38sp +P pressure data?

[Tristan]

I'm looking without luck for pressure data for the classic load of 158gr. cast 38sp. over 5gr. - 5.5gr. Unique.

I know and understand that this is today considered above +p, just looking for the data.

If you have a reference which specifies the pressure of this load, I'd appreciate if you'd be willing to post it!

Thanks,

Tristan

[zxcvbob]

Cartridge : .38 Special +P (SAAMI)
Bullet : .358, 158, LEE 358-158-RF
Cartridge O.A.L. L6: 1.427 inch or 36.24 mm
Barrel Length : 5.0 inch or 127.0 mm
Powder : Alliant UNIQUE

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 46 4.00 782 214 11075 3467 94.4 0.917
-18.0 47 4.10 798 223 11596 3569 95.1 0.899
-16.0 48 4.20 813 232 12131 3670 95.7 0.879
-14.0 49 4.30 829 241 12680 3770 96.3 0.860
-12.0 50 4.40 844 250 13243 3867 96.9 0.840
-10.0 51 4.50 859 259 13819 3963 97.4 0.822
-08.0 53 4.60 875 268 14410 4057 97.9 0.804
-06.0 54 4.70 889 278 15016 4149 98.3 0.787
-04.0 55 4.80 904 287 15635 4239 98.6 0.771
-02.0 56 4.90 919 296 16269 4327 98.9 0.755 ! Near Maximum !
+00.0 57 5.00 933 305 16918 4412 99.2 0.740 ! Near Maximum !
+02.0 58 5.10 947 315 17581 4495 99.4 0.726 ! Near Maximum !
+04.0 59 5.20 961 324 18259 4576 99.6 0.712 !DANGEROUS LOAD-DO NOT USE!
+06.0 61 5.30 975 334 18951 4654 99.8 0.698 !DANGEROUS LOAD-DO NOT USE!
+08.0 62 5.40 989 343 19659 4730 99.9 0.686 !DANGEROUS LOAD-DO NOT USE!
+10.0 63 5.50 1003 353 20382 4803 100.0 0.673 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 57 5.00 969 329 19455 4322 100.0 0.691 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 57 5.00 885 275 14366 4330 95.0 0.804

[Nora]

According to my Speer #13 the industry pressure limit for .38 SPL +P is 20,000psi compared to the standard .38 SPL of 17,000psi. They state that their loads do not exceed this limit and have 5.2 gr Unique (@919fps) as max for their .358, 158 gr swaged lead boolits. Take it for what it's worth but I wouldn't consider 5.5gr Unique to be a safe load by any standards.

Nora

[beagle]

May be a tad warm for older .38 Special guns. In a .357 Mag chamber it's all right but if you have a mixed house like I do with a .38 Special M15, you have to watch your ammo.

Yeah, I know, you've shot thousands of rounds of this load in a K framed .38 Special and I have too but darned if I'll recommend it to anybody.

The old Hodgdon manuals had pressure data for Hercules powder in them despite they were Hodgdon manuals. Might be a place to look.

I'm assuming it will exceed the industry standard for +P loads.

Too bad there are all of the old weak .38 Specials around that keep publishing of data for the .38 Special within limits. It's a really nice round when loaded to it's full potential./beagle

[jdgabbard]

zxcvbob, that is great info!!! Where did you get that from???

[Larry Gibson]

Tristan

Lyman Cast Bullet Handbook lists a max .38+P load of 18,000 CUP with 5.4 gr of Unique under a 158 gr cast 358311. That would probably max out at the approprite +P psi of todays piezo type pressure measurements. One of these days I may find a TC Contender .357 barrel and measure some pressures. I have shot several thousand +P loads using 5.5 gr of Unique (Hercules) under 150 gr 358477s in numerous K framed M10 and M15 S&Ws. That load always duplicated WW 15HP +p load's velocity (925-950 fps from 4" barreled M10/15s). Never had an indication of any problem with the load.

Larry Gibson

[Tristan]

Thanks to everyone that responded.

Looks like it's true, that over time the bar has been lowered regarding the max safe loads for the 38 special. I have to assume that this is due to the availability of light-weight alloy framed firearms on the market, or perhaps a concern over antiques or worn guns that are still potentially in use.

zxcvbob, thanks for that table of projected pressures. I'm curious where did it come from? Is that a software app that's available?

- Tristan

[zxcvbob]

That table was generated using QuickLOAD software (from NECO). The package is kind of expensive, but my inner engineer loves it. I wish it had more IMR and Winchester powder data.

http://www.neconos.com/details3.htm

[jdgabbard]

That table was generated using QuickLOAD software (from NECO). The package is kind of expensive, but my inner engineer loves it. I wish it had more IMR and Winchester powder data.

http://www.neconos.com/details3.htm

Thats a shame that it is $150 dollars, as I cannot justify purchasing a software program at that price. I've heard quite a bit of talk about that software. It looks like it can give some good data, but I think I'll stick with the manuals.

[RMc]

Several years back SAAMI increased the pressure standard for the .38 Special +P from 18,500psi to 20,000psi.

Also Buffalo Bore .38+P ammo is held to a 22,000psi standard.

See the discussion referenced below for more info:

http://shootersforum.com/showthread.htm?t=11047&highlight=ralph+mclaney

[geargnasher]

My Speer #11 book says standard .38spl is 18,900 cup, +p was 22,400 cup. That's COPPER units from a crusher gun and the data is copyrighted 1987. The modern piezo transducers don't generate exactly comparable pressure data, although it is undoubtably more accurate. The best data I can come up with for lead is 4.7 grains of HERCULES Unique and 158grain swc at 918fps for non-+p loads. Factor in Alliant's reformulation of Unique and let's just say that there are too many variables to try to use this "classic load" data with modern components. However, I've got some genuine antique Hercules Unique if you want to try. :Fire:

Gear

[JIMinPHX]

My Lyman Cast Boolit book (3'd edition) says that 5.1gr Unique under a 158 gr #358156 should give 16,100CUP. Same load under 158-grain #358311 - 16,400CUP.

[Will]

My oldest Lyman manual (1957) shows unique max +P at 6.4gr. Things have changed!

[jdgabbard]

My oldest Lyman manual (1957) shows unique max +P at 6.4gr. Things have changed!

Talk about some 38/44 loads!

[bowhunter]

Never trust a woman or an automatic pistol........................

[bowhunter]

My best load for 38sp. Is 158 flat nose lee,stright wheel weights.4.7 gr. 700x with cci500. This is around +p but very safe in my s&w model 15. It will out shoot the socks off any unique load that i have ever tried,and it is clean to.

[Jack Stanley]

I'm glad to see that load data , it came along at the right time . i finally got my Lyman cowboy molds back from the factory and was putting together some ammo . I wanted a load that was similar in velocity to a standard .38 special load .

I used four point seven grains of Universal Clays in a Federal case with a Winchester small pistol primers . The hundred and sixty grain Lyman "cowboy" bullet was seated to an overall length of 1.410" and the bullet diameter was .359" and lubed with Alox in the groove .

It shots pretty well with the stock sights on the Marlin carbine and I hope to get a reciever sight and a post front sight for the gun . I'm sure my groups will improve a little bit anyway .

Jack