Best SBR load?

[ruggedtraditions]

Anyone got some good data on optimized loads for a 10.5-12.5" barrels, chambered in 5.56mm?

I have been searching but havent found much.

Will a faster burning powder = higher velocities, or is this just a myth?

How about primers, standard or magnum?

I am considering getting a noveske barrel. I have heard rumors of the polygonal rifling having higher velocities. Can anyone confirm this?

Thanks for your help.

[ruggedtraditions]

Anybody?

I am new to this site, and I have found the answers to a lot of questions I have had. But I am having no luck on this one.

I have read all I can find about MK262 and the "brown" tip loads, but no luck on discussions of best powder for shorter barrels.

The rifle will be suppressed so I am not as worried about flash and noise I am just wondering if its possible to squeeze out some more velocity.

Anybody got some real world experience?

[Ttwwaack]

Look at 223 loads for 10-14" Contenders in the handgun section of reloading manuals, Sierra, Hornaday, ect.

I've been running IMR 4198 w/ WSR primers out of an old Oly Arms 11" for years with Hornaday 55 gr FMJBTs. If you have an older manual 15-20 years ago I think max used to be listed at 23-24 gains. The powder has changed alittle since then, [B]WORK UP CAREFULLY[B], perticularly changing lot #'s. Most books today are calling 20-9 to 21.1 max in case you've got an old manual. I've used 3031 w/ success in contenders but no luck in a SBR.

I'm getting about 2550-2600 if I recall correctly, about the same as AA-2230 or TAC, .75-1.5 MOA and saving 3.5-5. grains of powder. Backside, throwing stick powder sucks.

LEGAL: I'm not a Ballistisian, Doctor or slept at a Holiday Inn Express last night. Work up all loads. Faster rifle powders will expand primer pockets and crater primers sooner than slower powders, hence no 3031 data. To get it to shoot good it had an outtie instead of an innie.