686 Snub- Powder Question

[texasjarhead]

If loading .358 125gr FN bullets in 38 special cases, can I expect more accuracy by using Unique or Win 231 at comparable muzzle velocities?
There doesn't seem that much difference in these two powders on the burn rate chart.

Or--- should I be using a faster/slower powder for this 2.5" barrel for a particular reason? (I plan to shoot at 25 yards or less).

Could I expect better or worse accuracy using 357 magnum loadings (More velocity from a short barrel?)

I truly appreciate all the EXCELLENT responses I've gotten to my questions on this forum. I particularly appreciate the fact members are speaking from experience, which I don't have much of when it comes to reloading, but love to learn.

 

[Snapping Twig]

The biggest single thing you can do for accuracy is to use magnum cases.

Reason being the bullet jump - unguided as it were - for that small bit of time after it leaves the case and before it reaches the front of the cylinder.

Now, this is not a fixed in stone issue, plenty of people have no accuracy loss from this, but among purists, it's something to be considered.

There's POTENTIAL for the bullet to wobble and enter the forcing cone unevenly, leading to issues.

Like I said, this isn't an absolute, so test and verify.

As to accuracy with the two powders you mentioned, both are good and have impeccable reputations. Your biggest concern is consistency of charge.

IOW, keep the powder charge the same time after time and test various loads - make 10 of each with a starting point and go in .1g increments until you reach your maximum charge and take notes to decide which is best.

Then load with consistency.

The 125g JHP is best for SD at high velocity and neither of those powders is optimum for that, and the ones that are can be difficult on your forcing cone with a short bullet like the 125g JHP.

2400 might be your best choice for that bullet and your SD uses.

 

[texasjarhead]

Twig- Great suggestions! Followed your advice, and ran a few very un-scientific tests at the range today:

Gun- S&W 686-4 2.5" barrel
Bullets- 125gr FP; 130gr RNFP; 158gr SWC (all hard cast)
Cases- .357 Starline
Primers- Remington 1.5 small pistol
Powders- 6.4gr Unique; 5.4gr Win 231
Range- 25 yards (from sandbags)

Average group size- 7.65"
Worst group- 10.0" (158gr SWC- 6.4gr Unique)
Best Group- 4.15" (130gr RNFP- 6.4gr Unique)

Average Group Unique- 7.4"
Average Group Win 231- 7.9"

Average Group 158gr SWC- 9.08"
Average Group 130gr RNFP- 6.27"
Average Group 125gr FP- 6.22"

General conclusions:
This gun likes Unique better than Win 231
This gun likes lighter bullets better than heavy bullets
So far, this gun's favorite is 130gr RNFP with 6.4gr Unique

I wish we had math problems like this when I was in school- I might have done better.

 

[Snapping Twig]

Cool beans!

Magnum cases and bullets sized to .358?

Carry on and shoot in good health.

 

[texasjarhead]

Twig- That's correct- bullets were .358" out of Magnum cases.

Getting ready to go load 100 rounds of 130gr RNFP with 6.4gr Unique to make sure that good group wasn't a fluke.

Thanks again for your replies!

 

[Neumann]

I am getting very good performance using Alliant 2400 for .357 and a 4" barrel, with negligible secondary muzzle flash. I question the wisdom of using signficantly faster powder for a 2.5" or 3" barrel. The case is nearly full with a conservative charge of 13.5 grains under a 158 grain XTP, or 16 grains under a 125 grain XTP.

Fast powders like Unique and W231 don't fill the .357 case very well, which may cause variation depending on how the powder sits in the case. Mostly, though, you get higher pressure at lower muzzle velocity than with 2400.

If you want less recoil, you should consider +p loads in .38 SPL cases. All lead, 158 grain SWCHP, "FBI" bullets make excellent SD loads, keeping the velocity below 1000 fps to reduce leading.

I may change my mind if I get a 3" 686. At 34 oz, recoil won't be a major issue.

 

[ArchAngelCD]

Please don't take this the wrong way but if you are getting 7.5" to 10" groups you may not be shooting well enough to judge which powder is best in that revolver. You might want to shorten the distances and fire the revolver off a rest to give each round a better chance at accuracy.

Why are you using the same charge weights for all 3 bullets of different weights? Each bullet requires different powder weights for the best results. Each powder has a different "sweet spot" with each bullet. The test you did didn't do justice to the powders or bullets because of using the same powder charge for all combinations.

I'm not sure if you're trying to make ammo that's like a .38 Special or .357 Magnum. If you're trying to make .38 Special pressure ammo in a .357 Magnum case I would suggest trying a change of 4.1gr W231 under a 158gr LSWC bullet. If you are trying to make light .357 Magnum rounds up the charge to 5.0gr w231 under the same bullet. I'm betting the accuracy will be very good if you do your part...

 

[Rule3]

As ArchangleCD stated above and as others stated, generally a slower powder is better in a short barrel.

How accurate is a 2.5" gun at 25 yards when hand held? The only way to be precise is to have the gun locked in a ransom rest. With just a small sample of shots, it's all subjective, and the human element is not taken out of the equation. On any different day, different shooter, the results are all going to be different. Are the loads chronographed?

 

[OKFC05]

Please don't take this the wrong way but if you are getting 7.5" to 10" groups you may not be shooting well enough to judge which powder is best in that revolver.

Yes, I'm afraid all you're doing is seeing shooter effect. With any of my 3" barrel revolvers, groups under 4" at 25yds are routine with any decent load. The difference between your 7.4" and 7.9" is insignificant, and 7" is not nearly the capability of the gun.
The mechanical accuracy of a short barrel is nearly that of a 4" or 6" barrel, and the short sight radius and shooter technique cause greater dispersion in the groups.

My target load of 3 gr of 231 under a 148gr wadcutter has produced 1" groups (from rest) at 25yds in several different S&W revolvers. The reason I can do it with my 4" 686 and not with my 3" model 60 is my inability to maintain as precise sight alignment for each shot with the smaller gun.