Chronographed- Underwood 38 Spl +P 158 gr cast SWC

[38SPL HV]

Chronographed a ten shot string of Underwood’s 158 gr “Hard Cast Keith” 38 Special +P (purchased in 2019).

Firearm: Ruger 4 5/8 in Blackhawk
Load: Underwood 158 gr “Hard Cast Keith” SWC 38 Special +P

10 shots:
Hi 1249 fps
Lo 1235 fps
Avg 1241 fps
ES 14
SD 4

Notes: I was amazed at the consistency (checkout the ES/SDs) and power of this 38 Spl +P. Hats off to Underwood for an excellent load. This load rivals my standard 357 Magnum load using 2400 but Underwood is at 38 Spl +P pressures! It’s velocity as far as I’m concerned can only be duplicated using 357 Magnum cases and the appropriate magnum level powders…but then you would have a 357 Magnum and not a 38 Spl +P!

 

[Sevens]

With the numbers you are reporting, I would very seriously question exactly what pressure that ammo is running.

I'm not saying it is bad and I am not saying it is unsafe, and a Ruger Blackhawk is amongst the most stout platforms for that ammo, I'll guess even further that your revolver is a .357 Magnum as I don't believe they have ever made a ".38 only" Blackhawk.

But 17,500 PSI doesn't typically make a 158 grain bullet run well over 1,200fps in a sub-5 inch barrel.

.38 Special +P is one of the few, rare actual SAAMI classified and standardized +P ratings, which means that SAAMI has given a .38+P a 17,500 PSI max.

Buffalo Bore for example plays the "+P+ game fast and loose, to no set industry standard. A layman may believe that +P means "higher pressure" but for a SAAMI standardized load, it means a pressure that is quite specific.

 

[IronSkillet]

Have shot a lot of Underwood, decided the 733 Z(38+P 158gr Hi-Tek Coated SWC Hollow Point GC) is the most practical between my revolvers.

Is this Keiths from 2019 the same 734 that they show online today? Few years back I shot some of the 734 and my recollection recalls it differently.

 

[alwslate]

That's more like 38/44 velocities. Got to be above the 20,000 psi limit for +P.

 

[Nevada Ed]

In my 686 6" with a 38 case;

950fps is a 38 +P load and my maximum +P load with the 6" tube
maxed out at 1124fps.

I think Underwood mislabel that box of ammo.

1241fps is a .357 case, loading, with a 158 gr bullet.

 

[DWalt]

That's more like 38/44 velocities. Got to be above the 20,000 psi limit for +P.

Indeed it does. The .38-44 loads were usually advertised as having a MV in the range of 1100-1150 ft/sec from a revolver with metal-capped 158 grain bullets. I have used Quickload to back-calculate an approximate peak chamber pressure of around 25 KPSI required to get that MV. But I have yet to see any actual lab-measured chamber pressures of the old .38-44 load.

Underwood must be using some magical propellant if they are suggesting that it meets the established SAAMI peak chamber pressure for .38 Special +P.

 

[SuperMan]

Have not shot any of the Underwood ammo yet but have tried the two Buffalo Bore loadings with the 158 LSWC-GC HP and the 158 Hardcast Outdoorsman load.

Outdoorsman:
Colt Trooper 4":.............. 1118 fps
Colt Diamondback 2.5":... 1040 fps

HP:
Trooper 4":............. 1148 fps
Diamondback 2.5"... 1081 fps

158 grain .38-44 loads were listed at 1120 fps from a 5" barrel. There was a 110 grain load that was in the 1300s...

I'll take those loads or the Underwood over the Federal/Remington/Winchester version any day.

Bob

 

[DWalt]

Have not shot any of the Underwood ammo yet but have tried the two Buffalo Bore loadings with the 158 LSWC-GC HP and the 158 Hardcast Outdoorsman load.

Outdoorsman:
Colt Trooper 4":.............. 1118 fps
Colt Diamondback 2.5":... 1040 fps

HP:
Trooper 4":............. 1148 fps
Diamondback 2.5"... 1081 fps

I'll take those loads or the Underwood over the Federal/Remington/Winchester version any day.

Bob

I believe the BB loads are intended to duplicate the performance of the .38-44 loadings of yesteryear. Those were considered to be safe for use in any .38 Special revolvers, even though not especially good for gun longevity. I have no idea what peak chamber pressures the BB loads operate at. Do they provide that information?

 

[FortyFiveACP]

I've looked at these Underwood 38 +P loads before with their performance specs in 357 magnum range and wondered what kind of pressure they are really running. I've long read that some cartridges were run much hotter many decades ago but I don't know what hot 38 loads were like years ago.

Just looking at the real-world test results of 38 +P SD ammo from Lucky Gunner, they published 5-shot averages of 3 different 158 gr loads:
- Federal 158 gr +P: 892 fps
- Remington 158 gr +P: 921 fps
- Winchester 158 gr +P: 839 fps
(All with 4-inch barrel)

Looking at the LG tests for 357 magnum, they tested a couple of 158 gr 357 magnum loads. Those results showed 5 shot averages of:
- Speer Gold Dot 158 gr 357 mag: 1181 fps
- Remington 158 gr 357 mag: 1287 fps
(also 4-inch barrel)

I'm really kind of lost how this Underwood ammo is achieving these performance levels and not wildly exceeding accepted limits or getting into a range where they would be concerned about legal liability from some kind of kaboom.

Having said that, I've actually considered picking up a small amount of this ammo because I have a S&W M64 with 3-inch heavy barrel that I think would be reasonably well suited for this load. I wish I had bought a M65 at the time but that's another story.

 

[38SPL HV]

Here is pic of the Underwood box and cartridge sample. Pls see Underwood’s MV claim, pretty darn close to what I chronographed. Great load in my heavy duty Ruger 357 Blackhawk.

As many of us seasoned handloaders know, cast bullets usually have a greater velocity than jacketed bullets of same weight and charge…about 100 fps greater with cast in 357 Mag for example is not unusual.

 

[38SPL HV]

In my 686 6" with a 38 case;

950fps is a 38 +P load and my maximum +P load with the 6" tube
maxed out at 1124fps.

I think Underwood mislabel that box of ammo.

1241fps is a .357 case, loading, with a 158 gr bullet.

Ed, pls check the pic of the box which I just attached above and also check out Underwood’s website for this load and claims of 1250 fps…it’s not a mislabeling. Maybe it’s our higher altitude in Northern Nevada . Come down sometime and we’ll chronograph some loads together. I have some 357 Mags in the queue almost ready to go!

A lot of skeptics out there today, that’s ok, I’ll never use it in my S&W Heavy Duty but I really like this load in my Ruger Blackhawk and will continue to buy (when available) and use it.

 

[Sevens]

Nobody is skeptical of the results you got.

Everyone is extremely skeptical that these loads follow SAAMI standards for .38 Special+P.

 

[Paul in Nevada]

.38 Special +P is one of the few, rare actual SAAMI classified and standardized +P ratings, which means that SAAMI has given a .38+P a 17,500 PSI max.

Hang on a second. I think standard pressure is 17.5k and +P is 21k.

Personally, I think these boutique ammo makers get away with their excessive pressure loads by virtue of them being too expensive to shoot in large quantities. Much like the old question, "can I shoot +P in my pre-model Smith?" The answer is, it won't blow up your gun, but it will accelerate wear.

 

[38SPL HV]

38 Spl +P is 20K MAP. What’s in Underwood’s “secret sauce” and Buffalo Bore’s for that matter…whatever it is, I must commend them both for excellent ammo. I did test Double Tap 38 Spl +P 158 gr cast SWC and its performance, although better in my Ruger 4 5/8 (avg 947 fps 10 shots) than Rem/Fed/Win “FBI Loads,” was underwhelming compared to their advertised 1,000 fps from 4 inch revolver.

 

[38SPL HV]

Nobody is skeptical of the results you got.

Everyone is extremely skeptical that these loads follow SAAMI standards for .38 Special+P.

Underwood and Buffalo Bore have some very talented ballistic engineers and I personally trust their claims. Their powder formulas are certainly not obtainable under “Quickload” calculations. I’ll continue shooting their ammo, skeptics or no skeptics…everyone has a right to their opinions and skepticism…

 

[Sevens]

Hang on a second. I think standard pressure is 17.5k and +P is 21k.

Personally, I think these boutique ammo makers get away with their excessive pressure loads by virtue of them being too expensive to shoot in large quantities. Much like the old question, "can I shoot +P in my pre-model Smith?" The answer is, it won't blow up your gun, but it will accelerate wear.

Yep, I entered the standard pressure and not the SAAMI +P, thanks for catching that.

 

[38SPL HV]

Nope, MAP for 38 Special is 17K. SAAMI spec is on-line

 

[SuperMan]

I often ask the question to which no one replies...if S&W, Ruger, Taurus and others make their small frame guns in 9mm that have a SAAMI pressure almost double that of standard .38 Special ammo, why is everyone so worried about .38-44 loads at say 25-30k psi....

If one has a 50s vintage SHOOTERS BIBLE and look under the Colt section, they certified their Detective Special for "High-Speed" (as in .38-44) ammo. Their Agent and Cobra, which had aluminum frames, were not.

Is it going to accelerate wear, yes, but probably no more than a steady diet of full Magnum loads in a Model 29 vs a moderate load.

This ammo is made to be the optimum to save your life, not paper punching or tin cans.

Bob

 

[DWalt]

In the ammunition catalogs of the 1930s, there were no safety warnings given against using the high velocity .38-44 loads in any revolvers, old or new. Only a statement to the effect that there will be more recoil if used in lighter-weight guns. It appears that the main reason for using the N-frame for .38 Special revolvers was to provide more weight to better control recoil when firing the heavy loadings, and not for increased safety.

I would really like to know the actual measured peak chamber pressure of the BB loads. Note that the SAAMI standards are advisory and voluntary. SAAMI does no enforcement of its standards and there is nothing requiring individual ammunition loaders to follow them. For example, +P+ loads are not sanctioned, standardized, or defined by SAAMI, they are just whatever the individual manufacturer wants to do regarding pressure. If, say, Winchester wants to sell a .38 Special loading which produces a peak pressure of 50,000 PSI, there is nothing to stop them from doing so if they are not concerned about legal liability and consequences.

 

[16thVACav]

I'll need to dig out my old physics textbook, but I seem to remember that pressure (and other risk) decreases proportionately as the number of lawyers increases.