Can this powder charge be too low?

[Famousfamas]

Greetings!
This is my first posting here on THR so I would like to introduce myself.. I have lurked on this forum for a few months and I am looking forward to receive some of the great knowledge that you offer here. Thank you in advance.

Here's my first question: is there a long term or unseen risk with the load that I just developed for Cowboy SASS shooting?
I used to load 3.5 gn of Titegroup , 130gn lead RNFP, 38 Special Federal 100 primer. I want a lighter load to reduce recoil to a minimum which would help my wife and daughter as well. 5 of us shoot in the family.
So I went down to the range with a Uberti Cattleman 5" 1/2 and a Winchester 1873 18", as well as a Lee hand press, Hornady auto-charge, Chrony and I came up with a new charge that I'm really happy with, going down in charge weight gradually from 3.5 to 2.4gn. But before I load the first few thousand rounds a big WHAT IF came to my mind. So if after reading the results any of you has a red flag to raise please do.
I appreciate your time and experience.

Titegroup 3.5gn

Pistol velocity ranges from 251 to 758. Crazy isn't it? Average 495 fps
Rifle velocity ranges from 981 to 1027. Better. Average 1002 fps

Titegroup 3.0gn

Pistol velocity ranges from 642 to 670. Average 653 fps
Rifle velocity ranges from 779 to 905. Average 847 fps

Titegroup 2.5gn

Pistol velocity ranges from 530 to 548. Average 545 fps
Rifle velocity ranges from 649 to 754. Average 700 fps

Titegroup 2.4gn

Pistol velocity ranges from 496 to 525. Average 516 fps
Rifle velocity ranges from 593 to 644. Average 638 fps.

The wild range that I got from the 3.5 gn charge brought some memories from loading 45 Colt with Titegroup. There was so little powder in that big 45 case that some some of it failed to burn and was flying in front of my gun while shooting. I decided to load the 45 Colt with Trailboss and the results came very consistent. But for the 38 Special I am very surprised on how much more consistent the results are all the way down to the 2.4 charge. I still shot a 1"1/4 group at 10 yards with that low load.
I did notice that the cases coming out of the rifle were a bit more fouled with burnt powder as I went below 3.0 gn. I assume that it's because the case was under less pressure.

Thank you for reading this. Happy shooting all!

Famous Famas.

 

[Blue68f100]

Have you determine if these charges will be position sensitive? With the broad spread at the 3.5gr, indicates this. I would do some more testing on powder position. You may need to use a filler to keep the powder at the primer.

Trailboss may be better suited.

 

[243winxb]

Titegroup 3.5gn

Pistol velocity ranges from 251 to 758. Crazy isn't it? Average 495 fps

Maybe not a good reading from the chronograph? I have to wonder how the bullet made it out the end of the barrel at that velocity. Welcome to the High Road.

 

[Famousfamas]

Have you determine if these charges will be position sensitive? With the broad spread at the 3.5gr, indicates this. I would do some more testing on powder position. You may need to use a filler to keep the powder at the primer.

Trailboss may be better suited.

Put it this way, the bullets were shaken, stirred, some dropped on the loading table. So position was not a factor I think, especially since the variations decreased as the charge came lighter. Very odd to me. Maybe I became a better shot as the loads became lighter

 

[Famousfamas]

Maybe not a good reading from the chronograph? I have to wonder how the bullet made it out the end of the barrel at that velocity. Welcome to the High Road.

Thank you.
You're right, maybe the Chronograph malfunctioned. I'm still curious about possible dangers. The bullets made it just fine to the paper. SASS allows bullets to fly as low as 400fps which was my aim. According to their "Power Factor" formula, with the 130 gn bullets I'm allowed to shoot a low as 475 fps.

 

[Walkalong]

As pressure increases, the velocity spread tends to decrease. If you are too low, wide ES numbers can happen.

Position of the powder. It doesn't matter if the cartridges were shaken, or stored on their sides or upside down. If you are hanging the gun by your side, and then bring it up level to shoot, the powder position will be to the front and can greatly affect velocity with some powders. Titegroup is average as far as position sensitivity goes, despite advertising. If you point the gun up, then bring it level to shoot, the powder will be to the rear against the primer and the velocity will be greater. Almost all powders drop velocity when forward in the case when the fill volume is less than 100%, and it gets worse as that percentage decreases.

It's easy to test.

And yes, sometimes you'll get a bad chrono reading. Always repeat tests to see if the data is consistent.

 

[Famousfamas]

Thank you 243winxb. I'll go back to the range and test again.

 

[Famousfamas]

And thank you all as well.

 

[WestKentucky]

I would seriously look at a filler patch. That light of a load needs help with consistent ignition due to powder position and low volume. A filler patch or wad would solve both problems, or you could shoot a heavier bullet seated deeper in the case which is likely the direction I would go. A heavy bullet will fill more case so it will increase pressure and keep powder close to primer. Heavy bullets also tend to do better on staying straight on a windy day. Those light bullets tend to blow off but heavier stay true longer.

 

[BCRider]

You're really getting down to where it's going to feel more like a .22....

I've found Tightgroup to be very tolerant of small amounts in big cases. Another good powder for that is Bullseye. Bullseye in particular is/was the powder of choice for accurate bullseye match shooting in .38's with charges from 2.6 to 2.9gns behind lead HBWC bullets. This suggests that you may find a slightly tighter velocity variation with Bullseye over Tightgroup.

I too suspect that you had chrono issues with the low velocity readings on the 3.5gn loads. Or you managed to get some bad charge drops that came out REALLY light. The other loads all have variations that seem pretty decent so it's pretty much got to be a chrono or bad powder drop issue.