Hi All,

Am going to try H4350 in my 257 Roberts as the powder should work better in the conditions I hunt (Alberta, Canada, where the temp during hunting season can be 10 above or 30 below). I have been using 115 gr Nosler BT with IMR 4350 and am getting great groups (44 grains, which is over max. does not show pressure signs). Does anyone have a load range for H4350 for the +P and real life experience? Also, picked up some 100 gr Nosler BT and am wondering if anyone has been using this bullet/powder combination or H380, which I have a ton of.

Thanks in advance for your help.

45.5 grains of IMR 4350 and Nosler's 100 grain ballistic tip spell death for Montana mulies. I use standard 257 cases, not the +P variety and spark them with WLRs or F210s. I like the 117s too, but don't remember the data. 120s are an excellent choice for those rifles that prefere flat based bullets. It is at this end of the bullet spectrum where the Roberts kicks butt on the various 243s.

Here is a quote from gunwriter John Barsness, who has a lot of experience with the 257:

"I generally stick to IMR4350 or H4350 in the Bob, about 46-47 grains with 100-grain bullets and 43-44 with 115-120's. Have generally found that if the 4350's will not shoot with .25-caliber big game bullets, there is either something wrong with the bullets or the rifle."

I use 46.6 grs of IMR4350 with 117 Sierras in my standard 257 (98 Mauser action). This is the max load Sierra lists for the 257AI. I consider it a +P load. It's fast, accurate, and shows no pressure signs at all in my rifle.

Many Roberts magazines are extremely cramped with the 120 grain bullets and the 100 grain gets the call. When this is the case a 100 Grain A-Frame and H-414 gets my attention. Other 100 grain bullets have certainly taken deer over the years and will continue to do so.

I can push the 100 grain to 3,100 and at times a bit more. This has proven to be a very good load for antelope and deer.

Shadow:

I haven't played much with H4350 in my Roberts yet. However, I did make the switch from IMR4350 to H4350 in my 7x57. With the lots of powder I had on hand, I got essentially the same velocity with either powder in the early fall, powder weight and all other components the same. However, the H4350 maintained this velocity down around the freezing point, while the IMR4350 loads lost about 100 fps, along with some accuracy. Accuracy was comparable between the two loads when the weather was warm.

I would suggest dropping down from your IMR load by 2 or 3 grains and working back up with H4350. While the lot of H4350 that I tested against the lot of IMR4350 differed by only 2 fps in my 22-250 (all other components the same), the two lots of H4350 that I have used so far differed by 2.5% in velocity when tested side-by-side in identical loads. For refernce, this is comparable to the maximum velocity variation that I have encountered between different lots of IMR4350, and less than half that encountered with some other powders.

Good hunting!

Cheers, Al

Have used 45 gr. 4350 but have gone no higher. Probably could have but didn't.

49gr. of Accurate data 86 powder yielded an accurate 3100 fps. with no pressure sign. roger

I've used 46gr of IMR 4350 in mine with 100gr Nosler BT's and 44.5gr of the same with 117gr Hornady's. It is near max but I think this is one of the most under-rated pressure wise of any I have loaded for. In a modern rifle the +P data is quite safe. Nate

I've gone as high as 49.0 hr. as H4350 in my 257R M70 featherweight with the 100 gr. Sierra FB bullet, Fed 210, WW brass. It screams over the screens at 3287. The primers still had some radius left and the bolt lift was normal, but 48 gr. is a more reasonable load and will put 5 into less than an inch.

I suspect that this barrel has a fat bore, as it will shoot just about any 100 gr, flat base bullet into tight cluster, but the groups open up significantly with all the boat tail bullets I've tried in it.

Did some testing today on .257 roberts, identical loads the only difference being the cases.

It was plain wrap RPs vs. +P. The plus Ps always gave higher average velocities but the average difference was around 2%. These were thought to be rather stout loads. 100 grain bullets at close to 3100 fps. roger

Gentlemen-
It is my understanding that +P cases are heavier, thus the same load data used in a standard case will always give a bit more in the +P case. I see no weakness in the standard case as it has always been of modern design and construction, plus I don't own any 257s of questionable origin. So with no need to segregate cases, I load the standard cases to higher pressures on a routine basis and have experienced no abnormalities. I can see no reason to treat it any differently than the 6m/m Remington.

There is a need to separate the +P brass from standard.

If you are loading standard cases to max and then drop the same charge in a +P case it will yield a higher pressure. In most situations it would just be a small amount of velocity increase due to the higher pressures. But if your at the max pressure in a std case and then drop it in a +P, the pressure may spike.

I think the +P designation is simply to make note that it is a modern pressure load whereas the standard loads were pretty anemic. I have some +P brass only because I bought up several boxes of loaded ammo on a close-out. I have ordered standard cases for years and work up loads in them both seperately with equal success. Nate

Buckshot:

Winchester +P cases are heavier that their older standard cases. If I remember correctly, they introduced the +P in the 257 shortly after they introduced the 6mm Rem to their product line. The Winchester (and Federal) +P cases are about the same weight as the standard Remington cases. This is probably why Remington hasn't introduced +P brass - not necessary.

FWIW, there wasn't much added oomph to the W-W SUPER 117 gr. +P loads - I got an average 2526 fps from my 22" barrel with the lot I tried. The similar non+P R-P load averaged 2495 fps, and their 122 gr Extended Range load averaged 2503 fps. On the other hand, FC +P loads are markedly faster. I got 2704 fps average for their 117 gr. PSPbt, and 2678 fps for the 120 gr. Nosler Partition load.

Cheers, Al

A case full, drop tubed, of H4831 with a 100 gr bullet is very fast. 3300 fps

39 g of 4064 and a 100 grain bullet is super accurate.

A bunch of H4831 and 120g bullet is a pretty good hunting load. 3000fps

After fussing with a 25-06 and getting a little older and wiser I am thinking a 6.5-06 with 140 and longer bullets might be tough to beat. Super long bullets at moderate velocities seem to hold together and penetrate. Fast short bullets seem to bow up on impact. For now it is a boring old 308. Pick your poison.

ClassicAl, BigNate,
You're right on target about keeping +P and oridinary brass segregated. I should have said "since I don't have any +P brass, there is no need for me to keep it seperate."
I guess I need two cups of coffee before I post in the A.M. Sorry to have caused confusion,
buckshot

Scot, the 6.5-06 IS mighty hard to beat. I played with them for many years, and with a 140 grain slug, it's a super screamer and a "thinking man's .270" Even shoots well with 160 grain slugs if you want heavy.