For many years, at least 40, I have loaded a 140 grain JHP over 9 grains of SR 4756. From my 6 inch Model 28, my chronograph shows a bit over 1200 FPS. Good accuracy, but it does recoil a bit.

I had loaded 13.5 gr. of 2400 under the Speer 146 half jacket for a fairly stout load for my 28, but I refrained from using them in my Model 19. Your load sounds pretty hefty, since I only use 8.6 grains of 4756 in my 44 SPL.

Old70

Sounds like you found that load in the Speer #8 Manual. It had(has) a reputation of having starting loads,especially with SR4756, actually being close to max loads.

Though loaded in .38 Special cases, I wouldn't want to shoot them in a K frame .38 like a M15.

Back when I tried 2400 in my .38 Spec with 150 gr cast bullets, there was a lot of unburned granules. They got under my K-38 ejector, making it hard if not impossible to close the action. It may burn cleaner with heavier bullets.

I like full house .38 Spec loads with Unique. Very clean when burned hot, almost no residue.

DF

found it there yes, back many years ago. 1970 edition. I have played with the charge, going up and down. The 9 grains gives a good compromise. Fast, accurate and fun. It is a good load in my Model 60 three inch, instead of using a .357 mag load. With some 40 years of experience using the load, I'd say it was spot on for a 'max load'. No complaints here.

I just finished loading a batch of SWCs from my new RCBS 38-150KT mold. I put them over my standby load of 5.5gr Unique. It’s a bit hotter than normal +P stuff but not 357 territory. I mostly use this load in my N frames but it doesn’t bother me to use it in my Ks and sparingly in my all steel Chief Special.

5.5 grs. of Unique is hotter than +P?

It’s over what Alliant lists for +p with a 158. All of my newer manuals show loads stopping around 4.9-5.2gr. I think Skeeter used to use 6.5 or 7 grains under a 358156 for use in his 357s without using “expensive” 357 brass.

I seem to remember 5.5 showing about 1000fps out of my 6.5 Outdoorsman and I’ve shot several pigs with good results. Not a smoking hot load but hotter than what you get off the shelf at the store.

Using the same bullet as the "kid" and 5.0 grains of Unique I've shot a hell of a pile of them in K's L's and N's. It don't bother me at all to use them in my M60 DAO because J's got thicker cyl walls than K's. MB

Yeah that caught me off guard, I've been using 5.5 grs. of Unique with 158 gr. cast in my M15 for a woods roaming load for years. Pretty sure I have older load manuals that list that as a max +P load.