Cast vs Jacketed Bullets Effects on Pressure

[DMW1116]

I have some 125 grain cast bullets I want to try in my 357 Magnum using HS-6 powder. I have a load for 125 grain XTPs already. Looking at the load data the pressure is higher with jacketed bullets. The data show that with a charge weight about a grain less than the cast loads of similar weight. Does that sound right? Data is from Hodgdens site for XTP and from the Lyman Cast Bullet Manual for 120 grain round nose and conical nose. Those overlap but are different at the top and bottom end. I’m currently planning to go with 10 up to 11 grains in 0.2 grain increments. I’m testing the same bullet with 38 Special first to see how that goes.

 

[.38 Special]

With the same bullet weight and the same charge, cast bullets will almost always show less pressure than jacketed.

Maximum loads for both normally will require a bit more powder with cast than for jacketed.

A big catch is that many manuals do not show maximum pressure loads for cast, because they do not want to hear complaints about leading. So the "maximum" cast loads in many manuals are actually well below SAAMI specifications.

Beyond that, you can't really compare max. loads between manuals. Each manufacturer uses their own guns and their own pressure testing setups, so results are never going exactly duplicate each other.

 

[edwardware]

Looking at the load data the pressure is higher with jacketed bullets. The data show that with a charge weight about a grain less than the cast loads of similar weight.

Yes, sounds right.

Note that you can drive a 125gr cast bullet faster than most will take in a .357, so accuracy may be lousy at the top. This is why cast loads are often lower/slower than jacketed, leading to much confustication in poorly read corners of the interwebs.

 

[.38 Special]

Yes, sounds right.

Note that you can drive a 125gr cast bullet faster than most will take in a .357, so accuracy may be lousy at the top. This is why cast loads are often lower/slower than jacketed, leading to much confustication in poorly read corners of the interwebs.

That is a good point. Light cast bullets driven very fast are much more likely to lead. Beyond that, heavier cast bullets usually cause surprisingly little velocity loss, and so are almost always a better plan. I realize that the OP already has his bullets, but I generally find that best results with cast bullets in the .357 start with 158 grains and may peak somewhere around 180.

 

[Thomasss]

Why not look at it another way. In .38 Special using the same bullet and 6.5 grains of HS-6 powder will yield 935 fps. Cast bullets will start to lead up a barrel somewhere between 1,000 and 1,100 fps. Another option would be to powder coat your cast bullets and that would give you a little more velocity wiggle room.

 

[DMW1116]

These are high tech coated. I bought them with the intent to shoot them in 38 Special velocity loads, but what’s the fun in having a magnum if you can’t do magnum stuff. I would hav me gotten 158 grain bullets if they’d been available. These were on sale for about $35/500 so I grabbed them. They might shoot so bad it looks like I’m using shot shells but I haven’t tried them in anything yet.

 

[243winxb]

125 gr bullet, - 8.8 grs would be my start for HS-6 In 357 mag., looking at Hodgdon data for jacketed. Then jump 1/2 gr at a time.

Comparison of lead vs jacketed , factory data. https://www.thehighroad.org/index.php?media/albums/load-data-lead-vs-jacketed-bullets.265/

No HS-6

 

[243winxb]

38 special- Note that HS-6 & WIN 540, Same powder/Data. 158 gr for comparison. No 125 gr

HS-6/540 is cleaner in the 9mm luger at the higher pressures.

 

[CoalCrackerAl]

I have ran 44 coated cast up to 1600 fps in my CVA Hunter rifle. No leading. The bullets were from Summers enterprises.

 

[GeoDudeFlorida]

Pretty funny how everyone knows about driving force but forgets about centrifugal force. A copper jacket can spin a lot faster than a lead cylinder without expanding laterally. Once a spinning object in flight begins lateral expansion, it’s center of gravity and center of rotation change.

There’s a lot more going on with a bullet than just going down the barrel.

 

[AJC1]

I have not shot or cast bullets that have bearing surface where cast and jacketed are equal... noe does make HTC bullet molds without lube groves. I suspect that the pressure would be more equal with those.

 

[DMW1116]

The Lyman data for cast round nose starts over 10 grains for a 120 grain bullet but I don’t want to go that high. I’ll see how they shoot over a 38 Special charge of Silhouette before perusing the magnum load anymore.

I’ve loaded 125 grain XTPs over HS-6 in 357 Magnum up to near max but I didn’t like it. That’s why I’m exploring lower or at least different charges in the lower magnum range. Well that and I have 500 of these cast bullets and have to find something to do with them.

 

[Archie]

Reloading manuals typically show lower loads for cast bullets of equal weight for two reasons.
Cast bullets tend to fill out the bore better and make a better seal against gas blow by. That creates greater pressure.
Cast bullets tend to leave lead in the barrel of anything when pushed too hard.

For a starting load, if one doesn't have cast bullet specific data, the starting loads for the same weight jacked bullet may be used. However, starting loads only and then inspect for pressure signs.

 

[DMW1116]

38 special- Note that HS-6 & WIN 540, Same powder/Data. 158 gr for comparison. No 125 gr View attachment 1082967

HS-6/540 is cleaner in the 9mm luger at the higher pressures.

HS-6 seems to be one of those powders that work best at the upper end of the charge range in 9mm and 357 Magnum both.

 

[AJC1]

The Lyman data for cast round nose starts over 10 grains for a 120 grain bullet but I don’t want to go that high. I’ll see how they shoot over a 38 Special charge of Silhouette before perusing the magnum load anymore.

I’ve loaded 125 grain XTPs over HS-6 in 357 Magnum up to near max but I didn’t like it. That’s why I’m exploring lower or at least different charges in the lower magnum range. Well that and I have 500 of these cast bullets and have to find something to do with them.

I run 8.4 for 357 on a 154. With a 120 9 would not bother me in the least.

 

[.38 Special]

Just a quick note in defense of cast bullets...

When a cast bullet fits a revolver properly - and the revolver is properly dimensioned - it can be driven as hard as the chambers will take without significant leading.

 

[Hooda Thunkit]

This is why cast loads are often lower/slower than jacketed, leading to much confustication in poorly read corners of the interwebs.

I generally find that best results with cast bullets in the .357 start with 158 grains and may peak somewhere around 180.

Heavier bullets work better with cast, almost universally.

I’ve loaded 125 grain XTPs over HS-6 in 357 Magnum up to near max but I didn’t like it.

I've never been a fan of 125gr bullets in 357 Mag. Too much flash and bang, not enough of anything else.
Try something heavier.

HS-6 seems to be one of those powders that work best at the upper end of the charge range in 9mm and 357 Magnum both.

Absolutely what I have found in my use of the powder.

 

[DMW1116]

I have a pretty high stepping 2400 load with 158 grain XTPs that shoots better than my wadcutter target loads. I’ll probably relegate the 125 grain XTPs to 38 +P loads when I get there.

I want to try some Enforcer powder with these. It gets similar velocity to HS-6 but at 20% lower pressure according to Hodgden data.

I have enough test loads for this range trip. I’ll start at 9 and go up from there if these bullets shoot ok at 38 Special speed.

 

[black mamba]

Jacketed bullets, especially hollow points, are longer than the same weight of cast bullet. If the loaded OAL is the same, then the jacketed bullet is seated over a smaller powder space, making the pressure higher. Always pay attention to how deeply bullets are seated.

 

[DMW1116]

These 125 grain bullets seem to shoot pretty well with the proper load. A light charge of Silhouette put 4 through one hole at 10 yards. With that kind of accuracy I think I’ll just stick with what works. If that is repeatable that’s under 1.5” at 25 yards, which is way better than I can shoot typically. I’ll try some 125 grain XTPs at 38 +P and call it a day.

 

[AJC1]

These 125 grain bullets seem to shoot pretty well with the proper load. A light charge of Silhouette put 4 through one hole at 10 yards. With that kind of accuracy I think I’ll just stick with what works. If that is repeatable that’s under 1.5” at 25 yards, which is way better than I can shoot typically. I’ll try some 125 grain XTPs at 38 +P and call it a day.

I got great accuracy with Silhouette and terrible with true blue... found that strange

 

[DMW1116]

I have 4 powders which will all work for 9mm and 38 Special. I feel like I need to just pick one and go with it once I confirm it will shoot well. Silhouette, HS-6, W231, and CFE Pistol have all produced good 9mm loads. I have only tried W231 and Silhouette in 38. I wanted some options for each caliber given the state of supplies. I think I’m there.

I was a little concerned with the Gallant bullets but after a bit of digging they seem like a good company and their bullets will definitely shoot.

These 38 loads feel more substantial than the target wadcutter loads I’ve been shooting from my Blackhawk. It’s like picking up a knife that’s too light and wondering if it was made by the same people that make Dixie cups.

I didn’t test my lightest load. Those were sacrificed to some people that wanted to shoot a single action revolver. I doubt it would have done any better and it’s only 0.1 grain difference.

This 38/357 combo is loads of fun for people who just like trying different loads. I could keep going for months and not run out of combinations.

 

[DMW1116]

I want to try True Blue for 9mm but there are too many pistol powders around the house as it is. Blue Dot is another on my list. I shoot 90% cast or plated in that caliber too.

 

[AJC1]

I want to try True Blue for 9mm but there are too many pistol powders around the house as it is. Blue Dot is another on my list. I shoot 90% cast or plated in that caliber too.

I've done cfep and tb both sucked... if I could pick of what you listed I would choose 231 aka hp38.

 

[Kaldor]

I consider coated bullets the same as lead for pressure, but you can generally push them a lil harder due to the coating as they wont lead as easily.