W-760 in 308 with 150 gr FMJ

My Toy · May 26, 2013, 10:01 AM

Has anyone had any experience using W-760 in 308 cartridges with bullets as light as 150 gr. I've got a pretty good supply of W-760 that I've used successfully in 308 with 168gr BTHP in my Remington 700 /w 26"barrel and 30-30 with 170 gr FP in my 336XLR. I Just bought a AR-10 /w 16" barrel and was thinking about using up my some of my over supply of 760 and lesser quality 150 gr FMJ bullets.

stubbicatt · May 26, 2013, 05:26 PM

Ordinarily I would recommend you find a faster burning powder. However these are not ordinary times... if things there are anything like things here, you are probably lucky to find ANY powder at all.

The admonition with slower burning powders is the "BERP" that I have seen documented in some of the precision reloading magazines. The "BERP" is a secondary pressure spike when the bullet is a couple/few inches from the muzzle when one is using slow powders. I understand it can be dangerous. I do not know whether WW760 will present such phenomenon or not.

I wish you good luck, but would suggest you keep your eyes peeled for a more "appropriate for caliber" propellant.

Regards,
Stubb.

Paul B. · May 26, 2013, 05:47 PM

"The admonition with slower burning powders is the "BERP" that I have seen documented in some of the precision reloading magazines. The "BERP" is a secondary pressure spike when the bullet is a couple/few inches from the muzzle when one is using slow powders. I understand it can be dangerous. I do not know whether WW760 will present such phenomenon or not."

I don't think W760 would be a problem in this case, although efintiely not te best choice for a bullet that light. On that point we agree. I'm assuming by BERP (that's a new one on me) you're refering to the S.E.E, P.E.P. AND D.D.T phenomenon where a too slow powder blows up a gun or seriously damages it.
S.E.E. i secondary Explosion Effect, P.E.P. is Pressure Excursion Phenomen and D.D.T is Deflagration to Detonation Transition. All mean the same thing, KABOOM!

I use W760 in the .306 for two different loads. haven't tied it with 150 gr. bullets but I have a particular rifle I like so much that I spent two years trying to find a usable load for the gun. My standard for a hunting load for antelope, deer and up is 1.5" at 100 yards consistantly with the operative word being consistantly. The gun? That nice little Mannlicher style Ruger M77 RSI chambered to the .308 Win.. It took a fairly stiff charge of W760 and the 165 gr. Speer Hot Core to bring that gun around. It's no hot rod at 2550 FPS but it will keep three shots rapid fire into 1.5" consistantly. That same load will do 2610 FPS for another rifle with 22" barrel vs the Ruger's 18.5" barrel.
That load has proved to be too hot in a new .308 I ahd custom built so it's back to the drawing board for that rifle.
For spits and grins, I worked p a load with W760 and the 220 gr. Sierra round nose for use in the " gun. I get a solid 2310 FPS and very small groups. That load will only do 2200 FPS from the RSI and groups run 2.0 to 2.5".

I did do a bit of work with some 180 gr. bullets in the RSI but I got patterns, not groups. I call that RSI my "One Trick Pony".

Paul B.

May 26, 2013, 10:01 AM	#1
My Toy Member Join Date: August 8, 2008 Posts: 45	W-760 in 308 with 150 gr FMJ Has anyone had any experience using W-760 in 308 cartridges with bullets as light as 150 gr. I've got a pretty good supply of W-760 that I've used successfully in 308 with 168gr BTHP in my Remington 700 /w 26"barrel and 30-30 with 170 gr FP in my 336XLR. I Just bought a AR-10 /w 16" barrel and was thinking about using up my some of my over supply of 760 and lesser quality 150 gr FMJ bullets.

May 26, 2013, 05:47 PM	#3
Paul B. Senior Member Join Date: March 28, 1999 Location: Tucson, AZ Posts: 3,802	"The admonition with slower burning powders is the "BERP" that I have seen documented in some of the precision reloading magazines. The "BERP" is a secondary pressure spike when the bullet is a couple/few inches from the muzzle when one is using slow powders. I understand it can be dangerous. I do not know whether WW760 will present such phenomenon or not." I don't think W760 would be a problem in this case, although efintiely not te best choice for a bullet that light. On that point we agree. I'm assuming by BERP (that's a new one on me) you're refering to the S.E.E, P.E.P. AND D.D.T phenomenon where a too slow powder blows up a gun or seriously damages it. S.E.E. i secondary Explosion Effect, P.E.P. is Pressure Excursion Phenomen and D.D.T is Deflagration to Detonation Transition. All mean the same thing, KABOOM! I use W760 in the .306 for two different loads. haven't tied it with 150 gr. bullets but I have a particular rifle I like so much that I spent two years trying to find a usable load for the gun. My standard for a hunting load for antelope, deer and up is 1.5" at 100 yards consistantly with the operative word being consistantly. The gun? That nice little Mannlicher style Ruger M77 RSI chambered to the .308 Win.. It took a fairly stiff charge of W760 and the 165 gr. Speer Hot Core to bring that gun around. It's no hot rod at 2550 FPS but it will keep three shots rapid fire into 1.5" consistantly. That same load will do 2610 FPS for another rifle with 22" barrel vs the Ruger's 18.5" barrel. That load has proved to be too hot in a new .308 I ahd custom built so it's back to the drawing board for that rifle. For spits and grins, I worked p a load with W760 and the 220 gr. Sierra round nose for use in the " gun. I get a solid 2310 FPS and very small groups. That load will only do 2200 FPS from the RSI and groups run 2.0 to 2.5". I did do a bit of work with some 180 gr. bullets in the RSI but I got patterns, not groups. I call that RSI my "One Trick Pony". Paul B. __________________ COMPROMISE IS NOT AN OPTION!

May 26, 2013, 05:26 PM	#2
stubbicatt Senior Member Join Date: September 15, 2007 Posts: 1,707	Ordinarily I would recommend you find a faster burning powder. However these are not ordinary times... if things there are anything like things here, you are probably lucky to find ANY powder at all. The admonition with slower burning powders is the "BERP" that I have seen documented in some of the precision reloading magazines. The "BERP" is a secondary pressure spike when the bullet is a couple/few inches from the muzzle when one is using slow powders. I understand it can be dangerous. I do not know whether WW760 will present such phenomenon or not. I wish you good luck, but would suggest you keep your eyes peeled for a more "appropriate for caliber" propellant. Regards, Stubb.