.38 Special +P Overload?

[NailGun]

Help me out here guys. How does one go about determining if a .38 special + P handload is too hot (excessive pressure)? I loaded up 30 rounds the other day to try out in my new Smith 442. I worked up the load in 6 steps of 5 rounds, using Hodgdon HS-6, loading up to Hodgdon’s published max. The rounds showed no signs of high pressure. However, the recoil became unpleasant.
I was reminded today that the 38 special will probably not show signs of high pressure…the signs that I would have been inspecting for.
(with a big sigh, and in my best Jacques Clouseau accent…”I knew that”….hmmm.)
OK then, Hornady’s published max. load for HS-6 is 8.1 gr. using a 125 gr. HP XTP expecting a velocity of 1000 fps. with a 4” barrel.
Hodgdon lists 7.8 as max. using 125 gr. XTP (.3 grains less than Hornady) expecting a velocity of 1138 fps. out of a 7.7” barrel.
If I shoot 5 rounds through my chrony, at what velocity can I figure I am pushing the PSI limit with a 1 – 7/8” barrel? Or….is the published Max. a safe maximum limit? What other bad signs should I be looking for? Thanks, NailGun

 

[Waffen]

It's hard to say on a short barrel like that. I would say if you get anywhere around 850-900 FPS that would be your max. If this is a carry gun a robber isn't going to notice the difference between 100fps anyway so I wouldn't worry about it.

Other signs you can look for is brass being hard to eject, or flattened primers.

 

[stoky]

Please be careful. IMHO this is not a good gun to push max loads with. Besides being unpleasant to shoot, max loads will accelerate the wear on your fine little revolver. If you must have .357 velocities get a .357.
Having said that, the best way to look for pressure (sans a piezo sensor) is to measure case head expansion with a micrometer.

 

[NailGun]

Thanks for the info, guys. The 442 is my new attachment which follows me everywhere now. I have a 686 that I shoot for practice and fun, and it is MUCH more enjoyable to shoot. I worked up the HS-6 rounds to get a safe but maximum velocity/energy round for defense.
Question: Will a .38 Special +P Hodgdon max. published load of HS-6 develop enough internal pressure to actually show high pressure signs such as bulged cases, thinning head sections, loose - punctured - flowing primers, expanded primer pockets? Or...do we just observe chrony speeds, tight extraction, unpleasent recoil, and hope we are OK? OR....???
I really like the sans a piezo sensor idea. I will have to look into getting one. Reloading for rifles seems to be easier, since I usually work up a load for accuracy and achieve that goal before getting to any mfg's published max. Thanks again, NailGun

 

[griz]

Question: Will a .38 Special +P Hodgdon max. published load of HS-6 develop enough internal pressure to actually show high pressure signs such as bulged cases, thinning head sections, loose - punctured - flowing primers, expanded primer pockets?

In a word, no. Look at it this way, the same primer and brass (plus a little bit in length) is used in the 357 at twice the pressure, and the primers don't leak at those pressures. Some say that you can still measure case head expansion at 38 special pressure levels. I believe someone who measures very carefully can tell some changes compared to other loads, but we're talking tenths of a thousandth of an inch. Even then you have to have something (factory loads?) to compare the measurements to. By and large, I think your comparison of chrono readings with suitable powders is the best way to go.

 

[NailGun]

Thank You Griz. I suspect that the Hodgdon max. load, being less than the Hornady max. load, in a new firearm, will be safe. I have a day off tomorrow, and if it don't rain I will be running some rounds through the chrony. Mine, and Corbon's. Guess I will see what velocities a 1.875" barrel can produce. I'm supposing that if a Smith 442 is unpleasant to shoot, it will be equally unpleasant to be on the receiving end. Suppose I could pester Hodgdon with an e-mail too, and see what they say. Naah. Thanks again. NailGun

 

[griz]

I'm not sure you want to use Cor Bon as the comparative load if you don't want to exceed +P pressures. I can't measure pressures either, but I had some 125 grain 38 special Cor Bons that went over 1300 FPS from a four inch barrel. If that isn't over pressure, it sure is right at the edge of max. Hopefully someone here knows of some pressure testing done with that ammo?

 

[Steve C]

Only a few manuals actually list the pressures for their loads. Some of the small companies or custom loaders load their ammo to near maximum pressure like Buffalo Bore and Corbin but IMO the big 3 leave themselves a good margin of safety. A good example of this is a +P .38 spl load from the Winchester 2001 data of 4.7grs of W231 with a 158gr SWC listed at 860 fps and 17,100 psi. I've put together this exact load with Speer 158gr LSWC and LSWCHP's with Winchester cases and primers, the resulting velocities over a chrono where 879 fps from a 4" Smith M66 and 911 fps from a 4-5/8 Ruger BH. Winchesters 158gr Super X LSWCHP is listed at 890 fps from a 4" barrel so my results where pretty much spot on the factory load. SAAMI +P max pressure is 18,500 psi and standard .38 spl is maxed out at 17,000 psi. So if we where to judge velocity as a guide to pressure (which it isn't always) I'd suggest that factory Winchester +P is closer to the 17,000 psi maximum standard pressure with lots of room to grow before reaching over 18,000 psi putting it at the higher end of the +P pressure.

Personally I’m quite happy with an equivalent load to ammo as well proven as the Winchester 158gr LSWCHP +P is. I’m pretty much assured by both the pressure data listed in the load information as well as corroboration from the chrono that this particular load is on the modest side of +P. Even at that I still shoot it mostly from K frame .38’s, .357 magnums and only carry it in smaller “D” frame Colts after modest testing.

 

[NailGun]

Chrony Results.
Pro Chrony, 6 feet from muzzle, 5 shot strings, overcast, 62 deg.
S&W 442, .38 Special 1-7/8" barrel.
-----------------------HI-----LO-----AV----ES----SD
CorBon 110 +P JHP-----958----786----881---172---64---OEM
125 JHP 7.2 HS-6------865----818----847----47----25---Hand Load
Fed. AE 158 LRN-------738----720----732----18----10---OEM

The +P loads that I worked up to (and did not shoot through the chrony while working up the load) were indeed hot. When the velocity surpassed the lighter CorBon +P loads I was a bit surprised. And, no, I'm not sharing that data. The 7.2 gr. HS-6 is the Hodgdon published max. for .38 special (not +P) 125 XTP. It has pleanty of snap in the little 442, as did the CorBon and Federal. Gotta love that SD on those Fed. American Eagle rounds. Now that I have the testing out of my system, I will load up with the CorBon's and hope to not have to shoot it again for a long time. Thanks All, NailGun.

 

[NailGun]

Thank You Steve C. That is a lot of good info that you got posted there. When we can duplicate factory loads, I think we done good. And, a good reminder to me to use All my reloading resources and not get lazy. NailGun