Looking for input on 38 super load workup

I've been trying to work up a load for a 38 super.  Was experimenting with 115 grain SWC from Penn and also 125 grain truncated cones.  Using Titegroup for a number of reasons but maybe there are better powders for the 38 Super.  Anyway, I was getting less-than-stellar results from the 125g at 50 yds; best I could do was 3.6g TG for a 4" group.  I don't plan on using the 115g for long line so accuracy there is not an issue.  Then I started playing with the Magnus 130g SWC again and tried increasing the charge beyond 4.0g and found it was terrible.  Tried reducing it below what I thought was reliable with the 125g, and found that I got a 3" group with 2.6g TG.  Interesting, but I'm a little worried that's the very low end of reliability, and if I'm shooting on a cold day, I might have issues with FTEs.  Reduced my spring from 10 lb to 8 lb and found that the group size increased beyond what I was happy with, but that's another mystery I wasn't anticipating and maybe something for another thread.  Probably also confirms my fears of being on the edge of reliability.

I have not inspected my barrel but I am reading the manufacturer uses 1:16 twist.  I'm surprised that my loadings on the high end (4.0+) are not accurate; it seems like that is where other shooters are saying they have accurate loads for Bullseye powder, and Titegroup is almost always on par with Bullseye loadings.

My question:  I've seen some posts by shooters using 147g bullets, which is the direction I want to try next.  What profiles are you using?  The 130g Magnus bullet (no. 509, sized to .356) is what I was using; it has a lot of bearing surface/engagement length.  Also I'd like to have a SWC for ease of scoring.  Has anyone used the 148g button nose Magnus 502?  Would that "work", or do I risk not having enough powder area/too much pressure if I seat it all the way?  Does anyone use the 38 150g profile that Brazos has in their 38 super section?

I'm using the 150 Brazos with 5.5 of Accurate #7.
It's been good at the short line, but have not had chance to canoe out to the long line I have access to (busy designing an ark with a range).

I'm using Zero 125gr HP. They are a .356 bullet (4.6gr BE). I test my 50 yd ammo by shooting sitting down with my wrist resting on a sandbag. The 115gr HAP bullet needs 5.0 gr BE. I also like the Magnus 147 gr FP(also 4.6gr BE). I have not quite found the sweet load yet for the 147 gr but I'm getting close and they work great on the short line.

Thanks guys.  I'll try the 147-ish bullets and report back.  Lenv, those loads seem like they would be horrendous recoil.  What spring do you have installed?

I am getting great results (1.75" @ 50yds) with a 147gr Bevel Base Flat Point and 2.8gr of WST 1.25 OAL .379 crimp (frame mount & 6" barrel) others are using 3.0gr of WST (slide mount).  Bullets can be bought from Magnus (NO. 403).  Very soft shooting, almost like my M52.  The others I have exchanged info with are running 1-16 and 1-18 twist barrels, I'm running a super fast 1-10 twist - gun was built by KC.
- Dave
All with new Starline 38 Super Comp brass

Centerline, Not in any particular order. I use a 12# spring with a slide mounted dot. The recoil is very manageable. I use the same 4.6 gr for my 185gr JHP's with my .45. And most important with my 1:16 twist if I load it down it goes all over.

If you decide to go with jacketed bullets, there is some data here:

https://www.shootingtimes.com/editorial/super-accurate-38-super-loads/326242

Well I did some Close Inspection and Heavy Math on my barrel, and it looks like 1:13.  Which may not be a thing, but it's not 1:16, and it doesn't look to be 1:10.  I've heard of 1:12; maybe it's that.  I'm thrilled because I wanted to be able to shoot the lighter loads.  It explains why the heavy bullets were hitting everything but the target at high loads.  Now just waiting for new sample bullets to come in . . .

KC sent me this with the 38 Super he built...  454AA isn't made anymore.  I believe WST was the replacement.  I hear the Meister bullet is no more either.  The Magnus 147 is a good replacement bullet.  Terry at Magnus will size the bullet whatever size you need.  FWIW gun recoils like a 22...

You mean these?   https://www.meisterbullets.com/AWSProducts/411-C-22-P-0/09mm-150GR-SWC-356-1000-count

Bayou makes a similar bullet.   https://www.bayoubullets.net/38-super-150-gr-swc/

Following up on this if anyone searches in the future.  I sampled several different heavy bullets from Brazos including a 147g FP, 150g SWC, and also the 150g BNWC.  The 150g SWC was stable over a wide range of loadings from 2.6g to 3.2g (all Titegroup) but mostly gave about 6" spread from a sandbag rest at 50 yds.  Best was about 4" with 2.8g TG.  The flat point bullet showed some promise but I think I'm going to go back to the 130g Magnus bullet, which gave a 3.5" group with 2.6g TG, and makes a cleaner hole.  The BNWC was terrible at any loading so I gave up on that.
For 25yd shooting it's a tie between 125g truncated cone with 3.0g TG and the 115g Penn SWC at 3.2g Titegroup, which both give a 3" group.  I'm a bit disappointed in that because I feel they should do better at 25 yds.  Both have a similar, good recoil feel.  I could juice it up to match the 4" group at 50 yds I got with the TC bullets, but that's 3.5g TG, and a bit more recoil than I'd like to have for rapid fire.  All of this with 10lb spring and frame-mount optics.

I do have a load for the 115gr Penn that I worked up. It works nice for the short line but not so nice for the 50yd stuff.