Well, it has been an interesting learning experience handloading for the T/C Contender Super 14 .375 Win. I got a while back. This particular barrel seems to only like two loads that I can tell, but man it REALLY likes them.
Unfortunately, the best accuracy so far has come from the Winchester factory 200 gr. FP loads...but at $50 per 20 rounds thats just not an option for me. The factory ammo runs right at
1 1/4" @ 100 yards for 5 shot groups.
My best handload so far is with 35.5 gn. Reloader-7 pushing a Hornady 220 gn. Flat Point, using CCI primers. They come in at
1 3/8" to 1 1/2" @ 100 yards for 5 shot groups.
Reloader-7 is the only powder I have tried so far, but when funds allow i will try some other compeonents as well. But so far, here are my results...all loads have been tried more than once to confirm findings.

Primers: CCI large rifle
Powder: Reloader-7
Bullet: Hornady 220 gn. FP

33 gr. 3-4" vertical strings
33.5 gr. 4-5" vertical strings
34 gr. 10" vertical strings
34.5 gr. 7" vertical strings
35 gr. 3" groups
35.5 gr. 1 3/8-1 1/2" groups
36 gr. 2-2 1/4" groups
36.5 gr. 8" shotgun patterns

If any .375 Win owners out there have any suggestions on other suitable data please feel free to share. I think my next step will be to work in .10 gn. increments from 35 to 36 to see if there may be a magic area on either side of the 35.5 gn. load. If not, the 35.5 gn. load looks to be a mighty fine recipe for this barrel out to 100 yards.

I bet if you contact JD Jones/Sixgunner paper,he probably has some loads you may like.

My .375 Win:
220gr Horn FP / 33.0gr IMR 4198 / CCI200 = 1.5" @ 100
200gr Sierra FN / 32.0 IMR4198 / CCI200 = 1.5" @100

My load of Re-7 was too hot and it popped oen the bbl...I stopped!

I had the most fun loading Black Powder Round Balls over 9.5gr SR7625 but bullseye or x700 should work too.

There are a lot of onsite locations with loading data if you Google it.

Have fun,
Bill

I not on all the time so I have a few things to threw out…
Are you crimping?
Where are you setting your bullet?
What type of crimp did you use if you are?

I set my bullet .15 off the lands and then used my crimp. HOWEVER, it isn’t a roll crimp. (I “think” mine is a profile crimp?) And I engage it just to make it snug, not to deform jacket. {I don’t have access to my loading books to look it up right know so if someone would be willing to jump in here on this one and help it would be MOST appreciated!} My dies are CH-4D if that helps any.
You don’t HAVE to use a crimp for the 375 Win, in fact a lot of books suggest shooting them both ways.
Ps, the nice thing about the 220 Hornady is its REALLY flat point. I can’t reach the lands with a 200gr Sierra or a 235 Speer, but the 220 Hornady does it with ease.

I have not tried crimping yet, but I will on the next batch I load as I am curious if it will make a difference. If I remember correctly I am seating to an overall length of 2.550, I have not played with the seating depth as of yet either. So, there are two more variables I plan to work with eventually.
Since its shooting so good at 100 yards right now, Im just dying to see if I can play around with seating depth, crimp, different powder to see if I can get it to shoot under an inch at 100 yards. I do believe the barrel is capable of it...I just need to find the magic combination of componenets that will do it. Gonna be fun getting there for sure.

What are you using for a rest? Such vertical stringing can be an indication of inconsistancies in the hold or rest.

The rest was my first thought as well, but Im shooting on a dead solid padded rest. I rest the pistol right in front of the trigger guard every shot, same position every time as is recommended with the Contender pistols.
Repeated tests showed the same vertical stringing with the same loads that strung vertical before. The results were the same and showed that once you hit 35 grains with the charge...the vertical strings stop and you actually start shooting groups.

i really like the old surplus AA 2200 in mine , i havent tried the new stuff yet but it should be close , i also like their AA 1680 ( but i have a bit of the other ) i've been playing with cast in this lately but the speer 235 grain sp. does well in mine , h322 turned in my tightest group with that bullet , with what you listed i'd try around 35-36 grains seems that that was close to where your tightest accuracy was , a few tenths either way ... maybe seating depth or a different primer , just have to play to find it

Exactly what I was thinking fryboy, for now though 35.5 grains is where Im throwing loads for this deer season. Will experiment with different primers and seating depths next spring. Less than a month away from firearms season here and everything is ready to go, cant wait.

..tenderfan,

I've had my best luck with Accurate 1680, 38.6 grs., Hornady 220 RNIL, WLR primer, in all of my 375 WCFs ( 12" MGM, 14" T/C, Savage 99, Ruger #3, Marlin 375, and Win 94s ). Barrel lengths vary from 12" to 22". Group size averages approx. 3/4" @ 100 yards, assuming, I do my part.

Doc

Thanks for the data Doc, will jot the info down for later use.