H4350 is an excellent choice for the 284. It fits the case better than the old standby IMR 4350.
A little history. Back when this cartridge was introduced in 1963 Bob Hutton and others reported excellent performance with 57 or 58 gr of IMR 4350 with a 140 partition. I have used 57 gr in several rifles with the 140 partition and the 140 sierra pro hunter with excellent results.
Over time I switched to H4350 which also has an advantage over IMR as it is temperature insensitive.
I would say you will end up somewhere near 55-56 grains with H4350 and a 150 gr bullet. You might be able to use a bit more with the bullet seated out in your long action.
RL-17 is another powder that works well in the 284. It will give you higher velocities with its longer burning curve. Using 57 gr I got 3050 fps with a moly coated 150 nos ballistic tip and a 23" barrel with this powder. I should add that the rifle's magazine allowed an OAL of 3.050".
Here is the only 180 gr data I have:
My friend Dan make a long throated 284 for a LA Rem 700: (copied from my files)
The 28" lilja 1 in 7 twist 3 groove 284 win has finally shown what it likes. The load has been fired four times on different days.
51 gr of RL-17, fed 210 match, 284 win winchester brass neck turned enough to skim 80% of neck, 180 Berger VLD .030" into the lands, .002 neck tension, velocity 2875
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Another friend sent me some information which I also put in my files. While he is using the 284 shehane the information is still useful:
(SIC)"I have been talking to a friend of mine who is a 1000 yd benchrest guy. He has set several Three Points (Tucson) range records and has one world record.
He made a 284 Shehane recently using a Broughton 5C barrel.
The twist is 1 in 9. He has concluded that 1 in 9 isn't enough twist, in HIS rifle, for the accuracy he demands when shooting the 175 Sierra and 180 Berger VLD.
He sent me some details on a comparison of the 162 A-max and
the Sierra 175:
Test of 7mm 162 Amax vs 175SMK
I did some comparative tests today at 500 meters. From my 1-9 twist Broughton the 162's were clearly the winner. I shot both bullet weights seated .010 into the lands over 57gr of 4831sc and BR2 primers. At 80-85 degrees the 162's go out about 2,940fps and the 175's at about 2,850. 57gr is about max for the 175's in my chamber. I've tested different charge weights and seating depths before.
Three 5 shot groups of the 175's averaged 3.90" with average vertical spread of 2.73".
Three 5 shot groups of the 162's averaged 2.08" with average vertical spread of 1.60".
Best group with the 162's was 1.68" (4 rnds into .97") with vertical spread of .88".
My conclusion is the the 1-9 is just too slow to shoot either 175's or 180's as well as the lighter bullets. I'll bet the 175's will work much better in Dan's 1-7 barrel.
Next week I'm going to compare the best 7mm 162 Amax load against my best 6.5-284 load (142SMK 51.3 H4831sc BR2 jammed .060 (no typo! it's a weird chamber) and decide which I'm going to shoot at the Nationals. As things stand now I'd be pretty comfortable shooting the 7mm, particularly if there is much wind.
The fun never stops...nor does the expense. I thought you might be interested.
Bruce"
Another anecdote:
Bruce says that perhaps more twist is needed for the slower 284 and 180s compared to a 7 STW or 7 RUM case. I got the impression from him that a 1 in 8.5 would be minimum. On the other hand if you read the details on some of the rifles featured on 6mmBR.com's site you will see that at least one guy is using 1 in 9 twist for his 284 and doing quite well.
Record-Setting .284 Win F-Classer
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Hope this helps with some ideas on your new rifle's potential. If you want more load data for the 284 I have loaded for over 25 yrs just ask. I have pages of notes on bullets from 110 up to 168 shot in my sporter.
Ross
