Home Forums Reloading Big Game Rifles Letter from Jack O'Connor about the 270

bsa: Just like the 130, with the 150 in the 270 I would start with H4831.

The other "old" JOC load was 58.5 WW II surplus H4831 with the 150 Nosler Partition for a bit over 2900 fps from a 22" barrel. He used that load in Africa, India, and other hot places without incident.

I used the same charge from the 22" Douglas barrel of a Dale Goens rifle and it gave the 150 gr a hair over 3000 fps.

The H4831 we have today is a bit faster burning....(I think..some are finding it slower but I have not seen this) than WW II version.

I also would try 7828,but have only used it with 130's myself.

Bob,

My present lot of H4831SC is somewhat slower than my remaining batch of the original mil-surp powder.

The only .270 I own anymore is one of the recent O'Connor "Tribute" Model 70 Featherweights. As an experiment, I tried some of the original H4831, side-by-side with the new stuff, with 130-grain Hornady Interlocks, using the same 61.0 grain charge. The old H4831 got 3118 fps, while H4831SC got 3029. This was during the same range session, over the same chronograph, with the two strings shot one right after the other. The rifle will easily handle 58.5 grains of H4831SC with the 150 Partition, and velocity isn't quite 2900 from the 22" barrel.

I suspect the answer depends on the manufacturing lot of each powder.

John thanks that's interesting. I have so much of the H4831 that I have not purchased any recently. I have been using the 61 gr load for at least a decade now with the 130 NPT.

If some lots are slower now we may be working our way back to how it used to be ? Looks like maybe even slower, as you guys are seeing! pretty neat!

About 2 years ago I used a then-current batch of H4831SC, 61.5g of it with a 150g SST. It was so compressed it pushed the bullet out a little overnight.

Compared to many manuals I thought the velocity was very mild. 2990fps from the 23.5" bbl.

When I mention manuals, I mean that I don't remember ever seeing a 61+g load of that powder with a 150g bullet.

I worked up to the load gradually of course. Lighter powder charges had been very underwhelming.

You don't know what you don't know.

Bobnob: interesting because I have never seen that much H4831 recommended with a 150 gr bullet. The velocity is very good, too. Got a feeling lots of little things added up there...does the SST have short bearing surface maybe?

Other things to consider besides the powder are what kind of barrel was that? Were you throated on the long side? That's a barrel I would like to slug for groove diameter. A loose barrel and longsih throat can take heavier powder charges than a tighter barrel IME.

Little things we don't consider sometimes add up.

I finished up load development for my latest 270 shooting 150 gr Partitions. It got down to H4831 and H1000. 61.0 of H1000 was better than H4831 when I started shooting 5 shot groups. I use a drop tube and WW brass to get 61.0 in the case. Vel from my 24" Kimber is ~ 2925 ft/sec. IMR 7977 did fairly well as well.

I could use H4895, H4350, H4831, H1000 for the rest of my life and be really happy.

The 270 Win will utilize slower powders than we have come to accept as standard. H1000, RL25,7828 all work well IME.

bwinters good stuff!

Good info guys. Thanks... Any of you guys try magpro with a 150gr. partition? If so, how temp stable is that line of powder?? The Nosler reloading manual lists magpro as a good powder to use in the 270 with the 150gr. bullets.. I know there for a while, all I could find was magpro, IMR 4350 and H1000. Trying to find H4350 and H4831 was impossible, but now I'm seeing it on the shelves again.

I've not tried it in the 270 but did in a couple 7 mags. It gives advertised velocity but lost ~ 75 ft/sec between 60 and 30 for me. I quit using it.

Thanks Bill. That's useful information. Looks like I need to find some H4831.. Damn!!

Yeah I've mulled some of those things over in the past. I've never slugged the bore, but the throat isn't long. I can get into the lands with the 150g SST with the mag length a generous 3.375-ish.

The loose bore diameter is a possibility. I got around it by just adding more 4831, then going to H4350 before more recently with the R17.


Rifle is a Zastava aka Interarms X. It's an accurate rifle with 1.25moa with the worst of loads and a good 0.75 with a lot of loads.

It can be hard to figure sometimes why some barrels will take those kind of charges....but some do.

Keeps you guessing

Guys, it 'seems' to me that IMR 7828 is overlooked.
I suggest y'all give it a try.


Jerry

In this FN Mauser .270,I'm using 59.8 grs of RL-26,Federal 210 Match primer and a 150 gr Nosler Partition. Getting 3010 fps from the 22" barrel.

That's a beaut old rifle. If only those old guns could talk!

Good speed from R26 too.

Yeah,would love to stories of the hunts it's been on.

Here's the info/link.

http://www.alliantpowder.com/reload...ight=150&shellid=63&bulletid=367

Nice gun. I need to try some RL 26 what kind of compression are you getting with that load if any? I don't mind a compressed load as long as it isn't excessive.

None,IIRC.

Thanks, there are some really good powders coming out these days.