357 Magnum & Blue Dot confused

[TRE]

Gents,

By way of background, I have been reloading for over 25 years, and 357 Mags for nearly that long. I have loaded dozens of different calibers, and as a competitive shooter for many years and a high volume shooter for even longer, I have loaded literally hundreds of thousands of rounds of all types.

Having said all of that, until recently I had never used Blue Dot in the 357 Magnum. All of my full house 357s had been loaded with W296/H110 to this point, and I used various other powders for mid range & light loads. This week, I loaded some 357s with a can of Blue Dot that I have had in inventory for probably close to 10 years. It's still new powder, I broke the seal on it, just never had a reason to use it (bought it for shotgun loads) until now (I no longer load magnum shotshells, just target loads).

The specific load was; mixed brass, CCI 500 standard primers, 10.0grs Blue Dot and a 358156 LSWC GC bullet that I cast from air cooled wheelweights. Various manuals that I have on hand list 10.5 and higher as a maximum load with this bullet, so 10.0 seemed a safe starting point.

So, Friday I went to the range with a buddy to fire a few rounds with various guns. I fired 24 rounds of light 38 wadcutter loads out of my model 19-8, THEN I fired 6 rounds of the above mentioned 357 load with Blue Dot. Function was fine, accuracy was good, recoil was noticeable but not excessive, but when I went to extract the cases into my brass bucket it was VERY difficult to extract them. I have had minor extraction issues with 296/h110 loads in the past, but those were balls to the wall maximum loads with jacketed bullets. These are lead bullets at what I believe to be safely under maximum.

So, could this issue be due to cylinder fouling from firing the shorter 38 loads? (the gun was clean before shooting started) Is this load too hot? (I don't shoot a lot of full house mags in my K frame 357s, just to prolong their life) Am I missing something?
FWIW, I have fired factory Hornady 125gr critical defense loads in this same gun after firing wadcutters, with no extraction issues.

Thoughts?

I'm kind of stumped.

TRE

 

[TRE]

Here's a pic of the primers of those 6 rounds. 1 or 2 look a bit flattened, but I've had worse with other loads that extracted ok.

TRE

 

[arjay]

I remember a warning about weird pressure spikes with blue dot in 357s back in the 80s.
Seems that loads that were fine on a warm day could get too hot on a cold day?

 

[HKSmith]

I believe that Alliant no longer recommends Blue Dot for.357 or .41 Magnum.

 

[mekusapv.wcf]

TRE,
I see how it has flattened the primers. I have reloaded several rifle and revolver/pistol calibers. I've gotten flattened primers like that when I was loading just below maximum charge. My guess is that my powder dispenser and possibly yours are not as consistently accurate as we need it to be when loading cartridges within 0.5 grains of the limit.
If you are loading by weighing each charge on your scales and they are properly calibrated, then I don't have any further ideas.
My powder dispenser is a Lee and is well worn. I don't trust it any more. Before I get back on the bench I need to buy a new one.

Sent from my SAMSUNG-SM-G920A using Tapatalk

 

[muddocktor]

The warning was about not using BD with 125 grain bullets because of pressure excursions noted by Alliant/Hercules. With that said, I've fired thousands of reloads with BD in my 27s. But, I also live in south Louisiana, where we get very little in the way of low temperatures. So I've never seen any problems with BD like some folks say they have seen. Evidently it is temp sensitive, especially when loading hotter loads. But BD can be used for 357 loads other than for the 125 grain bullets. They still show loads for 110, 140, 158 and 170 grain bullets.

EDIT: Also, mekusapv.wcf brings up a point about powder measures and BD that I've noticed. My Lyman 55 and the measure on my old Dillon 450 both aren't the most accurate with measuring BD. They will throw the odd measure every once in a while that will be significantly lighter or heavier than norm. Light throws aren't too noticeable, but heavy throws can make for a high pressure round.

 

[TRE]

Thanks for the replies so far Gents.

All charges were weighed on a scale to plus/minus .1 grain. Shooting conditions were indoor range, probably about 70-75 degrees.

TRE

 

[muddocktor]

OK, thanks for the update on shooting and loading conditions.

Have you checked your cases for OAL lately? I've found that 357 Mag and 44 Mag cases will grow in length, unlike lower pressured rimmed rounds or rimless cases such as 9 MM. And if you shoot warm to hot loads a lot it seems to make them grow more. So I end up with cases at various lengths unless I trim them back every once in a while. And while the length doesn't directly affect feeding or firing, unlike with an auto case or bottleneck rifle cases, it will directly affect your roll crimp. So on some overly long cases you can get a very hard roll crimp, especially if you set your crimp on a shorter case. So a hard roll crimp could very well be raising pressures on some of your loads but not on others that have a little shorter case and didn't get quite as hard a roll crimp. I've also seen this happen with me with 296/H110 loaded close to max in the past, before checking my brass OAL as much as I presently do with 357 and 44.

 

[Big Cholla]

I would like to weigh in on this one. From your description and a very good picture; it is my humble opinion that your pressures as represented by the slightly flattened primers wasn't that all-fired high. The outer edge of each primer is still very nicely rounded. Excessive pressure will flatten that outside edge. I think you are right in assuming that the difficult extraction is a result of the combustion ring left in each chamber by the 38 Specials fired prior to a slightly higher than normal pressure 357 Mag. and nothing more. Blue Dot would not be my loading powder of choice for 357 Mag., but it would do as long as one is very careful in the powder measurements. ...............

And, I would take along cleaning equipment that would allow me to clean the cylinder with a few strokes of a bronze wire brush soaked in a solvent , followed by a clean patch before switching from 38 Spec. to 357 Mag.

 

[Dennis]

You could also try an old bore brush with pure copper chore boy in those chambers. I thought my 357 chambers were clean after a regular brushing after 38s, but they weren't. lol.

 

[BLUEDOT37]

I have had minor extraction issues with 296/h110 loads in the past, but those were balls to the wall maximum loads with jacketed bullets. These are lead bullets at what I believe to be safely under maximum.

If you look at Lyman #49, 10.5gr/B-D with a 155gr L-SWC-GC has higher pressure than 158gr JHP with 10.7gr/B-D. Gas checked aren't just lead bullets.

Probably should have reduced the max charge by 10% to start with. Some guns have chambers that are tighter & won't allow max. loads without sticky extraction. I have a 41 Mag like that.

However, I'd suspect it was the dirty chambers too. Clean them good. Reload some more rounds, starting lower and stepping up .2gr/ea, & use all the same brand brass & see if they start sticking at the same point again.

.

 

[TRE]

Thanks everyone. I too am leaning towards dirty chambers from 38 loads. I still have 44rds of this Blue Dot load, so when I get back to the range I'll fire them FIRST, from a totally clean gun.

Kinda funny how no matter how experienced you are at reloading, things like this can still crop up sometimes.

TRE

 

[gen3guy]

In my opinion you are correct in your use of W296/H110 for your hot loads. I use Blue Dot for "moderate" magnum loads as it is somewhat faster burning. 10 grains behind a 158 grain JHP gets me around 1100 FPS with my Ruger Security Six. Impressive to shoot, but if I wanted to go hotter than that I'd use H110.

 

[TRE]

gen3guy,

That is kinda why I'm using the Blue Dot, to load a sort of moderate load, plus it's been on the powder shelf for awhile and I no longer need it for shotshells.

I'm using 10 grains as well, so hopefully I'm in that 1100 FPS neighborhood. The recoil and blast are certainly less than the H110/296 loads.

TRE

 

[cjwils]

Over the years, I have loaded a gazillion hot loads in .357 with Blue Dot, with no problems. But I have only used it with jacketed bullets. Most published data for Blue Dot is for jacketed bullets only. I wonder if that is the difference.

 

[TRE]

cjwils,

I don't think that is the problem, but I may be wrong. However, the data I used was from a Lyman manual (#49 I think) that listed this charge of Blue Dot with this exact lead bullet (358156) from a Lyman mold. That is partly why I was a bit surprised to have an issue.

Thanks for the reply though, made me think for a minute and double check to make sure that I used the correct data.

TRE

 

[Bruce51]

I use to use BlueDot for my .357 magnum loads.

In a four inch revolver the fireball was always quite impressive.

Also flattened primers always seemed to be the norm but cases always extracted easily.

The data used was from the old Hercules guide.

FWIW I found that a 158 grain cast bullet in a Marlin 1894 was pretty accurate with ten grains of BD at 1400fps.
A jacketed 160 grain Speer SP with 12 grains hit 1600 fps the same velocity achieved with 16 grains of H110.

Boy were those primers flat but nothing ever blew up.

What you can expect in a four inch revolver depends on the gun.

A 158 grain JHP with 11 grains clocked 1220 fps in a 686 but only 1109 in a four inch model 19.

While not exactly the bullets you are using there is some chronograph data
that might provide some BD usage insight.

I do remember that twelve grains seemed a bit excessive as far as pressure and stuck with ten grains for cast and 11 grains for jacketed.

One final note: I have replaced BD with AA #7. It meters better and does not produce a fireball. However tests with cast bullets in the Marlin showed that the BD was far more accurate with cast bullets.

Just my .02

BLM

 

[Nevada Ed]

Back in 2008 I talked to two of Alliant's tech's about BD and the 125gr JHP..........
Reduced loads are doable.

I have had the heavier 158gr Lead bullet up to 1276fps with Blue Dot powder out of a 6" barrel but my best accuracy was with just 9.0grs of this powder.

It also works in a 38 case at 1024fps for a 357 Magnum or a K frame 38 special 6" ..... but a 38 case at 890fps worked in all my 38 revolvers with a recoil all family members could handle.

It works...........

 

[Doubless]

I have always felt BD got a bit "twitchy" at close to the top of the load chart, and felt that way long before the warning came out. IMHO, there are a whole lot of powders that are better in the 357 than Blue Dot. It is, at least to me, rather unpredictable...

I really like AA #9 for the 357.

 

[MichiganScott]

Funny. Alliant has loads for 110gr. and 140gr bullets and heavier, but nothing for 125gr. They must have seen something that really made them cautious.

FWIW, you can look at primers all day long and they don't tell you anything except whether or not the gun fired. You have soft cups, hard cups, excessive headspace, different size primers, different size primer pockets, etc. that can affect their appearance.

I believe Charles Petty has stated that you may have to be past 70,000 PSI before you really see flattened primers. Gunsmith John Linebaugh has stated that straight cases handle pressures different than bottlenecks and they have tested guns to destruction with pressures running from 70,000 to 100,000 PSI. The primers were normal looking amongst the cylinder and case fragments they managed to recover.

Stick to published data and remain safe.