H4831sc to H4350 Ratio in .284 Win

[Killick]

Is the rule of thumb roughly 3 grains less of H4350 vs. H4831sc for comparable FPS with the Berger 180gr Hybrid in a 1in9 twist 30" bbl.? I'm looking to hit @2775 FPS. My probable starting load is 50.0gr H4350 and up in .3gr increments. My current 4831sc load is 54.2gr=2800 FPS.

 

[brxbrad]

Is the rule of thumb roughly 3 grains less of H4350 vs. H4831sc for comparable FPS with the Berger 180gr Hybrid in a 1in9 twist 30" bbl.? I'm looking to hit @2775 FPS. My probable starting load is 50.0gr H4350 and up in .3gr increments. My current 4831sc load is 54.2gr=2800 FPS.

I curious as to "why" ? In a friendly way........

 

[coford]

In most of my 30" barrels 51.4 or 51.5 will get me 2810 FPS or so. I have one fast 32" barrel that goes 2847 FPS with 50.9 but that one is the exception.

 

[Killick]

I curious as to "why" ? In a friendly way........

BC I've never tried it and I have a few lbs. (Looking for an edge)

 

[Endyo]

Killick,

You should be on the money with the above stated. I might start a hair lower. My rifle tunes at 49.7gr of H4350 (1 in 9 twist, 32"), 50gr H4350 also shoots very well.

H4831sc tunes at 54.5gr.

 

[ShootDots]

This would be a difficult question to answer with any degree of "regularity"... BOTH H4350 and H4831 have "fast-to-slower" (burn speed / rate) between various lots of powder with H4831 generally being worse. I have seen as much as a full grain difference to get back to the same velocity node. Just beware of this idiosyncrasy..

 

[Killick]

Killick,

You should be on the money with the above stated. I might start a hair lower. My rifle tunes at 49.7gr of H4350 (1 in 9 twist, 32"), 50gr H4350 also shoots very well.

H4831sc tunes at 54.5gr.

Endyo, what fps are you getting with the 50gr?

 

[Endyo]

I actually shoot that load with 180SMK. That's my midrange load.

I was surprised velocity was low. 2750fps - 2760fps measured with a Magnetospeed.

Ben makes a great point I've seen .5 grain variance with H4831, and couldn't find replacement H4350.

That's when I decided to buy 5 - 8lb jugs of H4831 of the same lot and be done with it.

 

[ShootDots]

I actually shoot that load with 180SMK. That's my midrange load.

I was surprised velocity was low. 2750fps - 2760fps measured with a Magnetospeed.

Ben makes a great point I've seen .5 grain variance with H4831, and couldn't find replacement H4350.

That's when I decided to buy 5 - 8lb jugs of H4831 of the same lot and be done with it.

Buying a lot of one lot of powder is one way of accomplishing the goal of keeping lot-to-lot consistency. However, I am trying a different course of action. I am working with RL-23. It's burn rate is almost identical to H4831SC. It is not temp sensitive, it's lot-to-lot consistency appears (with the small amounts I have worked with so far) to be right on the money. AND it produces considerably more velocity than H4831SC.. There also seems to be something I can't explain. For whatever reason, my barrel does not get anywhere near as hot to the touch with RL-23 than with any other powder. So far whether with my .260A.I. or my 7 SAUM, after 100 rounds (75 from a match) in both rifles, my throat has only moved forward .001! That is excellent in my opinion..

 

[Endyo]

When I experimented (briefly) with RL powder my charge weight test produced a much higher ES/SD. I also didn't get very good groupings during the initial test so I scrapped the powder shortly after that.

The velocity increase is tempting with the RL powders if accuracy can match Hogdons. I may have to revisit it in the off season.