Question about 38 S&W commercial ammo in older top breaks

[tx77057]

   
Question about 38 S&W commercial ammo.
 
I have an old 3^rd model Iver Johnson in 38s&W. I have a chance to purchase PPU and had a question on the velocity /FPS side of things. But I’m not sure because of the possible higher pressure and FPS.
 
Taken from Midways website for a few other brands in the 38 s&w category, they are as follows:
 
All Bullet Styles are Lead Round Nose
 
PPU
 
Bullet Weight: 145 Grain
 
[/size]Muzzle Velocity: 787 fps
 
[/size]Muzzle Energy: 136 ft. lbs.[/font]
 
[/size]Remington
 
[/size]Bullet Weight: 146 Grain
 
[/size]Muzzle Velocity: 685 fps
 
[/size]Muzzle Energy: 150 ft. lbs.
 
[/size]Winchester
 
[/size]Bullet Weight: 145 Grains
 
[/size]Muzzle Velocity: 685 fps
 
[/size]Muzzle Energy: 150 ft. lbs.
 
[/size]MagTech
 
[/size]Bullet Weight: 146 Grain
 
[/size]Muzzle Velocity: 686 fps
 
[/size]Muzzle Energy: 152 ft. lbs.
 
[/size]If you notice, the bottom three manufactures all seem to have the same FPS and Muzzle energy (or very close) being under 700 FPS.
 
[/size]How does PPU get a lower Muzzle Energy while having almost 100 more FPS with the same weight bullet? And would this higher FPS be safe in an older top break revolver?
 
[/size]I have heard that PPU round for round equivalent is usually loaded milder but I just wanted to ask around first because everything I have read so far has told me to stay under the 700 FPS mark for safety.
 
[/size]Also, has anyone actually done a speed test with any of these, as I do not have a chronograph.
 
[/size]Thanks in advance.
 

[Ladobe]

Far too long ago to remember any of the specifics, but from the mid 60's to maybe the late 70's I had a bunch of IJ, F&W, etc Safety Automatic Hammer and Hammerless and Model 1900 revolvers in both 32 S&W and 38 S&W (2.5"-6" round and octagon barrels - top break and not).   Somewhere between 2-3 dozen of them because at the time you can buy all you wanted for $5-$10, and the nicest ones for $15.  A few were still in good enough condition to be shootable... but many of them were not.   Even way back then what factory ammo that was available at the time was questionable as safe for them, so I loaded all my own ammo with cast bullets.   Wasn't really worth the effort or expense, they were just pop guns.

[wolverine_1]

Probably depends on the design of the catch mechinism.  I have and IJ with the normal mechanism and the latch is a bit stretched.  I also have a S&W where the top strap slips over the frame and it carries the tension.  The release mechanism just keeps it in place but doesn't take any strain.  It is still as tight as when new even though it may be 100+-.

[Hank08]

Like Ladobe, in the 60s and 70s I had a bunch of them in 32 S&W, 32S&W long and .38 S&W and shot a lot of old & new factory ammo in them with never a problem but after I started Cowboy shooting I saw a lot of them that came unhinged from folks shooting reloads.  I loaded mine light and had no problems but if you unscrew that screw thru the hinge and take a look at the very small amount of metal holding the gun together I think you'll want to keep your loads down even below 700 fps and ,of course, it depends on the make and the condition of the gun. H08

[Mikey]

tx7:  Handguns magazibne just ran a article on the 38 S&W and the revolvers that fire it and it appears the ammo made in that caliber today is soft enough for those old top break revolvers.  There is certainly nothing high pressure about teh loads you quoted and they should be safe in your revolver but, have a qualified gunsmith check it out first. 
 
And, from my personal perspective, if you would like to shoot the 38 S&W you might wish to check out the Enfield and Webley revolvers as they are stronger and can use the British 38/200 or the 38 S&W.  HTH.

[gcrank1]

Round ball loads will help keep the pressures way down, and black powder loads are what they were made for (even those produced after the advent of smokeless). I have had some nice ones and decided I was NOT going to be the one who messed them up after they had survived so long; cant tell anybody what to do with their own stuff, but just sayin' ......