Different question about wadcutters....

[Harry O]

I have a light .38 Special 148gr wadcutter load I have been using for many years. It is exceedingly accurate in most of my guns. It is a Lyman 358395 Hollow-Base cast soft at about Bhn 7 to 8, sized at 0.359", with 2.8gr of Bullseye, SPG lube, and a light crimp. Before the Obama shortages, I used swaged Hornady 148gr hollow-base wadcutters with the same load.

One of my guns hates it. The gun is a S&W 642, J-frame airweight with a 1-7/8" barrel. Naturally, it is DAO so I cannot directly compare group sizes with DA/SA revolvers. However, I can compare the group sizes in it, with several other loads I have. The lightweight .38 Special load has a group size that is about 3 times larger than a different load I use with the same gun. It is a 125gr JHP with 4.4gr of Bullseye. I also have another common load, being a Lyman 358477-HP cast harder at about Bhn 10-11, sized at 0.358", with 6.2gr of HS-6, NRA lube, and a heavier crimp (this has considerably more recoil in the airweight). The light load has a group size that is about 2 times larger that this load.

The 642 is accurate enough for a short barrel belly gun, with any other load I use. The light .38 Special load is accurate in any of my other guns (they all have longer barrels, from 4" to 6". S&W's. Colts, and Rugers). They are also accurate with my other, heavier loads. However, the light load and the 642 do not work together well. I wonder if the short barrel cannot stabilize the bullet. Does anyone else have this kind of a problem with short barrel guns?

[TexasGrunt]

As I was reading your post I was thinking the barrel might be too short for the load. Have you slugged the barrel?

[Scharfschuetze]

Of all the loads you mention, that Wadcutter load should shoot well in your 642. My model 60s all shoot a similar load (148 WC and 2.7gr BE) exceedingly well. The short barrel will show the least velocity loss in comparison to all barrel lengths with the 2.8 grains of Bullseye. In addition a 1" long barrel or your 1 7/8" barrel with the S&W twist will shoot just as rotationally fast as an 8" long S&W barrel with the same pitch rifling at the same velocity. Barrel rifling twist rotates a bullet the same in any barrel length of the same twist if at the same velocity.

The S&W 1 in 18 3/4" twist is marginal for HBWC bullets at lower velocities. Perhaps if you up your load to 3.0 grains of BE you'll get to a velocity and rotational speed where the long HBWC is stabilized fully.

Here's another thread on wadcutters:

http://castboolits.gunloads.com/showthread.php?325023-Why-do-wadcutters-generally-group-the-best

[Outpost75]

I agree with increasing the powder charge slightly to improve grouping with cast wadcutters in the .38 snubby. I have found that with soft 8BHN alloy the "full charge" wadcutter does very well, but if you don't want the heavier recoil a charge of 3.0-3.2 grains should do the trick. My experience has been that the slow twist S&W barrels need a bit more velocity to prevent the wadcutters from yawing at 7 yards, but the Colts produce round bullet holes!

[Harry O]

As I was reading your post I was thinking the barrel might be too short for the load. Have you slugged the barrel?

No I haven't. I should. I thought that since it was much more accurate with the other loads, that it would not be a problem. I'll get it done tomorrow.

[Harry O]

My experience has been that the slow twist S&W barrels need a bit more velocity to prevent the wadcutters from yawing at 7 yards, but the Colts produce round bullet holes!

My Colt .38 Specials have a smaller groove diameter than my S&W's. The two that I have measure 0.355" to 0.356" ID. My S&W's (a dozen or so) have 0.357" barrels. All of my handloads are sized for the S&W's. They shoot well enough in the Colt's, but are just slightly less accurate.

[runfiverun]

looks like I don't need to say add more powder.

[Scharfschuetze]

My Colt .38 Specials have a smaller groove diameter than my S&W's. The two that I have measure 0.355" to 0.356" ID. My S&W's (a dozen or so) have 0.357" barrels. All of my handloads are sized for the S&W's. They shoot well enough in the Colt's, but are just slightly less accurate.

Very true that, and I also size for the Smiths even though I still shoot a nice Colt from time to time. Colt revolvers also enjoy a faster rifling twist than the S&W revolvers and this is probably where the increased performance with HBWCs come into play. With the long for weight and calibre HBWC, the S&Ws are challenged at lower velocities with the HBWC (stability-see Outpost's post above) while the Colt and their 1 in 14" twist handle the HBWC in a stellar manner.

That's one of the reasons the Colt Pythons did well in PPC competition and the custom open class PPC revolvers usually had a 1 in 16" or even a 1 in 14" twist.

For adequate stability the three options are usually:

A shorter bullet for the calibre (a solid WC v. a HBWC)
A faster rifling twist
Higher velocity

You'll get it sorted out I'm sure. The little J Frame Smiths can be exceptional shooters and really often belie their small size with performance on the target range.

Just a quick note about going with too high a powder charge. HBWCs when pushed very fast can often loose their skirt and leave it in the barrel. No need to hot rod them, but go up in charge weight just enough to obtain accuracy..

[Harry O]

I slugged the barrel of the 642 today. The problem is not the diameter. It was 0.357" to a hair over, just like my other S&W's. It must be the velocity vs bullet length that was mentioned here. I have a bunch of solid base 148gr wadcutters (shorter) that I might try. If that doesn't work, I will up the velocity of the solid base ones. My hollow-base bullets are cast at about 50:1 (3lbs of pure lead and a couple of ounces of 50-50 solder). I don't think I want to up the velocity of them.

[BigDanS]

In my humble opinion your problem is your lead. That barrel is 1.875 inches long on your 642. In order for a bullet to spin it has to grab the rifling and twist, and softer lead is going to "slide" before it grabs and spins. Try harder lead and failing that , try softer.

D

[centershot]

I can't believe that no one has asked this, but, what is the inside diameter of the cylinder throats? If they mike smaller than the barrel I.D. that may be your problem.

[GrizzLeeBear]

In my humble opinion your problem is your lead. That barrel is 1.875 inches long on your 642. In order for a bullet to spin it has to grab the rifling and twist, and softer lead is going to "slide" before it grabs and spins. Try harder lead and failing that , try softer.

D

I doubt its the soft lead at the low velocity of his load. Dead soft swaged lead HBWC with around 2.8 gr. of bullseye has been the standard target load and been shot accurately in bullseye competition for DECADES. With these loads in 4 and 6 inch barrels HBWC are on the ragged edge of stability and start to tumble past 50 yards. I agree that your best bet is to work the powder charge up gradually to get the velocity back up to what you would get out of the longer barrel with the light load.

[GooseGestapo]

I'm going to suggest large charge hole throats.
Ive got a 640 that's astonishing accurate with Lee 148gr tlwc over 2.8gr of Bullseye which is my standard PPC practice/short range Match load. For 50yd matches I use a Precision Delta 148gr HBWC.

Bumping up the charge to 3.2-3.4 MIGHT do the trick. However, try some unsized and see if that helps. Also, softer lead alloy.