Yay finally found a good load for my RFB! Only one problem....

[Drew P]

If you dont know, the RFB is a revolutionary design. It’s a bull pup 308 rifle with gas piston cycling and a very interesting method of operation. Due to the various design elements they can be tricky to load for and a bit finicky. I finally found a load that seems to be very compatible with this rifle! BuT..... it uses a discontinued powder called SR4759 from IMR. This is a strange tubular powder that’s about as unique as the gun I’m using it in. I’ve heard this powder came back by popular demand. Any chance it will again? It’s been gone for about 5 years I believe. Is there any powder that might mimick it’s operation in 308? I’m using 150gr bullets and pushing about 2330fps.

[sigep1764]

Google a burn rate chart for imr or hodgdon powders with 4759 included. Pick a couple powders in the same area of the chart. My Lyman book is showing H380 has the best accuracy at 48 grains loaded at 2.735 oal. Use at your own risk tho. What book are you loading from? I have a hornady book that i could send data from if you need, again at your own risk.

[runfiverun]

ones that would be close would be 4227-4198- rl-7-CFE Black.

[Texas by God]

I plead ignorance. Is that a Kel Tec?

[Drew P]

I plead ignorance. Is that a Kel Tec?

Yes it’s a Kel-Tec. It’s super fun to shoot. For sure the softest shooting 308 made.

But similar burn rates aren’t the whole story. This powder is wierd bulky tubes, has a strange density compared to a lot of powders. I’ve read up as much as I can on it but it doesn’t seem to fall into familiar lines for me.

[Texas by God]

It sounds like fun. Maybe H4895 will meet your needs as it's safe to reduce and kind to gas pistons. Just a thought.

[sigep1764]

What about Ramshot TAC?

[Bent Ramrod]

A lot of us are hoping somebody will see the light and re-reintroduce SR-4759. You might try (X)MP-5744, which is a bulky, crunchy powder on the same pattern, for the same applications. I’ve rarely found it to be as accurate as similar loads with 4759, but you might get lucky.

[runfiverun]

I'm familiar with the powder but they ain't making it anymore.
and I doubt they will again.
I would look to RL-7 as a replacement.

[Lloyd Smale]

if you don't mind weighting charges nothing beats good old 4895 in the 308. What is finiky about then gun. Is it feeding reliability or just that its accuracy challenged.

[Lloyd Smale]

if you don't mind weighting charges nothing beats good old 4895 in the 308. What is finiky about then gun. Is it feeding reliability or just that its accuracy challenged. If your shooting jacketed bullets id bump the speed up to about 2500 fps and id bet youd find better accuracy and better running. If you want to shoot cast it will for the most part be in your ball park as to speed and you might want to consider stepping up to a 180 grain bullet at the same speed your shooting the 150s.