Load too hot?

[epj]

158 gr. cast RNFP, mixed .38sp cases, 4.8 gr. Universal Clays, Federal primer.

I chronoed these loads and they average just under 900 fps. Pretty wide extreme spread 850-940. The one that hit 940 felt a bit different when I fired it. I could tell it was hot. If I throw that one out, ES was still 850-910. Very accurate load, under 2" at 50 ft. Didn't seem to be a hard recoiling out of my 627, kind of pleasant to shoot actually.

The only problem was slightly flattened primers. The cases just about fell out of the chambers, so I wonder if it's just the sort of "soft" Federal primers. 4.7 gr. is the top load in the Lyman manual (48), but the pressure at that level is in the 16K range. .38+P can go to 20K. I have trouble believing the extra .1 grain of powder upped the pressure that much.
Opinions?

 

[Dragon88]

Primers flattening out a little is not an issue. In some of my loads they flat out quite a bit due to pressure, but they are still not overpressure. When the primer starts to take on the shape of the bolt face, or even flows into the firing pin hole, that is when you truly have "flattened primers" that can be considered a sign of overpressure.

 

[Skip Sackett]

Well, considering that there is no data on the Hodgdon website for a 158gr RNFP in the 38spl +P section and the normal data stops at 4.3gr of Universal Clays, yes, your loads are a tad hot.

Not familiar with Universal and it's idiosyncrasies when loaded too hot so I am of no help there.

Some powders, SR4756 is one, like to be loaded towards the top of their data. When you do so, their numbers across the chronograph come way down, some don't.

 

[Titegroups]

If the same federal small pistol primers are used in a .38spl load at 20,000 psi, and a 357 mag load at 40,000 psi, why would they become flat at 20,000 psi? Having a hard time seeing this being a reliable indicator of over-pressure in low pressure rounds ie....45acp...45colt.?

 

[Dragon88]

I shot a black powder sub 45 colt load today that flattened the primers a little. Primers are not a reliable sign of pressure by themselves unless they are blown or look really bad. You have to look at your load data and other factors.

 

[Titegroups]

The same could be true of hard extractions, if the .38 cases were the same wall thickness, same alloy and heat treatment as a 357 case it should take roughly the same pressure to bring the case to the yield point of the metal so it wouldn't return close to it's original demensions, causing sticky extractions. Just some thoughts, I'm not new to reloading, just thinking metal deformation may not be a very good indicator of pressure in some rounds where the max. pressure is 1/3 of others.

 

[acl864]

I've experimented with Universal +P loads with lead bullets (148 gr. DEWC) in 38 Special. My gut tells me that your load is the very top end for 158 gr. bullet- but that's OPINION- not fact. There is no published data to back me up that I'm aware of and I have not loaded in that range with a 158 gr. bullet. If you'll PM an e-mail address I'll send you my load and chrono data from the 148 gr. DEWC/Universal load work-up for reference.

 

[TSQUARED]

Personally I do not go beyond the powder manufacturers presssure tested loads.

 

[LazarusLong]

Might be a little warm for a .38, Universal is a fairly fast powder to be getting that good a velocity with a 158.. Usually it takes something a little slower like 4756 to hit 900-1000 without a lot of hoopla. I see you are shooting them out of a 627 so you shouldn't have any issues. I've pushed a 173 grain SWC over 1100 FPS out of a .38 case so the case will take it fine, primers weren't even flat with that load IIRC

 

[Joed49]

I don't pay to much attention to flattened primers as they just don't tell the whole story. If a load is to hot you'll find they don't extract easily and that's how I tell a hot load.

 

[Jellybean]

Any chance you were throwing erratic charges of powder?

 

[Alk8944]

Just an observation for any of you who think you can load a .38 Spl or any other relatively low pressure cartridge and go until you see some "Sign of pressure". Sticky extraction doesn't show up in any cartridge until way beyond 30,000 PSI. .357 Magnum loaded to the original maximum of what is now referred to as 46,000 CUP, something above 36,000 PSI Piezo, will still extract freely. This is double the .38 Spl +P maximum pressure!

"Pressure signs" in any revolver cartridge are only signs that you have already exceeded maximum allowable pressure by a significant amount, even in the magnums.

 

[Missionary]

Good morning
If you are looking for top velocity loads, as fast burning powder is not the route to go. If that was all I had i would load to the recommended top load. There just is no reason to hot rod any powder.
You could switch to Unique, Acc #5 or whatever and happily have whatever velocity you desire within recommended levels.

 

[sourdough44]

I use Universal in several handgun loads, 40s&w,38,357,45acp,colt,Schofield & others. I have also chronogaphed it a fair amount. One thing I have noticed is it tends to have a high deviation across the chrony even with carefully measured charges. Much of the time I am measuring each charge & re-zeroing the scale often. This can be in the 75fps+ range with a mild 775 fps 40s&w load(approx from memory).

I like Universal & have used it in some upper end 38+p loads,(still within listed data). For the most part these upper end +p loads are fired in a 357 mag handgun.

 

[robctwo]

Unique and Universal Clays have about the same burn rate. I have loaded some 158gr Montana Gold jhp with 4.9 Unique with no problems from my model 10, and no issues at all in my .357s. I like Universal Clays, shoot it mostly in my .45 ACP loaded max for bowling pins.