Hello;
I enjoy my .257 Roberts, and I've been using H4350 Extreme and H4831 Short Cut powders in my .257 Roberts, due to their advertised lack of temperature sensitivity, with ho-hum results.

I see many people recommending IMR 4831 and 4350. If I switched manufacturers, might I see a difference?
Thanks

Its hard to say without more info.
What groups are you getting now?
Rifle, bullet, scope, combo, Bench?
my go to powders are IMR4831 and AA2700. 100 and 120gr bullets. H414 with 75 and 80gr bullets.
I have found with my 257 it likes loads at max.
With some pressure signs and after about 3 reloads the brass is shot.
I have backed the loads down and gave some accuracy for longer brass life.

I use 4350 as the slowest; others are too slow. Try 4320 with 100 grain bullets but watch for pressure. I get some amazing velocities out of my Ruger but the bullets are only seated 1/8th in the case. Will you see any diff; only one way to find out.

In my experience if you change anything you can change your groups size, sometimes that's good sometimes not. Powder, primers, brand of brass, seating depth, bullet all have an effect.
I personally shoot IMR 4350 in my 257 Roberts pushing 117 grain Sierras, groups are tiny and velocity is over 2900 with a 23" barrel, I am right at the lands is where my rifle found it's best accuracy. This rifle likes a max load.

My son's 257 shoots 100 grain Sierra's better than 117's and his rifle likes RL 17 and IMR 4064. also going about 2900 which is not a max load.

With that case capacity your in the right ballpark with the 4350. That said, this would also depend on which 4350 you use as the burn rates are slightly different. I did see though your using the Hodgdon version.

In my testing of the three different 4350's I found IMR the quicker with Hodgdon being next and Accurate being a touch slower. My testing was with my .243 with 95 & 100gr and .308 with 130-150's. I also had similar results working with my .270 using 130gr loads.

Switching primers, changing seating depths and even different bullet brands or construction however, can also on their own or combined can also influence this. Noting your location, you probably see more of the colder temps than I do.That being the case I can see why you went with the H4350, but it might be worth trying other powders as well. The RL series as well as some of the Ramshot powders might work equally or possibly even better.

Before switching things up though playing with the seating depth may be the easiest fix.

All good advice. I went w/ H4350 in my Roberts due to it's temp insensitivity and Barsness advice.
Try different primers, charge weights,seating depths and bullets. Make sure your barrel is clean. Most Roberts load data is on the mild side but you can get good info from Waters and Barsness.
I do not load mine at max and get right at 3000 fps w/ 100g NPs and great groups.
Good luck on your quest.

H-414/Win 760.....use a magnum primer.

From Hodgdon's...IMO, this a very good advice.

"What powder do you choose? When you look at reload data, the list of powders is usually long, and any one of them might work great. But here is the trick to hone in quickly on the ones that may work best.

First, choose the bullet for your intended use. Review the reload data to find the velocity level you wish to achieve. As you look at the powder charges, chances are very good one of the powders that meets your velocity criteria shows a “C” beside the maximum charge and/or gives one of the highest velocities. The “C” means a lightly compressed charge of powder. That is an ideal situation, as maximum or near maximum charge weights that yield from 95% to 103% load density tend to give the most uniform velocities, as well as top accuracy.

I’ve yet to see a benchrest shooter whose load does not completely fill the case, as well as give top velocity. The same holds true for a varmint shooter, case full or darn close to it. Along with that particular powder, the powders listed closest to it on either side will likely be in that 95% to 103% range as well. This is a great place to start. Simply start with the beginning load for that combination and carefully work your way into the maximum, at all times watching for case head pressure signs. You can save a lot of shooting by carefully going up in 1/2-grain increments at a time (in mid- to large-capacity cases). Fire only two rounds of each charge level, each pair at a different target. Shoot slow enough to not overheat the barrel. Some of these two-shot groups will show a willingness to group closely. When you find shots that group tightest, load several rounds and then shoot five-shot groups for verification.

I do not have one rifle that doesn’t group the best somewhere near the max load. Should this not provide the accuracy required, either change primer brands and repeat or try one of the powders on either side of the one you just tested. Chances are very good one of these will lead you to a load that meets your expectations."

For heavier bullets in the .257 Rob...I would definitely test IMR-4350. IMR-4350 tends to stand out as top powder for this cartridge with 100-120's. And yes...IMR can be much different from H.

Thanks for your input, all; I'm a bit late in responding, but I did discover one reason for decreasing/ho-hum accuracy with all my guns! CATARACTS! I have about recovered from double cataract surgery, and I can See! I hadn't realized it, but over the years, my eyes were increasingly covered by a yellowish-brown filter. I had one eye done, and discovered that my dim, yellowish tint LED flashlight was actually bright and the tint was a cool white! With my other eye, it was the same.
So, now, 20/20 for one eye, and 20/30 for the other, and very little astigmatism, but I do need readers from ~1'-6-7'.
Who knew?

Anyhow, not to hijack my own thread, but I agree with the recommendation to apply John Barnsness' advice, as I have found his opinions to be to be reliable, useful and conservative. Especially on the inTernet, you have to pick your "experts" very carefully...Over the years, mine have been Jack O'Connor, Edward Matunas, John Barnsness, and various reloading manuals...Speer, Hornady, and Lyman.

Now that my scope is back from the factory, My .22 barrel is corerctly installed, and shooting well, all the rifle reticles have been levelled, I will be returning to the range with speed and enthusiasm!
Gonna finish my experimentation with the H 4831sc, H 4350, H1ooV, and if none of those do what I want, I can always go back to the IMR flavor.

In the 250 Sav., 257 Robts. 30-06, 7x57 and a few others H-414 will get about the highest velocity with proper pressure, it the case of the 7x57 the book is usually extra mild due to the Rem rolling blocks, mod. 95 and 96s out there and frivoulous law suits in play...

try H-414, its shot great for me in the above calibers as to velocity and accuracy..

When I was doing load for my Roberts I chose Sierra's 100gr SBT Game King.
The powders I chose were RL15 IMR4064 4831 and Varget. I did a short ladder with each.
The end result was Varget .5gr short of max. It shoots sub-MOA out to 300yds
from my "po-boy" custom Savage 10, 22"barrel(Savage take-off), SSS trigger
and a Boyd's laminated stock. Here in Florida, with our seasonal swings in temperature
I find Varget to be insensitive to temp change.

My 257 Roberts liked the 4350 powders and shot very well with a 100 grain Sierra. This pre 64 had a short magazine conversion and the previous owner converted it to a long action. This allowed seating the bullet out two tenth’s longer than what I see in reloading manuals. I think this was critical for the good accuracy I got because I was able to seat the bullet 0.030” off the lands instead of having the bullet jump about a quarter inch.

Given that my loads pushed a 100 grain bullet just at 2800-2850 fps and maximum loads in my Nosler reloading manual show 3000 fps is possible, I really wonder why the 243 was created. The Roberts can do it all!


Pre 64 M70 Featherweight 257 Roberts

100 grain Sierra SP 44.0 grs IMR 4350 wtd, Lot RB 15 (60's) Fed 210S W-W brass
OAL 2.930", 2.950" touched lands.

19-Aug-13 T = 85 °F

Ave Vel = 2849
Std Dev = 27
ES = 90
Low = 2795
High = 2885
N = 10

Normal looking primers, good group except for one flyer


100 grain Sierra SP 45.0 grs H4350 wtd, Lot 22685 Fed 210S W-W brass
OAL 2.930", 2.950" touched lands.

19-Aug-13 T = 85 °F

Ave Vel = 2822
Std Dev = 14
ES = 36
Low = 2802
High = 2838
N = 5

Excellent group, under 1 MOA

100 grain Sierra SP 38.0 grs Varget wtd, Lot 4292 Fed 210S W-W brass
OAL 2.930", 2.950" touched lands.

19-Aug-13 T = 85 °F

Ave Vel = 2809
Std Dev = 12
ES = 28
Low = 2789
High = 2817
N = 5

About 3 MOA

quote:

I really wonder why the 243 was created.

Simple to sell more guns.

My first rifle that I loaded for in quantity was a Remington 722 in 257.

I found that old style H4831 gave the highest velocities. I used a drop tube to make a compressed load. With 100 grain bullets it was running 3300+ FPS. The same powder with 117s ran over 3000. These loads are hot, work up, slowly. I was 17 YO a the time and since the primers did not get loose I figured it was safe enough.

A case dipped full of H4831 with a 100 will be safe, fast, and may shoot.

I now own a 25-06 to do the same thing.

For all out accuracy the Speer HP 100s with 3031 shot really accurately but were slow at about 2700.

I eyeballed H414 quite a bit but never loaded any. I have no memory of 4895 or 4064. I must have tried them though.

That is a very nice rifle. How does it shoot factory ammo? Perhaps getting a base line is worth while? IMHO do not cut a long throat and lengthen the magazine. It is pointless, you might as well go with a 25-06. You would be messing up a very nice old rifle.

quote:

I really wonder why the 243 was created.

Simple to sell more guns.

Of course but, this cartridge precedes the 308. Our modern short family cartridges are based on the 308 length. 257, 6mm, and such were based on the 7mm Mauser. They hadn't standardized on what "short" was. So, the 257 is a bit cramped in a modern short and swims in a long action. It is in between.

Me too, the .243 never was as good as the 250-3000 and never will be! of course that's just my opinion and I am prejudice. Its my option however!