38 Special & Vihtavuori Powder

Hammbone81 · Mar 15, 2025

I'm looking for a practice load that matches Hornady Critical Defense 110gr FTX (non +P) in velocity and POI. Specifically for a S&W Model 36 1.875" barrel.

I have Zero 110gr JHP bullets and various powders, primarily Vihtavuori (N310, N320, N330, and N340), which I plan to test. (I also have Bullseye, Clay's, HP38, Power Pistol, and Universal)

I've noticed a significant discrepancy in load data, I'm specifically showing what I see with N320. The Complete Reloading Manual for .38 Spl. lists a starting load that's at or above the max load in most other sources, including my Lee manual and Hornady and Vihtavuori current online data. I understand that load manuals have become more conservative over time, but does anyone have experience with this older data?

BrBa · Mar 16, 2025

I have some recent experience with N320 that matched the Vihtavuori online data for 9mm. Haven't used it in .38 but I would trust their data. Hornady load data usually seems a bit watered down compared to other sources.

Hammbone81 · Mar 16, 2025

BrBa said:
I have some recent experience with N320 that matched the Vihtavuori online data for 9mm. Haven't used it in .38 but I would trust their data. Hornady load data usually seems a bit watered down compared to other sources.

Thanks. The challenge is that I have current Vihtavuori data as well as what appears to be old Vihtavuori data that is grossly different. (See images attached)

gwpercle · Mar 16, 2025

I usually defer to the powder manufacturer's Data ...
Start with the current data ...
The old adage of ... Start Low and work up Slowly ... Applies here .
The older data was at times done without the benefit of modern testing equiptment ... they use better testing and as my Mom would tell me ...
"Better Safe Than Sorry !"
Go with the current VV data and if needed ... work up slowly .
Load Safe
Gary

RDub · Mar 16, 2025

Hey Hammbone81
You didn't mention if you have a chronograph.
I've worked with N320 quite a bit in 38 SPL and found it delivering very respectable velocities with good accuracy, compared to similar powders. I would concentrate on N320 first in your testing. Also you can trust the newer VV data. I've found it to be very close to reality.

D Brown · Mar 16, 2025

I have the VIHTAVUORI First Edition Reloading Manual, published in 1994 and may be able to shed some light on your conundrum. The first edition lists maximum CIP values for the .38 Special as 21,700 PSI and SAAMI values for the same cartridge as 18,000 PSI.

The table for 110 gr. Hornady HP/XTP shows a starting load of 5.8 gr. of N320 at 16,000 PSI for 1147 fps from a 6.5" barrel.
The max load in the same table shows 6.4 gr. of N320 at 21,000 PSI
for 1259 fps from the same 6.5" barrel.

Obviously, there is a combination of SAAMI and CPI information in this book, and it's not made clear to the reader that this is the case.

The above referenced starting load is within SAAMI guidelines. The max load IS NOT within SAAMI guidelines but IS within CIP guidelines.

I don't have a more current manual from VIHTAVUORI, but it appears they are no longer mixing SAAMI and CIP data.

Conclusion: The old data is O.K. as long as you pay attention to the two maximums. Safest bet of all, use the most current data you can obtain.

Daimler1989 · Mar 16, 2025

VV reloading guide from 2019 says: 5.4 to 6.1 grs N320 for 110 grs XTP, or 6.2 to 6.9 N340

good luck

regards from Germany
Ulrich

rockquarry · Mar 16, 2025

I think the later Lyman books have VV powder listed for .38 Special loads.

Yendor357 · Mar 16, 2025

I used to go by the books.

Until I got my Garmin. I chronoed some 185 JHPs in my 645. The book said the 185s were going 1100. They chronoed 1300+! Needless to say, I pulled those apart, and re-did them.

If you’re serious about handloading, spend $600 and get a Garmin.

Hammbone81 · Mar 16, 2025

@everyone, OP here;

Okay more info. Yes I have a chronograph (just got the Garmin). And yes I did some initial testing. And yes I started low and worked my way up.

Vihtavuori current data with 6.5" barrel
Bullet: Hornady 110gr XTP
Powder: N320
4.8gr = 965fps
5.4gr = 1096

MY data with S&W 686 4" barrel
Bullet: Zero 110gr JHP
Powder: N320
Only 5 shots each group
4.6gr = 737fps, 108 spread, 45sd
4.8gr = 694fps, 124 spread, 51sd
5.0gr = 788fps, 110 spread, 39sd
5.2gr = 890fps, 232 spread, 86sd
5.4gr = 890fps, 138 spread, 54sd

Summary: At max of 5.4gr I get 890 in a 4" barrel to Vihtavuori's 1096 in a 6.5" barrel. In other experiments I "typically" see a difference of about 50fps per inch, which means I would've expected around 950-ish out of my loads. Also, I thought it was weird that going from 5.2 to 5.4gr didn't yield any more velocity. I wonder if I'm at a pressure limit?

BrBa · Mar 17, 2025

Hammbone81 said:
Thanks. The challenge is that I have current Vihtavuori data as well as what appears to be old Vihtavuori data that is grossly different. (See images attached)

Easy. Go with the current online data if the powder is a recent lot.

38 Special & Vihtavuori Powder

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