Skeeter(-ish) Load Pressure

[TXTad]

Sorry for the plated bullets, but I've been a bit too busy for casting, loading, and shooting, so something had to give.

I loaded these 240 gr bullets over Skeeter's load of 7.5 gr of Unique. The internet suggests that the pressure of these loads will be in 24 kpsi range. I would say the soot on the cases and the observed velocity indicates something less than that. I do recall seeing a PDF scan of an old NRA publication that suggested that 7.5 gr was only around 15 kpsi. These were fired in my 5.5" Ruger flat top Blackhawk.

Any thoughts?

 

[Brad]

Too many variables to really say?
Bet that revolver has larger than .429 throats which reduces pressure. Bore is likely bigger too which mitigates some Of the variation between a cast and a jacketed bullet.

Looking at those cases I don’t think you are getting 24K PSI.

 

[CZ93X62]

TX--your results don't vary from my own--velocity-wise or burn-back on cases. I share your view that 24 K-psi might be a little exaggerated. These days my Skeeter's Loads get put up and fired in 44 Magnum cases--8.2 x Unique and 9.0 X Herco. In 41 Magnum using 212 grain SWCs (Lyman #410028) 7.0 x Unique and 8.0 x Herco simulate the old lead-bullet 41 Mag 'Police Load' pretty closely.

 

[TXTad]

Too many variables to really say?
Bet that revolver has larger than .429 throats which reduces pressure. Bore is likely bigger too which mitigates some Of the variation between a cast and a jacketed bullet.

Looking at those cases I don’t think you are getting 24K PSI.

I've had this revolver, but I haven't slugged it yet. I should do that sooner than later.

I have a 429421 that I plan to start using for these loads for this gun. I'll want to know the throat and bore dimensions before I go to far down that path.

 

[fiver]

in the 45 colt that's a 14K load and you get the same line of soot down the case, only all the way down one side.

here's what i'd do....... [nuthin]

 

[TXTad]

TX--your results don't vary from my own--velocity-wise or burn-back on cases. I share your view that 24 K-psi might be a little exaggerated. These days my Skeeter's Loads get put up and fired in 44 Magnum cases--8.2 x Unique and 9.0 X Herco. In 41 Magnum using 212 grain SWCs (Lyman #410028) 7.0 x Unique and 8.0 x Herco simulate the old lead-bullet 41 Mag 'Police Load' pretty closely.

I will start casting for this revolver and my S&W 24, but I'm also going to keep loading these plated bullets just because they're so convenient. I'm not exactly complaining about 877 fps, but I'd be happier with anything over 900. I think I'll try seating to their cannelures next and see what that does. Velocity spread was pretty large with these.

 

[TXTad]

in the 45 colt that's a 14K load and you get the same line of soot down the case, only all the way down one side.

here's what i'd do....... [nuthin]

Nothing besides seating to the cannelures for the next batch is pretty much my plan.

I do want a 950 fps load for this revolver, but I'll worry about that once I have a batch of 429421s I'm loading.

 

[RicinYakima]

I also think the PMC cases you are using may be pretty hard. Seating to the crimp and using a heavy crimp will up velocity and lower ES, if that is important to you. How do they group?

 

[Petrol & Powder]

My "Skeeter" 44 Special load is about 8.2 - 8.3 Grain of Unique in a 44 Magnum case and a 245ish grain cast SWC bullet.

I would be shocked if that load is over 18K psi.

While the "Skeeter" load of 7.5 grains of Unique in a 44 Special casing and 250ish grain bullet is likely over the pathetic 15.5 K psi SAAMI limit for 44 Special, it is probably not that far over that arbitrarily low limit. And not above the limit enough in a modern good quality revolver to even be the slightest concern.

I've never been super impressed with plated bullets.

 

[JustJim]

FWIW, I've now slugged more than a dozen of the Flattops; only one was not .431-.431+" (and that one was .430"). Cases, seating depth, and bullet pull (before the crimp is applied) would be my guess. Try seating to the crimp groove, and crimping, first?

From there, maybe anneal the case mouths. I gave up long ago on PMC brass if I could get anything else. They do tend to be harder/have more spring-back after sizing, and I hate annealing cases.

In my limited tests with 7.5 gr. Unique (limited because I had very little Unique!) in my 5.5" Flattop, I was getting 940fps w/NOE's version of 429421. Starline brass, WLP, bullets sized to .431".

 

[TXTad]

I also think the PMC cases you are using may be pretty hard. Seating to the crimp and using a heavy crimp will up velocity and lower ES, if that is important to you. How do they group?

It is my impression from working with them that they are quite hard. I don't know about grouping yet: It was windy as heck yesterday, the rear sight is cranked way left and I forgot my tool set, and I was only shooting offhand because the goal was just to unwind and try out my new chronograph. I think they are OK, but I'll learn more when I'm better prepared.

 

[TXTad]

My "Skeeter" 44 Special load is about 8.2 - 8.3 Grain of Unique in a 44 Magnum case and a 245ish grain cast SWC bullet.

I should give that a try. I loaded 10 gr under a commercial LSWC for my converted M28, but those loads were a bit brisk.

I would be shocked if that load is over 18K psi.

I agree.

While the "Skeeter" load of 7.5 grains of Unique in a 44 Special casing and 250ish grain bullet is likely over the pathetic 15.5 K psi SAAMI limit for 44 Special, it is probably not that far over that arbitrarily low limit. And not above the limit enough in a modern good quality revolver to even be the slightest concern.

I also agree. I need to find that old 1950s NRA publication I mentioned above. I really do think that it was suggesting 15 or 17 k for 7.5 gr under a 240 or 250.

I've never been super impressed with plated bullets.

Same, but they're cheap and easy.

 

[TXTad]

FWIW, I've now slugged more than a dozen of the Flattops; only one was not .431-.431+" (and that one was .430"). Cases, seating depth, and bullet pull (before the crimp is applied) would be my guess. Try seating to the crimp groove, and crimping, first?

Seating to the cannelure is my next step. Even though the brass was new (well, 20 years old, but never loaded), the bullets were fairly snug to seat and they have a healthy taper crimp on them. I didn't want to deform them with a roll-crimp.

From there, maybe anneal the case mouths. I gave up long ago on PMC brass if I could get anything else. They do tend to be harder/have more spring-back after sizing, and I hate annealing cases.

I was thinking about it, but I may just load these until they start failing and toss the lot. I bought these 20 or more years ago when Nix in Lewisville had a big sale before it was sold.

In my limited tests with 7.5 gr. Unique (limited because I had very little Unique!) in my 5.5" Flattop, I was getting 940fps w/NOE's version of 429421. Starline brass, WLP, bullets sized to .431".

That is more like the velocity I was expecting. I'll try the seating depth first and see what that does. I'll be casting from my Lyman 429421 soon and will be able to compare those as well.