bullets using 3.6 - 4.2 grains of W231 powder...with OAL at 1.455

I"m fairly new to reloading...but to date have been pretty successful with making loads. This is the first time I've experienced any tumbling...but also the first time I've shot the snubby

What can I do to improve the bullet flight? what factors do I consider?


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November 6, 2008, 07:36 PM
Your cast bullets may not be fat enough. If they don't get grabbed by the rifling then they won't stabalize.

35 Whelen
November 6, 2008, 07:37 PM
Slug the throat of your cylinder, then your barrel. I bet you'll find that the throats are smaller in diameter than the grooves of the barrel. In this case, what happens with a lead bullet is that when it leaves the cartridges case, it is squeezed down to the diameter of the cylinder throat. If the throat measures, say, .355", then the bullet enters the barrel measuring .355". And with a barrel with a groove diameter of .358" or .359", then you're firing a very undersized bullet through the barrel.
This is not a problem with jacketed bullets as their jackets tend to spring back into shape after leaving the cylinder plus a slightly undersized jacketed bullet will normally shoot OK because it engages the rifling more easily than a soft lead bullet.
So, your assignment is to slug your cylinder throat with a soft lead bullet (NOT commercial cast) and report back to us!

November 6, 2008, 07:59 PM
Check for an undersize bullet. Normal bullet diameter is .357" to .358" Hodgdons website lists a maximum powder charge of 3.7gr of W231 with a 158gr Lead bullet for the 38 special. Load a few with 3.1 gr starting load, see what happens.

November 6, 2008, 08:20 PM
I doubt it's your charge that's causing the bullet to tumble. Usually a bullet that's traveling too slow will tumble but your recipe should be fine. One of my favorite loads is a 158gr LSWC over a charge of 4.0gr w231.

November 6, 2008, 09:33 PM
I love that folks on the HighRoad are willing to share their knowledge.....

A bit more info....I just sampled 10 of my MasterCast Bullets....they were all right at .358".....

As far as checking the actual diameter of the throat and bore....I've never done that..and dont have any soft lead bullets......I'll have to figure that out

Thanks guys....at least now I understand a bit more about how to diagnose the problem.....Thanks Whelen35 for the lesson

take care guys....

November 6, 2008, 11:18 PM
Just drop a new cast bullet into the chamber and see if you can push it through the cylinder throat with a wooden dowel. A bullet properly sized for the throat should push through without a whole lot of force. If you've got a few bullets with different diameters you can use them a pin gauges to check the throat diameter. As mentioned above the throat should not be smaller than the groove diameter of the barrel.

S&W's don't have a reputation for small throats, but I suppose it could happen.

What kind of target are you using? You may want to verify the bullets are really tumbling and not just hitting the paper too slow to cut a clean hole. Try gluing the target paper to a sheet of cardboard or pasteboard (like the back of a notepad). With a proper target backing the holes might clean up nicely. For instance, I've noticed that copy paper doesn't make a very good target unless it is has some support from behind.

November 7, 2008, 02:19 AM
That's not a bad idea. It is possible if he's shooting at paper without a backing he's tearing the paper and it only looks like the bullet is tumbling. I'm guessing even shooting at a thick piece of cardboard will let him know if the bullet holes will clean up or not. Good idea Sport45....

November 7, 2008, 06:07 AM
The groove diameter of the barrel can be checked by just recovering some fired bullets from the backstop and measuring them. If you start with .358" bullets and the reclamied ones are smaller in diameter, then you will know what you groove diameter is. And as said above, take you .358" diameter bullet and see if it fits the barrel side of the throat of the cylinder. This will be very tight, at most you will have clearence of only .001", so the .358" bullet will have to be perfectly aligned to enter the throat.

November 7, 2008, 09:22 AM
Sport45 may have hit on it....

I was using crappy paper targets hanging from a couple clips....

Tomorrow I'll put some cardboard backing and see what I get

Pushing a bullet through the chamber and the throat also sounds like a good approach

thanks guys!

November 8, 2008, 02:10 PM
Go down to wal mart and get egg shaped fishing weights and use those instead of cast bullets, they're soft and will go through easily. Use some wheel bearing grease to help lube things and a hardwood dowel road to help you push, along with a small hammer to tap the dowel rod with.



pilot teacher
November 8, 2008, 02:20 PM
Have you tried factory loads?
Also, if they are reloaded rounds the possibility exists that they are too hot for the lead hardness. A soft bullet might be stripping. Then again for self self defense at close up range it would rip some hole in the assailant.:D

If you discover the reason be sure to let us know.

November 8, 2008, 08:00 PM
It was the targets.

Because I was using large targets of cheap paper, just hanging....it cause the bullet to make a "key hole".....

I shot 40 rounds of the same loads today at a cardboard target...and all was well.....

Thanks one and all....if nothing else I've learned the value of putting a backing on my targets and how to slug a chamber and barrel.

Thanks guys.

November 8, 2008, 08:49 PM
Glad it worked out.

I imagine 90%, if not more, of the short range "tumbling" issues are really problems with the target rather than the gun or bullet/load. No telling how much time, money, and effort is spent by gun owners (including myself) fixing non-problems. I'll admit to spending good money to make a 1991A1 unreliable by adding a full-length guide rod, "better" recoil and sear springs, aftermarket trigger, sear and hammer, etc. I should have left the thing alone and been happy with it.

November 8, 2008, 10:39 PM
"...ugly holes in the target..." As in not clean, round holes? RN's will do that. If you want clean holes, load WC's or SWC's.

pilot teacher
November 9, 2008, 11:10 AM
See how much we can learn by sharing on the forum.
It's my experience that THR is the best one yet.:D

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